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ID / GUM 7.5 Flashcards

1
Q

What is amoebiasis caused by?

What does it cause?

A
  • Entamoeba histolytica (amoeboid protozoan)
  • spread by faeco-oral
  • 10% world chronically infected
  • can be aSx, mild diarrhoea or severe dysentery
  • liver & colonic abscesses
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2
Q

Sx of amoebic dysentery?
what is shown on stool microscopy?
Rx?

A
  • profuse, bloody diarrhoea
  • stool microscopy: trophozoites
  • metronidazole
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3
Q

Features of amoebic liver abscess?

A
  • usually single mass in right lobe but may be multiple
  • fever, RUQ pain
  • serology positive in >90%
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4
Q

Most common isolated organism in animal bites?

Rx of animal bites?

A
  • Pasteurella multocida
  • cleanse wound
  • Co-amoxiclav
  • if pen allergy then doxycycline + metronidazole
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5
Q

What organism is involved in Anthrax?
What type of bacteria is it?
What are the 3 components of the tripartite protein toxin?

A

Bacillus anthracis

  • Gram positive rod, spread by infected carcasses
  • produces a tripartite protein toxin
    1. protective Ag
    2. oedema factor: bacterial adenylate cyclase which increases cAMP
    3. lethal factor: toxic to macrophages
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6
Q

What are the features of Anthrax poisoning?

A
  • painless black eschar (cutaneous ‘malignant pustule’, but no pus)
  • typically painless & non-tender
  • may cause marked oedema
  • anthrax can cause GI bleeding
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7
Q

Rx of anthrax?

A
  • initial Rx of cutaneous anthrax = Ciprofloxacin

- further Rx based on microbio Ix & expert advice

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8
Q

What are the bactericidal Abx?

A
  • penicillins
  • cephalosporins
  • aminoglycosides
  • quinolones
  • nitrofurantoin
  • metronidazole
  • rifampicin
  • isoniazid
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9
Q

What are the bacteriostatic Abx?

A
  • macrolides
  • tetracyclines
  • sulphonamides
  • trimethoprim
  • chloramphenicol
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10
Q

What is an aspergilloma?
What are the features?
What is on CXR & Ix?

A
  • mycetoma (mass-like fungus ball) which often colonises an existing lung cavity (e.g. 2ry to TB, lung ca or CF)
  • usually aSx or cough & haemoptysis
  • CXR: rounded opacity
  • high titres Aspergillus precipitins
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11
Q

Anti-fungal that inhibits 14alpha-demethylase which produces ergosterol?

A

Azoles

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12
Q

What are the adverse effects of Azoles?

A
  • p450 inhibition

- liver toxicity

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13
Q

Anti-fungal which binds with ergosterol forming a transmembrane channel that leads to monovalent ion (K+, Na+, H+, Cl-) leakage?

A

Amphotericin B

- used for systemic fungal infections

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14
Q

What are the adverse effects of amphotericin B?

A
  • nephrotoxicity
  • hypokalaemia
  • hypomagnasaemia
  • flu-like Sx
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15
Q

Anti-fungal that interacts with microtubules to disrupt the mitotic spindle?

A

Griseofulvin

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16
Q

Adverse effects of Griseofulvin?

A
  • p450 enzyme inducer

- teratogenic

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17
Q

Anti fungal that inhibits squalene epoxidase?

A

Terbinafine

- commonly used in oral form to treat fungal nail infections

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18
Q

Anti fungal that is converted by cytosine deaminase to 5-fluorouracil, which inhibits thymidylate synthase & disrupts fungal protein synthesis?

A

Flucytosine

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19
Q

Adverse effect of flu cytosine?

A

vomiting

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20
Q

Anti fungal that inhibits synthesis of beta-glucan, a major fungal cell wall component?

A

Caspofungin

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21
Q

Adverse effect of caspofungin?

A

flushing

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22
Q

Anti fungal that binds with ergosterol forming a transmembrane channel that leads to monovalent ion leakage (K+, Na+, H+, Cl-) - but not amphotericin B?

A

Nystatin

- v toxic so can only be used topically e.g. for oral thrush

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23
Q

Antiviral agents that are analogs of guanosine, phosphorylated by thymidine kinase, which in turn inhibits viral DNA polymerase?

A

Aciclovir (HSV, VZV)

Ganciclovir (CMV)

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24
Q

Adverse effect of acyclovir?

A

crystalline nephropathy

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25
Q

Adverse effect of ganciclovir?

A

myelosuppression/agranulocytosis

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26
Q

Antiviral that is a guanosine analog that inhibits IMP: inosine monophosphate dehydrogenase, which interferes with the capping of viral mRNA?

A

Ribavirin (chronic hep C, RSV)

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27
Q

Adverse effect of ribavirin?

A

haemolytic anaemia

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28
Q

Antiviral that inhibits uncoating (M2 protein) of virus in cell?
- also releases dopamine from nerve endings

A

Amantadine (influenza, parkinson’s disease)

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29
Q

Adverse effects of amantadine?

A
  • confusion
  • ataxia
  • slurred speech
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30
Q

Antiviral that inhibits neuraminidase?

A

Oseltamivir (influenza)

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31
Q

Antiviral that is a pyrophosphate analog which inhibits viral DNA polymerase?

A

Foscarnet (CMV, HSV if not responding to aciclovir)

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32
Q

Adverse effects of Foscarnet?

A
  • nephrotoxicity
  • hypocalcaemia
  • hypomagnasaemia
  • seizures
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33
Q

Antiviral of human glycoproteins which inhibits synthesis of mRNA?

A

Interferon-alpha (chronic hepatitis B & C, hairy cell leukaemia)

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34
Q

Adverse effects of interferon-alpha?

A
  • flu-like Sx
  • anorexia
  • myelosuppression
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35
Q

Antiviral that is an acyclic nucleoside phosphonate, which inhibits viral replication by selectively inhibiting viral DNA polymerases
- independently of phosphorylation of viral enzymes?

A

Cidofovir (CMV retinitis in HIV)

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36
Q

Adverse effect of cidofovir?

A

nephrotoxicity

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37
Q

Examples of NRTIs: nucleoside analogue reverse transcriptase inhibitors?

A 
zidovudine (AZT)
didanosine
lamivudine
stavudine
zalcitabine
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38
Q

Examples of PIs: protease inhibitors?

A
  • inhibit a protease needed to make the virus able to survive outside the cell
  • indinavir, nelfinavir, ritonavir, saquinavir
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39
Q

Examples of NNRTIs: non-nucleoside reverse transcriptase inhibitors?

A

nevirapine

efavirenz

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40
Q

Recommended Rx for exacerbations of chronic bronchitis?

A

amoxicillin/tetracycline/clarithromycin

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41
Q

Recommended Rx for uncomplicated community-acquired pneumonia?
what about if staphylococci suspected?

A

amoxicillin (/doxycycline/clarithromycin if pen allergic)

+ flucloxacillin if staph suspected e.g. in influenza

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42
Q

Recommended Rx for possibly atypical pneumonia?

A

Clarithromycin

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43
Q

Recommended Rx for hospital-acquired pneumonia?

A

within 5days of admission: Co-amoxiclav/Cefuroxime

>5days after admission: Tazocin or board-spectrum cephalosporin e.g. ceftazidime or quinolone e.g. ciprofloxacin

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44
Q

Recommended Rx for a lower UTI?

A

trimethoprim/nitrofurantoin

alternative: amoxicillin/cephalosporin

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45
Q

Recommended Rx for acute pyelonephritis?

A

broad-spectrum cephalosporin or quinolone

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46
Q

Recommended Rx for acute prostatitis?

A

quinolone or trimethoprim

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47
Q

Recommended Rx for impetigo?

A

topical fusidic acid

po flucloxacillin/erythromycin if widespread

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48
Q

Recommended Rx for cellulitis?

A

flucloxacillin

clarithromycin/clindamycin if pen allergic

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49
Q

Recommended Rx for erysipelas?

A

phenoxymethylpenicillin

erythromycin if pen allergic

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50
Q

Recommended Rx for animal/human bite?

A

co-amoxiclav

doxycyclin + metronidazole if pen allergic

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51
Q

Recommended Rx for mastitis during breast-feeding?

A

flucloxacillin

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52
Q

Recommended Rx for bacterial throat infection?

A

phenoxymethylpenicillin

erythromycin if pen allergic

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53
Q

Recommended Rx for sinusitis?

A

amoxicillin/doxycycline/erythromycin

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54
Q

Recommended Rx for otitis media?

A

amoxicillin

erythromycin if pen allergic

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55
Q

Recommended Rx for otitis externa?

A

flucloxacillin
erythromycin if pen allergic
(if not top Abx + steroid)

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56
Q

Recommended Rx for periodical/periodontal abscess?

A

amoxicillin

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57
Q

Recommended Rx for gingivitis: acute necrotising ulcerative?

A

metronidazole

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58
Q

Recommended Rx for gonorrhoea?

A

IM ceftriaxone + PO azithromycin

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59
Q

Recommended Rx for chlamydia?

A

doxycycline/azithromycin

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60
Q

Recommended Rx for pelvic inflammatory disease

A

PO ofloxacin + PO metronidazole

or IM ceftriaxone + PO doxycycline + PO metronidazole

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61
Q

Recommended Rx for syphilis?

A

benzathine benzylpenicillin/doxycycline/erythromycin

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62
Q

Recommended Rx for bacterial vaginosis?

A

PO/top metronidazole or top clindamycin

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63
Q

Recommended Rx for C. diff?

A

1st ep metronidazole

2nd/subsequent: vancomycin

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64
Q

Recommended Rx for campylobacter enteritis?

A

clarithromycin

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65
Q

Recommended Rx for salmonella (non-typhoid)?

A

ciprofloxacin

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66
Q

Recommended Rx for shigellosis?

A

ciprofloxacin

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67
Q

What is the schistosomiasis bug?

A

parasitic flatworm infecttion

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68
Q

What are the features of schistosoma haematobium?
How does it occur?
Rx?

A
  • urinary frequency
  • haematuria
  • bladder calcification
  • RF for Squamous cell bladder cancer
  • worms deposite egg clusters (pseudopapillomas) in the bladder, causing inflammation
  • calcification seen on X-ray is actually calcification of the egg clusters (not the bladder itself)
  • depending on the site of the pseudopapillomas in the bladder, they can cause an obstructive uropathy & kidney damage
  • typically presents as a ‘swimmer’s itch’ in pts who have recently returned from Africa
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69
Q

Rx for schistosoma haematobium?

