tuberculosis Flashcards
is TB globally incerasing or decreasing?
decreasing
how many people are infected worldwide
2 billion
how is TB spread?
Airborne
are all AAFBs are TB
no
can tb be spread by Mycobacterium bovis, which can be spread by consumption of unpasteurized infected cows’ milk ??
yes common in uk
whats the immunopathology of activated macrophages?
goes to epithelioid cells which creates langhan’s giant cells
whats the immunopathology of Accumulation of macrophages, epithelioid & Langhan’s cells
granuloma
what does the Th1 cells do?
Eliminates / Reduces number of invading mycobacteria
what is tissue destruction a consequence of?
activation of macrophages
what part of the body spreads mycobacteria?
lymphatics to draining hilar lymph nodes
what are symptoms of tb with primary infection
usually no symptoms, can be fever, malaise
erythema nodosum
rarely chest signs
what are the fates of primary infection
progressive disease
contained latent
cleared cured
what are the 2 otcomes with primary infections?
Primary infection progresses to Tuberculous bronchopneumonia
Miliary TB (looked like millet seeds on autopsy) develops, with hematogenous spread of bacteria to multiple organs
what happens when primary infection progresses to Tuberculous bronchopneumonia
Primary focus continues to enlarge - cavitation
Enlarged hilar lymph compress bronchi, lobar collapse
Enlarged lymph node discharges into bronchus
what would it look like on an xray if you had miliary tb
fine mottling
do animals develop post-primary disease?
no humans do though
what are clinical presentations of TB
cough, fever, sweats, weight loss,
what are the tests to determine TB?
Sputum; 3 samples, 8-24hrs gap, at least 1 early morning sample
Induced sputum
Bronchoscopy with BAL
Endobronchial ultrasound (EBUS) with biopsy
Lumbar puncture in CNS TB
Urine in urogenital TB
Aspirate/biopsy from tissue ( lymph-node, bone, joint, brain, abscess …)
Mantoux or IGRA are NOT routinely used in diagnosing active TB
what is the treatment of tuberculosis?
Multiple drug therapy is essential
Single agent treatment leads to drug resistant organisms within 14 days
Therapy must continue for at least 6 months
TB therapy is a job for committed specialists only
Legal requirement to notify all cases
Test for HIV, Hepatitis B and C
whats the standard treatment for TB?
2 R/H/Z/E + 4 R/H Standard 70kg patient takes 12 tablets daily
6 months duration
7-9 months ( Monoresistance)
12 months (CNS TB, H monoresistance extensive disease)
9-12-18-20 months (MDR-RR TB)
Pyridoxine (Vitamin B6) with isoniazid to reduce risk of neuropathy
Steroids (CNS, Milliar, Pericardial)
Vitamin-D substitution ?
side effects of rifampicin
Orange ‘Irn Bru’ urine/tears/lenses
Induces liver enzymes, prednisolone, anticonvulsants
All hormonal contraceptive methods ineffective
Hepatitis
side effects of isoniazid
Hepatitis
Peripheral neuropathy (pyridoxine B6)
side effects of Pyrazinamide
Hepatitis
Gout
side effects of Ethambutol
Optic neuropathy (check visual acuity)
who is given the BCG vaccination?
Neonates, or unvaccinated children under 5, whose parents/grandparents were born in a country with an annual incidence of TB of 40/100,000 or greater
whats screening for latent TB
Contacts of people with active pulmonary or laryngeal TB who are aged ≤65 years (hepatotoxicity increases with age)
New entrants from high endemic areas
‘Pre-biologics’ (TNF-alpha inhibitors)
Outbreaks
treatment for latent TB
Rifampicin & Isoniazid for three months, or
Isoniazid only for six months, or
Rifampicin only for six months, or
Rifapentine & Isoniazide once weekly for 12 weeks (underserved population
