Microbiology Flashcards

1
Q

what type of organism causes gonorrhoea?

A

Neisseria gonorrhoea - obligate intracellular gram - diplococcus

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2
Q

what does gonorrhoea develop into if left untreated when transferred to child from the birth canal?

A

Opthlmia neonatorum - neonatal conjunctivitis

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3
Q

25 year old male with complement deficiency presents with tenosynovitis, dermatitis and polyarthralgia - likely diagnosis?

A

disseminated gonococcal infection (from Neisseria gonorrhoea)

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4
Q

what is the gold standard for diagnosing Gonorrhoea?

A

Culture from smears - Rectal or urethral

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5
Q

what is the difference in sensitivity when diagnosing gonorrhoea from either urethral or rectal smears?

A

urethral - 95%

rectal - 20%

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6
Q

What is the treatment for gonorrhoea?

A
  • ceftriaxone IM - 250mg single dose
    OR
    cefixime PO 400mg single dose
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7
Q

How does symptomatic gonorrhoea infection manifest in women?

A

vaginal pruritus +/- mucopurulent discharge

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8
Q

What % of gonorrhoea infections become complicated?

A

10%

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9
Q

How does complicated gonorrhoea infection manifest?

A

prostitis in men

pelvic inflammatory disease (PID)/Salpingitis

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10
Q

What is he most common cause of female infertility in europe?

A

Ascending complicated gonnorhoea infection resulting in PID / salpingitis

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11
Q

What % of chlamydia is unsymptomatic?

A

80% female

50% men

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12
Q

What organism causes chlamydia?

A

Chlamydia trachomatis - gram negative

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13
Q

what are the complications of chlamydia?

A

PID, tubal factor infertility (TFI), risk of ectopic, risk of endometriosis, chronic pelvic pain, epidydimitis, reiters syndrome, adult conjunctivitis

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14
Q

What serovars of chlamydia cause genital infection?

A

D-K

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15
Q

How do you diagnose Chlamydia?

A

NAATs (nucleic acid amplification tests)

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16
Q

Whats the Tx for uncomplicated chlamydia?

A

Azithromycin (1g) stat

doxycycline 100 mg BD 7/7

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17
Q

what is the name for lymphatic infection with Chlamydia trachomatis?

A

lympho-granuloma venereum (LGV)

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18
Q

What is the likely diagnosis when you see: painless genital ulcer, non-indurated, balanitis, proctitis (cerivcitis)?

A

Early LGV - 1st stage

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19
Q

Which serovars are responsible for LGV?

A

L1 L2 L3 Chalmydia trachomatis

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20
Q

What is the infectious agent causing syphilis?

A

Treponema pallidum - an obligate gram negative spirochaete

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21
Q

Name the nontreponemal tests for syphilis

A

VDRL slide test - detects lipoidal antibody on both host and treponemal cells
RPR (modified VDRL)

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22
Q

What are the 2 types of test for syphilis

A

Non-treponemal (RDR)

Treponemal (detects Abs from specific Treponema antigens - e.g. TPPA)

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23
Q

Tx for syphilis

A

IM benzathine penicillin (or doxycycline if allergic)

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24
Q

What tests must you do to diagnose Trichomonas vaginalis?

A

Wet prep microscopy, PCR

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25
Q

Tx for trichomoniasis vaginalis?

A

Metronidazole

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26
Q

How is BV diagnosed?

A
  • microscopy of gram stain
  • whiff test
  • raised pH (more alkaline as vagina is naturally quite acidic)
  • clue cells (epithelial cells coated with bacteria)
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27
Q

What is the Tx for Hep B infection?

A
  • vaccine
  • antivirals = interferon alpha
    direct acting antivirals (DAAs)
    tenofivir, entecavir,emtrictabine (esp with HIV infection)
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28
Q

What 5 tests would you do if you suspect hep C infection/.

A
Hep C antibodies (via immunoassay or recombinant immunoassay (RIBA) 
NAATs
LFTs - ALT probably raised
viral genotype
transient elastography
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29
Q

Tx for Hep C?

A
  • may have spontanous eradication (45% patients)

- sofosbuvir therapy + velpatasvir

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30
Q

what is the difference between bacteriuria and cystitis?

A

bacteriuria = presence of bacteria in the urine - not necessarily a problem!

cystitis = inflammation of the bladder, often caused by infection

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31
Q

what are the proper terms for lower and upper urinary tract infections?

A
upper = pyelonephritis 
lower = cystitis
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32
Q

what is the prevalence of women experiencing a UTI in their lifetime?

A

40-50%

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33
Q

What is the most common organism causing UTI?

A

E. coli (95%)

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34
Q

what is the 2nd most common cause of UTIs in young women?

A

Staph. saprophyticus

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35
Q

Which organism is commonly present in UTIs involving calculi/stones?

A

Proteus mirabilis

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36
Q

What are the 3 host defences against UTIs?

A
  1. urine (pH, osmolality)
  2. urine flow
  3. urinary tract mucosa
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37
Q

What is a specific risk factor for bacterial infection of the bladder in children resulting in pyelonephritis and possibly renal scarring?

A

urinary tract defects such as vesicoureteral reflux (retrograde flow of urine from bladder into kidneys)

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38
Q

what are 4 examples of neurogenic causes of bladder outflow obstruction?