A

single dose oral Praziquantel

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70
Q

What do Schistosoma mansoni and Schistosoma japonicum lead to?

A
  • these worms mature in the liver
  • travel via portal system
  • inhabit distal colon
  • presence in portal system can lead to progressive hepatosplenomegaly due to portal vein congestion
  • can also lead to cirrhosis, vatical disease & for pulmonale
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71
Q

Infections with incubation periods >3weeks?

A
  • EBV
  • CMV
  • HIV
  • viral hepatitis
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72
Q

Infections with incubation periods <1week?

A
  • meningococcus
  • diphtheria
  • influenza
  • scarlet fever
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73
Q

Infections with incubation periods 1-2weeks?

A
  • malaria
  • measles
  • typhoid
  • dengue fever
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74
Q

Infections with incubation periods 2-3weeks?

A
  • mumps
  • rubella
  • chickenpox
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75
Q

Main technique used to screen for latent TB?

A

Mantoux test

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76
Q

When is interferon-gamma blood test used to test for latent TB?

A
  • when Mantoux test is positive or equivocal

- people who may have a falsely negative tuberculin test

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77
Q

What is the Mantoux test?

A
  • 0.1ml of 1:1000 purified protein derivative (PPD) injected intradermally
  • result read 2-3days later
  • main technique used to screen for latent TB
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78
Q

Situations that may have a falsely negative tuberculin test?

A
  • miliary TB
  • sarcoid
  • HIV
  • lymphoma
  • v young age e.g. <6months
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79
Q

What is the Heaf test?

A
  • injection of PPD (purified protein derivative) equivalent to 100,000 units/ml to the skin over the flexor surface of the left forearm
  • read 3-10days later
  • used to be used in the UK for TB
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80
Q

Interpretation of Mantoux test with diameter of induration <6mm?

A

Negative - no signif hypersensitivity to tuberculin protein

- previously unvaccinated individuals may be given the BCG

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81
Q

Interpretation of Mantoux test with diameter of induration 6-15mm?

A

Positive - hypersensitive to tuberculin protein

  • should not be given BCG
  • may be due to previous TB infection or BCG
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82
Q

Interpretation of Mantoux test with diameter of induration >15mm?

A

Strongly positive

  • strongly hypersensitive to tuberculin protein
  • suggests TB infection
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83
Q

Focal neuro complication in HIV: commonest?

A

Toxoplasmosis 50% cerebral lesions in HIV

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84
Q

Focal neuro complication in HIV: Toxoplasmosis - how does it present?
what is seen on CT?
Rx?

A
  • constitutional Sx, headache, confusion, drowsiness
  • CT: usually single/multiple ring-enhancing lesions, mass effect may be seen
  • Rx = Sulfadiazine + Pyrimethamine
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85
Q

Focal neuro complication in HIV: associated with EBV?

A

Primary CNS lymphoma

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86
Q

Focal neuro complication in HIV: primary CNS lymphoma

  • what is seen on CT?
  • what is the Rx?
A

CT: single/multiple homogenous enhancing lesions
Rx: steroids (reduce tumour size), chemo e.g. MTX +/- whole brain irradiation
- consider surgery if lower grade

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87
Q

How to differentiate between toxoplasmosis & lymphoma in HIV patients:
how many lesions?
enhancement?
thallium spect?

A

Toxoplasmosis (multiple ring negative):

  • Multiple lesions
  • Ring/nodular enhancement
  • thallium spect negative

Lymphoma (single solid positive):

  • Single lesion
  • Solid (homogenous) enhancement
  • thallium spect Positive
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88
Q

Generalised neuro disease in HIV: encephalitis

  • cause?
  • CT?
A
  • may be due to CMV/HIV itself (HSV relatively rare in context of HIV)
  • CT: oedematous brain
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89
Q

Generalised neuro disease in HIV: commonest fungal infection?

A

Cryptococcus

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90
Q

Generalised neuro disease in HIV: cryptococcus

  • presentation?
  • features of CSF?
  • what is on CT?
A
  • typically presents as meningitis, may occasionally cause a SOL
  • headache, fever, malaise, nausea/vomit, seizures, focal neuro deficit
  • CSF: high opening pressure, India ink test positive
  • CT: meningeal enhancement, cerebral oedema
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91
Q

Generalised neuro disease in HIV: PML

  • what is it?
  • what causes it?
  • presentation?
  • what is on CT?
A
  • progressive multifocal leukoencephalopathy
  • widespread demyelination
  • due to infection of oligodendrocytes by JC virus (a polymer DNA virus)
  • Sx, subacute onset: behavioural changes, speech, motor, visual impairment
  • CT: single/multiple lesions, no mass effect don’t usually enhance
  • MRI is better - high-signal demyelinating white matter lesions
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92
Q

Generalised neuro disease in HIV: AIDS dementia complex

  • cause
  • Sx
  • CT?
A
  • caused by HIV virus itself
  • behavioural changes, motor impairment
  • CT: cortical & subcortical atrophy
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93
Q

What type of virus is hepatitis C?

what is the incubation period?

A
  • RNA flavivirus

- 6-9weeks

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94
Q

Risk of transmission of hepatitis C if:

  • needle stick injury
  • vertical transmission rate
  • sexual intercourse
  • breastfeeding
A

needle 2%
vertical 6% (higher if also HIV)
sex <5%
breastfeeding not C/I n mums with hepatitis C

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95
Q

Clinical features of hepatitis C?

Outcome?

A
  • only 30% will develop features e.g.
  • transient rise in serum aminotransferases/jaundice
  • fatigue
  • arthralgia
  • 15-45% wil clear the virus after an acute infection (depending on their age & underlying health) so the majority (55-85%) will develop chronic hepatitis C
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96
Q

Ix of choice to Dx acute hepatitis C?

A

HCV RNA

- pts eventually develop anti-HCV Ab but pts who spontaneously clear the virus will continue to have anti-HCV Ab

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97
Q

What is chronic hepatitis C?

A

persistence of HCV RNA in the blood for 6months

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98
Q

Potential complications of chronic hepatitis C infection?

A
  • eye: Sjogren’s
  • rheum: arthralgia, arthritis
  • cirrhosis 5-20%
  • hepatocellular cancer
  • cryoglobulinaemia: typically type II (mixed mono & polyclonal)
  • porphyria cutanea tarda - esp if other factors e.g. etoh abuse
  • membranoproliferative glomerulonephritis
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99
Q

Management of chronic hepatitis C infection?

what is the aim of Rx?

A
  • Rx depends on viral genotype
  • aim = SVR: sustained virological response = undetectable serum HCV RNA 6months after the end of therapy
  • currently: combo of protease inhibitors +/- Ribavirin
  • interferon based Rx no longer recommended
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100
Q

complications of Rx of chronic hepatitis C infection?

A

Ribavirin side effects = haemolytic anaemia, cough, teratogenic therefore avoid conception 6months after stopping Rx

Interferon-alpha side-effects = flu-like Sx, depression, fatigue, leukopenia, thrombocytopenia

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101
Q

African trypanosomiasis = sleeping sickness
what are the 2 forms?
how are they spread?
what are the clinical features?

A

protozoal disease, both spread by the tsetse fly

  • trypanosoma gambiense in west africa
  • trypanosoma rhodesiense in east africa (tends to follow a more acute course)
  • tryanosoma chancre = painless SC nodule at site of infection
  • intermittent fever
  • enlargement of posterior cervical LNs
  • later: CNS involvement e.g. somnolence, headaches, mood changes, meningoencephalitis
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102
Q

Rx of African trypanosomiasis (sleeping sickness) if:
early?
late/CNS involvement?

A

early disease = IV Pentamidine/Suramin

later/CNS involvement = IV Melarsoprol

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103
Q

What organisms causes American trypanosomiasis = Chagas’ disease?
Features of acute phase?
Features of chronic disease?

A
  • protozoan Trypanosoma cruzi
  • 95% aSx in acute phase, although a chagoma (erythematous nodule at site of infection_ & periorbital oedema sometimes seen

Chronic: heart + GI tract:

  • myocarditis, can lead to dilated cardiomyopathy (with apical atrophy) & arrhythmias
  • GI features inc megaoesophagus & megacolon causing dysphagia & constipation
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104
Q

Rx of American trypanosomiasis = Chagas’ disease?

A

Rx most effective in the acute phase using Azole or nitroderivatives e.g. benznidazole or nifurtimox
- chronic Rx involves treating the complications

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105
Q

What are the types of necrotising fasciitis?

features?

A

type 1 = mixed anaerobes & aerobes (often post-op in diabetics)
type 2 = streptococcus pyogenes

  • acute onset
  • painful, erythematous lesion develops
  • extremely tender over infected tissue
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106
Q

Rx of necrotising fasciitis?

A
  • urgent surgical referral for debridement

- IV Abx

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107
Q

Features of legionella pneumonia?

A
  • intracellular bacterium legionella pneumophilia
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108
Q

Dx of legionella?

Rx?

A

urinary Ag

Rx = Erythromycin

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109
Q

What virus & transmission is involved in hepatitis B?

incubation period?

A
  • double-stranded DNA hepadnavirus
  • exposure in infected blood/body fluids inc vertical transmission
  • incubation 6-20weeks
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110
Q

Features of hepatitis B infection?

A

fever
jaundice
elevated liver transaminases

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111
Q

Complications of hepatitis B infection?

A 
chronic hepatitis 5-10%
fulminant liver failure 1%
hepaticellular carcinoma
golmerulonephritis
polyarteritis nodosa
cryoglobulinaemia
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112
Q

How is the hepatitis B vaccine prepped?

A
  • contains HBsAg adsorbed onto aluminium hydroxide adjuvant

- prepared from yeast cells using recombinant DNA technology

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113
Q

RFs for responding poorly/failing to respond to 3 doses of hepatitis B vaccine?
In whom do you test for anti-HBs?

A

10-15%
- age>40, obesity, smoking, etoh xs, immunosuppression

  • at risk occupational exposure & pts with CKD
  • check anti-hsb 1-4months after 1ry immunisation
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114
Q

Interpretation of anti-HBs level:

>100

A

adequate response, no further testing required

- needs booster at 5 years

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115
Q

Interpretation of anti-HBs level:

10-100

A

suboptimal response - 1x additional vaccine dose required

- if immunocompetent, no further testing required

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116
Q

Interpretation of anti-HBs level:

<10

A

non-responder - test for current/past infection

  • give further vaccine course of 3 doses with testing again
  • if fails to respond again then HBIG required for protection if exposed to virus
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117
Q

Management of hepatitis B?

