Mycobacterium tuberculosis: Difference between revisions

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Mycobacterium tuberculosis causes tuberculosis
Most commonly pulmonary TB but extrapulmonary tuberculosis is possible (including adenitis, gastrointestinal TB, pericarditis, meningitis)
Standard treatment for susceptible TB is RIPE x2mo then RI x4mo

Primary tuberculosis is usually asymptomatic
Possible presentations include mild URTI with cough and/or fever
May be seen on CXR as infiltrate in mid-lung zones with hilar adenopathy
Ghon complex, especially in children
May progress in children and the immunocompromised patients
Immunological phenomena
- Erythema nodosum
- Phlyctenular conjunctivitis
- Erythema induratum

Subacute or chronic cough (at least 2 to 3 weeks) eventually becoming productive and occasionally involving hemoptysis
- Should be suspected in any patient with cough and HIV infection
Constitutional symptoms, with fevers, night sweats, and unexplained weight loss
Usually from reactivation of latent tuberculosis infection, and usually reactivates in lung apices
May transiently improve with partially-active antibiotics such as fluoroquinolones

Refers to chronic latent infection contained within granulomas that may reactivate in the future
Refer to Latent tuberculosis infection

Standard HREZ x2mo then HR x4mo
- Isoniazid 5mg/kg/d, max 300mg daily
- Rifampin 10mg/kg/d
- Pyrazinamide 25mg/kg/d, max 2g daily
- Ethambutol 20mg/kg/d, max 1.2g daily
- Pyridoxine
Airborne precautions until:
- Treated for at least 2 weeks
- 3x negative sputum smears
  - Collected at 8- to 24-hour intervals, including one early morning collection
- Improvement in symptoms

Most common complication leading to treatment interruption, with a mortality of 6-12% if drugs are not stopped
Rif > INH > PZA
Most patients can have the same TB drugs reintroduced without recurrence of DILI, though recurrence can be delayed
Procedure
- Hold if ALT >120 and symptoms, if ALT >200 even without symptoms, or bili >2x ULN
- Switch to second-line meds
- Reintroduce the original drugs once AST & ALT are <2x ULN
- Only rechallenge with pyrazinamide if it was a mild case

@@ Line 20: / Line 20: @@
 * Possible presentations include mild URTI with cough and/or fever
 * May be seen on CXR as infiltrate in mid-lung zones with hilar adenopathy
-** Ghon complex, especially in children
+* Ghon complex, especially in children
 * May progress in children and the immunocompromised patients
 * Immunological phenomena
@@ Line 27: / Line 27: @@
 ** Erythema induratum
-=== Reactivation pulmonary tuberculosis ===
+=== Pulmonary tuberculosis ===
+* Subacute or [[chronic cough]] (at least 2 to 3 weeks) eventually becoming productive and occasionally involving [[hemoptysis]]
-* Poorly-defined clinical course
+** Should be suspected in any patient with '''cough and [[HIV]] infection'''
-* Usually reactivates in lung apices
+* Constitutional symptoms, with fevers, night sweats, and unexplained weight loss
-* Active pulmonary tuberculosis
+* Usually from reactivation of [[latent tuberculosis infection]], and usually reactivates in lung apices
-** '''Cough and fever for more than two weeks'''
+* May transiently improve with partially-active antibiotics such as [[fluoroquinolones]]
-** '''Cough and HIV infection'''
 === Extra-pulmonary tuberculosis ===
-* Pleural tuberculosis is most common
+* Pleural tuberculosis is most common extrapulmonary site
 * [[Scrofula]] (cervical lymph node infection) next-most common
 * [[Tuberculous meningitis]]