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RW Pathology > Microbiology > Flashcards

Microbiology Flashcards

1
Q

Mechanism of action of Antibiotics

A 
Inhibit cell wall synthesis
------- β lactams(Penicillin, Cephlosporin, Carbapenems)
------- Glycopeptides (Vancoymycin, Teicoplanin)
Inhibit protein synthesis
------- Aminoglycosides (Gentamicin)
------- Tetracycline (Doxycycline)
------- Macrolide (Erythromycin)
------- Chloramphenicol
------- Oxazolidinones (Linezolid)
Inhibit DNA synthesis
------- Fluoquinolone (Ciprofloxacin)
------- Nitroimidazoles (Metronidazole)
Inhibit RNA synthesis
------- Rifamycin (Rifampacin)
Cell membrane toxin
------- Polymyxin (Colostin)
------- Cyclic lipopeptide (Daptomycin)
Inhibit folate metabolism
------- Sulfonamide (Sulphamethoxazole)
------- Diaminopyramidines (Trimethoprim)
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2
Q

Differences in cell structure in Gram +ve and Gram -ve

A

Gram +ve have thick peptidoglycan cell wall

Gram -ve have thin peptidoglycan cell wall + outer membrane

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3
Q

Inhibit cell wall synthesis

A
  • —– β lactams(Penicillin, Cephlosporin, Carbapenems)

- —– Glycopeptides (Vancoymycin, Teicoplanin)

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4
Q

Examples of βlactams

A 
Penicillin
---- Benzylpenicillin
Cephalosporin
---- 3rd gen: Ceftriaxone, Cefotaxime, Ceftrazidime
---- 2nd gen: Cefuroxime
---- 1st gen: Cephalexin
Carbapenams
---- Meropenam
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5
Q

MOA of β lactams

A

Bind to penicillin-binding proteins –> ↓cell wall cross links –> weaker membrane –> lysed

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6
Q

Risk of cross-reactivity between βlactams

A

10%

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7
Q

Co-amoxiclav

A

Amoxicillin + Clavulanic acid

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8
Q

Tazocin =

A

Piperacillin (β lactam) + Tazobactam (β lactamase inhibitor)

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9
Q

With ↑generation of cephalosporin

A

↑Gram -ve cover, ↓Gram +ve cover

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10
Q

Why is Cef (cephalosporin) often given with Metronidazole

A

Met provides anerobe cover

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11
Q

ESBL stands for

A

Extended spectrum β-lactams

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12
Q

ESBL Tx

A

Carbapenam-sensitive

Resistant to Penicillin and Cephalosporins)

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13
Q

Carbapenemase

A

Resistant to Pencillin, Cephalosporin and Carbapenem

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14
Q

Inhibit protein synthesis

A

Inhibit protein synthesis (cATOM)

  • —— Aminoglycosides (Gentamicin)
  • —— Tetracycline (Doxycycline)
  • —— Macrolide (Erythromycin)
  • —— Chloramphenicol
  • —— Oxazolidinones (Linezolid)
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15
Q

Example of Glycopeptides

A

Vancomycin, Teicoplanin

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16
Q

MOA of Glycopeptides

A

Bind to enzymatic target (peptidoglycan precursors) –> weakened cell wall –> lyse
Similar MOA in β lactams bt bind to substrate (precursors)

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17
Q

Nephrotoxic ABx

A

Gentamicin, Amikacin (aminoglycosides)

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18
Q

Example of Aminoglycoside

A

Gentamicin, Amikacin, Tobramycin

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19
Q

MOA of Aminoglycosides

A

Aminoglycoside binds to 30S ribosomal subunit to prevent causing misreading of dcodons along the mRNA–> inhibits protein synthesis

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20
Q

Example of Tetracycline

A

Doxycycline

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21
Q

MOA of Tetracycline

A

Binds to 30S ribosomal subunit to prevent aminoacyl-tRNA binding –> inhibits protein synthesis