A

diabetic neuropathy
polio
spinal cord injury
tabes dorsalis (untreated syphilis)

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39
Q

what is an organism which can cause UTIs and abscesses via the haematogenous route? (ie bacteraemia & seeding in the kidneys)

A

Staph. aureus

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40
Q

what are the classic features of UTI infection?

A

abdominal / flank pain
dysuria
frequency

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41
Q

what type of organism are rigors typically associated with?

A

gram negative bacteria

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42
Q

What investigations should you do for a suspected UTI?

A
  1. urine dipstick
  2. MSU for urine microscopy, culture and sensitivities
  3. Bloods - FBC, UE, CRP (inflammatory markers and renal function) if suspect pyelonephritis or more severe

COMPLICATED

  1. Renal USS
  2. IV urography
    - to look at structure/flow of urine
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43
Q

What positive test in a urine dispstick indicates the likely presence of coliform bacteria?

A

Nitrites (coliform bacteria have an enzyme that converts nitrates to nitrites)

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44
Q

why are pregnant women particularly vulnerable to UTIs?

A

outflow obstruction due to gravid uterus

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45
Q

what are squamous epithelial cells on a urine microscopy usually indicative of?

A

contamination.

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46
Q

what does a urine sample with <10^5 cfu/mL indicate?

A

No infection

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47
Q

What is the general threshold for cfu/mL in the bladder for indicating a urine infection?

A

> 10^5 cfu/mL (colony forming unit)

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48
Q

what is the empirical therapy for UTIs in the community?

A

Trimethoprim

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49
Q

What is the resitance level of trimethoprim?

A

40%

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50
Q

what is the common empirical treatment for UTIs in hospitals?

A

NOT trimethoprim due to resistance

SO cefalexin

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51
Q

What is the Tx for catheter associated UTIs?

A
  • remove the catheter (due to biofilm buildup and intro of organisms)
  • gentamycin
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52
Q

What is the Tx for pyelonephritis?

A

antibiotics:

co-amoxiclav + aminoglycoside (gentamycin

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53
Q

In men, what investigation should be done in pyelonephtitis?

A

USS - to look for structural problems perhaps causing obstruction

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54
Q

What are 4 complications of UTIs?

A
  • perinephric abscess
  • chronic pyelonephritis due to scarring
  • septic shock
  • acute papillary necrosis
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55
Q

why would you never use nitrofurantoin in catheter patients?

A

because it concentrates in the patient’s bladder - catheter drains continuously.

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56
Q

When should you advise patients to take nitorfurantoin tablets to Tx a UTI?

A

after they have just voided their bladder - it concs in thebladder so no point taking and then emptying bladder - wont clear

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57
Q

The presence of what would indicate a poorly taken urine sample

A

squamous epithelial cells

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58
Q

what is the difference between treponemal and non trepoemal tests for syphilis?

A

non-treponemal = detect biomarkers that are released during the cellular damage occuring from syphilis’ spirochete - Ab that reacto to cardiolipin

treponemal = antibodies: IgG IgM and IgA

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59
Q

What is the drawback of nontreponemal tests?

A

decreased sensitivity in early primary syphilis and late latent - and false positive reactions due to other infections

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60
Q

What is the likely cause of diarrhoea when the symptoms develop within 2-7 hours?

A

Staph aureus

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61
Q

What is the likely causative organism in a patient who had a chicken bbq at the weekend and has florrid diarrhoea at the end of the week?

A

campylobacter

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62
Q

What is the likey causative organism in a pt who presents with diarrhoea symptoms 24h after eating some prawns?

A

Vibrio parahaemolytics

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63
Q

what does a staphylococcal enterotoxin (SE) superantigen bind to?

A

directly to T cell receptrs ad MHC molecules (outside the peptide binding site)

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64
Q

what organism produces enterotoxin which can act as a superantigen in the GI tract

A

Staph. aureus

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65
Q

what does Staph aureus enterotoxin in the GI tract cause the release of, and what symptoms does this cause

A

IL1 and IL2

vomiting 
watery diarrhouea (non bloody)
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66
Q

how do you trea Staph aureus food poisoning?

A

Fluid resus

not Abx as its a pre formed toxin!

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67
Q

what organism is assocated with food poisoning from reheated fried rice?

A

Bacillus cereus

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68
Q

Why does heating rice not kill B. cereus?

A

very heat stable emetic toxin

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69
Q

What symptoms does Bacillus cereus infection cause (including 2 serious complications?)

A

watery non bloody diarrhoea - self limited

bacteraemia
cerebral abcess

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70
Q

What organism is associated with honey and infants?

A

Clostridium botulinum - which is a preformed toxin which causes botulism

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71
Q

where organism is normal flora of the colon but not the small bowel, resulting in food poisoning from reheated meat?

A

Clostridium pefringens

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72
Q

which bacteria causes pseudomembranous colitis after cephalosporin treatment?

A

Clostridium Difficile

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73
Q

What is the treatment plan for a patient with active diarrhoea C. diff

A

side room
stop offending antibiotics
metronidazole and vancomycin

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74
Q

what is a beta haemolytic organism which is aesculin positive and has tumbling motility?

A

Listeria monocytogenes

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75
Q

Treatment for Listeria infection?

A

ampicillin

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76
Q

which parts of the colon does E. coli eterotoxins act on?

