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NH cares Cyanosis (Blue colouration of lips, feet, body):

What is Cyanosis?

The nomenclature Cyanosis , very literally means the blue disease or the blue condition . It is derived from the colour cyan , which comes from cyanós (κυανός) , the Greek word for blue .

This condition commonly called “blue hands or feet,” signifies hypoxemia, or an abnormally low level of oxygen in the blood. It is also called deoxygenated haemoglobin.

High levels of deoxygenated haemoglobin within the superficial vessels of the skin cause this bluish appearance. Cyanosis is most pronounced where the overlying epidermis is thin, and the area has a rich network of blood vessels.

When the amount of reduced haemoglobin exceeds 5 gm% in the capillaries, the blood appears dark, giving the tissues a bluish hue.

Types of Cyanosis

Cyanosis can be divided into Central Cyanosis, Peripheral Cyanosis, Differential Cyanosis, or Cyanosis, amongst new-borns and babies.

Central Cyanosis

Central Cyanosis is a blue discoloration seen on the tongue and lips, and is due to lower levels of oxygen in the Central arterial blood; caused by cardiac or respiratory disorders.

Those suffering from Central Cyanosis will usually have Peripheral Cyanosis, which is a bluish or purple discoloration of the fingers and toes.

A type of Central Cyanosis could also occur when an abnormal pigment in the blood due to a drug intake or any other reason, imparts the abnormal bluish colour to the skin.

Peripheral Cyanosis

Peripheral Cyanosis is a blue or purple skin discoloration of the extremities, viz. fingers and toes, and is most intense in nail beds, especially if the external temperature gets really cold.

Differential Cyanosis

Differential or Mixed Cyanosis is diagnosed when the bluish discoloration is present in certain parts of the body and absent in others. It could be present only in the lower limbs, or only in the upper limbs, or only in the left upper and both lower limbs.

Cyanosis in new-borns and babies

Cyanosis in new-borns or babies, Cyanosis is commonly observed in the area around a baby’s mouth. Sometimes even the palms, soles of the feet, head, or torso turn blue. This a sign that the Cyanosis baby is not getting enough oxygen. Transient Cyanosis clears a few minutes after birth.

Central Cyanosis in new-borns, infants and young children, requires urgent admission and medical assessment.

Causes of Cyanosis

The underlying causes of Cyanosis, or blue hands or feet or blue fingernails, is the tissues of the body do not receive blood with the requisite levels of oxygen, this can happen due to a variety of reasons.

The blood is responsible for carrying oxygen through your body. Blood makes the journey from your lungs, where deoxygenated blood is replenished with oxygen from the air you breathe. This oxygenated blood travels to your heart, where it is pumped through your arteries to the rest of your body. Upon delivering the blood to your body’s tissues, the deoxygenated blood returns to your heart and lungs, through your veins.

A variety of conditions could prevent blood from reaching your tissues, or from returning to your heart through your veins. This results in your tissues not receiving the oxygenated blood needed, and the subsequent bluish discolouration.

Let’s now look at the underlying Cyanosis causes for each type.

Central Cyanosis Causes

Central Cyanosis is very often caused by a circulatory or ventilatory issue. This in turn could lead to poor blood oxygenation in the lungs. Central Cyanosis develops when the arterial oxygen saturation goes below 85% or 75%.

Acute Cyanosis is a condition that could result from asphyxiation or choking. It is amongst the sure signs of respiration being blocked.

Central Cyanosis may be caused by the following issues:

1. Central nervous system related conditions (impairing normal ventilation):

• Intracranial haemorrhage
• Drug overdose (e.g. heroin)
• Tonic–colonic seizure (e.g. grand mal seizure)

2. Respiratory system related conditions:

• Bronchiolitis
• Bronchospasm (e.g. asthma)
• Pulmonary hypertension
• Pulmonary embolism
• Hypoventilation
• Chronic obstructive pulmonary disease, or COPD ( emphysema )

3. Cardiovascular disease related conditions:

• Congenital heart disease
• Failure of the heart
• Valvular heart condition
• Myocardial infarction condition

4. Blood-related conditions:

• Methemoglobinemia
• Polycythaemia
• Congenital Cyanosis

5. Other conditions:

• High altitude may trigger off Cyanosis, which may be observed when ascending to altitudes over 2400mts
• Hypothermia
• Obstructive sleep apnea

Peripheral Cyanosis Causes

Peripheral Cyanosis is a bluish tint observed in the fingers or toes, caused by suboptimal or restricted blood circulation. Blood reaching the fingers and toes is not oxygen-rich enough; when observed through the skin, it gives off the appearance of a blue colour.

All the conditions that cause Central Cyanosis, can also cause Peripheral symptoms to appear. Peripheral Cyanosis can sometimes be noticed even in the absence of heart or lung failures. Small blood vessels could be constricted and may be treated by boosting normal oxygenation levels of the blood.

Peripheral Cyanosis could sometimes occur due to the following:

• All the common causes of Central Cyanosis
• Reduced cardiac output (e.g. heart failure or hypovolaemia)
• Cold exposure
• Chronic obstructive pulmonary disease (COPD)
• Arterial obstruction (e.g. Peripheral vascular disease, Raynaud phenomenon)
• Venous obstruction (e.g. deep vein thrombosis)

Differential or Mixed Cyanosis Causes

This condition is normally observed especially in patients with a patent ductus arteriosus. Patients with a large ductus develop progressive pulmonary vascular disease, and pressure overload of the right ventricle occurs. As soon as pulmonary pressure exceeds aortic pressure, shunt reversal (right-to-left shunt) occurs. Upper extremity of the body remains pink in colour because the brachiocephalic trunk, left common carotid trunk, and the left subclavian trunk is given off proximal to the PDA.

Symptoms of Cyanosis

1. Age-related and the nature of Cyanosis onset:

• Cyanosis caused by congenital heart disease, which in turn causes anatomical right-to-left shunts, that may have been prevalent from birth or the early years of life.
• Acute onset ofCyanosis, which could be caused by conditions like pulmonary emboli, cardiac failure, pneumonia or asthma.
• People suffering from COPD (Chronic Obstructive Pulmonary Disease) may develop Cyanosis over time and an associated condition called polycythaemia may exacerbate the intensity of Cyanosis.

2. Previous history: Cyanosis may also be caused by any lung disease of sufficient intensity.

3. Drug history: there are a set of drugs that may result in methemoglobinemia (e.g. nitrates, dapsone) or sulfhemoglobinemia (e.g. metoclopramide).

