TB, Histoplasmosis and Cocci Flashcards
What is the number 1 killer of the HIV pt?
TB
Where does mycobacterium affect?
Mostly the lungs (can be lymph nodes, kidneys, spine or brain)
How is TB transmitted?
Through airborne droplet nuclei
Occurs when inhaled nuclei reach the alveoli
Usually requires prolonged exposure from active TB
What is active TB classified as?
Disease sxs that occur within 2 yrs of transmission
What is a latent TB infection?
Macrophages ingested tubercle bacilli and created barrier shell called a granuloma so that pt is unable to transmit infection to others
When does LTBI become a disease state?
If pt becomes immunocompromised and granulomas break down because immune system is unable to fight the infection
What percent of TB cases are active?
10% (5 initially and 5 develop from latent)
Who else is at higher risk of developing active TB?
Pts with diabetes
When is CXR recommended?
With positive infection testing or sxs present
Who is at greater risk for TB?
Immunocompromised (HIV, <5, DM, silicosis, malnutrition, substance abuse, immunosuppressive therapy)
Immigrants from areas with high TB prevalence
Injection drug users
Close living quarters (nursing homes, institutions etc)
Sxs of TB
Fever
Cough (3+ weeks, maybe productive or hemopytis)
Pleuritic or retrosternal CP
May have weakness, weight loss, anorexia, chills, night sweats, dyspnea or extrapulm manifestations
What is seen on the physical exam with TB?
*might be normal Classic is posttussive crackles Dullness or decreased fremitus if pleural thickening LAD Clubbing if severe
What is the Mantoux tuberculin skin test?
Create wheal with .1 ml purified protein derivative in forearm intradermally
Rd 48-72 hrs later and measured mm
(may not be present for 2-8 wks after exposure)
What is measured on the TB skin test?
Induration not erythema
Who is positive based on TB skin test rxn > 5mm?
HIV positive pts Recent contacts of those with active TB Persons with evidence of TB on CXR Immunosuppressed pts (chronic steroids) Organ transplant pts
Who is positive based on TB skin test rxn > 10mm?
Recent immigrants from countries with high rate of TB infection
HIV negative injection drug users
Mycobacteriology lab personnel
Residents/employees of high risk congregate settings
Persons with certain high risk medical conditions
Kids <4
Kids and adolescents exposed to adults at high risk
Who is positive based on TB skin test rxn >15mm?
Everyone!!!
What is the 2 step TB test?
Recommended as initial test for health care workers and individuals that need periodic retesting
1st neg: repeat in 1-2 wks
2nd pos: TB infection is present and this creates a boosted response likely due to past exposure so don’t see a false positive
What might create a false positive on TB skin test?
Bacillus Calmette-Guerin vaccine
What is the IGRA:Quantiferon gold test?
Measures immune response in blood to TB because blood is incubated with TB antigen
Used when pt won’t follow up or if they have BCG vaccine
Neither can differentiate active and latent disease
More expensive
What is seen on a CXR in TB?
Hilar LAD or normal
May progress to pleural effusions or infiltrates
Cavities seen in progressive pulm TB
Miliary pattern
Cannot determine between active and latent
What is normal for latent TB on CXR?
Dense nodules or lesions with possible calcifications
What is seen for reactivation of latent TB on CXR?
Cavities, infiltrates and possible adenopathy
Where is the most common place to see abnormalities on CXR?
Apical/posterior upper lobes mostly (or superior areas of lower lobe)
What is Ranke complex?
Healed primary pulmonary TB with Ghon lesion (calcified parenchymal granuloma) and ipsilateral calcified hilar lymph node
How do you collect sputum?
3 specimens (8-24 hrs apart) At least one in the morning because that is the best specimen
3 ways to test sputum
Smear (acid-fast bacilli, easy and quick, supportive)
Cytology (nucleic acid amplification test, supportive)
Culture (gold standard to confirm dx but takes a long time)
What does it mean if AFB and NAA are both positive?
TB disease is presumed and tx begins (do not delay while waiting for culture)
What does it mean if the culture is positive?
TB disease is present (use drug susceptibility testing)
What does it mean if culture is negative and TB disease still suspected?
Treat and monitor response to tx
What is the hallmark of TB on biopsy?
Necrotizing (caseating) granulomas
only if needed
What is the Xpert MTB/RIF assay used for?
IDs M tuberculosis DNA and rifampin resistance (NAA test with cartridges)
Quick but costly
Approved for dx in pts with < 3 days of therapy
Where are active TB pts treated?
Isolated, negative pressure inpatient hospital room
First line drugs for active TB
Rifampin Isoniazid Pyrazinamide Ethambutol All with direct observed treatment
Side effects of rifampin
Orange secretions
Skin sensitivity
Side effects of isoniazid
Hepatotoxic Peripheral neuropathy (give vit B6) Fatal hepatitis (pregnant women at increased risk)
Side effects of pyrazidamide
Hepatotoxic
Hyperuricemia
Not in pregnancy!!