A

ileum and jejunum but not on large bowel

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77
Q

Give the 4 types of E. coli

A
  1. ETEC (E. coli enterotoxigenic)
  2. EPEC (pathogenic)
  3. EIEC (invasive)
  4. EHEC 0157 (haemorrhagic)
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78
Q

which type of E. coli can cause HUS?

A

EHEC - E. coli 0157

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79
Q

What are the 3 antigens found on Salmonellae species?

A
O = cell wall 
H = flagellum 
Vi  = capsular, virulence, antiphagocytic
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80
Q

give the 3 species of salmonellae

A
  1. S. Typhi
  2. S. enteriditis
  3. S. cholerasuis
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81
Q

What kind of bacteria are non lactose fermenters, H2S producers

A

Salmonellae

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82
Q

give 2 characteristics of S. typhi

A

constipation, splenomegaly, rose spots, Blood culture positive, anaemia, leucopenia

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83
Q

what organisms causes dysentry and is the most effective enteric pathogen - only needing an infective dose of 50

A

Shigellae

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84
Q

which group of vibrios causes epidemics?

A

group 01

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85
Q

what organism is transmitted by contaminated water and human faeces - shellfish, oysters, shrimp, and causes massive volume of rice water stool

A

Vibrio cholerae

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86
Q

what type of agar is required to grow Vibrio parahaemolyticus

A

Salty 8.5% NaCl

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87
Q

What organism causes cellulitis in shellfish handlers?

A

Vibrio vulnificus

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88
Q

How do you treat Vibrio vulnificus?

A

doxycycline

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89
Q

what organisms do you need special oxygen deplete jars to grow?

A

Campylobacter - microaerophilic

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90
Q

when would you treat campylobacter and how?

A

If immunocompromised - with a macrolide

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91
Q

how is campylobacter transmitted?

A

contaminated food & water with animal faeces

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92
Q

classic signs of campylobacter infection

A

watery foul smelling diarrhoea bloody stool, severe abdo pain

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93
Q

What are 3 complications of campylobacter infection?

A

Guillan Barre Syndrome (GBS)
Reiters
Reactive arthritis

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94
Q

what organism is known to cause acute diarrhoea, enterocolitis, mesenteric adenitis, and transmitted via food contaminated with domestic animal faeces

A

Yersinia enterelytica

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95
Q

name a protozoan organisms that causes infections on camping holidays when water isnt boiled

A

entamoeba histolytica

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96
Q

how do you treat entamoeba histolytica infection?

A

metronidazole + paromomycin in luminal disease

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97
Q

How does one become infected with Giardia lamblia?

A

ingestion of cysts from faecally contaminated water/food

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98
Q

how is Giardia lamblia diagnosed

A

stool micro
ELISA
string test

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99
Q

what 3 groups tend to be a risk of Giardia lamblia?

A

MSM
Mental patients
travellers/hikers

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100
Q

What type of microorganism is Giardia lamblia?

A

Protozoa

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101
Q

Why is norovirus so prone to outbreaks?

A

Very low infectious dose (18-1000)
Robust environmental resilience (0-60 deg.C)
No immunity long term

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102
Q

What viruses cause diarrhoea?

A
Norovirus 
Rotavirus 
Adenovirus 
Poliovirus 
Enteroviruses (coxsackie, ECHO) 
Hep A
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103
Q

Which strains of adenovirus can cause non bloody diarrhoea in children <2 years?

A

types 40 + 41

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104
Q

which types of cholera can you vaccinate against?

A

01 and 0139

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105
Q

What vaccinations vs rotavirus are there?

A

Rotarix - live attenuated (2 doses)

Rotateq

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106
Q

give 4 viruses we worry about when thinking about intrauterine viral infection?

A

Rubella, CMV, Parvovirus B19, VZV (also HSV, HIV, Hep B)

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107
Q

which 2 viral infections are we concerned about perinatally?

A

Herpes, VZV

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108
Q

What is the classic presentation of a child with parvovirus B19 at the end of infection?

A

slapped cheek syndrome - erythema infectiosum

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109
Q

why is screening for Rubella not offered in pregnancy?

A
  • vey rare now in UK due to MMR vaccine
  • also if there is infection, not much you can do as cannot offer vaccine - as it is a live vaccine - little intervention
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110
Q

what is the incubation period of CMV?

A

4-8 weeks

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111
Q

main transmission route of CMV?

A

saliva

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112
Q

what is the main congenital infectious cause of profound sensorineural hearing loss?

A

CMV (accounts for 10-15%)

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113
Q

Give some factors which can increase the risk of perinatal HSV infection?

A
  • recent maternal infection
  • mode of delivery
  • use of scalp monitors during delivery
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114
Q

a what point is HSV most commonly acquired periatally?

A

75-85% at delivery during birth canal exposure

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115
Q

What are the 3 clinical presentations of neonatal herpes?

A
  1. SEM disease –> limited to skin, eyes, mouth
  2. CNS disease - encepalopathy
  3. Disseminated disease - Sepsis, organ involvement, vesicular rash
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116
Q

What is the Tx of neonatal herpes infection?

A

IV aciclovir

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117
Q

what is the infectious period for Chicken pox?

A

2 days before appearance of rash –> when vesicles have crusted / are dry

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118
Q

what is the worry if a mother contracts VSV duringthe 1st 20 weeks of pregancy?

A

risk of congenital varicella syndrome

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119
Q

which infection do you get koplik spots?