4. Associated symptoms:

• Pain in the chest : Cyanosis that is associated with pleuritic chest pains could be caused by pulmonary embolism or pneumonia. Pulmonary oedema could cause dull, painful chest tightness.
• Dyspnoea: this is a condition that may suddenly occur in conjunction with pulmonary emboli, pulmonary oedema or asthma.
• Gasping for or shortness of breathing difficulties
• Profuse sweating profusely
• Pain or numbness in the arms, legs, hands, fingers, or toes
• Paling or whitening of the arms, legs, hands, fingers, or toes
• Dizziness or fainting.
• Temperature: conditions like pneumonia and pulmonary emboli that could be with pyrexia.

The patient will also exhibit symptoms like:

• Central Cyanosis - this condition produces a bluish discolouration, specially noticed on the mucous membranes of the lips, tongue, fingers and toes.
• Peripheral Cyanosis - this condition affects the fingers, toes and skin surrounding the lips, is not noticed around mucous membranes.
• A combination of clubbing and Cyanosis is frequent observed in congenital heart disease; it may be prevalent in pulmonary diseases, like lung abscess, bronchiectasis, cystic fibrosis; as also in pulmonary arteriovenous shunts.
• Pressure in the jugular venous system increases with congestive cardiac failure.

After a respiratory examination:

• Poor chest expansion is a condition that is noticed in patients with chronic bronchitis, and asthma. Reduced chest expansion may be noticed with conditions like lobar pneumonia.
• Dullness to percussion is sometimes noticed in an area of consolidation.
• Crepitation that is localised may sometimes be heard in conditions like lobar pneumonia. Crepitation is often more likely in conditions like bronchopneumonia and pulmonary oedema. Entry of air may be low with conditions like COPD or asthma. Bronchial breathing may be affected and wheezing sounds may sometimes be heard, in conditions like asthma.

Abnormal heart sounds that are sometimes heard, may suggest origins in the cardiac area.

Features that are localised may indicate aetiology of Peripheral Cyanosis. These could cover oedema in venous insufficiency or absence of Peripheral pulses and an ischaemic condition in arterial occlusion

Diagnosis of Cyanosis

Bluish skin is usually a sign of something serious. If normal colour does not return when your skin is rubbed or warmed, it is important to get medical attention right away to determine the cause.

The physical examination performed by your doctor will include listening to your heart and lungs. You may also have to undergo a series of other clinical tests.

Apart from the clinical assessment of hypoxemia, the diagnosis of Cyanosis may also include the following investigations:

• Arterial Blood Gas test: measures the acidity and levels of carbon dioxide and oxygen in your blood.
• Complete Blood Count: Haemoglobin levels are increased with the prevalence of chronic Cyanosis. The white cell count increases in conditions like pneumonia and pulmonary embolism.
• ECG: Taken to completely rule out the prevalence of cardiac abnormalities.
• Chest X-ray: the is taken to rule out conditions like pneumonia, pulmonary infarction and cardiac failure.
• Ventilation-perfusion scan or Pulmonary Angiography is taken to rule out pulmonary causes
• Echocardiography will serve to look for the presence of any cardiac defects.
• Haemoglobin spectroscopy will look for methemoglobinemia, or sulfhemoglobinemia.
• Digital Subtraction Angiography: is done to completely rule out conditions like acute arterial occlusion.
• A duplex Doppler or Venography can detect the prevalence of acute venous occlusion.

Cyanosis Treatment

You must seek medical attention if you have blue hands or feet, and warming them up doesn’t restore normal colour. The treatment involves identifying and correcting the underlying cause in order to restore the oxygenated blood flow to the affected parts of the body.

Receiving proper treatment in a timely manner will improve the outcome and limit any complications. It is important that any medication in Cyanosis Treatment should always be under the prescription and guidance of a registered medical practitioner.

There are some medications that can help blood vessels relax. These include:

• antidepressants
• antihypertensive drugs
• erectile dysfunction drugs

You may also need to avoid certain medications that constrict blood vessels as a side effect. These include types of:

• beta-blockers
• migraine medications
• birth control pills
• pseudoephedrine-based cold and allergy medicines

Serious medical situations, such as heart or pulmonary related conditions, should be treated in a hospital as an emergency.

Conditions, such as Raynaud’s phenomenon, may require longer term lifestyle changes. These include avoiding caffeine and nicotine, both of which can cause your blood vessels to constrict.

Cyanosis FAQs: All your concerns addressed

Q.  what is cyanosis.

• Cyanosis is generally a medical condition in which there's a blue tint to the skin, indicating the body is not receiving enough oxygen-rich blood.

Q.  What is cyanosis a symptom of?

• Cyanosis occurs when oxygen-depleted (deoxygenated) blood, which is bluish rather than red, circulates through the skin. Cyanosis can be caused by many types of severe lung or heart disease that cause levels of oxygen in the blood to be low.

Q.  What are the principal reasons for cyanosis?

The three primary reasons of cyanosis include - Decreased pumping of blood by the heart or reduced cardiac output often seen in heart failure or circulatory shock; Diseases of circulation like thrombosis or embolism, and constriction of blood vessels of the limbs, fingers, and toes (due to exposure to cold, spasm of the smaller skin capillaries or arteries called acrocyanosis). The other leading causes of Cyanosis in both adults and newborns include:

● Birth injury (Asphyxia) ● Pulmonary or Lung Edema ● Diaphragmatic Hernia ● Severe Pneumonia ● Chronic Obstructive Lung Disease ● Acute Adult Respiratory Distress Syndrome

Q.  Is cyanosis a sign of a heart attack?

In heart failure , lung embolism, pneumonia, or acute severe attack of asthma, the cyanosis may have a sudden or abrupt onset as the patient ‘begins to turn blue’ due to lack of oxygen. On the other hand, patients with chronic obstructive lung disease or COPD often develop cyanosis gradually over many years.

Q.  Should I treat blue lips in my child?

• It's common for new-borns to have some areas of blue skin once in a while. But if your baby's lips, mouth, head, or trunk are blue, seek emergency medical help.

Q.  What's the cause of my baby's skin turning blue?

• There are two reasons why the blood under your baby's skin may look blue:
• The lungs are not getting enough oxygen. Since it is the oxygen that makes the blood turn red in colour, blood cells without oxygen remain blue.
• The underlying blood is displays a slow movement, so the normal veins underneath that carrying blue, oxygen-poor blood back to the heart are more noticeable.