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22
Q

Example of Macrolide

A

Azithromycin, Clarithromycin

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23
Q

MOA of Macrolide

A

Binds to 50S ribsomal subunit –> prevents binding of peptidyl-tRNA

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24
Q

MOA of Chloramphenicol

A

Binds to 50S ribsomal subunit –> Prevents formation of peptide bonds

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25
Q

Example of Oxazolidinone

A

Linezolid

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26
Q

Inhibit DNA synthesis

A

Inhibit DNA synthesis

  • —— Fluoquinolone (Ciprofloxacin)
  • —— Nitroimidazoles (Metronidazole)
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27
Q

MOA of Oxazolidinone

A

Binds to 23S component of 50S subunit to prevent formation of functional 70S initial complex

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28
Q

Example of Quinolone

A

Ciprofloxacin

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29
Q

MOA of Fluroquinolone

A

Bind to DNA gyrase –> inhibit DNA synthesis

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30
Q

Example of Nitroimidazole

A

Metronidazole, Nitrofurantoin (related)

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31
Q

MOA of Nitroimidazole

A

Under anerobic conditions, active intermediated is produced which causes DNA strand breakage

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32
Q

Inhibit RNA synthesis

A

Inhibit RNA synthesis

——- Rifamycin (Rifampacin)

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33
Q

Example of Rifamycin

A

Rifampicin

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34
Q

MOA of Rifampicin

A

Binds to RNA polymerase –> inhibits initiation –> Inhibits RNA synthesis
S/E organse secretions, Liver enzyme inducer

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35
Q

Cell membrane toxin

A

Cell membrane toxin

  • —— Polymyxin (Colostin)
  • —— Cyclic lipopeptide (Daptomycin)
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36
Q

Examples of cell membrane toxins + MOA

A

Daptomycin - inserts into cell membranes –> leak ions

Colistin –> unknown

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37
Q

Inhibit folate metabolism

A

Inhibit folate metabolism

  • —— Sulfonamide (Sulphamethoxazole)
  • —— Diaminopyramidines (Trimethoprim)
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38
Q

Example of Sulfonamide + MOA

A

Sulphmethoxazole –> interferes with folate metabolism

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39
Q

Example of Diaminopyrimidine + MOA

A

Trimethoprim –> interferes with folate metabolism

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40
Q

Co-trimoxazole =

A

Sulphamethoxazole + Trimethoprim

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41
Q

Mechanisms of ABx resistance

A

BEAT drug action

  • Bypass ABx sensitive step in pathway (Trimethoprim)
  • Enzymatic drug inactivation (β lactamase)
  • ↓Accumulation of drug (Tetracycline resistance) - ↓uptake or efflux
  • change drug Target (MRSA, Quinolone resistance)
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42
Q

β-lactamases - types, act against

A

Breaks down β lactams

  • β-lactamase (against Penicillin)
  • ESBL (against cephalosporins)
  • AmpC (against cephalosporins, not inhibited by Clavulanic acid)
  • Carbapenemase (against all β lactams)
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43
Q

MRSA - resistance mechanism

A

Altered target (mecA gene encodes novel PBP called PBP-2a)

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44
Q

Abx for ESBL

A

β-lactam + Aminglyocoside (Gentamicin, Amikasin)

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45
Q

ABx for MRSA

A

Vancomycin (or Linezolid)

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46
Q

Abx for C diff

A

Metronidazole (or Vancomycin)

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47
Q

Abx for Chlamydia

A

Doxycycline

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48
Q

ABx for bacterial conjunctivitis

A

Chloramphenicol

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49
Q

ABx for VRE

A

Linezolid

Daptomycin

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50
Q

Cover for anerobes

A

Metronidazole

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51
Q

ABx fo PCP

A

Co-trimoxazole = Trimethoprim + Sulphamethoxazole

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52
Q

ABx for UTI

A

Trimethoprim or Nitrofurantoin

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53
Q

ABx for Hospital UTI

A

Augmentin (or Cephalexin)

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54
Q

ABx for pseudomonas

A

Gentamicin, or Tazocin

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55
Q

Main ABx for S aureus

A

Flucluoxacillin

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56
Q

Main ABx for Skin infections

A

Flucluoxacillin +/- Vancomycin (if MRSA)

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57
Q

Main ABx for meningitis

A

Ceftriaxone +/- Amoxicillin (listeria cover)

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58
Q

ABx for pharyngitis

A

Benzylpenicillin (cover Group A strep)

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59
Q

ABx for CAP (mild)

