tuberculosis

Question 1

primary TB lesions ghon focus vs ghon complex?

Answer 1

ghon focus: central caseation surrounded by epitheloid and giant cell langerhans

ghon complex: ghon focus + lesions in mediastinal and cervical LNs

Question 2

reasons for latent TB reactivation?

Answer 2

HIV coinfection, steroids, DM, ESKD, chemotherapy, old age, malnutrition

Question 3

clinical manifestations including physical findings?

Answer 3

low-grade fever followed by defervescence and night sweats, anorexia, weight loss, malaise.

dry cough progressing to productive and hemoptysis, SOB, pleuritic chest pain, pleural effusion.

physical findings:
clubbing in advanced stages, muscle wasting.
consolidation: dull percussion note, absent breath sounds, crackles
pleural effusion: dull percussion, absent breath sounds
cavitation: hyperresonant note on percussion, amphoric breath sounds

Question 4

diagnosis?

Answer 4

high risk countries: india, bangladesh, indonesia, philippines

sputum samples must take 3 or more samples separated by 8-24hr intervals. Smear microscopy with ziehl-neelsen stain, culture (takes 3wks), PCR

chest xray: consolidation, ghon complex, pleural effusion, cavitation, hilar lymphadenopathy

extrapulmonary: needs high index of suspicion plus organism in the organ. if miliary: do LP for meningitis

Question 5

treatment? intensive vs continuation phases?

Answer 5

intensive phase (to kill bacteria and prevent AB resistance)
-RIPE: give rifampin, isoniazid, pyrazinamide, ethambutol for 8wks/2months

continuation phase (to prevent relapse)
-give rifampin and isoniazid for 18wks/4months

also give pyridoxine (vit b6) and do baseline liver function tests

Question 6

important SE for rifampin, isoniazid, pyrazinamide, and ethambutol?

Answer 6

rifampin: orange-stained body secretions

isoniazid: vit b6 deficiency -> peripheral neuropathy, anemia, drug-induced lupus

pyrazinamide: hepatotoxicity, hyperuricemia, NOT FOR PREGNANCY

ethambutol: optic neuritis

Question 7

when can the continuation phase be extended to 7 months?

what to do if hepatotoxicity occurs?

Answer 7

-hiv coinfection
-positive sputum cultures or cavitary TB on CXR by the end of the 2 months

hepatotoxicity if bilirubin >3 mg/dL or transaminases >3-5 upper limits of normal
-stop all hepatotoxic drugs
-once LFT return to normal, restart drugs one at a time

Question 8

what is purified protein derivative test and when is it positive?

Answer 8

injects tuberculin to detect latent TB in asymptomatic patients.

depending on size of induration positive if:
>15mm in those without risk factors

> 10mm in those coming from high-incident countries, healthcare workers, those with close contact to TB patients, prisoners

> 5mm in HIV, organ transplant patients