A

Pegylated ifn-alpha used to be the only Rx available

  • reduces viral replication in upto 30% of chronic carriers
  • better response predicted if female, <50yrs, low HBV DNA level, non-Asian, HIV negative & if high degree of inflammation on liver biopsy

Other antivirals increasingly used with an aim to suppress viral replication
- e.g. tenofovir & entecavir

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118
Q

characteristic features of pneumococcal pneumonia?

A

rapid onset
high fever
pleuritic chest pain
herpes labialis

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119
Q

What is travellers’ diarrhoea gastroenteritis?

A

at least 3 loose/watery stools in 24h +/- 1 of
abdo cramps, fever, nausea, vomiting, blood in stool

commonest cause = E coli

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120
Q

What are the classic Sx of acute food poisoning gastroenteritis?

A

sudden-onset nausea, vomiting, diarrhoea after ingestion of a toxin
e.g. staph aureus, bacillus cereus, clostridium perfringens

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121
Q

Stereotypical gastroenteritis Hx of:
watery stools
abdo cramps & nausea
common with travellers

A

E. coli

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122
Q

Stereotypical gastroenteritis Hx of:

prolonged, non-bloody diarrhoea

A

Giardiasis

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123
Q

Stereotypical gastroenteritis Hx of:
profuse, watery diarrhoea
severe dehydratin resulting in weight loss
not common amongst travellers

A

Cholera

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124
Q

Stereotypical gastroenteritis Hx of:
bloody diarrhoea
vomiting & abdo pain

A

Shigella

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125
Q

Stereotypical gastroenteritis Hx of:

severe vomiting with short incubation period

A

staphylococcus aureus

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126
Q

Stereotypical gastroenteritis Hx of
flu-like prodrome then cramp abdo pains, fever & diarrhoea which may be bloody
may mimic appendicitis

A

campylobacter

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127
Q

Stereotypical gastroenteritis Hx of 2 types

  • vomiting within 6hours (rice)
  • diarrhoeal illness occurring after 6hours
A

bacillus cereus

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128
Q

Stereotypical gastroenteritis Hx of:

gradual onset bloody diarrhoea, abdo pain & tenderness - may last several weeks

A

Amoebiasis

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129
Q 
Gastroenteritis bugs incubation periods:
1-6h?
12-48h?
48-72h?
>7days?
A

1-6h: staph aureus, bacillus cereus vomiting
12-48h: salmonella, E coli
48-72h: shigella, campylobacter
>7days: giardiasis, amoebiasis

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130
Q

What is the organism in Rabies?

A

Rabies virus = RNA rhabdovirus (lyssavirus) that has a bullet-shaped capsid

  • causes acute encephalitis
  • following a bite, the virus travels up the nerve axons towards the CNS in a retrograde fashion
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131
Q

Features of Rabies?

A

prodrome: headache, fever, agitation
hydrophoboa: water-provoking muscle spasms
hypersalivation
Negri bodies: cytoplasmic inclusion bodies found in infected neurons

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132
Q

What to do re: rabies after an animal bite in at-risk countries?

A
  • wash wound
  • 2 further doses of vaccine if individual already immunised
  • human rabies IG with full coarse vaccination if not previously immunised
  • fatal if untreated
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133
Q

Gonorrhoea is caused by which organism?

A

gram negative intracellular diplococcus

  • acute infection can occur on any mucous membrane surface e.g. genitourinary, rectum, pharynx
  • incubation period 2-5days
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134
Q

Features of gonorrhoea?

Local complications?

A

males: urethral discharge, dysuria
females: cervicitis e.g. leading to vaginal discharge
rectal & pharyngeal infection: usually aSx

Locally e.g. urethral strictures, epididymitis, salpingitis (may lead to infertility)

  • disseminated gonococcal infection & gonococcal arthritis can also occur
  • gonococcal commonest cause of septic arthritis in young adults
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135
Q

Microbiology of gonorrhoea?

A
  • immunisation not possible
  • re-infection common due to antigen variation of type IV pili (proteins which adhere to surfaces) & Opa proteins (surface proteins which bind to receptors on immune cells)
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136
Q

Rx of choice in gonorrhoea?

A

IM Ceftriaxone stat + PO Azithromycin stat

  • azithromycin thought to act synergistically with ceftriaxone, and useful to eradicate any co-existent chlamydia
  • this combo ok in pregnancy as well
  • if ceftriaxone contraindicated, can use Cefixime PO
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137
Q

Disseminated gonococcal infection pathophysiology?

features?

A
  • haematogenous spread from mucosal infection (e.g. ax genital infection)

initially may be triad of Sx:

  1. tenosynovitis
  2. migratory polyarthritis
  3. dermatitis (maculopapular or vesicular)

later complications inc: septic arthritis, endocarditis, perihepatitis (Fitz-Hugh-Curtis syndrome)

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138
Q

Organism in PCP HIV pneumonia?

A

pneumocystis jiroveci
unicellular eukaryote (fungus/protozoa)
= commonest opportunistic infection in AIDS
- all pts with CD4<200 should receive PCP prophylaxis

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139
Q

Features of HIV PCP pneumonia?

Extrapulmonary manifestations?

A
  • dyspnoea, fever, dry cough
  • v few chest signs
  • common complication = pneumothorax

extrapulmonary manifestations are rare 1-2%

  • hepatosplenomegaly
  • lymphadenopathy
  • choroid lesions
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140
Q

Ix for PCP HIV pneumonia?

A
  • exercise-induced desaturation
  • CXR: can be normal, BL interstitial pulmonary infiltrates, etc
  • silver stain bronchoalveolar lavage shows characteristic cysts
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141
Q

Rx of PCP hiv pneumonia?

A

Co-trimoxazole

  • IV pentamidine in severe cases
  • steroids if hypoxic - reduces risk of rest failure & death
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142
Q

Painful genital ulcers, 1ry attacks often severe with fever, subsequent less severe & localised?

A

genital herpes HSV-2

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143
Q

genital solitary painless ulcer in 1ry stage (incubation period 9-90days). Dx?

A

syphilis

spirochaete treponema pallidum

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144
Q

painful genital ulcers that typically have a sharply defined, ragged undermined border
- ass with unilateral, painful inguinal LN enlargement

A

Chancroid

- tropical disease caused by haemophilia ducreyi

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145
Q

stage 1 of lymphogranuloma venereum caused by chlamydia?

A

small painless pustule which later forms an ulcer at the site of inoculation 3-12days later (self-limiting)

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146
Q

stage 2 of lymphogranuloma venereum caused by chlamydia?

A

painful inguinal lymphadenopathy 1-6months later

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147
Q

stage 3 of lymphogranuloma venereum caused by chlamydia?

A

proctocolitis

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148
Q

Rx of LGV: lymphogranuloma venereum?

A

Doxycycline (or macrolides)

+/- potential surgical drainage/aspiration of the buboes/abscesses

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149
Q

Causative organism in genital ulcers ass with granuloma inguinale?

A

klebsiella granulomatis

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150
Q

Causative organism in LGV: lymphogranuloma venereum?

A

chlamydia trachomatis
- gains entry through breaches in the epithelial/mucous membranes, travelling through lymphatics via macrophages to local nodes

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151
Q

Dx of chlamydia in LGV lymphogranuloma venereum?

A

enzyme-linked immunoassays or PCR of infected sample areas/pus

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152
Q

Live attenuated vaccines?

A 
BCG
MMR
intranasal influenza
rotavirus oral
polio oral
yellow fever
typhoid oral
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153
Q

Vaccines with inactivated preparations?

A

rabies
hepatitis A
IM influenza

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154
Q

Vaccines with toxoid i.e. inactivated toxin?

A

tetanus
diphtheria
pertussis

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155
Q

Examples of subunit vaccines?

A
  • only part of the pathogen is used to generate an immunogenic response
  • hepatitis B
  • HPV
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156
Q

Examples of conjugate vaccines?

A
  • type of subunit vaccine that links the poorly immunogenic bacterial polysaccharide outer coats to proteins to make them more immunogenic
  • pneumococcus
  • haemophilus
  • meningococcus
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157
Q

What is leprosy?

what are the features?

A
  • granulomatous disease affecting the peripheral nerves & skin caused by mycobacterium leprae
  • patches of hypopigmented skin typically affecting the buttocks, face & extensor surfaces of limbs
  • sensory loss
  • the degree of cell-mediated immunity determines the type of leprosy a patient will develop
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158
Q

Type of leprosy & features if there is a low degree of cell-mediated immunity?

A

Lepromatous leprosy (‘multibacillary’)

  • extensive skin involvement
  • symmetrical nerve involvement
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159
Q

Type of leprosy & features if there is a high degree of cell-mediated immunity?

A

Tuberculoid leprosy (‘paucibacillary’)

  • limited skin disease
  • asymmetric nerve involvement
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160
Q

Rx of leprosy?

A

triple therapy:
Rifampicin
Dapsone
Clofazimine

161
Q

Non-pregnant woman uncomplicated lower UTI Rx?

A

3 days trimethoprim/nitrofurantoin

162
Q

Sx bacteriuria Rx in pregnant women?

A

7 days Abx

163
Q

Protocol if aSx bacteruria in pregnant women?

A
  • routine urine culture at 1st visit, if positive send 2nd to confirm presence of bacteria
  • 7days Abx
164
Q

Rx for acute pyelonephritis?

A

10-14days broad-spectrum cephalosporin or quinolone

165
Q

What is the pathophysiology of diphtheria?

A
  • caused by gram positive Corynebacterium diphtheriae
  • releases an exotoxin encoded by a beta-prophage
  • exotoxin inhibits protein synthesis by catalysing ADP-ribosylation of elongation factor EF-2
166
Q

Possible presentations of diphtheria?

A
  • sore throat with a ‘diphtheric membrane’ on tonsils caused by necrotic mucosal cells
  • systemic distribution may produce necrosis of myocardial, neural & renal tissue
  • recent visitors to Eastern Europe/Russia/Asia
  • bulky cervical lymphadenopathy
  • neuritis e.g. cranial nerves
  • heart block
167
Q

MoA of trimethoprim?

