TB/Histo/Cocci Flashcards
What organism causes TB?
Mycobacterium tuberculosis
How is TB spread?
airborne droplets with ACTIVE TB infection
What are the two types of primary TB?
- Latent TB= 95%
2. Progressice Primary TB=5%= Active infection
Secondary TB
Reactivated TB from LTBI
Active Dz
What are the risk factors for TB
- Immunocompromised
- HIV/AIDS=#1
- Pt’s receiving immunosuppressive therapy
- Children <5 y.o - Crowded living conditions
- Exposure to someone with active infection
- Nationality/Geography
- Africa, Asia, Latin America
What is considered a classic physical exam finding in TB?
Post-tussive rales
CXR findings in primary progressive active infection?
- Hilar adenopathy
- Hilar/middle lobe infiltrate
- Pleural effusions
CXR findings in reactive active infection?
Apical/upper lobe infiltrates and cavitation
Ghon/Ranke complex
Calcified primary focus and hilar lymph nodes= evidence of healed primary TB
What is the diagnostic gold standard for TB?
Sputum culture
What is the histologic hallmark in TB?
Biopsy showing necrotizing, caseating granuloma
What does the Mantoux test, PPD measure?
Induration
What could give you a false positive for TB on a skin test?
Bacillus Calmette-Guerin (BCG) vaccine
What test has better sensitivity and specificity than PPD for diagnosing TB?
Interferon Gamma Release Assays (IGRAs) blood test
What are the advantages of IGRAs blood test?
- Single visit
- Results in 24 hrs
- Not subjet to reader bias
- Not affected by BCG vaccine
What are the disadvantages of IGRAs blood test?
- Expensive
- Blood sample must be processed in 12 hrs
- Limited availability
Drug treatment for Active TB
RIPE R-Rifampin I-Isoniazid P-Pyrazinamide E-Ethambutol
What is the main goal of latent TB treatment?
Prophylaxis tx to prevent active TB
Drug treatment for Latent TB
Isoniazid (INH) x 9 months
-AFTER you r/o active TB with hx and normal CXR
Rifampin (RIF) side effects
Excreted as red-orange compound in:
- Tears
- Sweat
- Urine
- Stool
Isonaizid (INH) side effects
- Hepatic toxicity- Monitor LFTs!
2. Peripheral neuropathy- Co-administer Vitamin B6 (pyridoxine)
Pyrazivlamide (PZA) side effects
- Hepatic toxicity
2. Hyperuricemia
Ethambutol (EMB) side effects
Optic neuritis
What organism causes Histoplasmosis fungal infection?
Histoplasma capsulatum
Where do you find Histoplasma capsulatum
Isolated from soil contaminated with bird or bad droppings
Where is Histoplasma capsulatum more common?
Midwestern states
-Oho and Mississippi River valleys
What is the most common form of histoplasmosis?
Asymptomatic primary histoplasmosis
Sign and sx’s of acute diffuse pulmonary dz in histoplasmosis infection
- Health people with intense exposure
- Fever and fatigue
- Duration: 1 wk-6 mos.
Signs and sx’s of acute localized pulmonary dz in histoplasmosis infection
- Pneumonia like sx’s: fever, cough, dyspnea
2. Local infiltrates
Signs and sx’s of chronic cavitary pulmonary histoplasmosis
- Apical cavities
2. Occurs in older COPD pt’s
Signs and sx’s of disseminated histoplasmosis
- Fever, fatigue, cough, dyspnea, wt. loss
- Multiple organ failure-often fatal
- Rare in immunocompetent host
CXR findings in histoplasmosis
- Hilar adenopathy
2. Patchy or nodular infiltrates in lower lung fields
Lab studies in histoplasmosis
- Antigen detection- acute xz
- Serology
- Biopsy
- Cultures- chronic dz
Histoplasmosis treatment for asymptotic pt’s
No treatment
Histoplasmosis treatment for acute pulmonary infection
Oral itraconazole or Ketoconazole
Histoplasmosis treatment for Severe infections
Amphotericin B IV
Histoplasmosis treatment for chronic infections
Amphotericin B or itraconazole
Histoplasmosis treatment for AIDS pt’s
Amphotericin B, maintenance therapy with itraconazole
What organism causes Coccidiodomycosis
Coccidioides immitis OR
Coccidioides posadasii
Where are Coccidiodomycosis organisms found?
Soil in semiarid areas
- SW US
- Mexico
- South America
Incubation period of Coccidiodomycosis
7-21 days (1-3 wks)
Coccidiodomycosis clinical presentation
- Pneumonia manifestations-Fever, cough, pleuritic CP
- HA, arthralgias
- Marked fatigue
- Rash- erythema multiform,e, erythema nodosum
- Disseminated extra pulmonary infection
- Residual granuloma (scar) on CXR
Who is @ an increased risk for disseminated cocci?
- HIV/immunocompromised pt’s
- African Americans, Asians
- Women in 3rd trimester
How does disseminated cocci present differently?
- Pulmonary findings more pronounced- lung abscess
- Meningitis, lymphadenitis
- Bone lesions @ bony bony prominences
Coccidiodomycosis CXR findings
- Hilar adenopathy
- Patchy, nodular pulmonary infiltrates
- Miliary infiltrates-disseminated dz
Coccidiodomycosis lab findings
- Eosinophilia
- Serologic (blood) detection of IgM, IgG antibodies
- Culture
When do you treat Coccidiodomycosis?
- > 10% loss body wt.
- Night sweats >3 wks
- Infiltrates >1/2 of one lung OR portions of both lungs
- Prominent/persistent hilar adenopathy
- Inability to work
- Sx’s > or equal 2 months
Coccidiodomycosis treatment
Fluconazole 3-6 months
What is the prognosis for disseminated and meningeal forms of Coccidiodomycosis?
- High mortality rate
- 50% in absence of therapy
Coccidiodomycosis treatment in 1st trimester of pregnancy? Why?
Amphotericin B IV
Azoles are contraindicated in 1st trimester
What do you want to watch out for when using Itraconazole?
CHF
What are -azoles (antifungals) drug interactions?
- Interact with everything
- CYP450
Major adverse reaction of Antifungal?
Hepatotoxicity
When would we want to use Amphotericin B-IV? Why?
Only for severe cases: progressive, potentially life-threatening
MANY adverse rxns
What is the most common opportunistic infection associated with AIDS?
Pneumocystis jiroveci pneumonia (formerly PCP)
Pneumocystis jiroveci pneumonia clinical presentation
- Fever, cough, SOB (pneumonia)
- Hypoxemia
- CXR- diffuse perihilar infiltrates