A

Measles

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120
Q

what are the complications of measles

A
opportunistic bacterial infections 
otitis media
pneumonia 
bronchitis 
encephalitis 
subacute sclerosing pan encephalitis (SSPE)
121
Q

What should happen if a pregnant woman comes into contact with suspected measles

A

Can give human immunoglobulin to attenuate the illness

122
Q

How long is someone infective with measles?

A

4 days before and 4 days after the appearance of the rash

123
Q

26 week pregnant patient has developed chicken pox 2 days ago - what is the treatment?

A

aciclovir

124
Q

what virology Ix would you advise in a mother who has foetal microcephaly on USS?

A

CMV and Rubella serology

HSV rarely transmitted in utero so less likely than these 2

125
Q

what are the major transmission routes of CMV?

A

saliva, intrauterine (infected maternal secretions, breast milk), sex, blood transfusion, organ transplant

126
Q

what type of virus is zika?

A

Flavivirus

127
Q

what is the incubation period for Zika virus?

A

3-12 days (no more than 2 weeks - so if symptoms develop 2 weeks post returning from danger area, will not be Zika)

128
Q

what are the 3 most common causes of bone/joint infection?

A
  1. Staph aureus
  2. E. coli
  3. Pseudomonas aeruginosa
129
Q

What are the 3 levels of SSI/

A
  1. superficial incisional
  2. deep incisional (fascial and muscle layers)
  3. organ/space infection
130
Q

Why is obesity a risk factor for infection in surgery?

A
  • adipose tissue poorly vascularised, so poor oxygenation and functioning of the immune response = increased risk of SSI
131
Q

What is the biggest risk for SSI following cardiothoracic surgery/

A

S. aureus carriage in nares (20-30% people carry it)

132
Q

Why can hypothermia increase the risk of SSIs?

A

causes vasoconstriction, resulting in decreased delivery of oxygen to wound space and subsequent impairment of neutrophil function

133
Q

give 3 routes of viral infection in a transplant patient

A
  1. virus from the graft
  2. viral reactivation from the host
  3. novel infection from infected individual
134
Q

which antibodies indicate chronic and acute infection?

A
chronic = IgG
acute = IgM

(remember IgM = IMmediately and IgG= aGes)

135
Q

where does CMV remain latent?

A

B lymphocytes

136
Q

where does EBV remain latent in the body? (2 sites)

A

leucocytes & epithelial cells

137
Q

which herpes viruses remain latent in the sensory nerve ganglia?

A

HSV1 HSV2 VZV

138
Q

where does HHV8 remain latent

A

epithelial cells

139
Q

where do HSV1 and HSV2 remain latent?

A

in the sensory nerve ganglia

140
Q

what are the complications of VZV infection in immunocompromised patients?

A
  1. bacterial superinfection
  2. bullous/haemorrhagic skin lesions - purpura fulminans
  3. visceral involvement - pneumonitis, hepatitis
141
Q

If an immunocompromise patient appears to have VZV skin lesions with no dermatomal distribution - what is this called and what is the risk?

A

Atypical generalised zoster

risk of visceral involvement

142
Q

What is the firt linke treatment for HSV and VSV infection?

A

Aciclovir

143
Q

What is the basic action of Aciclovir against HSV?

A

potent inhibitor of HSV encoded DNA polymerase

144
Q

After aciclovir, what is the 2nd line drug you would use to treat HSV?

A

Valaciclovir

145
Q

What is the other name for HSV4?

A

Epstein Barr Virus (EBV)

146
Q

What is the general name for the acute infection of EBV?

A

Infectious mononucleosis

147
Q

What is the treatment plan for someone with suspected post transplant lymphoproliferative disease? (PTLD)

A

Rituximab (CD-20 (a B cell marker) monoclonal antibody therapy)

148
Q

What is the biggest risk (in terms of donor and recipient status) for a lung transplant patient when thinking about CMV endogenous reactivation?

A

D+ R-

149
Q

What is the biggest risk (in terms of donor and recipient status) for a Bone Marrow transplant patient when thinking about CMV endogenous reactivation?

A

D- R+

150
Q

what are the 2 types of antibiotics which inhibit cell wall synthesis?

A
  1. beta-lactams (penicillins, cephalosporins and carbapenems)
  2. glycopeptides (vancomycin and teicoplanin)
151
Q

what is the target of beta lactam antibiotics?

A

transpeptidase enzymes (involved in synthesis of peptidoglycan cell wall)

152
Q

what is co-amoxiclav made of and what is the purpose of the combination>

A

amoxicillin + clavulanic acid. The clavulanic acid is beta-lactamase inhibitor - so protects the amoxicillin from being broken down by b lactamase produced by bacteria like S. aureus

153
Q

What are two types of glycopeptides?

A

vancomycin and teicoplanin

154
Q

What is the mechansm of action of glycopeptide antibiotics?

A

target cell wall synthesis

155
Q

Which b-lactam antibiotics are ESBL stable?

A

carbapenems

156
Q

What are ESBL infections?

A

extended spectrum beta lactamase producing organisms- resistant to all cephalosporins as well as penicillins

157
Q

what is a) IV b) oral vancomycin commonly used to treat

A

a) MRSA

b) C. diff

158
Q

What do aminoglycosides bind to?

