B65 Schistosomiasis [bilharziasis]

Name of the Condition

• Schistosomiasis [bilharziasis]

Summary

Schistosomiasis, also known as bilharziasis, is a parasitic infection caused by blood flukes of the genus Schistosoma. The disease primarily affects the urinary or gastrointestinal tract, depending on the species involved. It is transmitted through contact with contaminated freshwater where infected snails release larval forms of the parasite. The condition can range from acute to chronic, with potential for long-term organ damage if left untreated.

Causes

Schistosomiasis is caused by parasitic flatworms (schistosomes) that enter the body through the skin during contact with contaminated water. The larvae mature into adult worms in the bloodstream, where they reproduce and release eggs that can cause inflammation and tissue damage. The lifecycle involves freshwater snails as intermediate hosts, which release infectious larvae into water sources.

Risk Factors

• Exposure to freshwater in endemic regions, particularly for activities like bathing, washing, or swimming.
• Residence in or travel to areas with poor sanitation and high prevalence of the disease.
• Occupational contact with contaminated water, such as farming or fishing.
• Lack of access to safe water and hygiene facilities.

Symptoms

• Abdominal pain, diarrhea, or blood in stool (intestinal schistosomiasis).
• Blood in urine, painful urination, or kidney damage (urinary schistosomiasis).
• Fatigue, fever, or rash shortly after infection (acute phase).
• Chronic symptoms like liver enlargement, bladder scarring, or portal hypertension in advanced cases.

Diagnosis

Diagnosis typically involves detecting schistosome eggs in stool or urine samples under a microscope. Serological tests may be used to identify antibodies or antigens, especially in early or light infections. Imaging studies, such as ultrasound, can assess organ damage in chronic cases. A travel or exposure history is often critical for clinical suspicion.

Treatment Options

The primary treatment is praziquantel, an oral medication effective against all schistosome species. The drug targets adult worms, reducing egg production and symptoms. Supportive care, such as managing anemia or organ dysfunction, may be necessary in advanced cases. Prevention focuses on avoiding contaminated water and improving sanitation.

Prognosis and Follow-Up

With timely treatment, prognosis is generally good, and most individuals recover fully. Chronic infections may lead to irreversible organ damage, particularly in the liver or urinary tract. Follow-up may include repeat testing to confirm egg clearance and monitoring for complications. Long-term management may be required for severe cases.

Complications

• Liver fibrosis or cirrhosis (intestinal schistosomiasis).
• Bladder wall thickening, hydronephrosis, or kidney failure (urinary schistosomiasis).
• Increased risk of bladder cancer in chronic urinary infections.
• Growth impairment or cognitive delays in children with heavy infections.

Lifestyle & Prevention

• Avoid swimming or wading in freshwater in endemic areas; use safe water sources.
• Practice good hygiene, including handwashing and proper sanitation.
• Wear protective footwear in areas with potential snail habitats.
• Community-level interventions, such as snail control and water treatment, reduce transmission.

When to Seek Professional Help

Seek medical attention if you experience unexplained blood in urine or stool, especially after travel to endemic regions. Persistent abdominal pain, fatigue, or urinary symptoms should also prompt evaluation. Early diagnosis improves outcomes and prevents long-term damage.

Tips for Medical Coders

Document the specific type of schistosomiasis (intestinal or urinary) when available, as this may influence coding specificity. Note any associated complications, such as organ damage or malignancy, to ensure comprehensive coding. Include exposure history or travel details if relevant to support clinical correlation. Use B65 for unspecified schistosomiasis when the type is not documented.