Adverse effects?

A
  • interferes with DNA synthesis by inhibiting dihydrofolate reductase
  • myelosuppression
  • transient rise n creatinine (competitively inhibits the tubular secretion of creatinine resulting in a temp increase which reverses upon stopping the drug)
168
Q

Examples of gram-positive cocci

A

staph
strep
enterococci

169
Q

Examples of gram-negative cocci?

A

neisseria meningitidis
neisseria gonorrhoea
moraxella catarrhalis

170
Q

examples of gram positive rods?

A 
Actinomyces
Bacillus anthracis (anthrax)
Clostridium
Diphtheria (corynebacterium diphtheria)
Listeria monocytogenes
171
Q

examples of gram-negative rods?

A 
E coli
Haemophilus influenza
Pseudomonas aeruginosa
Salmonella sp
Shigella sp
Campylobacter jejuni
172
Q

2 types of serological tests in syphilis?

A 
Cardiolipin tests (not treponeme specific)
Treponemal specific Ab tests
173
Q

Treponemal specific antibody tests in syphilis?

A

e. g. TPHA: haemagglutination test

- remains positive after Rx

174
Q

Cardiolipin tests in syphilis?

A
  • syphilis infection leads to non-specific Ab produced, that react to cardiolipin
  • VDRL (Venereal Disease Research Laboratory) & RPR (rapid plasma reagin)
  • insensitive in late syphilis
  • becomes negative after treatment
175
Q

Causes of falsely positive cardiolipin tests (VRDL/RPR) in syphilis?

A 
pregnancy
SLE, anti-phospholipid syndrome
TB
leprosy
malaria
HIV
176
Q

Features of 1ry syphilis?

A
  • chancre - painless ulcer at site of sexual contact
  • local non-tender lymphadenopathy
  • often not seen in women (lesion may be on cervix)
177
Q

Features of 2ry syphilis?

A
  • occurs 6-10wks after 1ry infection
  • systemic: fever, lymphadenopathy
  • rash on trunk, palms, soles
  • buccal ‘snail track’ ulcers 30%
  • condylomata lata (painless, warty lesions on genitalia)
178
Q

Features of tertiary syphilis?

A
  • gummas (granulomatous lesions of skin & bones)
  • ascending aortic aneurysms
  • general paralysis of the insane
  • tabes dorsalis
  • Argyll-robertson pupil
179
Q

Features of congenital syphilis?

A
  • saddle nose
  • deafness
  • keratitis
  • blunted upper incisor teeth, mulberry molars
  • rhagades: linear scars at angle of the mouth
  • saber shins
180
Q

Cause & feature of cutaneous leishmaniasis?

A

leishmania tropica or mexicana

  • crusted lesion at site of bite
  • may be underlying ulcer
181
Q

Cause & feature of mucocutaneous leishmaniasis?

A

leishmania braziliensis

- skin lesions may spread to involve mucosae of nose, pharynx etc

182
Q

Cause & feature of visceral leishmaniasis?

A

leishmania donovani

  • fever, sweat, rigors
  • mediterranean, asia, south america, africa
  • massive splenomegaly, hepatomegaly
  • poor appetite, weight loss
  • grey skin = kala-azar
  • pancytopenia 2ry to hypersplenism
183
Q

Virulence factor of:
Streptococcus pneumoniae
Haemophilus influenzae
Neisseria gonorrhoeae?

A

IgA protease

184
Q

Virulence factor of Streptococcus pyogenes?

185
Q

Virulence factor of Haemophilus influenzae?

A

Polyribosyl ribitol phosphate capsule

186
Q

Virulence factor of Corynebacterium diphtheriae?

A

Bacteriophage

187
Q

Virulence factor of Bacillus anthracis
Clostridium perfringens
Clostridium tetani?

A

Spore formation

188
Q

Virulence factor of Clostridium perfringens?

A

Lecithinase alpha toxin

189
Q

Virulence factor of Bacillus anthracis?

A

D-glutamate polypeptide capsule

190
Q

Virulence factor of Listeria monocytogenes?

A

Actin rockets

191
Q

What is the mutation that leads to carbapenem resistance, typically found in klebsiella pneumonia, E. coli, enterobacter cloacae etc?

A

New Delhi metallo-beta-lactamase 1

- 1st line Rx is the old Abx Colistin

192
Q

What is the variation leading to loss of affinity to Abx in the mechanism of VRE: vancomycin resistant enterococci?

A

D-alanyl-D-lactate variation

193
Q

Mechanism behind MRSA?

A

Alteration to the penicillin binding protein 2

194
Q

presentation of meningococcal disease?

what Ix is most likely to reveal the Dx?

A

60% meningitis + septicaemia
25% septicaemia
15% meningitis

Blood PCR
(LP often contra-indicated)
blood mcs should be done
- check FBC & clotting for DIC

195
Q

how are patients screened for mrsa?

A

nasal swab & skin lesions/wounds
wipe around inside rim of nose for 5 seconds
microbio form to be labelled mrsa screen

196
Q

How to suppress MRSA from a carrier once identified?

A

nose: Mupirocin 2% in white soft paraffin tads for 5/7
skin: chlorhexidine gluconate od for 5/7 - apply all over esp to axilla, groin, perineum

197
Q

Abx commonly used in Rx of MRSA infections?

A

Vancomycin
Teicoplanin
Linezolid

198
Q

Dengue fever:
vector?
organism?
how can it progress?

A
  • transmitted by Aedes aegyti mosquito
  • viral infection
  • incubation period 7 days
  • haemorrhagic fever can develop with a form of DIC - 20-30% go on to develop dengue shock syndrome
199
Q

features of dengue fever?

A 
headache, often retro-orbital
fever
myalgia
pleuritic pain
facial flushing (dengue)
maculopapular rash
200
Q

Rx of dengue fever?

A

Sx Rx e.g. fluid resuscitation, blood transfusion

201
Q

Incubation period of chlamydia?

Features?

A

7-21days

  • aSx in 70% women, 50% men
  • women: cervicitis with discharge & bleeding, dysuria
  • men: urethral discharge, dysuria
202
Q

Potential complications of chlamydia infection?

A
  • epididymitis
  • PID
  • endometritis
  • increased incidence of ectopic pregnancies
  • infertility
  • reactive arthritis
  • perihepatitis (Fitz-Hugh-Curtis syndrome)
203
Q

Ix of chlamydia:
Ix of choice?
what else?

A
  • NAATs (nuclear acid amplification test) is Ix of choice
  • traditional cell culture no longer widely used
  • 1st void urine, vulvovaginal swab, cervical swab can be tested using NAAT
204
Q

Rx of chlamydia?

A

7 days Doxycycline or stat dose Azithromycin

  • in pregnancy: azithromycin/erythromycin/amoxicillin
  • partner notification
  • for men with urethral Sx, all contacts since and in the 4 wks before onset of `sx
  • women & aSx men: all partners from last 6months or most recent sexual partner
  • Rx contacts without waiting for results of Ix
205
Q

Features of Lyme disease:
early?
later?

A

Early:

  • erythema chronicum migrans in 70% - small papule often at site of tick bite which later develops into a bulls eye
  • systemic Sx of malaise, fever, arthralgia

Later:

  • CVS: heart block, myocarditis
  • neuro: CN palsies, meningitis
  • polyarthritis
206
Q

Organism in Lyme disease?

A

spirochaete Borrelia burgdorferi spread by ticks

207
Q

Ix of Lyme disease?

A
  • clinical if erythema migrants present
  • ELISA to Borrelia burgdorferi
  • if ELISA +ive or equivocal then an immunoblot test should be done
208
Q

Rx of suspected/confirmed Lyme disease?

A
  • if early then Doxycycline (Amoxicillin if contra-indicated)
  • Ceftriaxone if disseminated
  • Jarisch-Herxheimer reaction sometimes seen after initiating Rx (fever, rash, tachycardia after 1st dose)
209
Q

What is staphylococcal toxic shock syndrome?

Dx criteria/features?

A
  • severe systemic reaction to staphylococcal exotoxins
  • fever >38.9
  • hypotension sBP<90
  • diffuse erythematous rash
  • desquamation of rash, esp palms & soles
  • 3+ organ involvement e.g. gastro D&V, mucous membrane erythema, renal failure, hepatitis, thrombocytopenia, CNS involvement e.g. confusion
210
Q

MoA of Linezolid?
Spectrum?
Adverse effects?

A
  • oxazolidonone Abx
  • inhibits bacterial protein synthesis by stopping formation of the 70s initiation complex
  • bacteriostatic
  • spectrum v active against Gram +ve organisms inc: MRSA, VRE & GISA (glycopeptide intermediate staphylococcus aureus)
  • thrombocytopenia (reversible on stopping)
  • MAO-I (avoid tyramine containing foods)
211
Q

Causes of infectious mononucleosis?

Dx?

A
  • EBV (HHV-4) 90%
  • also CMV, HHV-6
  • Monospot heterophil Ab test (FBC & monospot test in 2nd wk of illness to confirm a Dx of glandular fever)
212
Q

Classic train of glandular fever?

Other features?

A
  1. sore throat
  2. fever
  3. lymphadenopathy (anterior & posterior triangles)
  • malaise, anorexia, headache
  • palatal petechiae
  • hepatitis, transient rise in ALT
  • splenomegaly in 50% (may rarely predispose to splenic rupture)
  • haemolytic anaemia 2ry to cold agglutinins IgM
  • maculopapular, pruritic rash in 99% who take ampicillin/amoxicillin whist having infectious mono

Sx usually resolve after 2-4wks

213
Q

Rx of glandular fever?

A
  • rest, fluids, avoid etch
  • simple analgesia for aches/pains
  • avoid contact sports 8wks after, to reduce risk of splenic rupture
214
Q

Ix for malaria:
gold standard?
new Dx tests?
other features on FBC?

A

Blood film = gold standard

thick: more sensitive
thin: determine species

Rapid Dx tests (detecting plasmodial histidine-rich protein 2) being trialled with sensitivities from 77-99%, spec 83-98% for falciparum malaria

  • thrombocytopenia characteristic
  • normochromic normocytic anaemia
  • normal WCC
  • reticulocytosis
215
Q

How to evaluate parasite burden in malaria?

A

THICK blood film

216
Q

How to determine species in malaria?