Q.  Can anemia cause cyanosis?

• Cyanosis is caused by an increase in the deoxygenated hemoglobin level to above 5 g/dL. Patients who have anemia do not develop cyanosis until the oxygen saturation (also called SaO2) falls below normal hemoglobin levels.

Q.  How long does Cyanosis last?

• It is a common finding and may persist for 24 to 48 hours. Central cyanosis caused by reduced arterial oxygen saturation lasts for nearly 5 to 10 minutes in a newborn infant as the oxygen saturation rises to 85 to 95 percent by 10 minutes of age.

Q.  How to differentiate between mild cyanosis and severe cyanosis?

Babies who suffer from cyanotic heart disease are often referred to as “Blue Babies”. To determine if the cyanosis is mild or severe can be done by analyzing the following:

• The nature of the defect
• The age of the child
• The level of activity

In general, cyanosis is known to worsen with activity, and only proper resting can one bring it down. Dark skin complexion and the presence of anemia can often make it hard for the parents and doctors alike to recognize signs of mild cyanosis.

Q.  Which speciality doctor should I consult in case my baby has Cyanosis?

• You should immediately go to the emergency room at the nearest hospital. The doctor there will refer you to a neonatologist.

Q.  Why do my nails look a bit bluish or purplish in colour ?

• Blue or purple nails, especially the area around the base of the nails can be caused by a condition called Cyanosis. You may notice it on other parts of your body too, such as lips, palms of the hands, soles of the feet, or even earlobes.

Q.  How are Cyanosis and hypoxia related?

• Cyanosis is a late-stage symptom of hypoxia, where vasoconstriction of the Peripheral blood vessels or decreased haemoglobin are responsible for the bluish cast of the skin.

Q.  Why does Cyanosis occur?

• Cyanosis occurs due to lack of oxygen in the blood. It happens when the tissues of the body do not receive blood with the requisite levels of oxygen, for a variety of reasons.

Q.  Is Cyanosis a serious condition?

• Cyanosis could be considered a significantly serious condition that requires immediate medical attention.

Q.  What’s the primary difference between Peripheral and Central Cyanosis?

• Peripheral cyanosis is primarily caused in an individual due to low blood pressure, Raynaud’s syndrome (fingers and toes become painful and blue in cold temperatures), hypothermia, heart failure, etc. The skin turning bluey-green, affected body part feels cold to the touch are common signs of identifying whether you’re suffering from peripheral cyanosis or not. The key difference between peripheral and central cyanosis is that the former affects an individual’s hands or legs, and other external body parts like fingernails, feet, etc. and can be seen either on one side of the body or both the sides in equal proportions. The latter i.e., Central cyanosis affects the core organs of the body causing a blue-green tint across lips, tongue, and unlike peripheral, symptoms of central cyanosis don’t get better when the body part is heated up. In both forms of cyanosis, you would notice problems with the heart, lungs, or nervous system.

Q.  What is Peripheral Cyanosis?

• Cyanosis refers to a blue tint to the skin and mucous membranes. Peripheral Cyanosis is a condition wherein there is a bluish discoloration to your hands or feet. It is generally said to be usually caused by low oxygen levels in the red blood cells or problems getting oxygenated blood to your body. Blood that’s rich in oxygen is the bright red colour typically associated with blood. When blood has a lower level of oxygen and becomes a darker red, more blue light is reflected, making the skin appear to have a blue tint.
• In some cases, cold temperatures are said to cause blood vessel narrowing and lead to temporarily blue-tinged skin. Warming or massaging the blue areas should return normal blood flow and colour to the skin.

Q.  What is Central Cyanosis?

• Central Cyanosis is a condition that is often caused due to a circulatory or ventilatory issue that leads to poor blood oxygenation in the lungs. It generally occurs when arterial oxygen saturation drops below 85% or 75%.

Q.  What is Differential Cyanosis?

• It is the term used for conditions where the Cyanosis is present in certain parts and absent in others.
• Only of lower limbs: due to patent ductus arteriosus (PDA) with reversal of shunt.
• Only of upper limbs: due to PDA with reversal of shunt in transposition of great vessels.
• Cyanosis of left upper and both lower limbs: due to PDA with reversal of shunt and pre-ductal coarctation of the aorta.

Q.  What is Pseudocyanosis?

• Pseudocyanosis is a condition that’s prevalent when a bluish tint is observed on the skin and/or mucous membranes; however, there may not be hypoxemia or Peripheral vasoconstriction.
• This condition is normally prevalent when there is an absence of either heart or lung disease and the skin also does not blanch under exertion of pressure.
• It has been found out that common metals like silver, lead or even drugs like phenothiazines, amiodarone, chloroquine hydrochloride, usually cause this condition.

Q.  Why does my tongue have a bluish or purple cast or spotting?

• The consumption of certain foods and beverages are normally the most common cause of a purple tongue, or spotting.
• If no such foods or beverages are consumed, then these causes of tongue staining with a purple or blue tint can be ruled out. This could then be a sign that the blood isn’t delivering adequate oxygen to the body’s tissues. Or, that blood with low oxygen levels, which is normally dark red, rather than bright red — is what is circulating through the arteries.
• The blueish tint or cast that is seen due to this condition is called cyanosis. Cyanosis can also be caused by conditions that impact the lung or heart, like coronary artery disease or chronic obstructive pulmonary disease (COPD). This blue tint may be prevalent in places other than just the tongue.
• The tongue can also turn bluish or purple due to low oxygen levels or an obstruction in the airways.

In situations like these, a purple or blue tongue is the sign of a medical emergency. Seeking emergency medical aid if the tongue is discoloured, appears suddenly or is even seen to be accompanied by:

• gasping for breath
• breathing difficulties
• pain in the chest

Q.  How to check for Cyanosis?

• Pulse oximetry, coupled with clinical symptoms can quickly diagnose Cyanosis.

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NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-.

StatPearls [Internet].

Adebayo Adeyinka ; Noah P. Kondamudi .

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Last Update: August 12, 2023 .