A

the amino-acyl site of the 30s ribosomal subunit

remember: a Gentleman in his 30s called amino went deaf due to the pseudoscience of snorting grams of neg and protein

159
Q

What is the mechanism of action of aminoglycosides?

A

They bind to the 30S ribosomal subunit of bacteria, preventing elongation of the polypeptide chain and causing misreading of codons along the RNA - thereby inhibiting protein synthesis

160
Q

What are two negative side effects of aminoglycosides?

A

ototoxic and nephrotoxic so levels must be monitored

161
Q

What is a common example of an aminoglycoside antibiotic?

A

Gentamycin

162
Q

What are the 5 types of antibiotics which are protein synthesis inhibitors?

A

ATOMC

aminoglycosides 
Tetracyclines 
Oxyzolidinones 
Macrolides
Chloramphenicol
163
Q

what is the mechanism of action of macrolide Abx?

A

they bind to the ribosomal 50s subunit, interfering with translocation and stimulation dissociation of peptidyl tRNA

164
Q

What is the mechanism of action of chloramphenicol eye drops?

A

binds to 50s ribosomal subunit, inhibiting protein synthesis

165
Q

Why is chloramphenicol rarely used despite its very broad action

A

risk of aplastic anaemia and grey baby syndrome in neonates

166
Q

which protein synthesis inhibiting antibiotic is used as eye drops commonly?

A

chloramphenicol

167
Q

give the example of an oxazolidinone abx

A

Linezolid

168
Q

What gram type is linezolid very active against?

A

Gram + e.g. MRSA

169
Q

What are the 2 types of antibiotics which inhibit DNA synthesis?

A

fluoroquinolones and nitromidazoles

170
Q

What is the mechanism of action of ciprofloxacin?

A

it’s a fluoroquinolone so a DNA synthesis inhibitor - acts on the alpha-subunit of DNA gyrase

171
Q

What antibiotics inhibit RNA synthesis?

A

Rifamycins eg rifampicin

172
Q

what does the antibiotic linezolid bind to

A

the 23s component of the 50s subunit

173
Q

What is co-trimoxazole useful for treating?

A

PCP

174
Q

what are the four mechanisms of antibiotic resistance?

A
BEAT 
Bypass the antibiotic sensitive step 
Enzyme mediated
Accumulation inhibition (either by enhancing efflux or impaired uptake) 
Target modification
175
Q

what is the mutation in MRSA which makes it so resistant to beta-lactams?

A

it modifies the target - the mecA gene codes for a new Penicillin binding protein which has a low affinity for beta lactams - therefore survives

176
Q

what does MRSA stand for?

A

methicillin resistant staph. aureus

177
Q

What Abx should you use in mild CAP?

A

amoxicillin

178
Q

what Abx should you use for severe CAP?

A

co-amoxiclav + clarithromycin (covers atypicals)

179
Q

what Abx should you use for HAP?

A

tazocin or amoxicillin + gentamycin

180
Q

what are the components of tazocin?

A

piperacillin - a penicillin with extended beta lactamase coverage and pseudomonas, + tazobactam which is a beta lactamase inhibitor

181
Q

what Abx should you use for nosocomial UTIs?

A

co-amoxiclav or cephalexin

182
Q

What triad of abx should you usually use for severe sepsis?

A

tazocin/ceftriaxone and metronidaxole +/- gentamycin

183
Q

What abx should you use for C. diff colitis?

A

metronidazole PO

184
Q

Which antibiotic can cause grey baby syndrome?

A

chloramphenicol

185
Q

What is grey baby syndrome and how can you treat?

A

Due to the accumulation of chloramphenicol antibiotic in neonates as they lack the liver enzymes required to metabolise it - resulting in reduced electron transport in liver myocardium and skeletal muscle. may need exchange transfusion

186
Q

What type of flu is H5N1

A

Bird flu

187
Q

What are the 3 antigenically distinct types of influenza that tend to strike humans every year?

A
Influenza A (H1) - Jan 
Influenza A (H1N1) - Dec 
Influenza B - March
188
Q

the loss of which gene is associated with a more severe influenza infection?

A

IFITM3

189
Q

what is the mutation making influenza A resistant to the antiviral treatment amantadine

A

a single amino acid mutation in the M2 ion channel –> S31N

190
Q

how are oseltamivir, zanamivir (relenza) and peramivir adminisrated?

A
O= oral 
Z = inhaled 
P = IV
191
Q

what is Tamiflu?

A

an antiviral drug for influenza - oseltamivir

192
Q

what antiviral treatments are available for influenza

A

amantadine

neuraminidase

193
Q

What are the 2 most common organisms causing hospital acquired UTI

A

E. coli and Klebsiella

194
Q

which antibiotics predispose patients in hospital to acquiring C. diff?

A

3 Cs
Clindamycin
Cefalosporins
Ciprofloxacin

195
Q

what are he 3 types of non tuberculosis mycobacteria (NTM) that can infect humans?

A

M. aviam intracellulare
M. marinum
M. ulcerans

196
Q

What is the likely diagnosis - patient in A&E with multiple superficial papules on his hands, is an aquarium cleaner

A

Mycobacterium Marinum

197
Q

describe features of extra-pulmonary TB

A
  • lymphadenitis (aka scrofula)
  • GI
  • peritoneal
  • genitourinary - slow progression to renal disease and lower urnary tract
  • bones and joints - spinal tb, Pott’s disease
198
Q

What investigations should you consider if you suspect TB?

