Term
| A patient comes in positive for M. leprae. What are your treatment options? What side effects should you warn them about? |
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Definition
Dapsone, which affects folate synthesis in leprae and pneumocystis. Warn about hemolysis, especially if GD6 deficient
Rifampin, inhibits RNA polymerase, can cause GI disturbance, orange body fluids and hepatotoxicity
Clofazimine, which binds to mycobacterial DNA. Very long half life; can redden skin |
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Term
| A patient is at high risk for re-activating their latent TB. Which drug would you give prophylactically? |
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Definition
| Isoniazid, mono-therapeutically |
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Term
| When culturing a patients TB, you notice the bacteria have a katG mutation. Which drug would that preclude from treatment? |
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Definition
| Isoniazid (INH), which is activated by katG. Other mechanisms of resistance includes inhA overproduction. |
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Term
| A patient's TB culture returns with a mutation in rpoB, an RNA polymerase. What drug would be precluded from treatment? |
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Definition
| Rifampin (and rifbutin), which targets RNA polymerase |
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Term
| You give a patient a drug that binds to ergosterol, which forms pores in an organism's membrane. What is the name of this drug? What is this patient being treated for? |
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Definition
- Amphotericin (ampho-terrible due to side effects)
- Most likely systemic fungal infection (Cryptococus, Candida, Coccicoides, Histoplasma, Blastomyces, etc.)
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Term
| You give a patient a drug for the fungal infection and they complain of headaches, chills and fever 2 hours after infusion. Which drug did you give them? What should you be on the look-out for later? |
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Definition
Amphotericin B
Renal toxicity, renal tubular acidosis, hypokalemia, and hypomagnesemia. Also watch out for phlebitis and hypochromic, normocytic anemia (reduced EPO levels) |
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Term
| What is one mechanism for minimizing amphotericin's adverse effects? |
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Definition
| Use liposomal packaging (more costly) |
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Term
| A patient comes into the AIDS clinic with oral thrush. What is the most likely treatment? |
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Definition
| Nystatin (topical relative of amphotericin, too toxic for systemic delivery) |
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Term
| A patient comes in with an aspergillus infection. You give a drug that disrupts synthesis of the fungal cell wall. What is the drug, and what molecule does it target? |
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Definition
| Echinocandins - Caspofungin. ß-1,3 glucan. |
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Term
| A patient comes in with a cryptococcus infection. In addition to amphotericin, what other drug do you administer? What is the mechanism of action? What are some concerns in administering the treatment? |
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Definition
- Flucytosine
- Drugsenter via cytosine permease (assisted by amphotericin) and is converted to fluorouracil by deaminase. Incorporates into dna
- Conversion to fluorouracil can cause cytopenia's, decreased bone marrow function and should be monitored in patients with renal impairment. Resistance can occur due to loss of permease, deaminase and other enzymes responsible for drug metabolization
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Term
| An AIDS patient is given a drug to prevent opportunistic fungal infections. The drug works by blocking an enzyme that generates ergosterol. What is the drug type? Which drug would you administer if you were concerned about cryptococcal meningitis? What are the side effects for that particular form? |
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Definition
Azoles (block lanosterol 14-alpha-demethylase, leading to accumulation of intermediate, which in turn leads to disruption of yeast cell membrane)
Fluconazole (GI distres, eosinophilia, Stevens-Johnson syndrome, thrombocytopenia) |
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Term
| A patient with GERD experiences a moderate aspergillus infection. You give them an azole, but there is no resolution to the illness. Assuming the fungi haven't built up resistance to the treatment, what is a likely reason the treatment didn't work? What possible side effects would you expect to see if it did work? |
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Definition
Itraconazole requires low pH to be absorbed, so it could be counteracted by the patient's antacids.
