Tuberculosis Flashcards
What are the risk factors of TB?
- Immunosuppression
- Drug abuse
- alcoholics
- malnutrition
What are the clinical features of TB?
- Latent TB- asymptomatic, patient is not contagious
- Active TB- constitutional symptoms like fever, weight loss, night sweats, fatigue, lymphadenopathy
- dyspnea, productive cough with sputum and possible haemoptysis for more than 3 weeks
What are the most common sites of extrapulmonary TB?
- Bones
- Pleura
- Lymphadenopathy
- Liver
- Urogenital TB-Haematuria, flank pain, dysuria
- Adrenal TB-adrenal insufficiency
What is milairy TB?
Massive lymphatogenous spread of TB from the lungs involving multiple organ damage and very small granuloma lesions (1-2mm)
Where in the bones does TB usually occur?
vertebral column 50% of the time
What are the X-ray changes of primary active TB?
- ghon complex
- hilar lymphadenopathy
- pleural effusions
What are the X-ray changes in reactivated TB?
- upper lobe cavitatory lung lesions
What are the special investigations we would do in a patient with PTB?
- Start with chest X-ray
- Then get 3 sputum samples and do culture(gold standard) and PCR, start patient on treatment while we wait
- Ziehl Neelson staining from the sputum but it lacks sensitivity
What special investiations do we do in latent TB?
- Tuberculin skin test
2. IGRA(Immune gamma release assay)
How do we interpret a tuberculin skin test?
- It is considered positive >5mm if: HIV positive, signs of TB on chest xray
- Positive if >10mm if: IV drug user, homelessness, chronic illness like diabetes, malignancy, kidney disease, healthcare workers
- Positive >15mm in healthy individuals
what is the differential diagnosis for PTB?
- Lung cancer
- Atypical pneumonia
3.
What is the treatment for PTB?
initiation phase: 2 months of rifampicin, isoniazid, pyrazinamide, ethambutol
continuation phase: 4 months of rifampicin and isoniazid