A

THIN blood film (visualise parasite)

217
Q

Salmonella organisms?

What illnesses does it cause?

A
  • aerobic Gram negative rods usually cause diarrhoea illnesses/enteric fevers
  • typhoid & paratyphoid caused by s. type & s. parathyphi (A, B, C) - enteric fevers producing systemic Sx of headache, fever, arthralgia
218
Q

Features of salmonella infection?

A
  • systemic upset of headache, fever, arthralgia
  • relative bradycardia
  • abdo pain, distension
  • constipation (more common than diarrhoea in typhoid)
  • rose spots: trunk in 40%, more common in paratyphoid
219
Q

Possible complications of typhoid infection?

A
  • osteomyelitis (esp in sickle cell)
  • GI bleed/perforation
  • meningitis
  • cholecystitis
  • chronic carriage (1%, more likely if adult female)
220
Q

What is HAART in HIV?

A

highly active anti-retroviral therapy

  • combo of at least 3 drugs
  • usually 2 NRTIs + PI/NNRTI
  • this combo decreases viral replication & helps reduce risk of viral resistance emerging
221
Q

What are entry inhibitors (CCR5 receptor antagonists) in HIV?

A
  • maraviroc, enfuvirtide

- prevent HIV-1 from entering & infecting immune cells by blocking CCR5 cell-surface receptor

222
Q

What are NRTIs in HIV?
general side-effect?
side effect of didanosine?
side effects of zidovudine?

A
  • generally cause peripheral neuropathy
  • didanosine: pancreatitis
  • zidovudine: anaemia, myopathy, black nails
  • also: abacavir, emtricitabine, lamivudine, stavudine, zalcitabine, tenofovir
223
Q

Side-effects & examples of NNRTIs in HIV?

A
  • nevirapine, efavirenz

- p450 enzyme interaction (nevirapine induces), rashes

224
Q

Side-effects & examples of protease inhibitors in HIV?

A
  • side effects inc diabetes, hyperlipidaemia, buffalo hump, central obesity, p450 enzyme inhibition
  • indinavir: renal stones, aSx hyperbilirubinaemia
  • ritonavir: potent inhibitor of p450 system
  • also: nelfinavir, saquinavir
225
Q

raltegravir, elvitegravir, dolutegravir are examples of what?

A

Integrase inhibitors (used in HIV)

226
Q

What are the features of severe falciparum malaria?

A
  • fever > 39C
  • severe anaemia
  • hypoglycaemia
  • acidosis
  • parasitaemia > 2%
  • schizonts on a blood film
    • complications
227
Q

Complications of severe falciparum malaria?

A
  • hypoglycaemia
  • DIC
  • ARDS
  • acute renal failure: blackwater fever, 2ry to intravascular haemolysis, mechanism unknown
  • cerebral malaria: seizures, coma
228
Q

Rx of uncomplicated falciparum malaria?

A
  • strains resistant to chloroquine prevalent in certain areas of Aisa & Africa
  • ACTs 1st line (Artemisinin-based combination therapies)
  • e.g. artemether + lumefantrine, artesunate + amodiaquin, artesunate + mefloquine, artseunate + sulfadoxine-pyrimethamine, dihydroartemisinin + piperaquine
229
Q

Rx of severe falciparum malaria?

A
  • parasite counts >2% need parenteral Rx irrespective of clinical state
  • IV Artesunate (preferred to IV quinine)
  • if parasite count >10% then consider exchange transfusion
  • shock may indicate coexistent bacterial septicaemia (malaria rarely causes haemodynamic collapse)
230
Q

HIV: multiple ring enhancing lesions on CT, what is the Dx?

A

Toxoplasmosis

231
Q

Causes of genital warts?
Features?
Rx?

A

HPV 6 & 8
(HPV 16, 18, 33 predispose to cervical cancer)
- small 2-5mm fleshy protuberances slightly pigmented, may bleed/itch

  • 1st line topical podophyllum. Cryotherapy if solitary keratinised lesion
  • imiquimod topical cream 2nd line
  • often resistant to Rx, recurrence common
232
Q

Malignancies associated with EBV infection?

A

Burkitt’s lymphoma
Hodgkin’s lymphoma
nasopharyngeal carcinoma
HIV-ass CNS lymphomas

233
Q

What is bacterial vaginosis?

Features?

A
  • overgrowth of anaerobes e.g. Gardeners vaginalis
  • leads to a fall in lactic acid producing aerobic lactobacilli -> raised vaginal pH
  • fishy, offensive discharge
  • aSx in 50%
234
Q

Ansel’s criteria for diagnosing bacterial vaginosis?

A

3 of 4 of:

  1. thin, white homogenous discharge
  2. clue cells on microscopy (stippled, vaginal epithelial cells)
  3. vaginal pH >4.5
    - positive whiff test (fishy odour after adding potassium hydroxide)
235
Q

Rx of bacterial vaginosis?

A

5-7days of oral Metronidazole
70-80% initial cure rate
relapse rate >50% within 3months

236
Q

Bacterial vaginosis in pregnancy?

A
  • increased risk of preterm labour, low birth weight & chorioamnionitis, late miscarriage
  • oral metronidazole safe throughout pregnancy
237
Q

Post-exposure prophylaxis of hepatitis A?

A

HNIG: human normal immunoglobulin or hepatitis A vaccine may be used depending on clinical situation

238
Q

Post-exposure prophylaxis of hepatitis C?

A
  • monthly PCR - if seroconversion then interferon +/- ribavirin
239
Q

Post-exposure prophylaxis of hepatitis B?

A

HBsAg positive source: booster dose if exposed person is a known responder. If not or in process of vaccination then they need Vaccine + HBIG

Unknown source: booster if known responder otherwise if non-responder then HBIG + vaccine, if being vaccinated the accelerated course of HBV vaccine

240
Q

Post-exposure prophylaxis of HIV?

A
  • combo of oral antiretrovirals asap (but within 72h) for 4 wks
  • serological testing at 12wks after completing PEP
  • reduces transmission risk by 80%
241
Q

Post-exposure prophylaxis of varicella zoster?

A

VZIG for IgG negative pregnant women or immunosuppressed

242
Q

What infections are people at risk of after a splenectomy?
what vaccinations do they need?
Abx prophylaxis?

A

pneumococcus, haemophilus, meningococcus, capnocytophaga

  • pneumococcal/5yrs
  • annual influenza
  • HiB, meningitis A & C - 2 weeks pre-op if elective surgery

Penicillin V (lifelong)

243
Q

Indications of splenectomy?

A
  • trauma (25% iatrogenic)
  • spontaneous rupture e.g. EBV
  • hypersplenism: hereditary spherocytosis, elliptocytosis etc
  • malignancy: lymphoma, leukaemia
  • splenic cysts, hydatid cysts, splenic abscesses
244
Q

Complications of a splenectomy?

A
  • haemorrhage
  • pancreatic fistula (iatrogenic damage to pancreatic tail)
  • thrombocytosis - give aspirin prophylaxis
  • encapsulated bacteria infection eg strep pneumonia, haemophilus influenza, neisseria meningitidis
245
Q

Post-splenectomy changes in bloods?

A
  • platelets rise first
  • blood film changes over next weeks, Howell-Jolly bodies appear
  • other blood film changes inc target cells & Pappenheimer bodies
  • inc risk of post-splenectomy sepsis
246
Q

Catalase negative gram positive coccus?

A

streptococcus

247
Q

Catalase positive gram positive coccus?

A

staphylococcus (coagulase +ve aureus, coagulase -ve epidermidis, saprophyticus)

248
Q

homeless of streptococci?

A

Alpha: partial haemolysis (green on blood agar)
Beta: complete haemolysis (clear)
Gamma: no haemolysis

249
Q

Shigella Rx?

A
  • usually self-limiting, rest, fluids, no Abx

- Abx if severe or immunocompromised or bloody diarrhoea e.g. Ciprofloxacin

250
Q

What is Orf disease?

A
  • caused by paradox virus usually in sheep/goats but can be transmitted to humans
  • hands & arms affected
  • initially small, raised, red-blue papule
  • later may increase in size to 2-3cm and become flat-topped & haemorrhagic
251
Q

Cause of leptospirosis/Weil’s disease?

when to suspect?

A
  • spirochaete Leptospira interrogans (contact with infected rat urine)
  • high risk groups who develop hepatorenal failure e.g. sewage worker, farmer, vets etc
252
Q

Features of Leptospirosis?

Rx?

A
  • fever, flu-like Sx
  • renal failure 50%
  • jaundice
  • subconjunctival haemorrhage
  • headache, may herald onset of meningitis

Rx with high-dose Benzylpenicillin or Doxycycline

253
Q

MoA of aciclovir?

A

inhibits viral DNA polymerase

254
Q

What is Listeria monocytogenes?

Features of infection?

A

Gram positive bacillus which can multiple at low temperatures, spread by contaminated food e.g. unpasteurised dairy products
- infection v dangerous to unborn child (can lead to miscarriage)

Variety of presentation, inc:

  • diarrhoea, flu-like illness
  • pneumonia, meningoencephalitis
  • ataxia & seizures
255
Q

Ix of Listeria?

Rx?

A
  • blood cultures
  • CSF may reveal a pleocytosis, with ‘tumbling motility’ on wet mounts

Rx: Amoxicillin/Ampicillin (cephalosporins usually inadequate)
If Listeria meningitis, Rx with IV Amoxicillin/Ampicillin + Gentamicin

256
Q

How to Rx Listeria in pregnancy?

A
  • pregnant women 20X more likely to develop listeriosis
  • fetal/neonatal infection can occur vertically during childbirth & transplacentally during pregnancy
  • Dx from blood cultures
  • Rx with Amoxicillin
  • complications inc: miscarriage, preterm labour, stillbirth & chorioamnionitis
257
Q

Explain nitrite positive on urine dip?

A

Gram negative organisms (convert nitrates to nitrites for energy)

258
Q

What causes Toxoplasmosis disease? Features of infection?

A
  • toxoplasma gondii protozoa which infects body via GI tract/lung/broken skin
  • its oocysts release trophozoites which migrate widely around the body inc eye, brain, muscle
  • main animal reservoir is the cat
  • most infections are aSx
  • Sx usually self-limiting, often having clinical features resembling glandular fever
  • other less common manifestations inc meningoencephalitis & myocarditis
259
Q

Ix of toxoplasmosis?

