TB Flashcards
MTB
- Acid Fast means what
- Sputum + ve means what
- Diagnosis
Acid Fast
- mycolic acid in cell wall do not pick up Gram Stain
- hence ZN stain, AF smear
- Sputum +ve means infectious
Diagnosis
- AF Smear - 1 day
- AF Culture - 4-8 weeks
- then plus Drug sensitivity 4-6 weeks
start treatment need do what
- give what
- give how long
- why?
Check Liver enzymes; GI symptoms need check liver
Check acuity, color vision
RIPE + Streptomycin IM
- 2 months RIPE; 4 months RI
- cos RI good for LATENT bacterial; P for persistent
General AE of TB drugs
GI, RIP - careful liver
Cutaneous, rash, puritis
Hepatotoxicity - R < I < P
Rifampicin
- MOA
- Special what
- AE
- DDI
- ROE
MOA
- DNA RNA polymerase
- special need Vit K jab or else thrombocytopenia
- AE: orange fluid/ flu like ++ General AEs; Hepatotoxic
- DDI: CYP INDUCER
- Liver
Isoniazid
- MOA
- Special what [3]
- AE
- DDI
- ROE
MOA
- prodrug
- Catalase-Peroxidase Enzyme to give free radicals
- radicals fuck up DNA, fuck up mycolic acid for cell wall
Special
- need Pyridoxine inactive B6 for pregnant
- to prevent PERIPHERAL NEUROPATHY
- also need check genetic polymorph for NAT enzyme in liver for metabolism
- also FDI, dont take w food; dont take histamine, tyramine rich food or else flushing
AE
- PN
ROE
- renal
Co-trimoxazole give waht and why
B9 Folinic acid
- prevent anemia, leukopenia, thrombocytopenia
Pyrazinamide
- MOA
AE
Prodrug to pyrazinoic acid
- by pyraziamidasE
- ACID - decreases pH such that critical pathways affected
AE
- pyrazinoic acid interferes w secretion of uric acid at kidneys
- Hyperuricemia, arthralgia - GOUT SYMPTOMS
Ethambutol
inhibit arabinosyltransferase
- polymerises arabinose to arabinogalactan for cell wall
AE
- visual toxicity
- GOUT SYMPTOMS TOO
What needs renal adjustment
PE
Which ones have DDI and for what
Also in HIV drugs which have DDI
Rifampicin - inducer
Isoniazid - Inhibitor
Protease inhibitors
- darunavir, lopinavir, ritonavir
Efavirenz - NNRTI
- INDUCER
Pathogenesis of TB from start to diff spreads uwu
Droplets - terminal air spaces
- Primary pulmonary foci
- Alveolar macrophage ingestion but unable to kill
- MTB prevents fusion of phagosome w lysosome;
- Macrophages die, further recruits macrophages and lymphocytes
- Mets spread
- Lymph to hilum, mediastinum
- Blood to apical-posterior lungs; other organs
- stay there, pneumonitis
First 3 weeks
- uninterrupted MTB replication at Primary foci and mets
4th Week onwards
- type IV hypersensitivity
- if antigen load low - HS high
- well organized
- well-formed granuloma;
- fibrosis, healing, scar
- if antigen load high - HS low
- poor organization - INCOMPLETE necrosis
- caseating granuloma
- can spread through bronchial tree
- Miliary spread, meningitis
- AP lung
- lymph nodes - can lead to bronchial collapse - hemoptysis
- pleural space - pleural effusion
Note if TB is non-replicating - latent;
Note that spread of TB is via infected macrophaes
Note caseating granuloma is unsuccessful containment;
okie
TESTS for latent TB infection
RF for reinfection
Tuberculin Skin Test
- tuberculin from MTB - local inflammation from T cells
IFGamma Assay
- Age, old, young, HIV, IC, Diabetes
Gimme pathology of Type IV hypersensitivity
MHC presentation
- Macrophages - IL2 - TH1 CD4 helper cell
- CD4 then further give IL2 and IFN gamma
Whats caseating granuloma
- contrast w Coagulative necrosis
Mass of disintegrated cell, not completely digested;
- central acellular pink necrosis
- Langhan’s giant cell
Coagulative is due to ischemia
- since no enzyme involved
- ghost outline