A

imaging - CXR to look for caseation esp in upper lobes. can do a CT.

Tuberculin skin test to see if primary infection has occurred.

Culture - sputum (x3) and can do bronchioalveolar lavage. Microscopy: gram + rods, acid fast, intracellular, aerobic.

IGRA - interferon-gamma release assay: measures release of interferon gamma on exposure to antigen

NAAT - CR probe assay

Jenson medium is the gold standard but takes about 4 weeks for results

199
Q

when diagnosing TB how many repeats of the sputum culture should you do?

A

3

200
Q

what are the 1st ine meds for TB treatment?

A
RIPE 
Rifampicin 
Isoniazid 
Pyrazinamide 
Ethambutol
201
Q

what should you prescribe alongside isoniazid and why?

A

To prevent peripheral neuropathy - give vitamin B6 pyrodoxine

202
Q

Which viruses are responsible for 8090% cases of aseptic meningitis?

A

Enteroviruses e.g. Coxsackieviruses and echoviruses

203
Q

which virus i becoming the leading cause of encephlitis internationally?

A

West Nile Virus

204
Q

out of the the most common bacterial causes of meningitis, which one is Gram - cocci and which one is gram + cocci?

A

Neisseria meningitides = gram negative

Strep. pneumoniae = gram +

205
Q

Which bacteria are more commonly causes of meningitis in the elderly and neonates?

A

Group B strep and Listeria monocytogenes

206
Q

Treatment for meningitis?

A

Ceftriaxone 2g IV bd

+ amoxicillin if >50 or immunocompromised

207
Q

Tx for meningoencephalitis?

A

Aciclovir 10mg/kg tds
Ceftriaxone 2g iv BD
+ amoxicillin if >50 or immunocompromised (2g IV 4hourly)

208
Q

What is the likely diagnosis from these CSF results: Slightly turbid, high WCC mainly monocytes, high protein,

A

TB meningitis / cryptococcal

209
Q

What is the likely diagnosis from these CSF results:Glucose normal, WCC high with polymorphs

A

partially treated bacterial meningitis

210
Q

What is the likely diagnosis from these CSF results: normal glucose, high WCC mononuclear cells, normal protein

A

Aseptic meningitis (vira)

211
Q

The antiviral which is given to untreated pregnant women with HIV to prevent vertical transmission of the virus during childbirth.

A

Nevirapine - has been shown to be more effectve than zidovidine

(NEVER give the baby HIV)

212
Q

An antiviral which can be used in aerosol form to prevent respiratory syncytial virus in children with heart and lung disease

A

Ribavirin

aerosol spray to prevent RSV smells like RIBS

213
Q

The drug which can be delivered by inhalation to treat both influenza A and B.

A

zanamivir

214
Q

A forty year old ornithologist presents with malaise, muscular pains and a cough. On examination he has a fever and several distinctive rose spots on his abdomen. Chest x-ray reveals a diffuse pneumonia.

A

Parrot fever - psittacosis

parrott in a pitta - cosis

215
Q

The final metabolite of the antiviral used to treat Herpes Simplex

A

Aciclovir triphosphate

216
Q

The synthetic nucleoside analogue ganciclovir is the drug of choice against which infective virus?

A

CMV

217
Q

how to NRTIs and NNRTIS differ in their modes of action?

A

NRTIs - nucleoside reverse transcriptase inhibitors - are analogues of deoxynucleotides needed for DNA synthesis - so they competitive fr incorporation into growing strand, but as they lack a 3’ hydroxyl group they cause chain termination.

NNRTIs - non-nucleoside reverse transcriptase inihbitors work by completely different mechanism - they bind directly to the enzyme, preventing DNA synthesis and therefore are non-competitive inhibitors.

218
Q

what is the main side effect of NRTIs?

A

lactic acidosis

219
Q

What are the 5 most important cytochrome p450 substrates

A
  1. Warfarin
  2. Anti-epileptic drugs
  3. OCP and prednisolone
  4. Ciclosporin A, Tacrolimus
  5. NNRTIs and PIs
220
Q

Which are painful out of Janeway lesions and Oslers nodes?

A
Oslers = painful nodular 
Janeway = painless haemorrhagic
221
Q

Which part of the heart is most commonly affected in infective endocarditis of an IVDU?

A

Tricuspid valve (52%)

222
Q

what is the name of the Criteria for diagnosing infective endocarditis?

A

Duke’s criteria

223
Q

What are the major and minor criteria for diagnosing infective endocarditis?

A

DUKES CRITERIA

Major:

  • Echo shows vegetation
  • Blood culture repeatedly + for suspicious organisms such as Strep Viridans and S. aureus
  • Persistent bacteraemia

Minor

  • predisposing heart condition or IVDU
  • Fever >38
  • signs of immune complex formation e.g. glomerulonephritis, splinter haemorrhages
  • signs of vascular phenomena -septic emboli janeway lesions and oslers nodes
  • blood cultures
  • echo sugestive
224
Q

what are the most common organisms causing Infectious endocarditis?

A

Strep. Viridans
Enterococci
S. aureus

225
Q

What is the antibiotic regimen for infective endocarditis caused by Strep. Viridans?

A

Benzopenicillin + Gentamycin

226
Q

What are classic examples of Gram negative bacilli?

