TB Flashcards
Rod shaped
0.2 - 0.5 mu in D
2-4 mu in L
M tuberculosis
M TB is acid fast because of its
Mycolic acid
It resists decolorization with acid and alcohol
Aerobic and non-motile
Multiplies slowly can remain dormant for decades
M tuberculosis
Fast grower mycobacterium
Mycobacterium fortuitum
Acid fast Slow growing Aerobic Produces niacin Facultative intracellular
M TB
M TB medium
Lowenstein-Jensen
Inhibits phagosome lysosome function
Sulfatides
Causes serpentine growth in vitro
Inhibits leukocyte migration
Cord factor/trehalose dimycolate
CMI delayed hypersensitivity
Tuberculin
TB stain
Ziel Nielsen Stain detecting long chain mycolic acids
Stain For identification of acid fast bacilli
Ziehl Neilsen Stain
Slipping form of TB
Parallel
Snapping form of TB
V
Niacin +
Catalase -
Grows at 68 deg
TB
Serpentine growth
TB
Can take up to 6 weeks to identify positive cultures
TB
Person-to-person through air by a person with active TB disease of lungs
Inoculation
Transplacental route (very rarely)
TB
Most common site of TB
Pulmonary TB 80%
Extrapulmonary: Lymph node GU Bones and joints Meninges Intestine Skin
Most common extrapulmonary site of TB
Lymph node
Mycobacterium other than TB that affects lymph node
Mycobacterium scrofulaceum
The progression to clinical disease in a previously unexposed immunocompetent person depends on 3 factors
Number of M tb inhaled
Disease that develops in a previously uninfected person
Primary TB
Inhaled bacilli implant in the distal air spaces of
lower part of upper lobe
Upper part of lower lobe
1-1.5 cm area of grey white inflammation with consolidation develops that often
Macrophage
Lymphocyte
Multinucleated giant cells
caseates
caseous necrosis
Bactermia with seeding of multiple sites result from
Natural Resistance Associated Macrophage Protein1 (NRAMP1) polymorphism
after 3 weeks, activation of macrophage lead to formation of
Epitheloid granuloma hypersensitivity
TST is a type of
Type IV Delayed hypersensitivity reaction
Assay that detects MTBC and resistance to Rifampin
Xpert MTB/RIF
Uses DNA strip that allows simultaneous molecular identification of TB and the most common genetic mutations causing resistance to Rifampicin and Isoniazid
Provides result in 5 hours
Line Probe Assay
Used for rapid identification of TB
Buffy coat
Most common form of MTB
Pulmonary
Responsible for caseous necrosis in TB
Phosphatides
Classical tubercular lesion
Granuloma with typical epitheloid cells, lymphocytes fibrosis and
Langhan’s giant cells
Provides a definitive diagnosis for active tuberculosis
Used to monitor progress of patients while on treatment
Confirm cure at the end of treatment
Direct Sputum Smear Microscopy
Abnormalities often seen in xray
apicolordotic view
Subpleural granuloma
Ghon’s focus
Subpleural granuloma + associated LN
Ghon’s complex
Usual site of primary TB
Middle to lower lobe
Usual site of reactivation tuberculosis
Apex of the lungs
Extrapulmonary TB
Renal
Colon
Spine
TB of spine/bone
Pott’s
Children most commonly affected vertebrae
Thoracic
Adult most commonly affected vertebrae
Lower thoracic
Upper lumbar
Present with skip lesions
Cobble stone appearance
Caseation
TB Colon
Present with skip lesions
Cobblestone apearance
Noncaseating
Crohn’s
Low grade fever Night sweats Weight loss Fatigue Cough and hemoptysis
TB
TB cachexia is caused by
TNF alpha
Cachectin
Delayed hypersensitivity Type IV skin test to assay
Cel mediated immunity
Read reaction 48-72 h
Induration is considered + if 10 mm
PPD
Mantoux test
PPD + reading for immunocompromised (HIV)
> 5mm
+ TST indicates
Exposure to organism
Does not indicate active disease
