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Cardiorespiratory CC > Tuberculosis > Flashcards

Tuberculosis Flashcards

1
Q

TB

A

Bacterial disease caused by rod shaped mycobacterium

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2
Q

Mycobacteria

A 
Mycobacterium tuberculosis
Slow Growing
Rod shaped
02 rich environment (e.g. lungs)
Lipid rich walls
Waxy coat- prevents penetration of toxic compounds
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3
Q

TB Spread

A

Air- cough, sneeze

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4
Q

Epidemiology

A

1 in 3 infected
Healthy people- contain it in inactive form
Bacteria active when person’s immunity reduced- HIV, age

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5
Q

Classification

A

Difficult + slow to grow in culture

Require Lowenstein-Jensen media

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6
Q

M. leprae

A

Can’t be grown in vitro

V slow- doubling time is 2 weeks

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7
Q

Primary TB

A

Inhaled mycobacteria settle in middle regions of lung, just under pleura –> O2 rich
Excite acute inflammatory response from neutrophils
–> neutrophils phagocytose bacteria, sequester them in intracellular phagosome

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8
Q

Healthy vs immunocompromised response to TB

A

Healthy- release toxic compounds into phagosome + kill bacteria
Immunocompromised- neutrophils can’t destroy bacteria as have waxy coat that prevents penetration of toxic compounds

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9
Q

Immunocompromised Primary TB

A

Neutrophils release cytokines when fail to kill bacteria
Neutrophils die –> caseous necrosis
Bacteria survive in caseous tissue
Cytokines attract macrophages + T cells to area
Macrophages accumulate in rings around caseous tissue –> start to phagocytose bacteria
Soma bacteria killed but some survive even in macrophages
Macrophages can fuse to form giant cells –> more effective at attacking bacteria
Macrophages release more cytokines –> attract lymphocytes
Lymphocytes form layer around macrophages
Outer wall of fibroblasts form

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10
Q

Granuloma

A

Accumulation of macrophages + other cells

Wall off/contain TB and stop it spreading

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11
Q

Ghon Focus

A

Granuloma around a tuberculous necrotic centre

Calcium deposited in outer layer of focus (collagen layer) –> can be seen on X ray

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12
Q

Langhans cells

A

Giant cells formed by macrophages being fused together in granuloma

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13
Q

Ghon Complex

A

Calcified Ghon focus and any associated affected lymph node

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14
Q

Chest X Ray

A

Opacities, mainly in upper zone, with a patchy or nodular appearance
Cavitation
Calcification
Hilar shadowing

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15
Q

Miliary TB

A

Diffuse nodular shadowing

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16
Q

Post-primary TB

A

Bacteria remain alive in Ghon Complex

Later if patient immunocompromised, bacteria escape + TB symptoms recur

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17
Q

Open or active TB

A

Bacilli in sputum

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18
Q

Active TB signs

A 
Fever
Malaise
Weight loss
Night sweats
Cough
Haemoptysis
Chest pain
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19
Q

Bronchus TB

A

Tuberculosis Bronchopneumonia

20
Q

Vessel TB

A

Miliary or isolated organ TB

21
Q

TB Diagnosis - Constitutional signs

A

Fever
Malaise
Weight loss
Night sweats

22
Q

TB Diagnosis- Focal signs

A

Cough
Haemoptysis
Chest pain

23
Q

TB Diagnosis

A 
Signs
Chest X Ray
Sputum swab
Sputum sample culture
Skin test
24
Q

Extrapulmonary spread

A

15-20% cases of active cases of progressive primary TB
Infection spread outside lungs –> other kinds of TB
More common in immunosuppressed + young children
Occurs in more than 50% in those with HIV

25
Q

Extrapulmonary spread sites

A 
Pleura- TB pleurisy
CNS- TB Meningitis
Lymphatic system- Scrofula of the neck
Genitourinary system- Urogenital TB
Bones + Joints- Potts disease of the spine
26
Q

Staining/Culture samples

A

3 early morning sputum specimens from different days

3 early morning urine specimens

27
Q

Staining methods

A 
Ziehl-Neeson
Stain with heated strong carbol-fuchsin
Decolorise with acid/alcohol
Counterstain with malachite green
Show up as pink rods against blue tissue
28
Q

Fluorescent stain with Auramine

A

Mycobacteria fluoresce against dark background

29
Q

PCR

A

Culture takes too long

30
Q

Mantoux test

A

Tuberculin (glycerol extract of TB) inject intradermally
Skin reaction viewed 48-72 hours later
Reaction read by measuring diameter of induration in mm
Small 5-9mm - Active infection in “high risk” individuals
Medium 10-15mm - Active infection in “medium risk” individuals (injecting drug users, homeless, prisoners)
Large >15mm - Sign of active infection in individuals with no risk factors

31
Q

BCG vaccine

A

Strain of attenuated live bovine tuberculosis bacillus, Mycobacterium bovis, that has lost its virulence in humans
0-80% effective for 15 years

32
Q

Treatment

A

Isoniazid
Rifampicin
Pyrazinamide
Ethambutol/Streptomycin

33
Q

Treatment once TB isolate known to be fully susceptible

A

Ethambutol/Streptomycin stopped

34
Q

Treatment after 2 months

A

Pyrazinamide stopped

35
Q

Isoniazid + Rifampicin

A

Daily or intermittent therapy for 4 more months after stop pyrazinamide

36
Q

Isoniazid resistance

A

Rifampicin, pyrazinamide + ethambutol for entire 6 months

37
Q

Directly Observed Therapy

A

Recommended for all patients

Can switch to 2-3 times/week dosing after initial 2 weeks daily dosing

38
Q

Isoniazid

A

Prevent synthesis of mycolic acid (part of TB wall)
Bactericidal to rapidly dividing bacteria
Bacteriostatic to slow growing bacteria

39
Q

Isoniazid side effects

A

Can cause neuropathy

–> B supplements

40
Q

Rifampicin

A

Antibiotic

Inhibits bacterial DNA-dependent RNA synthesis by inhibiting DNA-dependent RNA polymerase

41
Q

Pyrazinamide

A

Thought to inhibit the enzyme fatty acid synthase (FAS) I

–> fatty acid production

42
Q

Ethambutamol

A

Bacteriostatic against actively growing TB

Prevents cell wall formation

43
Q

Streptomycin

A

Antibiotic Aminoglycoside

44
Q

Streptomycin side effects

A

Ototoxicity

Nephrotoxicity

45
Q

Multi drug resistant TB

A

Resistant to Rifampicin + Isoniazid
40-50% mortality rate
80% mortality in HIV patients

46
Q

Second line TB drugs

A

Aminoglycosides- amikacin
Fluoroquinolones- levofloxacin
Thioamides- ethionamide

47
Q

MDR- TB drug length

A

18-24 months

Cardiorespiratory CC (34 decks)

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