Side effects of ethambutol
Optic neuritis (test visual acuity and color vision)
Initial and continuation phase of TB tx
Initial: 4 meds daily X 2 mos
Continuation: RIF and INH daily or twice weekly x 4 mos
Modifications to tx
HIV: extends tx 9-12+ mos (intermittent dosing)
Pregnant women: no pyrazinamide
Infants/kids: ethambutol not given and may extend tx
What are the criteria to not be considered infectious?
2 wks of tx regimen
3 negative sputum smears
Sxs improve
When can someone go home while still infectious?
If they have strict f/u
DOT is arranged
No kids <5 or immunocompromised ppl in the home
Unable to travel except for healthcare visits
When is tx completion for TB?
Based on doses not duration
Initial for 8 wks: 56 doses
Continuation for 18 wks: 126 doses daily or 36 doses twice weekly
*for active
Options for tx of latent TB
Isoniazid for 9 mos (300 mg daily for 900 mg twice weekly with DOT)- preferred in pregnancy and kids 2-11
INH and rifapentine is newly preferred for adults (not pregnant) and kids >12- 12 weekly doses
Rifampin at 4 mos regiment with 120 doses
What drugs classify MDR TB?
INH and RIF (because of inadequate medication, premature tx interruption or spontaneous mutation)
XDR-TB
Responds to less drugs including fluoroquinolones
Surgery to remove necrotic tissue is important
Bacille Calmette-Guerin vaccine
Intradermal live strain vaccine
Decreases risk of severe consequences due to TB (does not prevent primary infection or activation)- proven to protect against meningitis and disseminated TB in kids
Recommendations for BCG vaccine
Kids with negative TST and have continual exposure (not HIV+ tho)
Healthcare workers if high risk for MDR
Contraindications for BCG vaccine
Immunosuppressed
Pregnancy
Where do you contract histoplasmosis?
From soil contaminated with bird or bat droppings (inhale fungal spores)
Mostly in OH and mississippi river valleys
History associated with histoplasmossis
Recent exposure (spelunking, construction etc) 90% asymptomatic or mild-flu like sxs that resolve in a few wks
Asymptomatic primary histoplasmosis
Most common in healthy people
CXR may show residual granuloma
Acute symptomatic pulmonary histoplasmosis
Fever, marked fatigue, few respiratory sxs
Sxs 1 wk-6 mos
Mild sxs usually self-limited
Progressive disseminated histoplasmosis
Pt typically immunocompromised
Fever, fatigue, cough, dyspnea, weight loss
Multiple organ involvement
Fatal within 6 wks
Chronic pulmonary histoplasmosis
Older COPD pts
Progressive lung changes like apical cavities
Serology for histoplasmosis
Antibody tests like immunodiffusion test (acute and chronic) or complement fixation (more sensitive but takes longer)
Antigen detections with enzyme immunoassay (urine or serum testing)
What can be seen on the CXR in histoplasmosis?
Hilar adenopathy
Patchy or nodular infiltrates in lower lobes
Tx for asymptomatic histoplasmosis
None (<4 wks)
What kinds of drugs might be used for histoplasmosis?
Amphotericin or azoles
When to suspect histoplasmosis?
Pneumonia with mediastinal or hilar LAD Mediastinal or hilar mass Pulm nodule Cavitary lung disease Pulmonary sx with rheumatologic arthritis/arthralgia +erythema nodosum Dysphagia with esophageal narrowing
How do you get coccidiomycosis?
Contaminated soil (lower deserts of western hemisphere)–AZ, San Joaquin Valley CA, new mexco etc
Who has a more severe presentation of cocci?
Immunocompromised, pregnant, diabetics and in African or Filipino descent
Sxs of cocci
Most are asymptomatic (residual granuloma on CXR)
Mild respiratory sxs that are self-limited about wks to mos- may progress with chronic pulm disease or disseminated disease
Primary infection of cocci
Usually present with CAP (7-21 days after exposed)
Fever, cough, pleuritic CP (may also have fatigue, HA or arthralgia-desert rheumatism)
Rash: erythema multiform or erythema nodosum
Disseminated disease of cocci
Seen in those higher risk groups
More pronounced lung findings
Bone lesions
Lymphadenitis, meningitis
Serology for cocci
Enzyme immunoassay Immunodiffusion test (IgM antibodies) Complement fixation (IgG antibodies- detect severity)
Other diagnostics for cocci
Labs (eosinophilia with slight leukocytosis)
SPutum culture
Skin test (not diagnostic)
What might be seen on a CXR with cocci?
Hilar adenopathy
Patchy nodular, pulmonary infiltrates
Miliary infiltrates
Thin wall cavities
CXR of chronic pulmonary disease of cocci
Residual lung nodules with thin walled cavities (disappear within 2 yrs)
Chronic cavitary lesions with infiltrates (may mimic TB)
Tx for cocci
Tx typically not required (only for high risk group or have severe illness)-use azoles but not ketoconazole (increased side effects)
Tx in pregnancy for cocci
Amphotericin b (because azoles are teratogenic)
F/u for cocci
Every 2-4 wks regardless of tx (goes for 1 yr if no meds, if tx then for 2 years for recurrence)
When do you think cocci??
Pulmonary complaints AND One or more of the 3 Es: Erythema nodosum Erythema multiforme Eosinophilia
