Condition- Tuberculosis Flashcards
What is Tuberculosis? Which pathogen causes it?
A granulomatous disease caused by Mycobacterium Tuberculosis
which organ system must TB infect to become communicable?
the lungs
What is Miliary TB
Lymphohaemoatogenous dissemination of TB
How is the Mycobacterium pathogen spread?
Through aerosolised droplets
Which groups of people are at a higher risk of activation of latent TB/ progression into primary TB?
Requires infection by M tuberculosis and inadequate containment by the immune system:
- Recent Travel/ S Asians
- Immunocompromised/ HIV
- Cigarette smokers
In which cell of the immune system do Mycobacterium pathogens proliferate?
Macrophages- they become engulfed by macrophages where they survive and proliferate.
Eventually, the cell ruptures and dies.
Mycobacterium can then spread –> immune response
Which immune cells are implicated in the containment of TB?
- T-helper cells (TH1 response)
- Macrophages
T-cells and macrophages can form a granuloma to prevent the further growth and spread of TB. What are the contents of it?
- A necrotic caseous centre
- M tuberculosis
- Peripheral granulation tissue consisting primarily of macrophages and lymphocytes
What are the three outcomes following exposure to M. tuberculosis?
- clearance of M tuberculosis
- persistent latent infection
- progression to primary disease
list the signs and symptoms of tb
- FLAWS
- cough- dry then productive, lasting 2-3 weeks
- pleuritic chest pain
- dyspnoea
- haemoptysis
- psch symptoms- depression
- erthema nodosum- Painful raised erythematous nodules over pretibial region
- Lymphadenopathy
Which oher body systems could tb infect?
- Lungs: LRTI
- Brain: meningitis
- Skin: erythema nodosus
- Spinal cord: Pott’s disease–> spinal cord compression
- Testes: epididymo-orchitis
- Kindeys: renal failure
- Adrenals: Addisons
What is the first line investigation for tb? What would you see?
CXR
- fibronodular opacities in upper lobes with or without cavitation
- Peripheral consolidation
- Hilar lymphadenopathy
- (pleural effusion)
- (nodular shadowing = milliary TB)
List some other appropriate investigations for tuberculosis
- CXR
- sputum acid-fast bacilli smear
-
SPUTUM CULTURE= Gold standard but takes up to 6 weeks
- woud see caseating granulomas
- FBC
- TST-tuberculin skin tets (Mantoux test)- just to see if you’ve been infected with TB in our life.
- Lymph node biopsy
Which 4 drugs are given to patients with TB?
RIPE
- Rifampicin- 6 months
- Isoniazid- 6 months
- Pyrazinamide- 2 months
- Ethambutol- 2 months
- Note: start after clinical suspicion + histology, don’t need to wait for culture results
Which stain is used to identify TB in sputum cultures?
Ziehl Nielson Stain (acid fast bacili)
Which CXR finding might be indicative of miliary TB?
Nodular shadowing
