What Is Cyanosis?

Cyanosis is an unusual bluish cast or discolouration of the skin and mucous membranes, which is commonly noticed around the lips, mouth, palms of the hands, fingernails and soles of the feet.

Cyanosis means blue disease or 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 oxygen level 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 when the overlying epidermis is thin, and the area has a rich network of blood vessels.

When reduced haemoglobin in the capillaries exceeds five gm%, 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 newborns and babies.

Central Cyanosis

Central Cyanosis is a blue discolouration of the tongue and lips. Lower oxygen levels in the central arterial blood and cardiac or respiratory disorders cause it.

Those suffering from central cytosis usually have peripheral cytosis, a bluish or purple discolouration of the fingers and toes.

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

Peripheral Cyanosis

Peripheral cyanosis is a blue or purple skin discolouration of the extremities, fingers and toes. It is most intense in nail beds, especially if the external temperature gets cold.

Differential Cyanosis

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

Cyanosis in newborns and babies

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

Central Cyanosis in newborns, infants and young children requires urgent admission and medical assessment.

Causes Of Cyanosis

The underlying cause of cyanosis, or blue hands, feet, or fingernails, is that the body's tissues do not receive blood with the requisite oxygen levels; this can happen for various reasons.

The blood is responsible for carrying oxygen through your body. Blood journeys from your lungs, where deoxygenated blood is replenished with oxygen from the air you breathe. This oxygenated blood travels to your heart, pumping 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.

Various conditions could prevent blood from reaching your tissues or 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 causes of cyanosis for each type.

Central Cyanosis Causes

A circulatory or ventilatory issue very often causes Central Cyanosis, which can lead to poor blood oxygenation in the lungs. Central Cyanosis develops when the arterial oxygen saturation exceeds 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.

The following issues may cause Central Cyanosis:

Central nervous system-related conditions (impairing normal ventilation):

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

Respiratory system-related conditions:

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

Cardiovascular disease-related conditions:

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

Blood-related conditions:

Methemoglobinemia
Polycythaemia
Congenital Cyanosis

Other conditions:

High altitude may trigger 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, giving it the appearance of a blue colour when observed through the skin.

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 failure. Small blood vessels could be constricted and may be treated by boosting normal blood oxygenation levels.

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 usually 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. Shunt reversal (right-to-left shunt) occurs when pulmonary pressure exceeds aortic pressure. The upper extremity of the body remains pink in colour because the brachiocephalic trunk left common carotid trunk, and left subclavian trunk are given off proximal to the PDA.

Symptoms Of Cyanosis

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 of cyanosis, which conditions like pulmonary emboli, cardiac failure, pneumonia or asthma could cause.
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.

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

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

Associated symptoms:

Pain in the chest: Cyanosis associated with pleuritic chest pains could be caused by pulmonary embolism or pneumonia. Pulmonary oedema could cause dull, painful chest tightness.
Dyspnoea: this condition may suddenly occur with pulmonary emboli, oedema or asthma.
Gasping for or shortness of breathing difficulties
Fever
Headache
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 produces a bluish discolouration, especially on the mucous membranes of the lips, tongue, fingers and toes.
Peripheral Cyanosis - this condition affects the fingers, toes and skin surrounding the lips and is not noticed around mucous membranes.
A combination of clubbing and cyanosis is frequently observed in congenital heart disease; it may be prevalent in pulmonary diseases, like lung abscesses, bronchiectasis, and cystic fibrosis, as well as 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.
Localised Crepitation 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 sometimes heard may suggest origins in the cardiac area.

Localised features the aetiology of peripheral cytosis. 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 the standard colour does not return when your skin is rubbed or warmed, it is important to get medical attention immediately 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 rule out the prevalence of cardiac abnormalities completely.
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: This 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

If you have blue hands or feet and warming them up doesn't restore normal colour, you must seek medical attention. Treatment involves identifying and correcting the underlying cause to restore oxygenated blood flow to the affected parts of the body.

Receiving proper treatment promptly will improve the outcome and limit any complications. A registered medical practitioner should always prescribe and guide any medication used in Cyanosis Treatment.

Some medications 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

In severe medical situations, such as heart or pulmonary conditions, patients 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 blood vessels to constrict.

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

Receiving proper treatment on time will improve the outcome and limit any complications. A registered medical practitioner should always prescribe and guide any medication used in Cyanosis Treatment.

Some medications 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

In severe medical situations, such as heart or pulmonary conditions, patients 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 blood vessels to constrict.