Schistosoma mansoni - Clinical Manifestation, Complication, Prognosis

Clinical Manifestations of Schistosoma mansoni

Schistosoma mansoni can cause acute schistosomiasis or chronic schistosomiasis in the intestines and sometimes in the liver, and lungs.

Acute schistosomiasis

Cercarial dermatitis

• also called swimmer’s itch

• cercarial dermatitis is rarely a primary infection and mainly occurs in previously exposed individuals

• infection may be acquired from both freshwater and saltwater

• within 24 hours of infection, pruritic rash occurs

Katayama fever

• commonly in infections caused by Schistosoma mansoni and Schistosoma japnicum infections

• the incubation period for Katayama fever is 4 weeks to 6 weeks

• serum-like sickness occurring at the time when the first egg batch is released in the intestine

• common symptoms include fever, myalgia, and right upper quadrant pain while rare symptoms are cough, rash, anorexia, headache

• although the symptoms resolve after several weeks, the condition may become fatal if left untreated

Chronic schistosomiasis

Schistosoma mansoni infections are mostly asymptomatic or mildly symptomatic while clinical syndromes are present in heavy infections. The onset of chronic schistosomiasis is insidious.

Intestinal schisosomiasis

• intestinal schistosomiasis is caused by the formation of granuloma along the intestinal wall and retention of Schistosoma mansoni eggs

• clinical symptoms include schistosomiasis dysentery (mucosal diarrhea), abdominal pain, bloody stool along with the passage of parasite eggs

• in cases of heavy infections, recurrent Salmonella infection with negative stool culture but with positive blood cultures is seen

Hepato-splenic schisosomiasis

• hepato-splenic schistosomiasis occurs when the Schistosoma mansoni infection spreads to the liver

• associated with portal hypertension, ascites, periportal fibrosis, and splenomegaly

• during the early stages, common symptoms include pain in the left hypochondrium, dyspepsia, flatulence

• in later stages symptoms includes melena, haematemesis, edema of the lower, abdominal distension

• if toxic hepatitis and other infections in the liver occurs, liver failure may occur

Complications of Schistosoma mansoni

• Symmers clay pipe stem or periportal fibrosis is the most common complication of intestinal schistosomiasis caused by Schistosoma mansoni which leads to gastrointestinal hemorrhage and portal hypertension

• hepato-schistosomiasis may develop into schistosomal cor pulmonale which occurs in 5% of cases and is associated with dyspnoea, hemoptysis, palpitation

• if the spinal cord is involved, the central nervous complication is transverse myelitis

• in some cases, the spleen may also be involved which leads to complications such as follicular lymphoma

Prognosis of Schistosoma mansoni

In patients who are in the early stage of Schistosoma mansoni infection or without severe end-organ involvement, treatment is successful.

In cases of severe intestinal schistosomiasis and hepato-splenic schistosomiasis, treatment can be done over months or years.

However, if complications include schistosomal cor pulmonale and transverse myelitis, the prognosis is poor even after treatment.