A
E. coli 
Shigella 
Klebsiella 
Yersinia 
-
227
Q

What is the treatment for enterococcal infective endocarditis

A

ampicillin + gentamycin

228
Q

treatment for MSSA endocarditis?

A

Fluclox for 4 weeks and moitor for abscesses refer to cardio

229
Q

treatment for MRSA endocarditis

A

vancomycin + gent/rifampicin/fucidin

230
Q

what are the indications for surgery in infective endocarditis?

A
  1. severe valvular dysfunction
  2. congestive heart failure
  3. 1+ septic emboli
  4. unresponsive to Abx
  5. perivalvular abscess
  6. uncontrolled infection
231
Q

What are some complications of Brucellosis?

A

osteomyelitis, endocarditis, meningoencephalitis

232
Q

How do you treat Brucellosis?

A

Oral doxycycline + rifampicin for 8 weeks

233
Q

What are Negri Bodies and what are they pathognomic for?

A

eosinophilic, sharply outlined, pathognomic inclusion bodies found in nerve cells infected with Rabies virus

234
Q

What is he organism causing the plague

A

yersinia pestis - a gram negative lactose fermenter

235
Q

how do you diagnose plague?

A

molecular methods - PCR

236
Q

What is the treatment for infection with yersinia pestis?

A

doxycycline, streptomycin, gentamycin, chloramphencol (meningitis)

237
Q

what are the early, early disseminated and late symptoms of lyme borreliosis?

A

early: cyclical fevers, non-specific flu like symptoms, erythema migrans (bulls eye rash)

Early disseminated - malaise, lymphadenopathy, hepatits, carditis, arthritis

late: focal neurology, neuropsychiatric disturbance, ACA - acrodermatitis chonic atrophicans, encephalopathy

238
Q

What is the vector in lyme borreliosis?

A

Ixodes ticks

239
Q

what infection is acrodermatitis chronic atrophicans associated with

A

Lyme Borreliosis

240
Q

what is the name of the bullseye rash associated with early focal lyme disease?

A

Erythema chronicum migrans (or just erythema migrans)

241
Q

what is the chronic fibrotic skin condition associated with late lyme borreliosis?

A

Acrodermatitis chronicum atrophicans

242
Q

How do you diagnose Lyme disease?

A

Biopsy at the edge of the erythema migrans if possible and ELISA for anti-lyme antibodies.

243
Q

Treatment fo lymes disease?

A

3 weeks doxycycline, or IV ceftriaxone if CNS symptomes

244
Q

which types of leishmania cause Visceral leishmania aka Kala-azar

A

L. infantum and L. donovani

245
Q

what is the vector for leishmania/

A

Sand fly

246
Q

which herpes type causes encephalitis?

A

HSV-1 (remember 1 brain)

247
Q

What are the complications of chicken pox?

A

Pneumonitis, scarring, Reye’s syndrome, haemorrhage, eye involvement, encephalitis

Can get neurological complications - Guillan-Barre, acute cerebellar ataxia, facial palsy

248
Q

What skin test should you do to diagnose VZV chicken pox?

A

Tzanck smear - get scrapings looking for multinucleated giant cells called Tzanck cells

249
Q

what can you give to help alleviate itch in children with chicken pox?

A

chlorphenamine if >1 year old

or calamine topical lotion

250
Q

What should you advise parents with a child with chicken pox about infecting others?

A

Most infective 2 days before the rash started, but then remains infective until the lesions crust over so should stay off school until that has happened. Should also avoid anyone who is immunocompromised, pregnant women and children under 4 weeks old.

251
Q

what are 3 encapsulated organisms you should worry about in a splenomectomy patient with respiratory symptoms?

A

H. influenza, S. pneumonia, N. meningitides - remember SHiN

- should offer vaccinations to these paients

252
Q

which organisms should you worry about in Cystic fibrosis patients?

A

Pseudomonas aeringinosa, Burkholderia cepacia, Staph aureus, MRSA

253
Q

What are the most common pathogens causing pneumonia in infants 0-1 month old?

A

GBS, E. Coli, Listeria

think birth canal

254
Q

What are the most common pathogens causing pneumonia in infants 1 month-6 months

A

chlamydia trachomitis, RSV, S. aureus

255
Q

What are the most common pathogens causing pneumonia in 6 months-5 years

A

mycoplasma, influenza

256
Q

Whatt is the likely organism: 65 year old man presenting with SOB, low sats 91%, confusion, bilateral interstitial changes, Chest exam normal, Hyponatraemia

A

Legionella pneumophilia - remember low sodium in legionella and sometimes hepatitis

257
Q

how do you diagnose Legionella pneumophilia

A

Clinical picture
antigen in urine/serum
+ special culture on buffered charcoal yeast extract

258
Q

what symptoms/signs is legionella pneumonia associated with?

A

SOB, fevers, confusion, hyponatraemia, abdo pain, diarrhoea,

259
Q

What vacinnes are available for pneumonia in high risk groups?

A

pneumococcal vaccine: PCV available for children uunder 2 years old, and the PPV available for over 65s

also influenza vaccine - offered to children and people at high risk e.g. healthcre workeers

260
Q

Treatment for PCP

A

Co-trimoxazole

261
Q

For which pneumonia organisms are there urine antigen tests available?