GI distress |
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Term
| A patient you were treating comes in complaining of vision problems. If you were treating the patient for TB, what would the most likely culprit be? What if you were treating a fungal infection? |
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Definition
Ethambutol (optic neuropathy)
Voriconazole (visual disturbance in 30%) |
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Term
| A patient comes in with a dramatic fungal infection in their toenails. You give them a drug that inhibits fungal mitosis. What was the drug being used? How long do you have to administer it for? |
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Definition
Griseofulvin (used for Microsporum, Epidermophyton and Trichophyton)
1 year for toenails (1 month for scalp and hair, 6-9 months for fingernails) |
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Term
| Weeks after treatment for respiratory syncytial virus, a child comes in with respiratory distress. What drug was used, and what was its mode of action? What other side effects should be monitored? Why did it take so long for the adverse effects to manifest? |
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Definition
- Ribavarin, phosphorylated to RMP by host enzymes, which prevents guanine synthesis.
- Cardiac arrest, hypotension, rash, conjuctivitis
- If given in aerosolized form, drug is sequestered in erythrocytes, and thus has a long half-life
Note: should not be given with zidovudine (prevents zido activation)
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Term
| A 9 month old child, who was born premature, comes in with symptoms suggesting RSV virus. What treatment should be administered? |
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Definition
| Palivizumab (ribavarin too toxic). Also indicated for infants born with bronchopulmonary dysplasia |
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Term
| What are the four fungi that are endemic? Dimorphic? Cosmopolitan (opportunistic)? |
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Definition
- Histoplasmosis, coccidiodomycosis, blastomycosis, paracoccidiomycosis
- Same as the endemic, except sporotrichosis instead of para
- Sporotrichosis, cryptococcosis
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Term
| A patient comes in with basic flu symptoms (fever, weakness, malaise, headache) and non-productive cough. Patchy pneumonia and hilar LAD is seen on CXR. He was on vacation, spelunking near the Ohio River, 10-16 days ago. What is the most likely diagnosis? What are some additional symptoms that could confirm the diagnosis? |
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Definition
- Histoplasmosis (Summer Flu)
- Erythema nodosum and rheumatological pain (5%); mediastinal nodes can enlarge (granulomatous) and mediastinum can fibrose. Other complications include pericarditis.
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Term
| A patient comes back from vacation in Haiti in severe respiratory distress. CXR shows diffuse reticulonodular infiltrates, and a biopsy reveals calcified nodules ("buckshot"). What is the most likely diagnosis? |
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Definition
| Acute pulmonary histoplasmosis with heavy exposure or cell mediated immunity |
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Term
| What is the pathogenesis of Histoplasma? What are some of its "miscellaneous" manifestations? In what circumstances can TB-like symptoms develop? |
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Definition
- Inhalation of microconidia, phagocytosis by alveolar macrophages, migration to hilar and mediastinal nodes
- Granulomatous mediastinitis, mediastinal fibrosis, pericarditis (younger patients)
- Cavitary histoplasmosis
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Term
| You're given a CXR showing a miliary pattern in an infant's lungs. They've had fever, anorexia, cytopenia, and GI tract ulceration. Which fungi is most likely to cause these symptoms? What would be the best way to make the diagnosis? What are some other diagnostic tools? |
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Definition
- Disseminated histoplasmosis (infection of reticuloendothelial system)
- Culture (takes 6 weeks) with DNA probe. Bone marrow biopsy with stain and culture more sensitive
- Polysaccharide antigen in urine (cross reactions with blasto), skin test (too many other fungi)
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Term
| Which fungi selectively targets pregnant females in the third trimester? |
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Definition
| Coccidiomycosis (diffusive) |
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Term
| 3 weeks after a trip to Arizona, an immunocompromised patient comes in with signs of meningitis. What is the most likely diagnosis? What are some diagnosis criteria? |
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Definition
Disseminated coccidiomycoses
IgM precipitins (1-4 weeks after infection), IgG titer (>1:32), spherule in tissue sample. For meningitis, lymphocytic pleocytosis. Coccidioidal IgG in CSF |
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Term
| AIDS patient presents at Kings County hospital with severe headache, fever and mild personality change. The organism is found and cultured in their CSF and only exists in the yeast form (not dimorphic). What is the most likely diagnosis? What are the tests can be ordered to confirm? |
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Definition
Cryptococcal infection
Latex particle agglutination (less sensitive for pure pulmonary disease), India ink prep from CSF |
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Term
