Why does pneumonia cause cyanosis

Cyanosis is a bluish discoloration of the skin resulting from an inadequate amount of oxygen in the blood. 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.

It can also result from certain blood vessel and heart malformations that allow blood to flow directly to the heart without ever flowing past the air sacs of the lung alveoli where oxygen is extracted from the air. This abnormal blood flow is called a shunt.

In a shunt, blood from veins in the body, which is oxygen-depleted, may flow directly into blood vessels returning blood from the lungs to the left side of the heart or directly into the left side of the heart itself. The oxygen-depleted blood then is pumped out to the body, to circulate through the skin and other tissues.

The amount of oxygen in the blood can be estimated by pulse oximetry Arterial Blood Gas ABG Analysis and Pulse Oximetry Both arterial blood gas testing and pulse oximetry measure the amount of oxygen in the blood, which helps determine how well the lungs are functioning. Content on this website is provided for information purposes only. Information about a therapy, service, product or treatment does not in any way endorse or support such therapy, service, product or treatment and is not intended to replace advice from your doctor or other registered health professional.

The information and materials contained on this website are not intended to constitute a comprehensive guide concerning all aspects of the therapy, product or treatment described on the website. All users are urged to always seek advice from a registered health care professional for diagnosis and answers to their medical questions and to ascertain whether the particular therapy, service, product or treatment described on the website is suitable in their circumstances.

The State of Victoria and the Department of Health shall not bear any liability for reliance by any user on the materials contained on this website. Skip to main content. Home Lungs. Actions for this page Listen Print. Summary Read the full fact sheet. On this page. Symptoms of pneumonia Causes of pneumonia Diagnosis for pneumonia Treatment for pneumonia Immunisation for pneumonia Where to get help.

Symptoms of pneumonia The symptoms of pneumonia depend on the age of the person, the cause and severity of the infection, and any existing problems with immunity.

Some of the symptoms may include: rapid breathing breathing difficulties fever general malaise loss of appetite abdominal pain headache chest pain cough blue colouration of the skin around the mouth cyanosis , caused by lack of oxygen. Causes of pneumonia Pneumonia can be triggered by a cold or bout of flu, which allows the germs to gain access to the alveoli. Some of the micro-organisms that can cause pneumonia include: Bacteria — symptoms include rust or green-coloured phlegm. In five normal subjects the mean arterial unsaturation was 5 per cent of the total oxygen capacity; the mean venous unsaturation was In the pneumonia cases the arterial oxygen unsaturation varied over a wide range.

The arterial unsaturation varied from 0. In the fatal cases as opposed to the non-fatal cases of pneumonia, the mean arterial oxygen unsaturation was 32 per cent as against As a rule, an arterial unsaturation of over 20 per cent was associated with a fatal outcome.

Similarly, the mean venous oxygen unsaturation was 57 per cent in the fatal cases and Children admitted with lower respiratory tract infections should be evaluated for hypoxaemia. Pulse oximetry, a non-invasive and accurate method of estimating arterial oxygen saturation, is by far the best method.

In centres where pulse oximetry is not available, clinical signs must be used to predict hypoxaemia. No single sign has been found to be a reliable predictor of hypoxaemia.

Cyanosis and head nodding are highly specific for hypoxaemia, but lack sensitivity. The advice of an informal WHO group collaborating to produce evidence summaries that inform guidelines for care of children in low-income settings is gratefully acknowledged. Google Scholar. Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide.

Sign In or Create an Account. Sign In. Advanced Search. Search Menu. Article Navigation. Close mobile search navigation Article Navigation. Volume Article Contents Introduction. Philip Ayieko , Philip Ayieko. Oxford Academic. Mike English. Select Format Select format. Permissions Icon Permissions. Introduction A plausible gold standard for the presence of severe disease in lower respiratory tract infection LRTI is the presence of hypoxaemia.

Methodology The clinical search strategy used was that of Haynes et al. Results Systematic review Published studies evaluating the value of clinical signs in predicting hypoxaemia in children with acute lower respiratory infection were reviewed in [ 7 ]. T able 1 Sensitivities and specificities of clinical signs for hypoxaemia. Laman et al. Lodha et al. Usen et al. Smyth et al.