Clinical Presentation and Treatment of Intestinal Parasitic Infections
Taenia Species (Beef and Pork Tapeworm)
Clinical Presentation
Most patients with intestinal Taenia infection are completely asymptomatic, though some may experience minor abdominal discomfort 1. The hallmark presentation is passage of worm segments (proglottids) in stool, which may actively expel themselves per rectum 1.
Treatment and Dosage
Praziquantel 10 mg/kg as a single oral dose is the definitive treatment 1.
Critical Management Considerations
- Species identification is essential because T. solium (pork tapeworm) can coexist with neurocysticercosis, requiring different management 1
- If T. solium is identified or species cannot be determined, obtain cysticercosis serology 1
- Neurocysticercosis requires treatment with steroids plus albendazole, not praziquantel alone 1
Hymenolepis nana (Dwarf Tapeworm)
Clinical Presentation
Usually asymptomatic, particularly in children, though may present with diarrhea and abdominal cramps 1. Transmission is associated with poor hygiene 1.
Treatment and Dosage
Praziquantel 25 mg/kg as a single oral dose (note the higher dose than for Taenia) 1.
Hookworm (Ancylostoma duodenale/Necator americanus)
Clinical Presentation
- Most infections are asymptomatic 1
- Initial presentation: transient "ground itch" with maculopapular rash at site of larval skin penetration 1
- After 5-12 weeks (prepatent period): nausea, vomiting, diarrhea, and abdominal pain 1
- Heavy infections cause iron-deficiency anemia, especially in young children 1
Treatment and Dosage
Albendazole 400 mg as a single oral dose 1.
Enterobius vermicularis (Pinworm)
Clinical Presentation
- Intense perianal pruritus is the cardinal symptom 1
- Additional symptoms: weight loss, irritability, diarrhea, abdominal pain 1
- Occasionally causes colitis with eosinophilia 1
- May colonize female genital tract causing vaginal discharge 1
Diagnosis
"Sellotape test" is diagnostic: apply sticky side of tape to perianal skin in morning before bathing, then examine microscopically for ova 1.
Treatment and Dosage
Albendazole 400 mg OR mebendazole 100 mg, both as a single oral dose 1.
Trichinellosis (Trichinella species)
Clinical Presentation
Biphasic illness with distinct enteral and parenteral phases 1:
Enteral Phase (7-30 days post-ingestion):
- Upper abdominal pain, fever, vomiting, diarrhea 1
Parenteral Phase (2-6 weeks, as larvae migrate to muscle):
- Severe myalgia and muscle weakness (potentially causing respiratory failure) 1
- Periorbital and facial edema 1
- Conjunctivitis 1
- Dysphagia 1
- Urticarial rash 1
- Life-threatening complications: meningoencephalitis, myocarditis, cardiac conduction disturbances 1
- May require intensive care 1
Laboratory Findings
Treatment and Dosage
Mild disease: Albendazole 400 mg once daily for 3 days 1
Severe disease: Treatment duration and dosing not fully specified in the guideline, but albendazole is indicated 1
Common Pitfall
Trichinellosis typically occurs in outbreaks from consumption of raw or undercooked pork, particularly in Eastern Europe, Russia, Argentina, and China 1. Maintain high clinical suspicion in patients with appropriate exposure history and characteristic biphasic presentation.