Tuberculosis Flashcards
(18 cards)
What organism causes tuberculosis?
Properties of this organism?
Which staining do you use and what findings on histology?
Mycobacterium tuberculosis
- slow-growing
- acid-fast bacillus
- waxy coat and mycolic acid cell wall
Ziehl Nielsen stain
- Bright red cells against blue background
What are the sites of TB infection?
Lungs
Extrapulmonary TB: Lymph nodes, CNS, pleura, bones, joints GI, GU, skin
What are the common symptoms of TB?
Cough
Weight loss
Haemoptysis
Fever
Fatigue
Lymphadenopathy
Spinal pain
Erythema nodosum
Disease course of TB?
Breathed in through the air
Immediate bacterial clearance - most common outcome
OR
Latent TB - asymptomatic and not contagious
Primary active TB - active infection after exposure
Secondary TB
What CXR finding is typical of primary TB?
Other findings on CXR?
Ghon focus
Consolidation, pleural effusion, bilateral hilar lymphadenopathy
Investigations for TB?
Mantoux test
IGRA test
Chest x-ray
Deep cough sputum cultures
NAAT
What is miliary TB and how does it appear on chest x ray?
What are the complications of miliary TB?
Disseminated TB that spreads to other organs. Millet-seed pattern on CXR.
Meningitis
Hepatitis
Pyuria
Addisons disease
Management of active TB?
Rifampicin, Isoniazid, Pyrazinamide and Ethambutol for 2 months.
Then for 4 months use Rifampicin + isoniazid only
Which type of TB shoes cavitation and patchy or nodular consolidation on chest x-ray?
Secondary TB
Ways to collect deep cough sputum cultures in a patient with suspected TB?
Sputum induction w/ nebulised hypertonic saline
Bronchoscopy with bronchoalveolar lavage
Ways of collecting mycobacterium cultures in a patient with TB?
3 separate sputum cultures
Blood cultures
What precautions to take when managing patients with TB?
Isolate patient for atleast 2 weeks in negative pressure room
Check BCG status
Contact tracing
Screen for HIV/Hep B/Hep C
Notify UKHSA
If multidrug resistant TB or extrapulmonary TB -> individualised drug regimes
Management of latent TB?
3 months Rifampicin, isoniazid
or 6 months izoniazid and pyrazinamide
Which TB drugs are hepatotoxic?
Rifampicin
Isoniazid
Pyrazinamide
Side effects of rifampicin?
Orange/red body fluids, reduced efficacy of COCP (“Rifam-piss-in”)
What side effect is associated with pyrazinamide?
Hyperuricaemia → risk of gout or renal stones.
What are the side effects of ethambutol?
What precaution to take before prescribing ethambutol?
Visual toxicity: color blindness, reduced visual acuity.
Check visual acuity before and after taking ethambutol
What is a major side effect of isoniazid and how is it prevented?
Peripheral neuropathy
Prevented with pyridoxine (vitamin B6).
