Parasites/Fungi — Flashcards

Flashcard 11: What are the key clinical features, treatment, and transmission of Strongyloides stercoralis?

Answer: Causes intestinal infection; DOC: Ivermectin; Transmission: Filariform larvae in soil penetrate skin.

Extra: Commonly presents as Larva currens and can cause hyperinfection syndrome in immunocompromised patients. Diagnosis is by finding rhabditiform larvae in stool.

Flashcard 12: What is the causative agent of amebiasis?

Answer: Entamoeba histolytica

Extra: Clinical features: Dysentery (bloody diarrhea), liver abscess (anchovy paste sputum), RUQ pain. Treatment: Metronidazole or Tinidazole followed by a luminal amebicide (e.g., Iodoquinol or Paromomycin) for carriers/luminal parasites.

Flashcard 13: Pneumocystis jirovecii

Answer: disc-shaped yeast

Extra: silver stainPneumocyctis pneumonia aka PCPTMP-SMX, pentamidine, dapsone

Flashcard 14: What are the most common causative agents of mucormycosis?

Answer: Mucor and Rhizopus species

Extra: Clinical presentation: Rhinocerebral disease, headache, facial pain, black necrotic eschar on face/palate, frontal lobe abscess, and cranial nerve involvement. Risk factors: DKA (ketone reductase enzyme allows growth) and leukemia (neutropenia).

Flashcard 15: Mucor spp.

Answer: irregular, broad, nonseptate hyphae branching at wide angles

Extra: 

Flashcard 16: What media can be used to culture Cryptococcus neoformans?

Answer: Sabouraud's agar

Flashcard 17: Key characteristics of Cryptococcus neoformans?

Answer: Encapsulated yeast (not dimorphic)

Extra: • Diagnosis: India ink (halos), Mucicarmine (red capsule), Latex agglutination (capsular antigen). • Transmission: Inhalation of soil enriched with pigeon droppings. • Clinical: Cryptococcal meningitis, pneumonia (especially in immunocompromised).

Flashcard 18: tinea versicolor

Answer: Malassezia furfur

Extra: fungal metabolites damage melanocyteshyper- or hypopigmented patches"spaghetti and meatball" on KOHtopical miconazole, selenium sulfide

Flashcard 19: Which group of fungi causes Tinea?

Answer: Dermatophytes (Microsporum, Trichophyton, Epidermophyton)

Extra: - Pruritic skin lesions with central clearing (forming a ring shape)\n- Mold hyphae on KOH prep (not dimorphic)\n- Common types: Tinea pedis, cruris, corporis, capitis, and unguium (onychomycosis)

Flashcard 20: Morphology of Aspergillus fumigatus

Answer: Not dimorphic, septate hyphae with acute angle branching (45°), conidiophores with terminal vesicles (conidia)                                                                                                                                                                                                                                                                                                                                                                                 

Extra: Causes: Invasive aspergillosis (immunocompromised), Allergic Bronchopulmonary Aspergillosis (ABPA - asthma/CF), Aspergilloma (fungus ball in pre-existing cavities).