A

Amoxicillin (cover Strep pneumoniae + Hib)

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60
Q

ABx for CAP (severe)

A

Co-amoxiclav + Clarithromycin

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61
Q

ABx for HAP

A

Amoxicillin + Gentamicin OR Tazocin

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62
Q

Abx for E. coli

A

Gentamicin

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63
Q

Define minimum inhibitory concentration

A

Least amount of drug required to inhibit growth of organism in culture
Assessed using agara disc diffusion (calculate from boundary of growing + inhibited growth)

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64
Q

Empirical ABx therapy

A

Use BSABx which is likely to cover the likely organisms

Then change based on culture sults to ↑specific/narrow agent

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65
Q

Pharmacokinetic/Pharmacodynamic ideal for Gentamicin

A

Peak above MIC (Cmax)

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66
Q

Pharmacokinetic/Pharmacodynamic ideal for Penicillin

A

Time above MIC

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67
Q

Causes of secretory diarrhoea (profuse, watery diarrhoea)

A 
Vibrio cholera
E coli (ETEC, ERPC, EHEC)
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68
Q

Causes of inflammatory diarrhoea (neutrophil in stools)

A

Campylobacter
Shigella
Salmonella (non-typhoidal)
EIEC

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69
Q

Causes of enteric fever (lymphocytes in stool)

A

Salmonella (typhoidal)
Yersinia spp
Brucella

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70
Q

Staphylococcus aureus

A

Aetiology: Pre-formed enterotoxin (exotoxin) –> superAg in GIT
Sx: Diarrhoea (non-bloody) and Vomiting
<6 hr incubation
Micro: Catalase +ve, Coagulase +ve, Gram +ve coccus, Clusters/Clonies, Protein A, β haemolytic on blood agar
Self-limiting

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71
Q

Bacillus cereus

A 
Reheated rice --> spre germinate
Microscopy: spore-forming Gram +ve rod
Aetiology: Heat stable emetic toxin (remains after heating) + Heat labile diarrhoeal toxin (can be destroyed by heating)
Sx: Watery diarrhoea (non-bloody)
<6hr incubation
Self-limiting
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72
Q

Clostridia botulinum

A

Gram +ve anaerobe
Canned/Vacuum packed food
Preformed toxin INACTIVATED by cooking (blocks Ach release from nerves)
Tx: Antitoxin

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73
Q

Clostrdia perfringens

A

Gram +ve anaerobe
Reheated meat
Watery diarrhoea +/- Vomiting (24 hours)
Incubation 8-16 hours

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74
Q

Clostridia difficile

A 
Gram +ve anaerobe
2 toxins (A, B)
Associated with ABx
Ix: Pseudomembranous colitis
Tx: 
(1) Metronidazole, Infection control
(2) Vancomycin
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75
Q

Listeria monocytogenes

A

Outbreaks of febrile gastroneteritis
Refrigerated food, Unpasteruised diary, Vegetables
Microscopy: β-haemolytic, aesculin +ve, tumbling motility
Sx: Watery diarrhoea, Fever, Vomiting
Tx: Ampicillin or Ceftriaxone

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76
Q

Types of E coli

A 
Diarrhoea +/- bloody (if haemorrhagic form)
Faecal-ortal route
Self limiting
- ETEC
- EIEC
- EHEC
- EPEC
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77
Q

ETEC

A

Toxigenic –> traveller’s diarrhoea

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78
Q

EIEC

A

Invasive dysentery

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79
Q

EHEC

A

Haemorrhage (shiga-like verocytotoxin) (Haemorrhagic 0157)

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80
Q

EPEC

A

Infantile diarrhoea (Paeds)

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81
Q

Salmonella typhi / paratyphi (enteric fever)

A 
Constipation (slow onset)
Rose spots
Splenomegaly
Anaemia, Leukopenia
Fever
Blood culture +ve
Multiples in Peyer's patches
Tx: Ceftriaxone
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82
Q

Salmonella enteritidis

A

Poultry, Eggs, Meat
Diarrhoea (non-bloody)
Self-limiting

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83
Q

Shigella

A

Shiga toxin –> affects distal ileum/colon
Fever
Bloody diarrhoea
Tx: avoid ABx

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84
Q

Vibrio cholerae

A

Rice water stool (with no inflammatory cells)
Enterotoxin A and B
Water contaminated with huan faeces
Tx: supportive