• Continuing Education Activity

Cyanosis is characterized by a blueish discoloration of the skin or mucous membranes. Cyanosis is frequently encountered in clinical practice, and the differential diagnosis of can be challenging as there are many conditions that can cause cyanosis. Diagnosis of cyanosis is based on a careful history, thorough physical examination, and the use of ancillary studies. Since in most instances, the cardiopulmonary system is involved, a focused assessment of both systems is warranted. If a congenital heart condition is suspected, transthoracic and transesophageal echocardiography can be used to evaluate the cardiovascular system. To assess blood flow and shunting, cardiac Doppler is an important diagnostic tool. Pulmonary causes of cyanosis like pneumonia, pleural effusion, and pulmonary embolism can best be evaluated with imaging studies like radiographs, computed tomography scans, and ultrasounds of the chest. If hypoxemia is suspected as a cause of cyanosis, the primary assessment should include pulse oximetry and arterial blood gas. If congenital hemoglobin M is suspected, hemoglobin electrophoresis can best detect this. This activity describes the evaluation, diagnosis, and management of cyanosis and highlights the importance of providing team-based interprofessional care to affected patients.

• Describe the evaluation of cyanosis.
• Identify the differential diagnosis of central and peripheral cyanosis.
• Explain the management of cyanosis.
• Explain the importance of improving coordination amongst the interprofessional team to enhance care for patients with cyanosis.
• Introduction

Cyanosis is a pathologic condition that is characterized by a bluish discoloration of the skin or mucous membrane1 [1] . The word cyanosis is a derivative of the word cyan , a blue-green color. The presence of cyanosis can pose a serious diagnostic challenge. A careful and thorough evaluation with the proper diagnostic tools can help discern the cause.

Cyanosis, broadly speaking, is caused by disorders of deoxygenated hemoglobin and disorders of abnormal hemoglobin. Oxygen might not reach hemoglobin in an adequate or sufficient amount as a result of conditions affecting the respiratory system, cardiovascular system, and the central nervous system (CNS) [2] .

Disorders of deoxygenated hemoglobin are further divided into two broad groups: central cyanosis and peripheral cyanosis. Central cyanosis occurs when the level of deoxygenated hemoglobin in the arteries is above 5 g/dL with oxygen saturation below 85%. The bluish hue is generally seen over the entire body surface and visible mucosa. In contrast, peripheral cyanosis is usually only seen in the upper and lower extremities where the blood flow is less rapid. In peripheral cyanosis, there is a significant difference in the saturation between the arterial and venous blood. This occurs as a result of increased oxygen extraction by the peripheral tissue in the capillary bed. Low cardiac output, venous stasis, and exposure to extreme cold causing vasoconstrictions are some of the conditions that can cause peripheral cyanosis.

Common Causes of Central Cyanosis

• Impaired gas exchange secondary to pneumonia
• Embolism and ventilation perfusion mismatch
• Impaired gas diffusion via the alveoli
• High altitude
• Anatomic shunts
• Right to left shunt in congenital heart disease
• Arteriovenous malformation 
• Intrapulmonary shunt

Furthermore, cyanosis can be caused by the presence of abnormal hemoglobin. Hemoglobin is the major carrier of oxygen in the blood. It is made up of four subunits. Each of the four subunits is made of polypeptide chains, two alpha, and two beta. At the center is a heme group that contains iron. The presence of abnormal hemoglobin causes significant impairment in the oxygen-carrying capacity of the blood. This can cause tissue hypoxia which can manifest clinically as cyanosis.

Methemoglobinemia is a condition that can produce congenital or acquired cyanosis. The condition arises when the iron in hemoglobin is converted from the ferrous (Fe2+) to the ferric (Fe3+) state. Approximately 2% of hemoglobin is present in this form. The presence of methemoglobin can impart a bluish tinge to the skin color. Methemoglobinemia can be triggered by exposure to the topical anesthetic agent dapsone, nitroglycerin, or other strong oxidizing agents [3] . Congenital methemoglobinemia type I and II is an autosomal recessive condition that is caused by a mutation in the gene for cytochrome b5 reductase enzyme. The condition is extremely rare. The lack of enzymatic activity by cytochrome b5 reductase causes decreased reduction of methemoglobin [3] .

Sulfhemoglobin is another rare cause of cyanosis that arises from sulfur binding to hemoglobin. This causes the uncoupling of oxygen from hemoglobin to be very difficult. The iron in the hemoglobin remains unchanged in its ferrous state in sulfhemoglobinemia.

Pseuodcyanosis is another uncommon condition that occurs as a result of contact with drugs such as amiodarone. Exposure to gold or silver salts also can cause pseudocyanosis. Diagnosis can be easily established by careful review of medications.

• Pathophysiology

Cyanosis typically occurs when the amount of oxygen bound to hemoglobin is very low [4] [5] . Oxygen in the blood is carried in two physical states. Approximately 2% is dissolved in plasma and the other 98% bound to hemoglobin [4] [5] . The presence of cyanosis might be an indication of inadequate oxygen delivery to the peripheral tissues. It also could be related to an increased oxygen extraction by the peripheral tissues. Several factors play a significant role regarding oxygen delivery to the end organs. Oxygen delivery is the product of the cardiac output and arterial oxygen content [6] . Cardiac output is determined by the preload, afterload, and contractility. The arterial oxygen content is the sum of oxygen bonded to hemoglobin and dissolved in plasma, approximately 1.34 mL per 1 g of hemoglobin and 0.003 mL of oxygen per 100 mL of plasma [6] .

Typically, when the level of deoxygenated hemoglobin is around 3 to 5 g/dL, cyanosis becomes very evident. The presence of jaundice, skin color, ambient temperature, or light exposure might affect the assessment of cyanosis [7] . Anemia or polycythemia also plays a role in cyanosis. The level of hypoxia required to produce clinically evidenced cyanosis varies for a given level of hemoglobin [8] . Cyanosis is more difficult to discern when the level of hemoglobin is low. In other words, cyanosis might not be clinically evident in a patient with severe anemia.

• History and Physical

The history and physical examination are very important in determining the cause of cyanosis and establishing an appropriate diagnostic algorithm. The onset of cyanosis in the early perinatal period is highly suggestive of a congenital cause whereas a more recent onset is most likely related to an acquired etiology. The next issue to clarify is if the cyanosis is central or peripheral. Central cyanosis suggests a cardiopulmonary disease. This is especially true if there is an associated digital clubbing. 

