Sandbox 2

Medical therapy

Uncomplicated strongylidiasis

• Strongyloides stercoralis

• Preferred regimen (1): Ivermectin 200 μg/kg/day PO q24h for 2 days
  • Note: For immunocompromised patients several treatment courses at 2-week intervals is recommended.
• Alternative regimen (1): Thiabendazole 1.5 g PO q24h for 2 consecutive days.
  • Note: The maximum dosage is 3 g/d every 2 days (this dosage is likely to be toxic and needs to be reduced)
  • Note: Cure rates are as high as 87% to 94%, but the drug may not be effective in the disease that is disseminated beyond the gastrointestinal tract.
  • Note: Many patients have gastrointestinal adverse effects, it is used rarely in the U.S. because of adverse effects
• Alternative regimen (2): Albendazole 400 mg PO bid for 3 days

Complicated strongyloidiasis (Disseminated or hyper-infection syndrome)

• Preferred regimen (1): Ivermectin 200 μg/kg/d PO q24h orally for at least 7 to 10 days (until larvae are no longer detected in stool, sputum, or urine)
  • Note: For hyper-infection and disseminated disease, adding albendazole (400 mg PO bid for 7 days) to ivermectin may be warranted.

Overview

Above all, schistosomiasis is a chronic disease. Pathology of S. mansoni and S. japonicum schistosomiasis includes: Katayama fever, hepatic perisinusoidal egg granulomas, Symmers’ pipe stem periportal fibrosis, portal hypertension, and occasional embolic egg granulomas in brain or spinal cord. Pathology of S. haematobium schistosomiasis includes: hematuria, scarring, calcification, squamous cell carcinoma, and occasional embolic egg granulomas in brain or spinal cord. Bladder cancer diagnosis and mortality are generally elevated in affected areas.

Natural History and Complications

Occasionally central nervous system lesions occur: cerebral granulomatous disease may be caused by ectopic S. japonicum eggs in the brain, and granulomatous lesions around ectopic eggs in the spinal cord from S. mansoni and S. haematobium infections may result in a transverse myelitis with flaccid paraplegia. Continuing infection may cause granulomatous reactions and fibrosis in the affected organs, which may result in manifestations that include:

• Colonic polyposis with bloody diarrhea (Schistosoma mansoni mostly);
• Portal hypertension with hematemesis and splenomegaly (S. mansoni, S. japonicum);
• Cystitis and ureteritis (S. haematobium) with hematuria, which can progress to bladder cancer;
• Pulmonary hypertension (S. mansoni, S. japonicum, more rarely S. haematobium);
• Glomerulonephritis; and central nervous system lesions.

Prognosis

Treatment before significant damage or severe complications occur usually produces good results.