Cyanosis

Original Editor - Natalie Patterson Top Contributors - Natalie Patterson, Stefano Berrone and Kim Jackson

Introduction

The word cyanosis derives etymologically from the greek word kyanos, that means dark blue color. Cyanosis is the condition when the skin or the mucous membranes turn blue. The differential diagnosis of cyanosis can be difficult because there are many possible causes for this condition.

Peripheral cyanosis in the fingers.

Presentation

Cyanosis can be best appreciated in areas with rich superficial vasculature and thin overlying dermis. In fact,the parts of the body most commonly affected are:

• lips
• tongue
• gums
• skin
• ends of fingers, toes and earlobes

for dark skin, cyanosis may be easier to see:

• on the lips, tongue and gums
• ends of fingers
• around the eyes

Cyanosis can be classified as central, peripheral, and differential.

Causes

Cyanosis is a pathologic sign taht does not represent a disease by itself. Cyanosis can mean that there is not enough oxygen in the arterial blood (<80-85%) , or poor blood circulation. The blue colouration is due to the unsaturated haemoglobin in the blood.

It can be caused by:

• asthma
• pneumonia
• choking
• croup
• heart failure
• congenital heart disease

Other causes of cyanosis include:

• Raynaud's Phenomenon, which affects your fingers and toes
• Ventricular failure
• beta blockers, a medicine used to treat high blood pressure
• a blood clot that stops the blood supply to or from a limb
• being in cold air or water
• wearing clothing or jewellery that's too tight

Peripheral Cyanosis

Peripheral Cyanosis (fingers, toes and ears) occurs as a result of increased oxygen extraction by the peripheral tissue in the capillary bed. Low cardiac output, venous stasis (the pooling of blood in the veins), or exposure to extreme cold causing vasoconstrictions.

Central Cyanosis

Central Cyanosis (mouth, lips and tongue) indicates a gaseous exchange problem, although it is an unreliable measure for hypoxaemia. This could be caused by:

• 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
• COPD - in both chronic bronchitis and emphysema
• End stages of Cystic Fibrosis
• ARDs (Acute Respiratory Distress Syndrome) due to impaired gaseous exchange.

Treatment

To treat central cyanosis, it is necessary to manage the underlying conditions. If not the other treatments options according to the clinical situation are:

• Oxygen therapy
• correction of metabolic abnormalities
• different types of drugs such as diuretics and ACE inhibitors

Physiotherapy

The most frequent intrinsic causes of cyanosis are cardiac and respiratory diseases, where physiotherapy plays a role in the treatment of these conditions. In this area of physiotherapy the most effective and evidence-based interventions are not only the traditional ones such as airway clearance and breathing exercises, but also general and specific muscular training for both the aerobic and anaerobic systems.