Tuberculosis (pathology) Flashcards
What is the main cause of tuberculosis?
Mycobacterium tuberculosis
What is mycobacterium tuberculosis?
- Non motile bacillus
- Slow growth
- Aerobic – predilection for lung apices
- Very thick fatty cell wall-AAFBs
Transmission of tuberculosis
Airborne- pulmonary and laryngeal TB spreads
*M. bovis spread via unpasteurised infected cow’s milk- rare in UK
What is the pathophysiology of tuberculosis?
- Macrophage activation-> epithelioid cells-> Langhan’s giant cells
- Indigestible material= Granuloma
- Central caseating necrosis
Vulnerable groups to tuberculosis (10)
- People from high prevalence countries
- HIV +ve
- Immunocompromised
- Elderly & neonates
- Diabetics
- Homeless
- Alcoholics
- IVDU
- Mental health problems
- Prison inmates
What is primary infection of TB
- Initial lesion + spread to hilar LN
• May calcify= Ghon focus+ complex
Tuberculosis bronchopneumonia pathophysiology
- Cavitation
- Lobar collapse
- Spread of pus
- Poor prognosis
Post primary disease spread of tuberculosis
- Pulmonary
- Skeletal
- Genitourinary
- Cutaneous
Symptoms of tuberculosis
- Cough
- Fever
- (Night) sweats
- Weight loss
What would be seen on CXR of primary TB
- Apices, soft fluffy, nodular upper zone
- Cavitation
- Lymphadenopathy rare
Order CT if clinical suspicion
What is the treatment of active TB?
Rifampicin (R) + Isoniazid (H)6 m.
Ethambutol (E)+ pyrazinamide (Z) 2 m.
4months= R+H
2 months = R+H+E+Z
What is the treatment of latent TB?
- Screen (CXR and Mantoux test/IGRA test )
- Treatment= R+H for 3 months
What are the side effects of rifampicin?
Orange tears, urine, lenses
Ineffective contraceptive pill
Hepatitis
Rash
Side effects of isoniazid
Hepatitis
Polyneuropathy (give Vit B6)
Rash
Side effects pyrazinamide
Hepatitis
Gout
Rash