A

Ab test

Sabin-Feldman dye test

260
Q

Rx of toxoplasmosis?

A

If severe or immunesuppressed then:

Pyrimethamine + Sulphadiazine for at least 6 weeks

261
Q

Effects of congenital toxoplasmosis?

A
  • due to transplacental spread from mum

- microcephaly, hydrocephalus, cerebral calcification & choroidoretinitis

262
Q

What is an aspergilloma?
Features?
Ix?

A

Mycetoma (mass-like fungus ball) which often colonises an existing lng cavity e.g. 2ry to TB, lung ca, CF

Usually aSx but features may inc:
- cough, haemoptysis

Ix:
CXR rounded opacity
high titres Aspergillus precipitins

263
Q

1st line immune response in aspergillosis?

A

Macrophages - they help to recruit neutrophils

  • this is why diseases with deficiencies of macrophages & neutrophils are prone to aspergillosis
  • in healthy people, the spree are inhaled, mucociliary clearance initiated & spores phagocytes clearing the infection
264
Q

Standard Rx for active TB - initial phase?

A

RIPE 2months

265
Q

Standard Rx for active TB - continuation phase?

A

RI next 4months

266
Q

Rx for latent TB?

A 
3months RI(+pyridoxine)
or 6months Isoniazid (+p)
267
Q

Rx for meningeal TB?

A

RIPE prolonged course at least 12months + Steroids

268
Q

Erin Class I cellulitis?

A
  • no signs of systemic toxicity, no uncontrolled co-morbidities
269
Q

Erin Class II cellulitis?

A
  • systemically unwell or well with a co-morbidity that may complicate or delay resolution of infection
270
Q

Erin Class III cellulitis?

A

significant systemic upset or unstable co-morbidities that may interfere with response, or a limb-threatening infection due to vascular compromise

271
Q

Erin Class IV cellulitis?

A

sepsis syndrome or a severe life-threatening infection e.g. necrotising fasciitis

272
Q

Cellulitis - who to admit for IV Abx?

A
  • Eron class III/IV
  • severe/rapidly deteriorating cellulitis
  • v young <1yr or frail
  • immunocompromised
  • significant lymphoedema
  • facial or periorbital cellulitis
273
Q

Cellulitis Rx?

A

1st Flucloxacillin
if allergic then Clarithromycin/Clindamycin (of clindamycin if failure to respond to fluclox)

If severe then IV Benzylpenicillin + Flucloxacillin

274
Q

Cloudy CSF, low glucose, high protein, 10-5000 polymorphs?

A

bacterial meningitis

275
Q

Clear/cloudy CSF, 60-80% plasma glucose, normal/raised protein, 15-1000 lymphocytes?

A

Viral meningitis

276
Q

Slight cloudy CSF, fibrin web, low glucose, high protein, 10-1000 lymphocytes

A

Tuberculous meningitis

277
Q

If pt on flucloxacillin for cellulitis, and group A streptococcal infection confirmed - what should you do with Abx?

A

Switch to phenoxymethylpenicillin because it is more sensitive (but balance this with its variable absorption)

278
Q

Examples of alpha haemolytic streptococci?

A

(partial haemolysis)

  • pneumococcus (pneumonia, meningitis, otitis media)
  • strep viridans
279
Q

Examples of beta haemolytic streptococci?

A

(complete haemolysis)
Group A:
- pyogenes
- erysipelas, impetigo, cellulitis, type 2 nec fasc, pharyngitis/tonsillitis
- immunological reactions can cause rheumatic fever or post-strep glomerulonephritis
- erythrogenic toxins cause scarlet fever

Group B:
- strep agalactiae may leas to neonatal meningitis & septicaemia

Group D:
- enterococcus

280
Q

Chickenpox in pregnancy

  • risk to mother?
  • risk to fetus?
A 
Mum: 5X greater risk of pneumonitis
Fetus:
- fetal varicella syndrome
- shingles in infancy
- severe neonatal varicella (if mum gets rash between 5days before &amp; 2 days after birth, then risk of neonatal varicella, which may be fatal to newborn in 20%)
281
Q

Features of fetal varicella syndrome?

A
  • 1% risk if exposure before 20wks gestation
  • lower risk 20-28wks, virtually no risk after 28wks
  • skin scarring
  • microphthalmia
  • limb hypoplasia
  • microcephaly
  • learning disabilities
282
Q

Management of chickenpox exposure in pregnancy?

A
  • if unsure about prev chickenpox then urgently CHECK varicella Ab
  • VZIG asap if not immune to varicella (unto 10days after exposure)
  • pregnant women with chickenpox within 24h onset of rash: give PO aciclovir
283
Q

What is the tetanus vaccine?

A

cell-free purified toxin normally given as part of a combined vaccine
- 5 doses

284
Q

When to give IM human tetanus Ig?

A

anyone with high-risk wound irrespective of vaccination Hx

- if unknown/incomplete vaccination Hx then give a dose of tetanus vaccine + G

285
Q

Severe hepatitis in a pregnant coman - think?

A

hepatitis E

286
Q

hepatitis E

  • type of virus?
  • spread?
  • incubation period?
  • disease?
A

RNA hepevirus
faeco-oral
3-8wks incubation
- similar disease to hepatitis A but significant mortality 20% in pregnancy
- doesn’t cause chronic disease or inc risk of hepaticellular cancer

287
Q

Zika virus transmission?
Sx?
complications?

A
  • bite of infected Aedes mosquito (small number of sexual cases)
  • via placenta from mum-fetas
  • majority aSx
  • mild, short live 2-7days febrile illness
  • fever, rash, arthralgia, conjunctivitis, myalgia, headache, retro-orbital pain, pruritus
  • microcephaly & other congenital abnormalities
  • avoid conception 6months after illness, if worries
288
Q

Pathophysiology of CMV?

A
  • infected cells have an ‘Owl’s eye’ appearance due to intranuclear inclusion bodies
  • congenital, mononuleosis, retinitis, encephalopathy, pneumonitis, colitis etc
289
Q

Features of congenital CMV infection?

A 
growth retardation
pinpoint petechial 'blueberry muffin' skin lesions
microcephaly
sensorinueral deafness
encephalitis (seizures)
hepatosplenomegaly
290
Q

Features of CMV mononucleosis?

A
  • glandular fever-like illness

- may develop in immunocompetent individuals

291
Q

Features of CMV retinitis?

A
  • common in HIV with CD4<50
  • visual impairment
  • pizza retina of retinal haemorrhages & necrosis on fundoscopy
  • rx with IV ganciclovir
292
Q

What is cysticercosis?

Rx?

A
  • tapeworm parasite infection
  • Taenia solium (pork), Taenia saginata (beef)
    Rx = Niclosamide
293
Q

What is hydatid disease?

Rx?

A
  • dog tapeworm Echinococcus granulosus
  • life-cycle involves dogs ingesting hydatid cysts from sheep liver, often seen in farmers, may cause liver cysts
  • Rx = Albendazole
294
Q

What is chikungunya?
Sx?
Rx?

A
  • alpha virus disease caused by infected mosquitoes
  • abrupt onset high fever, severe joint pain
  • flu-like illness of muscle ache, headache, fatigue
  • shares Sx with dengue but more joint pain which can be debilitating
  • can get joint swelling & rash

Rx supportive

295
Q

HIV anti-retrovirals that inhibit p450?

A

Protease inhibitors e.g. ritonavir, indinavir, nelfinavir, saquinavir

296
Q

HIV anti-retroviral that induces p450?

A

NNRTI e.g. Nevirapine

297
Q

What causes amoebiasis?

A

Entamoeba histolytica (amoeboid protozoan)

  • spread faec-orally
  • 10% world has chronic infection
  • can be aSx, mild diarrhoea or severe amoebic dysentery
  • causes liver & colonic abscesses
298
Q

Clinical Sx of amoebic dysentery?
What is shown on stool microscopy?
Rx?

A
  • profuse bloody diarrhoea
  • stool microscopy may show trophozoites
  • Rx = Metronidazole
299
Q

Features of amoebic liver abscess?

A
  • usually single/multiple mass in right lobe of liver
  • fever, RUQ pain, bloody diarrhoea
  • serology positive in >90%
300
Q

What is the most common cause of cutaneous larva migrants?

Rx?

A

Ancylostoma braziliense
- common in central & southern america
Rx with Thiabendazole

301
Q

Features of strongyloides stercoralis?

Rx?

A
  • acquired percutaneously
  • causes pruritus & larva currens (moves through skin quicker)
  • abdo pain, diarrhoea, pneumonitis
  • may cause Gram negative septicaemia
  • sometimes eosinophilia

Rx: Thiabendazole, Albendazole (Ivermectin also used, esp in chronic infections)

302
Q

Commones cause of visceral larva migrans?
How is it acquired?
features?

A

Toxocara canis

  • ingesting eggs from soil contaminated by dog faeces
  • eye granulomas, liver/lung involvement
303
Q

Meningitis initial empirical Rx aged <3months?

A

IV Cefotaxime + Amoxicillin

304
Q

Meningitis initial empirical Rx aged 3months - 50yrs?

A

IV Cefotaxime

305
Q

Meningitis initial empirial Rx aged >50yrs?

A

IV Cefotaxime + Amoxicillin

306
Q

Rx for meningococcal meningitis?

A

IV Benzylpenicillin or Cefotaxime

307
Q

Rx for pneumococcal meningitis?

A

IV Cefotaxime

308
Q

Rx for meningitis caused by haemophilia influenza?

A

IV Cefotaxime

309
Q

Rx for meningitis caused by Listeria?

A

IV Amoxicillin + Gentamicin

310
Q

Meningitis contacts prophylaxis management?

  • risk highest in first 7days, but persists at least 4wks
  • if pneumococcal?
A

Ciprofloxacin
(2nd line Rifampicin)
- meningococcal vaccination when serotype results available, inc booster doses if already had vaccine in infancy
- unless cluster of cases of pneumococcal meningitis then Abx prophylaxis generally not indicated with pneumococcal

311
Q

MoA of antiviral agent Ribavirin?

