Tuberculosis Flashcards
What Gram stain is TB?
Positive
Is it aerobic or anaerobic?
Aerobic
Which stain is used to diagnose TB
Ziehl-Neelsen
Typical lesion on CX-ray
Caseating Granuloma
Presentation of TB
Cough +/- Haemoptysis Fever (with night sweats) Weight Loss (anorexia) Malaise Ethnicity
Features of post-primary infection?
?Re-activation/re-infection Upper lobes Progresses rapidly to cavitation CLassic: caseating granuloma Miliary spread rare Healing by fibrosis+calcification
Features of primary infection in children, elderly and immunocompromised
Multiplies at pleural surface (Ghon focus - sub pleural lesion in mid-lower zones)
Taken to LN by macrophage (Primary complex)
Generalised lymphohaematogenous spread
Granuloma (Langhans giant cells)
Can be asymptomatic esp in children
Rarely:
Tuberculoma
Progressive primary - focus or node ulcerates - pneumonia, cavity, bronchiectasis, consolidation, collapse
Miliary TB - Progressive, dissemintaed, haematogenous spread. Rich foci
1st Line Treatment of TB
Rifampicin - Drug interactions (rasied transaminases, induces cytochrome p450), orange secretions, hepatotoxicity
Isoniazid - peripheral neuropathy )give B6), hepatotoxicity
Pyrazinamide - Hyperuricaemia, hepatotoxicity
Ethambutol - Optic neuritis, visual disturbances
4 for 2 months then 2 for 4
TB meningitis - 4 for 2 then 2 for 8-10
Latent TB - 6 mo INA
DOTS, adherence is key, Vit D supplements
2nd Line treatment of TB
Injectables (capreomycin, kanamycin, amikacin)
Quinolones (moxifloxacin)
Cycloserine, Ethionamide/Protionamide, PAS, Linezolid, Clofazamine
Resistance patterns of TB
Mono - one drug
MDRTB - RIF + INA
XDRTB - RIF + INA + Injectables + Quinolones
Investigations for TB
Imaging - CXR (Upper lobe cavitation - post primary), CT
Culture - Suptum x3, bronchoaveolar lavage, urine (early morning), pus in Lowenstein Jensen medium (gold standard)
Sputum microscopy - Ziehl-Neelsen stain
Fram +ve rods, acid fast, aerobic, intracellular
Tuberculin skin Tests - Mantoux, Heaf testing
IGRA - interferon gamma release assays
NAAT - PCR-line probe assays
Liquid culture mediums
Symptoms of TB meningitis
Subacute Weight loss Fever Night sweats Headache Neck stiffness Personality change Drop in GCS Focal neuro deficit
Diagnosis of TB Meningitis
CT - tuberculomata
LP - Lymphocytic
Treatment of TB MEningitis -
12/12 anti-TB
Steroids
Symptoms of extra pulmonary TB
Lymphadenitis Pericarditis Abdominal - peritonitis, ileitis Genito-urinary, renal, testicular Misc - Skin, liver Increased risk of HIV co infection
Risk factors of TB
Recent migrant HIV+ Homeless Drug user Prison Close contacts Young Elderly
Rsik factors for TB reactivation
Immunosuppression
Malnutrition
Ageing
Chronic Alcohol excess
Symptoms of Spinal TB
Fever Sweats Weight loss Back pain Haematogenous spread - vertebral destruction, collapse, anterior extension, iliopsoas abscess
Investigations for Spinal TB
MRI/CT
Biopsy Aspirate
Treatment for spinal TB
12/12 Anti TB
BCG vaccination
Attenuated strain of M Bovis
Efficacy 0-80%
Bad for pulmonary Tb good for leprosy, meningitis and disseminated
Babies born in or with grand/parents with incidence over 40/100000
Previously unvaccinated immigrants
Contraindicated in HIV
Features of Leprosy
M. Leprae and M Lepromatosis Life long Incubation 2-10 years Poor tranmission via nasal secretions Most disability secondary to nerve damage
Treament of Leprosy
Rifampicin
dapsone
clofazimine - if multibacillary
Manifestations of Leprosy
Skin - depigmentation, macules, plaques, nodules, trophic ulcers
Nerves - thickened nerves, sensory neuropathy
Eyes - Keratitis, Iridocyclitis
Bone - Periositis aseptic necrosis
CLinical spectrum of leprosy
Tuberculoid - Paucibacillary. Th1 mediated depigemntd lesions
BT - Nerve damage
Borderline - multple plaques
BL
Lepromatous - Multibacillary, Th2 mediated, Neuropathic ulcers
Features of other mycobacterium infections
Environmental
No transmission
ASsoc with impaired immunity
Poor response to standard drugs
Features of M. Avium
Children - Pharyngitis, cervical adenitis
Pulmonary - Underlying lung disease (resembles TB)
Disseminated - cytotoxics, lymphoma
AIDS - Disseminated multibacillary infection, mycobacteraemia
Features of M Marinarum
Fish tank granuloma
Single or clusters of papules/plaques
Swimming pool?aquarium owners
Features of M Ulcerans
Insect transmission Tropics/Aus Buruli Ulcer Early - painless nodule SLow progression to ulceration and scarring + contractures Seldom fatal, hideous deformity