| You isolate a fungi that forms long lines of branching yeast (pseudohyphae) in an immunocompromised patient. What is the most likely diagnosis? |
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Definition
| Candida (confirm with lysis-centrifugation or empirical treatment) |
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Term
| A diabetic patient presents with proptosis, erythema of the eye, and black nasal eschars. Isolation of the offending organism shows a filamentous fungi with broad-angle branching, lacking true septation. What is the most likely diagnosis? |
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Definition
| Mucormycosis (rhinocerebral mucor) |
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Term
| A neutropenic, immunocompromised patient comes in with signs of multiple infarctions. Assuming they are infected with a fungus, what is the most likely diagnosis and accompanying histology? |
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Definition
| Aspergillosis, an acute angled, filamentous fungus capable of invading blood vessels. |
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Term
| What is the Ghon complex? |
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Definition
| In primary TB, the site of calcification and fibrosis accompanied by hilar lymph drainage. |
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Term
| What does liquefaction necrosis refer to? |
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Definition
Softening of the caseous material. Bacilli generally multiply, especially in instances of bronchiolar communication. Manifests as cavity formation; generally observed in patients uninfected with AIDS (may be mediated by cellular immunity)
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Term
| What is the best confirmation for diagnosis of "miliary" TB? |
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Definition
| Blood culture; sputum is only 30% sensitive, and infection typically occurs in immunocompromised patients (cutaneous anergy) so PPD - |
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Term
| How does TB infection differ in HIV+ patient? |
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Definition
- More similarity to primary TB
- Less cavitation and upper lobe involvement, often negative CXR and positive sputum
- More LAD (not only cervical) and dissemination
- Less PPD reactivity
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Term
| What are the two immunological screen methodologies for TB, and their respective drawbacks |
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Definition
- Tuberculin Test/PPD- Low specificity (other mycobacteria, latent TB, and BCG vaccine exposure can generate false positive), low sensitivity (anergy)
- Quantiferon- Blood test measuring IFN-gamma response to TB antigens. Specific to M.tb (no reactivity to BCG vaccination), but TB treatment can throw off test results
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Term
| You treat a patient for TB, but the patient accidently only takes on of the prescribed medications. They subsequently develop an MDR strain of TB. What is the most likely mechanism of resistance? |
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Definition
| Spontaneous mutation of drug-targeted enzyme; no plasmid or transferable element has ever been found in M.tb. |
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Term
| A patient comes in to be screened for treatment of latent TB infection. What history would suggest "prophylactic" treatment with INH? |
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Definition
- Recent converter
- Silicolosis
- PPD+ HIV+
- Fibrotic CXR changes
- Patient with diabetes, end-stage kidney disease or malnutrition
Treat all patients with PPD 5-15mm induration.
RULE OUT ACTIVE DISEASE – history, physical, chest X-ray.
RULE OUT PRIOR THERAPY. ASSESS for hepatotoxic risk |
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Term
| What is the most common pneumonia in patients with COPD? How does this bacteria typically manifest in (unvaccinated) children? |
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Definition
| Haemophilus influenzae; LRT |
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Term
| An IV drug-user comes in with pneumonia. Given the most likely cause of infection, what would you expect to see in a sputum sample? What are other populations at risk for infection with this bacteria? What are possible sequelae? |
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Definition
- G+ coccus in grape like clusters (S. aureus)
- Adults with the flu, children with measles
- Empyema, lung abscesses
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Term
| Your cystic fibrosis patient comes down with pneumonia. What prevalent morphology would you expect to see in a sputum sample? What are some possible sequelae? |
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Definition
| G- rod (Pseudomonas); vasculitis do to hematogenous spread |
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Term
| An elderly patient with a history of smoking comes down with pneumonia. He's recently returned from a trip spent in an inexpensive hotel room. What would you expect to see on sputum sample? What would be the golden diagnostic tool for this particular organism? |
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Definition
| G- rods best seen with silver stain (Legionella); urine or sputum antigen, both PMN and macrophages present in histology |
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Term
| What type of exudate would you expect to see in someone with atypical pneumonia? |
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Definition
| Proteinaceous and acellular (note: very little sputum). Lacks alveolar fibrinopurulent exudate |
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