A

Strep. pneumonia

Legionella

262
Q

first line Tx for HAP

A

ciprofloxacin +/- vancomycin

263
Q

what is the other name for co-amoxiclav

A

augmentin

264
Q

what is the pathogen responsible for athletes foot, ringworm and fungal infection of the nail

A

Tinea - trichophytum rubrum

265
Q

What is ringworm caused by

A

Fungal infection e.g. with Trichophyton

266
Q

what organisms causes pityriasis versicolour?

A

Melassazia fungus

267
Q

What does Melassazia fungus cause?

A

Seborrhoeic dermatitis, cradle cap, P. versicolour.

268
Q

What test would you do to diagnose invasive candida?

A

Anti-mannan antibodies

269
Q

likely diagnosis in a neutropenic patient with fever, pleuritic chest pain and haemoptysis

A

Aspergillosis

270
Q

What dignostic investigation would you do in a HIV patient with insidious meningitis?

A

serum or CSF cryptococcal antigen

271
Q

What would you use to treat cryptococcal meningigtis?

A

Amphotericin B

272
Q

What is the most common human prion disease?

A

Creutzfelt-Jakob disese (CJD) - sporadic, 80% prion diseases

273
Q

What are the five types of human prion diseases known?

A
  1. creutzfelt-Jakob disease (CJD)
  2. variant CJD (OR iatrogenic CJD)
  3. KURU
  4. Familial fatal insomnia
  5. Gerstmann-Straussler-sheinker syndrome (GSS)
274
Q

What are the genetic elements of human prion disease

A

PrP gene is on chromosome 20 - mutations in the PRNP are associated with the inherited prion diseases
Also codon 129 polymorphisms (MM or methionie-methionine) are linked

275
Q

What might triphasic changes on an EEG, and basal ganglia highlights on an MRI in a patient with progressve dementia indicate?

A

CJD

276
Q

Which of these is NOT true of CJD

a) Median survival time is <6 months
b) Tonsillar biopsy is diagnostic
c) EEG usually shows periodic complexes
d) Mean age of onset is 65 years old
e) CSF markers (S100, 14-3-3) of neuronal damage may be elevated

A

b) - tonsilar biopsy is not helpful

277
Q

What might the ‘pulvinar sign’ on an MRI indicate?

A

vCJD

278
Q

What is the diagnostic test for vCJD?

A

tonsilar biopsy - 100% specific and sensitive

279
Q

Treatment for bacterial meningitis in young child?

A

Ceftriaxone and corticosteroids (+ampiccilin to cover listeria)

280
Q

What score can you use to assess prognosis in meningitis?

A

Glasgow meningococcal septicaemia prognostic score

281
Q

treatment for meningoencephalitis?

A

aciclovir + ceftriaxone

282
Q

transmission of hep A, hep B and Hep C?

A

faeco-oral

283
Q

Incubation period for Hep A is:

A

2-6 weeks (v short compares to the others)

284
Q

How do you diagnose Hep A?

A

Anti-HAV- IgM antibodies if its a very recent infection/vaccine
OR
Anti-HAV-IgG antibodies if a previous infection/vaccine

285
Q

What is the management of Hep A

A

Supportive - often resolves sponataneously in 2 months.

  • can have painkillers to treat aches and pains
  • cool ventilated no hot baths to stop itching
  • avoid alcohol, more strain on liver
  • stay off school/work for at least a week after symptoms started and avoid sex
  • good hygiene
286
Q

Who is at increased risk of Hepatitis A infecton?

A

MSM
Travellers (to areas of poor sanitation)
IVDU
Occupational e.g. healthcare/sewage workers

287
Q

What are the odds of having severe liver complications from Hep A?

A

rare - 1 in 250

288
Q

What is the incubation for Hep B?

A

2-6 months

289
Q

What serology markers would tell you that someone is immune from Hep B?

A

Negative HBsAg
positive HBsAb
postive HBeAb

290
Q

Treatment of chronic Hep B infection?

A

pegylated IFN alpha 2b

lamivudine

291
Q

What are the major complications of chronic HepB infection?

A

hepatocellular carcinoma

Liver cirrhosis

292
Q

What is the main test for Heb B infection?

A

HBVsAg

293
Q

What other tests should you consider if a patient is HBVsAg positive?

A
  • HBVeAg
  • HBV DNA level
  • IgM antibody to Hep B core antigen
  • HepC virus antibody
  • HIV antibody
  • IgG to Hep A
    =- ALT AST GGT serum albumin, total bilirubin, total globulins, FBC and PTT
  • test for hepatocellular cacinoma e.g. hepatic ultrasound and alpha-fetoprotein testing
294
Q

What are signs of decompensated liver disease?

A

encephalopathy, ascites, GI haemorhage

295
Q

What are the incubation times for Hep A, Hep B and Heb C?

A

Hep A- 2-6 weeks
Heb B- 2-6 Months
Hep C- 6-9 weeks

Remember: i”m 26 + 69

296
Q

What proportion of hep C patients will develop chronic infection?

A

60-80%

297
Q

Side effects of interferon alpha

A

flu-like symptoms, depression, fatigue, leukopenia, thrombocytopenia

298
Q

Treatment of HEP C

A

pegylates IFN alpha 2b + ribavarin + protease inhibitor

299
Q

What is the TORCH screen

A

screen for congenital infections

Toxoplasmosis
Other (HIV, Hep B/C) 
Rubella 
CMV 
HSv