Tuberculosis Flashcards
Describe the global distribution of tuberculosis and its impact on tuberculosis in the UK
- 2/3 of cases in 8 countries: China, India, Indonesia, Philippines, Pakistan, Nigeria, Bangladesh, South Africa
- Approx. 2 billion infected worldwide
- UK: major cause is immigratio, 39% in London, vulnerable groups
Describe the pathogenesis of tuberculosis in its primary form in the lung
- Mycobacteria spread via lymphatic to hilarious lymph nodes
- Asymptomatic, fever, malaise, erythema nodosum
- Initial lesion and local lymph node (primary complex)
- ^May calcify (Ghon complex)
- Heals +/- scar, may calcify
- Associated with developing immunity to tuberculoprotein
Describe the pathogenesis of tuberculosis in its post-primary (secondary) form in the lung
Two theories;
- Bacteria go into dormant state
- Equal replication of bacteria and destruction by immune system
Describe the immunopathology of tuberculosis
Accumulation of activated macrophages, epithelioid cells, Langhan’s giant cells –> granuloma –> tissue damage –> central caveating necrosis
Describe the complications of primary tuberculosis
Tuberculosis pneumonia;
- Cavitation
- Enlarged hilar lymph nodes compress bronchi (lobar collapse)
- ^Discharge into bronchus
Miliary TB (progressive primary); - Bacteria spread to several organs
Describe the common clinical presentations of tuberculosis
- Cough
- Fever
- Sweats
- Weight loss
(All three absent in 25%) - CRP, ESR
Define the major groups of antituberculous drugs and their pharmacological profiles
- Isoniazid (H): inhibits synthesis of mycelia acid in cell wall
- Pyrazinamide (Z): stops growth
- Rifampicin (R): inhibits RNA synthesis
- Ethambutol (E): unknown
Describe the diagnosis of primary and post-primary tuberculosis on CXR
Primary;
- Mediastinal lymphadenopathy (often bilateral)
- Pleural effusion
- Lesion with enlarged hilar lymph nodes
Post-primary (reactivated);
- Fluffy/nodular upper zone
- Can appear normal
Describe the investigations of tuberculosis
- Sputum
- EBUS with biopsy
- CNS TB: lumbar puncture
- Urogenital TB: urine sample
Describe the diagnosis of primary and post-primary tuberculosis on CXR
Primary;
- Mediastinal lymphadenopathy (often bilateral)
- Pleural effusion
- Miliary TB
- Lesion with enlarged hilar lymph nodes
Post-primary (reactivated);
- Fluffy/nodular upper zone
- Can appear normal
Define the side effects of antituberculous drugs
Isoniazid (H);
- Hepatitis
- Peripheral neuropathy (reduced by pyridoxine B6)
Pyrazimadine (Z);
- Hepatitis
- Gout
Rifampicin (R);
- Orange urine/tears/sweat
- Inducdes liver enzymes, makes prednisolone and anticonvulsants
Ethambutol (E);
- Optic neuropathy
All four can cause rash.
Define the practical application of antituberculous drugs in the management of tuberculosis
- 2 weeks of RHZE + 4 weeks RH
- 99% dead within 14 days
Describe the ‘rules’ of treating tuberculosis
- Multiple drug therapy essential: single will cause resistance within 14 days
- Treat at least 6 months
- Only specialists treat
- Legal requirement to inform
- Test for HIV, hep B and C
Define the practical application of antituberculous drugs in the management of tuberculosis
- 2 weeks of RHZE + 4 weeks of RH: 12 tablets daily standard
- 99% dead within 14 days
- Min. 6 months
Describe the pathogenesis of tuberculosis in its fibrocasous form in the lung
- One form of secondary TB
- Enhanced lesions extended over more than one lobe
- Caseating necrosis
- Fibrosis