In taking the history, an attempt should be made to find out any associated cardiopulmonary conditions that can lead to cyanosis. In patients with tachycardia and tachypnea with associated low blood pressure, sepsis with septic shock is the most probable cause. History of exposure or physical contact with substances like dapsone, sulfur-containing drugs, and topical anesthetic agents should be sought as this may also help uncover the presence of hemoglobinopathies like methemoglobinemia. Current or frequent exposure to cold should be elicited in the history taking because vasospasm can cause peripheral cyanosis.

Physical examination is best done where there is adequate illumination as the assessment might be impaired if there is insufficient light exposure. The thickness of the skin and cutaneous pigmentation might also affect the physical assessment. The best area to assess for cyanosis is where the outer layer of the skin is very thin, and the blood supply is very generous such as the cheeks, nose, ears, and oral mucosa.

Diagnosis of cyanosis is based on a careful history, a thorough physical examination, and the use of ancillary studies. Since in most instances, the cardiopulmonary system is involved in the development of cyanosis, a focused assessment of both systems is warranted. If a congenital heart condition is suspected, transthoracic and transesophageal echocardiography can be used to evaluate the cardiovascular system. To assess blood flow and shunting, cardiac Doppler is a very important diagnostic tool. Other tests include cardiac catheterization, CT scan, and MRI of the heart [9] .

Pulmonary causes of cyanosis like pneumonia, pleural effusion, and pulmonary embolism can best be evaluated by using imaging studies like X-Ray, CT Scan, and ultrasound of the chest.

If hypoxemia is suspected as a cause of cyanosis, the primary assessment should include pulse oximetry and arterial blood gas. The arterial blood gas shows the partial pressure of dissolved oxygen in the blood as well as the saturation of hemoglobin. The pulse oximeter measures the absorption of light at only two wavelengths which correspond to that of oxyhemoglobin and deoxyhemoglobin. The drawback of measuring only two wavelengths is that it can create a misleading picture when evaluating a patient with cyanosis secondary to methemoglobinemia. This is because abnormal hemoglobin is not picked up by the pulse oximetry; therefore, in methemoglobinemia, the pulse oximetry reading is falsely elevated [10] [11] . Co-oximetry provides a more accurate evaluation of oxygen saturation because it measures the absorption of light at four different wavelengths corresponding to oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, and methemoglobin. For a patient presenting with cyanosis in which abnormal hemoglobin is suspected, co-oximetry is a useful diagnostic tool.

Another abnormal hemoglobin that can cause congenital cyanosis is hemoglobin M. This hemoglobin is formed as a result of mild structural changes in the alpha and beta chains that keep it in an oxidized ferric state, thereby reducing the oxygen-carrying capacity. Routine hemoglobin electrophoresis can best detect this [12] .

• Treatment / Management

Cyanosis is a symptom of a disease process. The goal is to treat the underlying condition causing cyanosis. Surgical intervention is required for the correction of congenital heart disease-causing cyanosis. In infants and neonates with cyanotic congenital heart disease like tetralogy of Fallot, tricuspid atresia, truncus arteriosus, or total anomalous venous return, prompt referral for cardiology assessment and intervention is necessary. If the cardiac lesion is ductal dependent for pulmonary blood flow, prostaglandin E1 infusion might be necessary to keep the ductus arteriosus open. In the management of neonates with cyanosis, careful attention should be paid to the correction of metabolic derangements like hypoglycemia and hypocalcemia.

Impairment of oxygen diffusion and transfer and other conditions affecting the respiratory system that lead to hypoxia also can cause cyanosis. Oxygen support can be provided to resolve the hypoxia. The regular nasal cannula, high flow nasal cannula, and in some instances, assisted ventilation might be required to provide adequate respiratory support.

For methemoglobinemia-induced cyanosis, the standard treatment is methylene blue. Nicotinamide adenine dinucleotide phosphate helps in the conversion of methylene blue to leucomethylene blue. This end product helps reduce methemoglobin to normal hemoglobin. [13] [14] [15]

Exposure to gold or silver salts also can produce cyanosis. The best therapy in this instance is to remove the offending agents. 

In summary, treatment of cyanosis can be very challenging, and a multidisciplinary approach with different subspecialists might be needed in the management.

• Differential Diagnosis
• Acrodermatitis enteropathica
• Heart failure
• Herb poisoning
• Hydrocarbon toxicity
• Metabolic acidosis
• Pediatric anaphylaxis
• Pulmonary embolism
• Enhancing Healthcare Team Outcomes

The presence of cyanosis has a lot of clinical significance because of the multitude of differential diagnoses. an interprofessional approach with the involvement of specialists which include nursing, critical care, and cardiologist physicians is necessary. A good resource to use is the Poison Control Center if poisoning is suspected. [Level 5]

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Disclosure: Adebayo Adeyinka declares no relevant financial relationships with ineligible companies.

Disclosure: Noah Kondamudi declares no relevant financial relationships with ineligible companies.

This book is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ), which permits others to distribute the work, provided that the article is not altered or used commercially. You are not required to obtain permission to distribute this article, provided that you credit the author and journal.

• Cite this Page Adeyinka A, Kondamudi NP. Cyanosis. [Updated 2023 Aug 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-.

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• Central and Peripheral Cyanosis. [StatPearls. 2023] Central and Peripheral Cyanosis. Pahal P, Goyal A. StatPearls. 2023 Jan
• Harnessing color vision for visual oximetry in central cyanosis. [Med Hypotheses. 2010] Harnessing color vision for visual oximetry in central cyanosis. Changizi M, Rio K. Med Hypotheses. 2010 Jan; 74(1):87-91. Epub 2009 Aug 21.
• Review Diagnostic considerations in infants and children with cyanosis. [Pediatr Ann. 2015] Review Diagnostic considerations in infants and children with cyanosis. Hiremath G, Kamat D. Pediatr Ann. 2015 Feb; 44(2):76-80.
• In Vivo Transcutaneous Monitoring of Hemoglobin Derivatives Using a Red-Green-Blue Camera-Based Spectral Imaging Technique. [Int J Mol Sci. 2021] In Vivo Transcutaneous Monitoring of Hemoglobin Derivatives Using a Red-Green-Blue Camera-Based Spectral Imaging Technique. Khatun F, Aizu Y, Nishidate I. Int J Mol Sci. 2021 Feb 3; 22(4). Epub 2021 Feb 3.
• Review Cyanosis. [Clinical Methods: The History,...] Review Cyanosis. Snider HL. Clinical Methods: The History, Physical, and Laboratory Examinations. 1990

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Cyanosis Overview

Cyanosis is the bluish-purple discoloration of the skin due to reduced oxygen concentration in the blood. This bluish hue does not reflect on the whole skin but rather regions where the skin is thin. The appearance of cyanosis can vary in different people. In dark-skinned people, cyanosis can be noticed in lips, gums, eyes, and nails. It can be difficult to detect cyanosis in obese people. Cyanosis is often present with other symptoms, which can signify an underlying disease. 