A

Interferes with the capping of viral mRNA

312
Q 
Malaria prophylaxis of
Atorvaquone + Proguanil (Malarone):
side effect?
when to start?
when to end?
A

GI upset
start 1-2days before travel
end 7days after travel

313
Q 
Malaria prophylaxis of
Chloroquine:
side effects?
when is it C/I?
when to start?
when to end?
A
  • headache
  • C/I in epilepsy
  • take 1wk before travel, take weekly, end 4wks after travel
314
Q 
Malaria prophylaxis of
Doxycycline:
side effects?
when to start?
when to end?
A
  • photosensitivity, oesophagitis
  • start 1-2days before travel
  • end 4wks after travel
  • only licensed if above age 12
315
Q 
Malaria prophylaxis of
Mefloquine (Lariam):
side effects?
when is it C/I?
when to start?
when to end?
A
  • dizziness, neuropsychiatric disturbance
  • C/I in epilepsy
  • start 2-3wks before travel, tae weekly, end 4wks after travel
316
Q

Malaria prophylaxis of
Proguanil (Paludrine):
when to start?
when to end?

A
  • start 1wk before

- end 4wks after travel

317
Q

If travel can’t be avoided for a pregnant women to a malaria region:

  • why can Dx be difficult?
  • chloroquine?
  • proguanil?
  • malarone (atovaquone + proguanil)?
  • mefloquine?
  • doxycycline?
A
  • parasites may not be detectable in the blood film due to placental sequestration
  • chloroquine ok
  • proguanil - give late 5mg od
  • avoid malarian - if taken must take folate
  • mefloquine - caution
  • doxycycline contra-indicated
318
Q

What are the features of trichomoniasis?

A
  • trichomonas vaginalis = highly motile flagellated protozoan parasite
  • offensive yellow/green, frothy vaginal discharge
  • vulvovaginitis
  • strawberry cervix
  • pH>4.5
  • men usually aSx but can cause urethritis
319
Q

trichomonas vaginalis:
Ix?
Rx?

A
  • microscopy of a wet mount shows motile trophozoites

- Rx 5-7 days metronidazole

320
Q

H1N1 = subtype of influenza A virus

Features?
What may a minority develop?

A
  • fever >38, myalgia, lethargy, headache, rhinitis, sore throat, cough, D&V
  • minority may develop ARDS which may require ventilatory support
321
Q

2 main Rx for H1N1 influenza?

A

Oseltamivir/Tamiflu:

  • oral neuraminidase inhibitor which prevents new viral particles from being released by infected cells
  • common side-effects inc nausea, vomiting, diarrhoea, headaches

Zanamivir/Relenza:

  • inhaled neuraminidase inhibitor
  • may induce bronchospasm in asthmatics
322
Q

Features of non-falciparum malaria?

A
  • fever, headache, splenomegaly
  • vivax/ovale: cyclical fever every 48h
  • malariae: cyclical fever every 72h; ass with nephrotic syndrome
323
Q

Rx of non-falciparum malaria?

A
  • ACT (artemisinin-based combo therapy) or Chloroquine if in a chloroquine-sensitive area
  • ACT if chloroquine-resistant area
  • avoid ACTs in pregnant women
  • if ovale/vivax malaria, give PRIMAQUINE after acute Rx with chloroquine to destroy liver hypnozoites & prevent relapse (ovale & vivax malaria have a hypnozoite stage so may relapse after Rx)
324
Q

4 factors which reduce vertical transmission of HIV from 25-30% to 2%?

A
  1. maternal antiretroviral Rx
  2. mode of delivery (C-section)
  3. neonatal antiretroviral Rx
  4. infant bottle feeding
325
Q

Mode of delivery in pregnant women with HIV - when is vaginal delivery ok?
what should be started?

A
  • Vaginal delivery ok if viral load <50 copies/ml at 36wks, otherwise C-section
  • start Zidovudine infusion 4hours before starting C-section
326
Q

Neonatal antiretroviral therapy when mum has HIV?

A
  • oral Zidovudine to neonate if maternal viral load <50 copies/ml
  • otherwise triple ART
  • continue 4-6wks
327
Q

Cause of tetanus

A

tetanospasmin exotoxin released from clostridium tetani

  • tetanus spores in soil
  • tetanospasmin prevents release of GABA
328
Q

Features of tetanus?

A
  • prodrome fever, lethargy, headache
  • trismus/lockjaw
  • risus sardonicus
  • opisthotonus
  • spasms e.g. dysphagia
329
Q

Rx of tetanus?

A
  • supportive therapy inc ventilatory support & muscle relaxants
  • IM human tetanus IG for high-risk wounds
  • Metronidazole preferred Abx
330
Q

Cause & features of cat scratch disease?

A
  • Gram negative rod Bartonella henselae
  • fever, headache, malaise
  • regional lymphadenopathy
  • Hx of cat scratch
331
Q

Rx of syphilis?

A

IM benzathine penicillin
(or doxycycline)
- Jarisch-Herxheimer reaction sometimes seen with fever, rash, tachycardia after 1st dose due to release of endotoxins after bacterial death, within few hours of Rx

332
Q

Abx that may be sensitive to MRSA but shouldn’t generally be used alone because resistance may develop?

A 
rifampicin
macorlides
tetracyclines
aminoglycosides
clindamycin
333
Q

CXR makes you suspicious of an aspergilloma - what is the next best Ix step?

A

Serology for aspergillum precipitins - -high titres

334
Q

MoA of oseltamivir (tamiflu)?

A

Neuraminidase inhibitor

335
Q

MoA of cephalosporins?

A

They are a type of beta-lactam Abx which are bactericidal - less susceptible to penicillinases than penicillins

  • beta-lactams work by disrupting synthesis of bacterial cell walls, by inhibiting peptidoglycan cross-linking
336
Q

mechanism of resistance of cephalosporins?

A
  • changes to PBPs: penicillin-binding-proteins, which are a type of transpeptidases: enzymes produced by bacteria that cross-links peptidoglycan chains to form rigid cell walls
337
Q

bacterial vaginosis is an overgrowth of predominately which anaerobe?

A

Gardnerella vaginalis

338
Q

Strongyloides stercoralis = human parasitic nematode worm - larvae in soil and gain access to body by generating the skin.
What are the features?

A
  • abdo pain, bloating, diarrhoea
  • papulovesicular lesions where the skin has been penetrated by infective larvae e.g. soles of feet & buttocks
  • larva currens: pruritic, linear urticarial rash
  • if larvae migrate to the lungs a pneumnitis is triggered
339
Q

Rx of strongyloidiasis?

A

Albendazole

- ivermectin if chronic

340
Q

Features of cholera?

A
  • profuse ricewater diarrhoea, dehydration
  • hypoglycaemia
  • gram negative rod
341
Q

Rx of cholera?

A

oral rehdration therapy

Abx: Doxycycline, ciprofloxacin

342
Q

What is the most effective method to help differentiate between lymphoma and toxoplasmosis?

A

Thallium SPECT (positive in lymphoma)

343
Q

What is Brucellosis?

A

Zoonosis more common in middle-east/farmers
- incubation period 2-6wks
Main species that cause infection in humans:
B melitensis - sheep
B abortus - cattle
B canis & B suis - pigs

344
Q

Features of brucellosis?

A
  • fever, malaise, hepatospenomegaly, leukopenia, sacroilitis

- complications: osteomyelitis, infective endocarditis, meningoencephalitis, orchitis

345
Q

Dx of brucellosis:
screening?
most specific?

A

Rose bengal plate test for screening
Broccoli serology is best to confirm
- blood & marrow cultures can be suitable but often negative

346
Q

Rx of brucellosis?

A

doxycycline + streptomycin

347
Q

24y.o. man with a worsening headache to ED. He emigrated from Sudan two wks ago. Has a cough for 6wks. His GP did a tuberculin skin test (negative) has not responded to oral antibiotics. No PMHx/DHx. Blood tests show positive HIV serology but cryptococcal Ag negative, Toxoplasmosis serology is negative, and other tests are normal. CT: a single 3cm lesion & meningeal enhancement but no other abnormalities. What is the most likely organism that is responsible for his headache?

A

mycobacterium TB

  • tuberculin test often negative in immunosuppression
  • untreated HIV, probably low CD4 count
  • Sudan - high risk TB
  • cough 6 wks - TB
  • meningeal enhancement… TB
348
Q

MoA of amphotericin B?

A

Binds with Ergosterol = component of fungal cell membranes, forming pores that cause lysis of cell wall and subsequent fungal cell death

349
Q

What is Tularaemia?
How does it present?
Rx?

A

Zoonotic infection involving F. tularensis commonly transmitted through lagomorphs e.g. rabbits, hares, pikas but also in aquatic rodents & ticks
Variety of presentation, commonly erythematous papule-ulcerative lesion at site of bite with reactive & ulcerating regional lymphadenopathy
Rx = Abx e.g. doxycycline

350
Q

Opportunistic infections in HIV when CD4 200-500?

A

oral thrush
shingles
hairy leukoplakia (EBV)
Kaposi sarcoma

351
Q

Opportunistic infections in HIV when CD4 100-200?

A 
cryptosporidiosis
cerebral toxoplasmosis
progressive multifocal leukoencephalopathy 2ry to JC virus
PCP
HIV dementia
352
Q

Opportunistic infections in HIV when CD4 50-100?

A

aspergillosis
oesophageal candida
cryptococcal meningitis
1ry CNS lymphoma (EBV)

353
Q

Opportunistic infections in HIV when CD4 <50?

A

CMV retinitis in 30-40%

mycobacterium avium-intracellulare infection

354
Q

Ovale & vivax malaria have a hypnozoite stage so pts may relapse after Rx - what can be given to help prevent this?

A

PRIMAQUINE

- to destroy liver hypnozoites

355
Q

HIV seroconversion

  • when does it occur?
  • what are the features?
A
  • 3-12wks after infection in 60-80%
  • sore throat, malaise, myalgia, arthralgia, lymphadenopathy
  • diarrhoea, mouth ulcers, maculopapular rash
  • rarely meningoencephalitis
356
Q

Steps of HIV replication cycle?

A
  1. fusion of HIV to host cell surface
  2. HIV RNA, reverse transcriptase, integrase & other viral proteins enter the cell
  3. viral DNA formed by reverse transcription
  4. viral DNA transported across the nucleus and integrates into host DNA
  5. new viral RNA is used as genomic RNA and to make viral proteins
  6. new viral RNA & proteins move to cell surface and a new, immature HIV forms
  7. virus matures by protease releasing individual proteins: mature virion
357
Q

Giardiasis:
cause?
features?
Rx?

