Infectious disease Pathology

Question 1

which class of antibiotics target cell wall synthesis ? (2)

Answer 1

• beta lactams
• glycopeptides

Question 2

name some beta lactams ?

Answer 2

• penicillins
• cephalosporins

Question 3

tazocin is a mix of what ?

Answer 3

• piperacillin (abx)
• tazobactam (beta lactam inhibitor)

Question 4

name some glycopeptides ?

Answer 4

• vancomycin
• teicoplanin

Question 5

what is the pathogen in TB ?

Answer 5

mycobacterium tuberculosis
(bacteria)

Question 6

what staining does TB have ? (2)

Answer 6

• acid fast bacillus with waxy coating (so gram stain ineffective)
• zeihl-neelsen (red)

Question 7

TB epidemiology: in who more common ?

Answer 7

• south East Asian
• immunocompromised (HIV)
• close TB contact

Question 8

what does the slow growing of TB mean ?

Answer 8

slow reproduction => slow onset of disease and slow response to treatment
- difficult to culture and treat

Question 9

what is primary TB ?

Answer 9

bacteria has initial contact with alveolar macrophage => uses macrophages to proliferate => then to lymph nodes => cell mediated immunity

Question 10

what is active TB ?

Answer 10

where there is active infection in parts of the body

Question 11

what is latent TB ? bodys response ?

Answer 11

immune system encapsulates site of infection (granuloma) => slow progression

Question 12

what happens to the granulomas in TB ?

Answer 12

provides area for TB to grow + block from systemic infection => latent, dormancy §

Question 13

what is secondary TB ?

Answer 13

when latent TB reactivates

Question 14

what is miliary TB ?

Answer 14

immun system unable to control disease

Question 15

where are the most common site for TB ? why ?

Answer 15

• lungs - apex (plenty of oxy and low blood => low immune cells)

Question 16

name some locations of extra pulmonary TB ?

Answer 16

• lymph nodes
• pleura
• CNS
• pericardium
• GI/GU system

Question 17

BCG vaccine: who offered to ?

Answer 17

• neonates with a FHx
• healthcare workers
• <35 with close contact to TB

Question 18

TB Px ?

Answer 18

Hx of chronic gradually worsening sx (mostly pulmonary)
- lethary
- fever
- weight loss
- cough (+/- haemoptysis)
- lymphadenopathy
- spinal pain

Question 19

what is gold standard Ix for active TB ?

Answer 19

• sputum culture

Question 20

why would you do NAAT acid fast test for TB ?

Answer 20

sputum culture takes 2-3 weeks
whereas NAAT takes 24-48 hrs (alot quicker but less specific)

Question 21

what test is done to screen for latent TB ? (2)

Answer 21

• Mantoux test
  (indicates prev vaccination/latent/active)
• interferon-gamma blood test

Question 22

what imaging would be done for active TB px ? what would this show ?

Answer 22

CXR
- primary TB: pleural effusions
- reactivated: nodular consolidation with cavitations
- disseminated miliary (millet seeds)

Question 23

latent TB Mx ?

Answer 23

if at risk of reactivation
- isoniazid + rifampicin (3 months)

Question 24

acute active pulmonary TB Mx ? how long of each

Answer 24

6 months
- rifampicin + isoniazid
2 months
- pyrazinamide + ethambutol

Question 25

what else should you test for when pt has TB ? (5)

Answer 25

- hep B/C - HIV - test contacts for TB - notify public health - isolate during active TB

Question 26

rfiampicid SE ?

Answer 26

- red/orange discolouration of secretions

Question 27

isoniazid SE ?

Answer 27

peripheral neurophathy

Question 28

which Tb med can cause peripheral neuropathy ? what do you give alongside ?

Answer 28

pyridoxone prophylaxis (isoniazid causes it)

Question 29

ethambutol SE ?

Answer 29

colour blindness

Question 30

which TB drugs cause hepatotoxicity ?

Answer 30

RIP

Question 31

what cells does HIV target ? what does this cause ?

Answer 31

damages CD4 presenting cells of the immune system (T-helper cells, monocytes, macrophages, dendritic cells) => makes body prone to opportunistic disease + cancer

Question 32

what is AIDS ?

Answer 32

acquired immunodeficiency syndrome - describes a group of potentially life threatening infections + diseases that happen when immune system is compromised (because of HIV)

Question 33

what determines when someone has AIDS ?

Answer 33

when CD4 count is <200 (should be above 500)

Question 34

HIV sx ?

Answer 34

short flu like illness (2-6 weeks after infection) - headache, fatigue, ulcers in mouth/anus/genitals - red rash that doesn't itch

Question 35

which pregnant women get HIV antenatal testing ?

Answer 35

every pregnant women

Question 36

what is first line for HIV screening ?

Answer 36

HIV antibody and HIV antigen (p24 antigen)

Question 37

HIV treatment ? aim of it ?

Answer 37

try to decrease viral load (undetectable) and increase CD4 count

Question 38

what is the most common opportunistic infection in HIV ?

