Acquired Platelet Dysfunction

Platelets are cell fragments that circulate within the blood. They are essential to the formation of blood clots (haemostasis), which halts bleeding. The life-span of a platelet is between 7 to 10 days, after which it is destroyed primarily by the spleen.

The platelet count usually ranges from 150,000 to 450,000/μL (/10^-6L) of blood, and is known to fluctuate. This figure is inversely proportional to the risk of excessive or prolonged bleeding, and thus, the failure of haemostasis.

In some cases, adequate platelet count does not ensure proper function. In these instances, the platelets, though sufficient in number, are dysfunctional, and are unable to cause the proper coagulation of blood.

Causes

Acquired platelet dysfunction is usually the effect of drugs interfering with platelets’ haemostatic ability. The most commonly responsible drug is aspirin, followed by a number of non-steroidal anti-inflammatory drugs (NSAIDs).

Significant blood replacement or transfusion has also been known to affect platelet function, due to the detrimental effect of storage on platelet viability.

Symptoms and diagnosis

Symptoms of platelet dysfunction include:

·         High susceptibility to bruising;

·         Frequent nosebleeds;

·         Abnormally heavy and/or prolonged menstrual period; and

·         Excessive post-surgical bleeding.

Upon recognition of physical symptoms, clinical tests such as blood cell counts, coagulation studies and bone marrow examinations can be used to confirm platelet dysfunction.

Treatment

Drug-induced platelet dysfunction can usually be rectified by ceasing intake of the responsible drug, although several days will are required for the affected platelets to be destroyed and replaced. For this reason, aspirin and NSAIDs are not administered to patients in the days leading up to surgery.