177: Helminthic Infections Flashcards
What are the hallmark features of cutaneous larva migrans caused by Ancylostoma braziliense?
Hallmark: creeping eruption
Characteristic lesion: erythematous, raised, and vesicular, linear or serpentine cutaneous trail that progresses at a rate of 2-3 cm per day.
Typically 1 to 3 serpiginous lesions, 3 mm wide and up to 20 cm in length.
Pruritus and urticaria after skin penetration and during larval migration.
Sites: feet and buttocks.
What are the clinical features associated with Ascaris lumbricoides?
Pruritus and urticaria during larval migration (with Loeffler syndrome).
Loeffler syndrome: hypersensitivity syndrome consisting of dyspnea, wheezing, cough; also seen with Strongyloides.
What is the primary treatment for Enterobius vermicularis (pinworm infection)?
Primary treatment: Albendazole 400 mg by mouth once.
Alternative treatments: Mebendazole 100 mg once; Pyrantel pamoate 11 mg/kg (max 1g) once.
What is the significance of Wolbachia bacteria in the treatment of filarial infections?
Wolbachia bacteria play a role in filarial development and host response for all filariasis except loiasis.
Doxycycline 100 to 200 mg by mouth daily for 6 to 8 weeks can reduce Wolbachia and block microfilariae production.
What are the common clinical features of Dirofilaria spp. infections?
Single erythematous, well-defined, firm nodule or mass, usually 1 to 5 cm in diameter; usually asymptomatic but may be tender.
Rarely may be migratory.
What is the most likely diagnosis for a patient with a creeping eruption on their foot characterized by a linear, serpentine cutaneous trail progressing at 2-3 cm per day, and what is the primary treatment?
The most likely diagnosis is Cutaneous Larva Migrans caused by Ancylostoma braziliense. The primary treatment is Albendazole 400 mg by mouth daily for 3 days.
What diagnostic method should be used for a patient with nocturnal anal pruritus suspected of having Enterobiasis, and what is the primary treatment?
The diagnostic method is the sticky-tape method. The primary treatment is Albendazole 400 mg by mouth once.
What is the causative organism for pruritic papular lesions at the site of larval entry, commonly referred to as ‘ground itch,’ and what is the treatment?
The causative organism is Ancylostoma duodenale or Necator americanus (human hookworm). Treatment includes Albendazole 400 mg by mouth daily for 3 days.
What is the likely causative organism for a patient presenting with a firm, erythematous nodule that is 1-5 cm in diameter and tender, and what is the typical presentation?
The likely causative organism is Dirofilaria spp. The typical presentation includes a single erythematous, well-defined, firm nodule or mass, usually asymptomatic but may be tender.
What is the diagnosis for a patient reporting a moving mass under their skin followed by the emergence of an adult worm, and what is the causative organism?
The diagnosis is Dracunculiasis, caused by Dracunculus medinensis.
What is the associated intestinal protozoan for a patient presenting with nocturnal pruritus ani and vulvovaginitis, and what symptoms might it produce?
The associated intestinal protozoan is Dientamoeba fragilis, which may produce gastrointestinal upset.
What diagnostic imaging sign is associated with tropical pulmonary eosinophilia and inguinal lymph node swelling?
The diagnostic imaging sign is the ‘filarial dance sign,’ observed in inguinal lymph node ultrasonography.
What is the recommended approach to minimize severe allergic reactions in a patient undergoing treatment for filariasis?
Start with a low dose of diethylcarbamazine (DEC) and escalate gradually to minimize allergic or febrile reactions.
What is the primary cause of Bancroftian filariasis and its main clinical features?
Bancroftian filariasis is primarily caused by Wuchereria bancrofti, which accounts for 90% of lymphatic filariasis cases. The main clinical features include:
- Hydrocele/scrotal mass caused by lymphatic obstruction
- Limb edema
- Extensive exfoliation of the skin of the affected limb.
What are the management options for Malayan filariasis caused by Brugia species?
Management options for Malayan filariasis, caused by Brugia malayi and Brugia timori, include:
- DEC 2 mg/kg by mouth thrice daily for 12 days
- In chronic cases, elevation of the affected limb, compression stockings, good skin care, and treatment of superficial fungal and bacterial infections are important.
- Surgical treatment can be considered in severe cases.
What is the characteristic symptom of Loiasis and how is it managed?
The characteristic symptom of Loiasis, caused by Loa Loa, is calabar swelling, which is localized angioedema due to the migration of adult worms through subcutaneous tissues. Management includes:
- DEC 3 mg/kg by mouth thrice daily for 21 days
- Surgical removal of the adult worm may be required in some cases.
What are the clinical features and treatment options for Mansonelliasis?
Mansonelliasis, caused by Mansonella perstans and Mansonella streptocerca, presents with:
- Early pruritus, which may be the only symptom
- Calabar-like swellings in the forearms, hands, and face
- Multiple pruritic papules, hypopigmented and hyperpigmented macules, and lichenification.
Treatment options include:
- For M. perstans: Doxycycline 100 to 200 mg daily for 6 to 8 weeks.
- For M. streptocerca: DEC 2 mg/kg by mouth thrice daily for 12 days or alternative Ivermectin 150 μg/kg by mouth once.
What are the key clinical features of Onchocerciasis and its management?
Onchocerciasis, caused by Onchocerca volvulus, is characterized by:
- Pruritus as the most prominent and persistent symptom
- Acute symptoms include widespread small pruritic papules, vesicles, and pustules on the face, extremities, and trunk.
- Chronic symptoms include intensely pruritic flat papules or macules on the buttocks, shoulders, and waist, and well-defined painless nodules containing adult worms.
Management includes:
- Ivermectin 150 μg/kg by mouth once, then every 6 months until asymptomatic.
- DEC should not be used due to the risk of ocular side effects from rapid killing of worms.
What is the most likely diagnosis for a patient presenting with hydrocele and limb edema, with blood tests revealing microfilariae, and what is the primary treatment?
The most likely diagnosis is Bancroftian Filariasis caused by Wuchereria bancrofti. The primary treatment is DEC 2 mg/kg by mouth thrice daily for 12 days.
What is the diagnosis for a patient presenting with localized angioedema around the joints of the upper extremities lasting 2-4 days, and what is the causative organism?
The diagnosis is Loiasis, caused by Loa Loa.
What is the diagnosis for a patient presenting with pruritic papules and hypopigmented macules on the forearms and face, and what is the treatment?
The diagnosis is Mansonelliasis caused by Mansonella perstans. The treatment is Doxycycline 100 to 200 mg daily for 6 to 8 weeks.
What is the diagnosis for a patient presenting with intensely pruritic flat papules on the buttocks and shoulders, along with well-defined, fixed nodules over bony prominences, and what is the primary treatment?
The diagnosis is Onchocerciasis (River Blindness) caused by Onchocerca volvulus. The primary treatment is Ivermectin 150 μg/kg by mouth once, then every 6 months until asymptomatic.
What is the diagnosis for a patient presenting with localized angioedema and migration of adult worms across the conjunctiva, and what surgical intervention might be required?
The diagnosis is Loiasis caused by Loa Loa. Surgical removal of the adult worm may be required.
What is the alternative treatment for Mansonella streptocerca for a patient presenting with pruritic papules and lichenification on the forearms and face?
The alternative treatment is Ivermectin 150 μg/kg by mouth once.