Types of Cyanosis

Cyanosis is divided into types: Central cyanosis and peripheral cyanosis.

Central cyanosis results due to a reduced amount of oxygen in arterial blood. It can develop when your oxygen saturation level drops below 85%. Central cyanosis is observed on mucous membrane covering gums, inside of cheeks, tongue, sublingual tissue, and tongue.

Peripheral cyanosis occurs when the amount of deoxyhemoglobin increases in the venous blood, especially in regions that supply your peripheries. For this reason, peripheral cyanosis is noticed on the skin from the peripheral areas, such as the hands and feet. 

Causes Of Cyanosis

Central cyanosis can occur due to a problem with blood circulation or ventilation. Acute central cyanosis can result from choking or blockage of the respiratory passage. It can also happen if the intake of oxygen is reduced or compromised. This occurs in case of being stuck in a house fire, carbon monoxide poisoning, hydrogen cyanide poisoning, high altitude, etc. Systemic diseases which can lead to cyanosis include pneumonia , bronchiolitis, asthma , COPD , pulmonary embolism, obstructive sleep apnea , congenital heart disease , valvular heart disease , heart attack , and heart failure . Certain abnormalities associated with hemoglobin can also cause cyanosis.

The causes for peripheral cyanosis are almost similar to that of peripheral cyanosis. But it can also occur if the blood circulation to extremities is blocked or reduced. Cold exposure can cause a bluish tinge in hands and feet due to reduced blood supply. Other causes are hypovolemia, heart failure, Raynaud’s phenomenon, deep vein thrombosis, peripheral vascular disease, etc. 

Cyanosis Risk Factors And Epidemiology

The risk of cyanosis is present in any person who develops a reduced oxygen saturation level or decreased blood supply. If you have a respiratory, cardiovascular, or circulatory condition, the risk of cyanosis is high. Common diseases like heart attack, COPD, obstructive sleep apnea, and asthma can lower the oxygen saturation level in your blood. If you travel to higher altitudes or live in areas with very low temperatures, you may develop peripheral cyanosis due to diminished blood circulation.

Cyanosis can occur in individuals of any age. Congenital cyanotic heart disease is more common among newborn infants. These babies need immediate medical attention for this condition. 

Cyanosis Signs And Symptoms

Cyanosis itself is a sign of reduced oxygen saturation due to external factors or an underlying medical condition. It can occur with other symptoms depending on the type of condition present. If you have a condition that blocks or obstructs your respiratory passage, you may present with other symptoms such as shortness of breath, dizziness, disorientation, wheezing, coughing, weakness, generalized tiredness, etc. Severe symptoms include tachycardia, dyspnea, chest pain, pallor, increased sweating, etc. 

Cyanosis Diagnosis

The diagnosis of cyanosis is made on the basis of history, physical examination, and diagnostic tests. History will include the onset of symptoms, duration, severity, and past medical history. Physical examination is done to observe areas affected by cyanosis. This includes checking your hands, feet, lips, eyes, and inside of your mouth for bluish discoloration. Lab tests that can be done to diagnose a possible cause include CBC, pulse oximetry, arterial blood gases, ECG, echocardiogram, and hemoglobin electrophoresis. Your doctor can also require X-rays or CT scans to visualize the condition of your heart and lungs. 

CBC (includes Differential and Platelets)

X-ray chest pa, hemoglobinopathy, differential diagnosis.

Cyanosis occurs due to various causes, so it needs to be differentiated on the basis of history, symptoms, physical examination, and diagnostic tests. Remember that discoloration of the skin due to certain medicines, dyes, birthmarks, or Mongolian spots is different from cyanosis. These skin discolorations are not usually associated with the circulatory or respiratory system. 

Cyanosis Treatment

The treatment for cyanosis depends on its underlying cause. If it occurs due to a freezing temperature or change in altitude, try altering these external factors if possible. Place your hands and feet close to a fire or heating appliance to restore blood circulation. If you have developed any respiratory blockage, it becomes a medical emergency. The first line measures are maintaining a stable airway and improving oxygen supply. This is also known as the ABC of emergency treatment which begins with securing Airway, Breathing, and Circulation. If you have been diagnosed with an underlying medical condition, follow your doctor's guidelines and treatment measures to improve your symptoms. 

Medications are given after the diagnosis of the causative factor. Your doctor can prescribe oral or intravenous medications to reduce cyanotic discoloration and improve oxygen saturation.  

Prognosis depends on the severity of the underlying condition. In the majority of the cases, cyanosis is visibly reduced after treatment. If left untreated, the disease may worsen and cause further complications.

Prevention of cyanosis is associated with preventing causes that may lead to impaired blood circulation or reduced oxygen saturation. Annual tests can guide you about your cardiac and respiratory symptoms, and any abnormalities may get diagnosed earlier. If you have a history of a medical condition that may lead to cyanosis, consult with your doctor to reduce the risk of this condition. 

Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on Nov 09th, 2023.

https://medlineplus.gov/ency/article/003215.htm

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8271248/

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Definition and Pathogenesis Top

Cyanosis is characterized by abnormal bluish discoloration of the skin and mucous membranes. It is caused by increased concentration of deoxygenated hemoglobin in the capillary blood (>3.1 mmol/L [50 g/L]) or presence of an abnormal hemoglobin (most frequently methemoglobin >0.31 mmol/L [5 g/L]).

1. Central cyanosis : Generalized, visible on the mucous membranes (mainly lips) and skin, which is usually warm. As cyanosis may not be clearly apparent in patients with darker skin pigmentation, close evaluation of the nail beds, tongue, and mucous membranes is critical. Causes:

1) Hypoxemia (usually hemoglobin oxygen saturation [ SaO 2 ] <85%, partial pressure of oxygen [ PaO 2 ] <60 mm Hg): Ventilation-perfusion mismatch (obstructive lung disease, pulmonary embolism), impaired diffusion (pulmonary fibrosis), shunt (alveolar collapse, congenital heart disease [right to left shunting], pulmonary arteriovenous malformation), decreased oxygen partial pressure in inhaled air (at high altitudes).

