Tuberculosis

26/8/10

OH

- devastating world wide disease

- organisms: Mycobacterium tuberculosis, M. bovis, M. africanum, M. microtti, and M. canetti

- all of these organisms are acid fast bacilli

- once infected there are 4 potential outcomes:

1. immediate clearance

2. primary disease

3. latent infection

4. reactivation of disease

RISK FACTORS

- HIV

- silicosis

- DM

- CRF

- malnutrition

- solid organ transplant

- gastrectomy

- jejunoilieal bypass

- drug abuse

- chronic pulmonary disease

- prolonged steroid use

- institutional living

- poverty

- smoking

CLINICAL FEATURES

- fever

- night sweats

- unexplained weight loss

- fatigue

- anorexia

- can effect any organ system!

Tuberculosis Pneumonia

- cough and sputum

- haemoptysis

- chest wall pain

- SOB

- crackles (apical)

- recurrent pneumonia

- pleural effusions

- spontaneous pneumonthorax

Tuberculosis Meningitis

- contact history

- vague illness for 2-8 weeks

- headache

- neck stiffness

- cranial nerve palsies

- papilloedema

- hemiplegia

- seizures

Tuberculosis Emergencies

- massive haemoptypsis

- respiratory failure

- pericardial tamponade

- small intestinal obstruction

- tuberculous meningitis

- status epilepticus due to tuberculomas

INVESTIGATIONS

- CXR: patchy/nodular shadowing in upper zones, cavitation, calcification, hilar or mediastinal lymphadenopathy, diffuse millary shadowing

- 3-6 sputum samples -> acid fast bacilli

- quantiferon test: confirms exposure and possibly disease

- bronchial washings

- gastric lavage

- aspiration of collections

- pleural fluid – send for total protein, glucose, WCC and differential, pH, adenosine deminase (if > 70U/L -> highly suggestive of Tb)

- pleural biopsy

- mediastinoscopy -> lymph node resection

- LP: smear examination or bacterial culture

- CT or MRI: thickening and enhancement of meninges in basilar region

- nucleic acid amplication: amplify target nucleic acid regions that uniquely identify the M. tuberculosis complex -> useful in ruling in Tb rather than ruling out.

MANAGEMENT

Patient

- ID consult!

- patients are infective while coughing until after 2 weeks of treatment

- check bronchial washing for smear positive -> if positive then highly infectious

- 8 month course:

- rifampicin

- isoniazid

- ethambutol

- pyrazinamide

- steroids in pericardial disease and meningitis

- if organisms are resistant -> IV aminoglycosides (streptomycin, amikacin) and fluoroquinolones (ciprofloxacin).

ICU Environment

- aerosol isolation + standard contact isolation

- room: private, door closed, negative pressure (12 air changes/hour)

- mask: N95 or N100

- bacterial filter and closed suction on circuit

- warning signs on doors

- bronchoscopy: minimise aerosols (paralyze, consider apnoeic ventilation during procedure)

- education for staff on symptoms

- staff screening: CXR, mantoux (baseline and 2 months)

- early ID involvement in staff exposed

Jeremy Fernando (2011)