Hypersplenism

Disease class: Splenic diseases

Pathophysiology

In some patients, the spleen removes blood cells too quickly. This reduces the levels of circulating erythrocytes, platelets, or granulocytes. To compensate, the bone marrow produces new blood cells (haematopoesis) at a greater rate. The spleen becomes enlarged.

This can be primary, where no obvious cause is found. For example:

• The immune system may be overactive in response to infections. 
• A patient may have accessory spleens.

It can also be secondary:

• Hypersplenism secondary to cirrhosis
• Malaria
• Polycythaemia vera
• Tuberculosis

Finally it can be occult. This describes hypersplenism which is asymptomatic because the bone marrow has compensated sufficiently for the destruction of blood cells. These patients may be asymptomatic until the haematopoiesis is suppressed by systemic disease (e.g. infection).