2) Presence of a pathologic hemoglobin: Methemoglobinemia (congenital or acquired), sulfhemoglobinemia (in such cases PaO 2 is normal).

2. Peripheral cyanosis : Visible only over the skin of distal body parts, where blood flow is less rapid. The skin is usually cold. When present over the pinna, it disappears with pressure. Peripheral cyanosis is a manifestation of excessive deoxygenation (increased oxygen extraction) of hemoglobin in peripheral tissues. Normal arterial oxygen saturation ( SaO 2 ) is usually observed. Causes:

1) Significant hypothermia (physiologic vasoconstriction).

2) Decreased cardiac output (eg, cardiogenic shock, advanced heart failure, mitral or aortic stenosis).

3) Local abnormalities of arterial circulation (eg, atheroma, arterial emboli, Buerger disease, diabetic angiopathy).

4) Vasomotor disturbances (anxiety-related, Raynaud phenomenon, acrocyanosis).

5) Impaired venous drainage (thrombosis, postthrombotic syndrome, superficial vein phlebitis).

6) Increased blood viscosity (polycythemia vera, cryoglobulinemia, gammopathy).

3. Pseudocyanosis : As opposed to central and peripheral cyanosis, this does not disappear with the application of pressure to the skin. It is a rare phenomenon. Causes: abnormal pigmentation of the skin (drugs: chlorpromazine, amiodarone, minocycline; exposure to heavy metals, eg, to silver [argyria] or gold [chrysiasis]).

Diagnosis Top

1. Assess stability (mental status, airway patency, respiratory distress) and vital signs (respiratory rate, pulse, blood pressure, body temperature, pulse oximetry).

2. Take a focused history (timing of cyanosis, exposures) and perform physical examination (central or peripheral cyanosis; exclude pseudocyanosis; assess respiratory and cardiovascular systems).

3. Co-oximetry provides a more accurate assessment of oxygen saturation as it measures absorption of light at 4 different wavelengths, including oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, and methemoglobin.

4. Perform arterial blood gas analysis (cyanosis is not a reliable sign of hypoxemia) and measurement of carboxyhemoglobin and methemoglobin levels.

5. Assess response to oxygen therapy. Response is poor in patients with cyanotic congenital heart disease, in cases of significant pulmonary shunts of deoxygenated blood, and in patients with a pathologic hemoglobin.

6. Perform a complete blood count ( CBC ) (true cyanosis [central or peripheral] is masked in individuals with severe anemia and manifests earlier in those with polycythemia vera), chest radiography, and, depending on the suspected cause, other cardiovascular (electrocardiography [ ECG ], echocardiography, contrast-enhanced echocardiography) or respiratory (pulmonary function tests, computed tomography [ CT ] of the thorax) studies as well as measurement of pathologic hemoglobin levels (eg, congenital or acquired methemoglobinemia).

• DEFINITION AND PATHOGENESIS

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Manage Notes

Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find one of our health articles more useful.

Treatment of almost all medical conditions has been affected by the COVID-19 pandemic. NICE has issued rapid update guidelines in relation to many of these. This guidance is changing frequently. Please visit https://www.nice.org.uk/covid-19 to see if there is temporary guidance issued by NICE in relation to the management of this condition, which may vary from the information given below.

In this article

Differential diagnosis, presentation, investigations.

Cyanosis is the abnormal blue discoloration of the skin and mucous membranes, caused by an increase in the deoxygenated haemoglobin level to above 5 g/dL. Patients with anaemia do not develop cyanosis until the oxygen saturation (SaO 2 ) has fallen to lower levels than for patients with normal haemoglobin levels and patients with polycythaemia develop cyanosis at higher oxygen saturation levels. Cyanosis can be divided into either central or peripheral [ 1 ] .

Central cyanosis

• Central cyanosis is caused by diseases of the heart or lungs, or abnormal haemoglobin (methaemoglobinaemia or sulfhaemoglobinaemia).
• Cyanosis is seen in the tongue and lips and is due to desaturation of central arterial blood resulting from cardiac and respiratory disorders associated with shunting of deoxygenated venous blood into the systemic circulation.
• Patients who are centrally cyanosed will usually also be peripherally cyanosed.
• Associated features of central cyanosis depend on the underlying cause and include dyspnoea and tachypnoea, secondary polycythaemia and bluish or purple discolouration of the oral mucous membranes, fingers and toes. The hands and feet are usually normal temperature or warm but not cold unless there is an associated poor peripheral circulation.

Peripheral cyanosis

• Peripheral cyanosis is caused by decreased local circulation and increased extraction of oxygen in the peripheral tissues.
• Isolated peripheral cyanosis occurs in conditions associated with peripheral vasoconstriction and stasis of blood in the extremities, leading to increased peripheral oxygen extraction - eg, congestive heart failure, circulatory shock, exposure to cold temperatures and abnormalities of the peripheral circulation.
• Features of peripheral cyanosis therefore include peripheral vasoconstriction and bluish or purple discolouration of the affected area, which is usually cold. Peripheral cyanosis is most intense in nail beds and may resolve with gentle warming of the extremity. The mucous membranes of the oral cavity are usually spared.

Unless the cause is already established, episodes of central cyanosis require urgent assessment, especially infants and young children, who require urgent admission.

Central cyanosis in neonates [ 2 ]

• Transient cyanosis after delivery: central cyanosis should clear within a few minutes of the birth. Peripheral cyanosis clears within a few days. Increased sensitivity of the peripheral circulation to cold temperature may persist well into infancy.
• Transposition of the great arteries .
• Fallot's tetralogy .
• Stenosis or atresia of the pulmonary valve or tricuspid valve.
• Total anomalous pulmonary venous return (all four pulmonary veins drain into systemic veins or the right atrium, associated with a right-to-left shunt through an atrial septal defect .
• Hypoplastic left heart.
• Truncus arteriosus (a single great artery leaves the heart and divides into the pulmonary artery and the aorta).
• Persistent fetal circulation (blood continues to be shunted through the foramen ovale and a patent ductus arteriosus ).
• Respiratory distress syndrome .
• Birth asphyxia, birth injury or haemorrhage.
• Transient tachypnoea of the newborn.
• Pneumothorax .
• Meconium aspiration .
• Pulmonary oedema .
• Congenital diaphragmatic hernia .
• Tracheo-oesophageal fistula.
• Pleural effusion .
• Obstruction of the upper respiratory tract - for example, in Pierre Robin sequence or choanal atresia .
• Other causes include infection, seizures and metabolic abnormalities - eg, hypoglycaemia, hypomagnesaemia.

