Cyanosis is an unusual bluish cast or discoloration of the skin and mucous membranes, which is commonly noticed around the lips, mouth, palms of the hands, fingernails and soles of the feet.
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.
Cyanosis can be divided into Central Cyanosis, Peripheral Cyanosis, Differential Cyanosis, or Cyanosis, amongst new-borns and babies.
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 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 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 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.
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 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):
2. Respiratory system related conditions:
3. Cardiovascular disease related conditions:
4. Blood-related conditions:
5. Other conditions:
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:
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.
1. Age-related and the nature of Cyanosis onset:
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:
The patient will also exhibit symptoms like:
After a respiratory examination:
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
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:
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:
You may also need to avoid certain medications that constrict blood vessels as a side effect. These include types of:
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.
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
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
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.
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:
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.
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:
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