A
  • giardia lamblia, spead faeco-orally
  • often aSx, lethargy, bloating, abdo pain, flatulence
  • chronic diarrhoea, malabsorption & lactose intolerance can occur
  • stool microscopy for trophozoite & cysts classically negative, so duodenal fluid aspirates or ‘string tests’ sometimes needed
  • Rx metronidazole
358
Q

Cryptosporidium diarrhoea in HIV

  • Dx?
  • Rx?
A
  • intracellular protozoa with incubation period 7days
  • variable presentation
  • Dx: modified acid-fast Ziehl-Neelsen stain may reveal characteristic RED CYSTS
  • Rx generally supportive
359
Q

Mycobacterium avium intracellulare diarrhoea in HIV

  • when does it occur?
  • features?
  • Dx?
  • Rx?
A
  • atypical mycobacteria when CD4<50
  • fever, sweats, abdo pain, diarrhoea
  • sometimes deranged LFTs & hepatomegaly
  • Dx: blood cultures & bone marrow examination
  • Rx with Rifabutin + Ethambutol + Clarithromycin
360
Q

Diarrhoea causes in HIV?

A 
HIV enteritis
Opportunistic infections:
- cryptosporidium, other protozoa
- CMV
- mycobacterium avium intracellulare
- giardia
361
Q

Meningitis Rx if If the patient has a Hx of immediate hypersensitivity reaction to penicillins/cephalosporins, what does the BNF recommend?

A

Chloramphenicol

362
Q

What makes Plasmodium knowlesi infections particularly dangerous?

A

it has the shortest erythrocyte replication cycle, leading to high parasite counts in short periods of time
- severe parasitaemia is defined as >1%

363
Q

What are the 2 reproductive cycles of Plasmodium species?

A

Exo-Erythrocytic cycle (in hepatocytes)
Erythocytic cycle (in RBCs)
- the end stage involves lysis of red cells, and release of additional parasites

364
Q

A 28y.o. man who has recently emigrated from Nigeria presents with a penile ulcer. It initially started as a papule which later progressed to become a painful ulcer with an undermined ragged edge. Examination of the testes was unremarkable but tender inguinal lymphadenopathy was noted. What is the most likely diagnosis?

A

Chancroid (Haemophilus ducreyi)

  • papule then painful ulcer
  • ulcers typically have a sharply defined ragged undermined border
  • UL inguinal lymphadenopathy
365
Q

Viruses in genital warts?

A

HPV 6 & 11

366
Q

What is an atypical pneumonia?

A

Caused by bacteria that may not respond to penicillins/cephalosporins due to it lacking a peptidoglycan cell wall?

367
Q

Features of mycoplasma pneumonia?

A
  • typically prolonged & gradual onset
  • flu-like Sx classically precede a dry cough
  • BL consolidation on CXR
  • complications may occur
368
Q

Dx of mycoplasma pneumonia?

A
  • mycoplasma serology

- positive cold agglutination test

369
Q

Complications of mycoplasma pneumonia?

A
  • erythema multiform, erythema nodosum
  • thrombocytopenia, cold IgM agglutinins may cause a thrombocytopenia
  • meningoencephalitis, GBS
  • bullous myringitis: painful vesicles on the tympanic membrane
  • pericarditis/myocarditis
  • GI: hepatitis, pancreatitis
  • renal: acute glomerulonephritis
370
Q

How do the potential complications occur of falciparum malaria?

A
  • parasites ability to sequester blood cells in capillary beds -> ischaemia
371
Q

What is blackwater fever in malaria?

A
  • rare complication of malaria that can be fatal
  • large intravascular haemolysis -> haemoglobinuria, anaemia, jaundice & AKI
  • urine classically black/dark red
  • unknown cause
  • Rx = antimalarials, IV fluids +/- dialysis
  • urinalysis reveals blood NOT seen on microscopy (because it is Hburia)
372
Q

Erythema infectiosum = fifth disease = slapped-cheek syndrome

  • cause?
  • spread?
  • antenatal implication?
A

Parvovirus B19 = DNA virus

  • respiratory route spread
  • infectious from 3-5 days before appearance of rash, children no longer infectious once rash has appeared, with no specific Rx
  • if woman exposed in early pregnancy before 20wks, can affect unborn baby so should seek advice
373
Q

Presentations of parvovirus B19?

A
  • aSx
  • erythema infectiosum in kids
  • pancytopenia in immunosuppressed pts
  • aplastic crisis e.g. sickle cell disease (parvovirus suppresses erythropoiesis for a week, so aplastic anaemia is rare unless there is a chronic haemolytic anaemia)
374
Q

W?at viral meningitis can be associated with a low glucose level?

A

Mumps

Herpes encephalitis

375
Q

MoA of tetracyclines?

A
  • protein synthesis inhibitors

- bind to 30S subunit blocking binding of aminoacyl-tRNA

376
Q

Mechanism of resistance of tetracyclines?

A
  • increased efflux of bacteria by plasmid-encoded transport pumps, ribosomal protection
377
Q

Adverse effects of tetracyclines?

A
  • photosensitivity
  • discolouration of teeth
  • C/I in pregnancy/breastfeeding
378
Q

C/I to BCG vaccine?

A
  • previous BCG vaccine
  • past Hx of TB
  • HIV
  • pregnancy
  • positive tuberculin test (Heaf/Mantoux)
  • also not given to anyone over age of 35, as no evidence that it works in this age group
379
Q

Who to give BCG vaccine?

A
  • all infants <12m where annual incidence TB >40/100,000, or if parents born in a country with this incidence (extended unto 6rys, those above 6 need a tuberculin test first)
  • prev unvaccinated tuberculin-negative: contacts of cases of respiratory TB, new entrants under 16
  • healthcare workers, prison staff, staff of care home for elderly, those who work with homeless people
380
Q

What does BCG vaccine contain?

How is it administered?

A
  • live attenuated mycobacterium bovis; also offers limited protection against leprosy
381
Q

What does BCG vaccine contain?

How is it administered?

A
  • live attenuated mycobacterium bovis; also offers limited protection against leprosy
  • first give tuberculin skin test (unless under 6 with no prev TB contact)
  • intraDermally
382
Q

What is the rule on giving live vaccines together?

A
  • either together or minimum interval of 4 wks apart, to prevent risk of immunological interference
383
Q

Which pts immunised against hepatitis B require an anti-HBs check to assess their response to the vaccine?

A
  • occupational exposure e.g. healthcare workers

- those with CKD

384
Q

What type of bacteria is clostridium botulinum?

How does botulinum toxin work?

A
  • gram positive anaerobic bacillus, 7 serotypes A-G
  • neurotoxin irreversibly blocks release of acetylcholine both peripherally & centrally, often affecting bulbar muscles & autonomic nervous system
385
Q

Features of botulism?

Rx?

A
  • usually fully conscious with no sensory disturbance
  • diplopia
  • ataxia
  • bulbar palsy - often descending flaccid paralysis

Rx with Antitoxin - only effective if given early - once toxin has bound, its actions can’t be reversed

386
Q

Kaposi’s sarcoma:
what virus?
how does it present?
Rx?

A

HHV-8
- purple papules/plaques on skin/mucosa e.g. GI & resp tract
- skin lesions may later ulcerate
- resp involvement may cause massive haemoptysis & pleural effusion
Rx = RT & resection

387
Q

What organism is Listeria monocytogenes? What is an unusual property of it?
Features?

A

Gram positive bacillus
- can multiply at low temperatures

Variety of presentations inc:

  • diarrhoea, flu-like illness
  • pneumonia, meningoencephalitis
  • ataxia & seizures
  • particularly dangerous to unborn child (can lead to miscarriage)
388
Q

Ix for suspected Listeria?
What may CSF reveal?
Rx?

A
  • blood cultures
  • CSF may reveal a pleocytosis, with ‘tumbling motility’ on wet mounts
  • sensitive to amoxicillin/ampicillin (cephalosporins usually inadequate)
  • Rx listeria meningitis with IV amoxicillin/ampicillin + Gentamicin
389
Q

Listeria in pregnant women

  • Dx? Rx?
  • complications?
A

Pregnant women 20x more likely to develop listeriosis due to changes in immune system
- fetal/neonatal infection can occur both transplacentally & vertically during childbirth
Dx = blood cultures Rx = amoxicillin

  • miscarriage, premature labour, stillbirth, chorioamnionitis
390
Q

MoA of Vancomycin?

A
  • glycopeptide used in Gram +ve infections, esp MRSA
  • inhibits cell wall formation by binding to D-Ala-D-Ala moieties, preventing polymerisation of peptidoglycans (separate to beta-lactams)
391
Q

Mechanism of resistance of vancomycin?

A
  • alteration to the terminal amino acid residues of the NAM/NAG-peptide subunits (normally D-alanyl-D-alanine) to which the Abx binds
392
Q

Adverse effects of vancomycin?

A
  • nephrotoxicity
  • ototoxicity
  • thrombophlebitis
  • red man syndrome
393
Q

What is red man syndrome?

A
  • flushing/maculopapular rash, 2ry to non-IgE mediated mast cell degranulation
  • can occur on rapid infusion of vancomycin
  • Rx = antihistamines
394
Q

What can happen to the HR in typhoid fever?

A

relative bradycardia

395
Q

Genital herpes in pregnancy - when to Rx? - impact on delivery?

A

Recurrent herpes in pregnancy - Rx with suppressive therapy, blood transmission to baby is low
Elective C section if a PRIMARY attack occurs after 28wks

396
Q

Bisexual man with 7 day Hx of rectal discharge, pain on passing stools & tenesmus
O/E tender inguinal LN
proctoscopy - red mucosa with yellow discharge & some shallow ulcers
Dx?

A 
Chlamydia trachomatis (LGV proctocolitis)
- N.b. gonorrhoea similar but wouldn't cause ulcers
397
Q

Japanese encephalitis = flavivirus transmitted by culex mosquitos which breeds in rice paddy fields
- reservoir = aquatic birds; pigs are an amplification host
Clinical features if Sx?
Dx?

A
  • headache, fever, seizures
  • parkinsonian features indicate basal ganglia involvement
  • can also present with acute flaccid paralysis
  • Dx by serology/PCR
  • Rx = supportive
398
Q

Rx if low exposure to HIV?

A

Rpt STI screen in 2wks, HIV test in 8-12 wks

399
Q

Rx if high exposure to HIV?

A

Rapid Ag test +/- PEP

EXAM (21 decks)

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