Answer 38

pneumocystis pneumonia (PCP)

Question 39

what is kaposis sarcoma ? caused by what pathogen ?

Answer 39

AIDs defining illness - causes by HHV 8

Question 40

what pathogen causes cold sores on the mouth ?

Answer 40

mainly HSV1

Question 41

what pathogen causes genital herpes ?

Answer 41

mainly HSV 2

Question 42

name some pathogens that cause diarrhoea without blood ? (4)

Answer 42

- norovirus - rotavirus - enterotoxigenic E.Coli - cholera

Question 43

name some pathogens that cause bloody diarrhoea ?

Answer 43

- shigella - shiva-toxin producing E.Coli (STEC) - campylobacter - salmonella

Question 44

in a bacterial eye disease, describe: the secretions ? other features ?

Answer 44

secretions: prurulent features: red and swollen

Question 45

in a viral eye disease, describe: the secretions ? other features ?

Answer 45

secretions: watery features: +/- corneal lesion

Question 46

bacterial eye disease tx ?

Answer 46

topical abx for 5 days

Question 47

viral eye disease tx ?

Answer 47

symptomatic

Question 48

chlamydial eye disease presentaiton ?

Answer 48

mucopurulent secretions - follicles + papillae on lid

Question 49

chlamydial eye disease tx ?

Answer 49

azithromycin

Question 50

what is malaria ? caused by what sort of pathogen ?

Answer 50

infectious disease caused by plasmodium family of protozoan parasites ?

Question 51

what is the most common pathogen of malaria ? most dangerous ?

Answer 51

most common and dangerous is plasmodium falciparum

Question 52

how is malaria spread ?

Answer 52

spread through bites from female anopheles mosquito

Question 53

describe the life cycle of a mosquito in terms of malaria transmission ?

Answer 53

- mosquito bite, usually at night - sporozoites lie dormant in liver - mature to merozoites + infect RBC - RBC rupture - merozoites relate into blood stream => haemolytic anaemia

Question 54

malaria px ?

Answer 54

lives or travelled to endemic area, 1-4 weeks incubation - fever, sweats, riggers, malaise, myalgia, headaches, vomiting - pallor (due to haemolytic anaemia) - hepatosplenomegaly - jaundice

Question 55

how is malaria diagnosis made ? how is dx excluded ?

Answer 55

giemsa-stained thick and thin blood smears (shows ring trophozoites) - to exclude diagnosis: 3 samples over 3 consecutive days (48 hr cycle)

Question 56

malaria mx ?

Answer 56

IV artesunate - IV fluids - blood transfusion if necessary

Question 57

falciparum complications ?

Answer 57

- cerebral malaria - siezures - reduced consciousness - AKI - DIC - death

Question 58

what can be used for malaria prophylaxis ?

Answer 58

none 100% effective - malarone - nefloquein - doxycycline

Question 59

Lyme disease Mx ?

Answer 59

oral doxycycline

Question 60

how is dengue diagnosed ?

Answer 60

PCR for virus

Question 61

what pathogen causes typhoid ? what type of pathogen

Answer 61

salmonella typhi - gram -ve bacillus

Question 62

typhoid px ?

Answer 62

- gradual onset fever, malaise, dry cough - rose spots on trunk

Question 63

important complication of typhoid ?

Answer 63

intestinal perforation => death

Question 64

what test to diagnose typhoid ?

Answer 64

- blood culture

Question 65

typed mx ?

Answer 65

- IV ceftriaxone + supportive care (IV fluids, paracetamol, isolation)

Question 66

What is infectious mononucleosis ? aka? what pathogen ?

Answer 66

kissing disease, glandular fever, mono - caused by infection with Epstein Barr virus (EBV)

Question 67

what is typical infectious mononucleosis px? presents following what ?

Answer 67

adolescent with a sore throat who develop itch rash (v v itchy) after taking amoxicillin (99% of pts with mono who take amoxicillin develop pruritic maculopapular rash)

Question 68

infectious mononucleosis presentation? (6) typical triad

Answer 68

- fever* - sore throat* - lymphadenopathy * - tonsillar enlargement - splenomegaly - fatigue

Question 69

how is infectious mononucleosis diagnosed ? (2)

Answer 69

- FBC and monospot in the 2nd week of illness

Question 70

infectious mononucleosis mx ? (3)

Answer 70

- supportive (usually self limiting: 2-3 weeks) - don't give amoxicillin - avoid playing contact sport for 4 weeks after having glandular fever to reduce risk of spenic rupture

Question 71

EBV causes what condition ? which what cancer is it associated ?

Answer 71

- EBV infection in kids is mild, subclinical - presents as infectious mononucleosis in adolescence - associated with burkitts lymphoma

Question 72

Otitis externa px? (3)

Answer 72

- ear pain - itch - discharge

Question 73

what is seen in otitis external on otoscopy ? (3)

Answer 73

- red - swollen - or eczematous canal

Question 74

otitis externa mx ? if this doesn't work ?

Answer 74

- topical abx or combine topical abx with a steroid - if pt fails to respond to topical abx then the patient should be referred to ENT