Central cyanosis in adults

• Lung disease: any severe respiratory disease, pulmonary oedema , pulmonary embolism , decreased PO 2 of inspired air (eg, high altitude), severe pneumonia , chronic obstructive pulmonary disease (COPD) , acute severe asthma , acute adult respiratory distress syndrome .
• Right-to-left cardiac shunt: eg, cyanotic congenital heart disease , Eisenmenger's syndrome , pulmonary arteriovenous fistulas.
• Methaemoglobinaemia: may be genetic or associated with certain drugs - eg, quinones, primaquine, sulfonamides [ 3 ] .
• Sulfhaemoglobinaemia is usually associated with certain drugs, especially sulfonamides.
• Polycythaemia vera or any other cause of polycythaemia may present with central cyanosis.

Causes of peripheral cyanosis

• All causes of central cyanosis cause peripheral cyanosis.
• Reduced cardiac output - eg, heart failure, shock.
• Peripheral arterial disease  - eg, thrombosis, atheroma or embolism.
• Cold exposure .
• Raynaud's phenomenon .
• Acrocyanosis: benign, caused by spasm of smaller skin arteries and arterioles, causing hands and feet to be cold and mottled [ 4 ] .
• Erythrocyanosis: usually affects young women; blotches of cyanosis occur in the lower legs.
• Beta-blocker drugs.
• Venous obstruction (eg, lower limb deep vein thrombosis ) can occasionally produce a painful blue leg (phlegmasia cerulea dolens). Obstruction of the superior vena cava can cause cyanosis, venous engorgement and oedema affecting the face.
• Cyanosis due to congenital heart disease causing anatomical right-to-left shunts may have been present since birth or the first few years of life.
• Acute onset of cyanosis may be due to pulmonary emboli, cardiac failure, pneumonia or asthma.
• Patients with COPD develop cyanosis over many years and associated polycythaemia may exacerbate the degree of cyanosis.
• The description may be typical of Raynaud's phenomenon.
• Past history: cyanosis can result from any lung disease of sufficient severity.
• Drug history: certain drugs may cause methaemoglobinaemia (eg, nitrates, dapsone) or sulfhaemoglobinaemia (eg, metoclopramide).
• Chest pain: cyanosis associated with pleuritic chest pains may be due to pulmonary emboli or pneumonia. Pulmonary oedema may cause dull, aching chest tightness.
• Dyspnoea: sudden onset of dyspnoea can occur with pulmonary emboli, pulmonary oedema or asthma.
• Temperature: pneumonia and pulmonary emboli may be associated with pyrexia.
• Central cyanosis produces a blue discolouration of the mucous membranes of the lips and tongue as well as the extremities.
• Peripheral cyanosis affects the extremities and the skin around the lips but not the mucous membranes.
• The combination of clubbing and cyanosis is frequent in congenital heart disease and may also occur in pulmonary disease (lung abscess, bronchiectasis, cystic fibrosis) and pulmonary arteriovenous shunts.
• The jugular venous pressure is elevated with congestive cardiac failure.
• Poor chest expansion occurs with chronic bronchitis, and asthma. Unilateral reduced chest expansion may occur with lobar pneumonia.
• Dullness to percussion occurs over an area of consolidation.
• Localised crepitation may be heard with lobar pneumonia. Crepitation is more widespread with bronchopneumonia and pulmonary oedema. Air entry may be poor with COPD and asthma. Bronchial breathing may be auscultated over an area of consolidation, and wheezing may be heard with asthma.
• Heart sounds may be abnormal or added heart murmurs may suggest a cardiac origin.
• Localised features suggesting an aetiology of peripheral cyanosis, such as oedema in venous insufficiency or absent peripheral pulses and ischaemia in arterial occlusion.
• Arterial blood gases : oxygen saturation for patients with central cyanosis is usually below 85%. If the oxygen saturation does not increase to above 95% while the patient inhales 100% oxygen then there is likely to be pulmonary intravascular shunting of blood bypassing the alveoli (eg, right-to-left intracardiac shunt or pulmonary arteriovenous fistulae).
• FBC: haemoglobin level is increased with chronic cyanosis. White cell count is increased in pneumonia and pulmonary embolism.
• ECG: features of myocardial infarction; nonspecific ST abnormalities with pulmonary emboli.
• CXR: pneumonia, pulmonary infarction, cardiac failure.
• Sputum and blood cultures: pneumonia.
• Ventilation-perfusion scan - 'VQ scan', or pulmonary angiography: pulmonary embolus.
• Echocardiography: cardiac defects.
• Haemoglobin spectroscopy: methaemoglobinaemia, sulfhaemoglobinaemia.
• Digital subtraction angiography: acute arterial occlusion.
• Duplex Doppler or venography: acute venous occlusion.
• Oxygen therapy for patients who are hypoxic.
• Treatment of the underlying cause.

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Further reading and references

Desai K, Rabinowitz EJ, Epstein S ; Physiologic diagnosis of congenital heart disease in cyanotic neonates. Curr Opin Pediatr. 2019 Apr31(2):274-283. doi: 10.1097/MOP.0000000000000742.

Adeyinka A et al ; Cyanosis. In: StatPearls, 2020.

Dani C, Drovandi L, Bertini G, et al ; Unexpected episodes of cyanosis in late preterm and term neonates prompted admission to a neonatal care unit. Ital J Pediatr. 2017 Apr 1443(1):35. doi: 10.1186/s13052-017-0349-9.

Trivedi DJ, Joshiraj B, Bidkar V, et al ; Methemoglobinemia: Living with Dormant Devil. Indian J Clin Biochem. 2017 Jun32(2):248-250. doi: 10.1007/s12291-016-0586-5. Epub 2016 Jun 13.

Das S, Maiti A ; Acrocyanosis: an overview. Indian J Dermatol. 2013 Nov58(6):417-20. doi: 10.4103/0019-5154.119946.

Hello, I couldn't find a Hypertension group, so I am hoping this group will be knowledgeable about hypertension. I was diagnosed with hypertension several weeks ago following two readings at my GP... annakarenina

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Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Egton Medical Information Systems Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions .