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)