Parasitic and fungal lung infections Flashcards
Benzimidazole
- Bind microtubules and prevent movement and associated cell processes
i.e. albendazole
Avermectin
- Acts on worm GABA complex
- Inhibits GABA synapses in peripheral NS leading to paralysis
i.e. ivermectin
Pyrazino isoquilnoline
- Broad spectrum calcium agonist (against trematodes and cestodes)
- Results in increased intracellular Ca release that leads to muscular contraction
i.e. praziquantel
Asacaris lumbricoides infection sxs and pathology
Tx. of Ascaris lumbricoides infection
Albendazole
Tx. for Strongyloides stercocalis infection (threadworm)
Ivermectin
Repeat Tx common (ivermectin only effective against adult form)
Hookworm infection
Necator americanus
Ancylostoma duodenale
Dx of hookworm infection
Eggs in stool
Tx of hookworm infection
Tx anemia
Albendazole or mebendazole
Hookworm egg
Mnemonic for intestinal roundworms
Only intestinal roundworms that shows larval form in stool
Strongyloides stercoralis
Paragonimus westermani
Tx: praziquantel
Dx: ID eggs in sputum or feces
Most common pulmonary and systemic mycosis of humans
Histoplasma capsulatum
The spores (microcondidia – not the larger macrocondidia, chlamydospores) are inhaled from disturbed
airborne soil.
Histoplasma capsulatum syndrome in immune-competent hosts
- severe acute pulmonary syndrome (caseating lesions that can calcify - “birdshot” CXR)
- Histoplasmoma - single pulmonary parenchymal nodule - “coin lesion on CXR)
- Mediastinal obstructuve syndrome
Histoplasma capsulatum syndrome in immunocompromised hosts
- Chronic pulmonary histoplasmosis (COPD - presentation similar to TB)
What is the most common and likely clinical manifestation of cyptoccocal disease?
CNS disorder
A man presents with high eosinophilia and pneumonia like symptoms. A sputum sample is obtained and an unusual yeast form is found. It is round with multiple buddings. This morphology is associated with what fungal infection?
Paracoccidioides
In whi US state is one most likely to contract Blastomyces infection?
TN
Endemic to TN
In Cryptococcal infections, which diagnostic test is often used for identification?
Latex agglutination of CSF antigens
The parasite Necator americanus is acquired by humans how?
Skin penetration
Loeffler’s Syndrome is best characterized as which of the following?
A. Eosinophilic myocarditis
B. Elevated eosinophils in blood
C. Pulmonary eosinophilia
D. PNA due to a respiratory pathogen
C. Pulmonary eosinophilia
MOA of amphotericin B
It binds to ergosterol directly to cause oxidation and disruption of the cellular membrane
Amphotericin B binds to ergosterol in the fungal cell membrane, which leads to the formation of pores, ion leakage and ultimately fungal cell death
First-line Tx for Pneumoncystis pneumonia
TMP-SMX
Which of the following parasites is associated with fecal/oral transmission?
A. Ascaris lumbricoides
What drug inhibits cytochrome P-450 dependent 14-alpha-demethylase?
-Azole drugs (prevents fromation of lanosterol - precursor to ergosterol)
Which parasitic pathogen undergoes its complete life-cycle in a single human host?
Strogyloides stercoralis
Acquired through skin penetration
What is the MOA for the drug that Tx’s Strogyloides stercoralis
Inhibit GABA synapses in peripheral nervous system leading to paralysis
Ivermectin
A. Septation
D. Hyphal branching
A. Galactomannan
Galactomannan test
Voriconazole
B. Other people
Dx: Lung fluke (Paragonimus)
Trematode
Secondary host - snail/crustacean
D. Binds to calcium receptor leading to release of intracellular calcium and muscular contraction (Praziquantel)
Blastomyces dermatitidis
Geographic distribution of Coccidiodes in US
US SW (desert)
A. Spherule w/ endospores
B = Blastomyces
ID
Histoplasma
From which ecological niche can one most likely acquire histoplasmosis?
Bat and bird droppings
High nitrogen content faciliates histo growth
Cryptococcus is also associated w/ birds (pigeon roosts)
What Rx is used in Tx in mild cases of histoplasmosis?
Itraconazole
DOC to Tx mild cases of systemic, dimorphic fungal infections
Intraconazole
