Clinical Characteristics

The patient usually complains of weakness, weight loss, a swollen abdomen, and, not surprisingly, a dragging abdominal pain. There is increased susceptibility to infection (due to the neutropenia), and often mild, recurrent pyrexia. There is also an increased risk of trauma to the spleen. The clinical illness may persist for years, and, in children, development may be slowed and growth stunted. Although ultrasound or angiography may show a dilated portal vein, esophageal varices are not common. If there is hematemesis, it is usually because of the thrombocytopenia.

Although the condition may be chronic, in some parts of Africa the prognosis is poor, with a 50% mortality being recorded. Treatment with antimalarial drugs over a long period may reduce the size of the spleen and improve the anemia, but this is a slow process and relapse may occur when treatment stops. Surgery because of increasing pain or portal hypertension is very risky: there is a high rate of death during surgery and of overwhelming infections during convalescence.

Imaging Diagnosis

Ultrasonography, and even plain abdominal radiographs, will confirm and monitor the splenomegaly. The spleen is entirely homogeneous, unless there are other complications (e.g., hydatid cyst, abscess, trauma). In Uganda, nearly half the enlarged spleens showed small intraparenchymal calcifications, and in many the splenic vessels were enlarged with increased wall echogenicity: ultrasonography can also demonstrate vascular changes, such as a dilated portal system, and collaterals. Doppler ultrasonography will show the increased portal and splenic blood circulation. Portal cirrhosis can be demonstrated by ultrasonography and angiography can show clearly any collateral vessels. The enlarged spleen may displace and distort the left kidney, as well as the bowel. There are, however, no pathognomonic imaging findings and the main purpose of imaging is to exclude other causes of splenomegaly, many of which will be more responsive to treatment.

Tropical Splenic Abscess

A "primary abscess" of the spleen was described in 1922 (by Wallace), and in some texts is listed as a separate entity. It was thought to be due to splenic vein thrombosis, which resulted in central necrosis and sterile pus, although some abscesses were known to have contained staphylococci. No further reports have been traced confirming this as a separate clinical problem. There are many causes of abscesses in the spleens of patients in the tropics, with or without thrombosis of the splenic vein.