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85
Q

Vibrio parahaemolyticus

A

Raw undercooked seafood (in Japan)
Diarrhoea
Self-limiting
Tx: Doxycycline

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86
Q

Vibrio vulnificus

A

Water-bourne organism
Shellfish handler / Scuba diver
Fetal sepsis with D&V in HIV patients
Tx: Doxycycline

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87
Q

Campylobacter jejuni

A 
Upasteurised milk, poultry
Prodrome of headache + fever
Bloody diarrhoea (foul smelling)
Cx
- GBS
- Reactive arthritis
Tx: Erythromycin
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88
Q

Yersinia enterocolitis

A 
Food contaminated with animal faeces
Prefers cold environment (4o)
Enterocolitis
Mesenteric adenitis
Cx
- Reactive arthritis 
- Erythema nodosum
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89
Q

Mycobacteria

A

HIV patients

Diarrhoea

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90
Q

Entamoeba histolytica

A 
Mobile trophozoite found in diarrhoea
MSM
Food, water, soil
Non-motile cyst in non-diarrhoea illness
Histology: flask shaped ulcer
Dysentery
Flatuence
Tenesmus
Chronic weight loss
Liver abscess
Tx: Metronidazole
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91
Q

Giardia lamblia

A

Pear shaped trophozoite
Traveller / Hiker / MSM / Mental hospital
Ingesting cysts from faceally contaminated water
Non-bloody diarrhoea (foul smelling)
Flatulence
ELISA string test: string attached to ingested capules –> fished out
Tx: Metronidazole

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92
Q

Cryptosporidium parvum

A

Swimming
Oocysts seen in stool by modified Kinyoun acid fast stain
Severe diarrhoea in immunocompromised

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93
Q

Norovirus

A

Outbreaks
D&V
Cruse ships

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94
Q

Rotavirus

A

< 6 years old

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95
Q

Adenovirus

A

Type 40+41 –> non-blood diarrhoea
< 2 year olds
Immunocompromised

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96
Q

DDx Bloody diarrhoea

A

Shigella
Campylobacter
E coli

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97
Q

Hepatitis A transmission

A

Faecal-oral route (infected water)

RNA virus

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98
Q

Hepatitis A Serology

A

Anti-HAV IgM = recent infection

Anti-HAV = previous infection or vaccine

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99
Q

Hepatitis A disease course

A

↑ALT, ↑IgM

Later, ↑IgG

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100
Q

Hepatitis A - Tx

A

Supportive only

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101
Q

Hepatitis B - route of infection

A

dsDNA virus
Sexual
Vertical
Blood / needlestick

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102
Q

Hepatitis B - Ix

A

↑ ↑ALT, ↑AST
HBsAG (infection or vaccine)
HbcAb (acute IgM, chronic IgG)

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103
Q

Hepatitis B - Tx

A

PegIFN- α2a (direct anti-viral effect, upregulates MHC)
Tenofovir (RT inhibitor)
Lamivudine (inhibits viral polymerase)
Entecavir (inhibits viral polymerase)

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104
Q

Hepatitis C - route of infection

A

RNA virus

Blood products

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105
Q

Hepatitis C - Ix

A

ALT

Anti-HCV

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106
Q

Hepatitis C - Tx

A

PEG-IFN- α2b

Ribavirin

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107
Q

Hepatitis D

A

Only infect Hepatitis B +ve patients

Ix: IgM anti-HDV

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108
Q

Hepatitis E

A

RNA virus
Faecal-oral transmission
India
Tx: Supportive

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109
Q

Complications of Hepatitis B / C

A

Hepatitis –> Fibrosis –> Cirrhosis –> Cancer
↑ risk of Hepatocellular carcinoma
Liver transplant

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110
Q

uncomplicated vs complicated UTI

A

Complicated UTI has functional or structural abnormality (including: male, pregnancy, children, hospitalised)

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111
Q

Most common cause of UTI

A

E coli

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112
Q

Non E coli organisms causing UTI

A 
Proteus mirabilis
Klebsiella aerogenes
Enterococcus faecalis
Staphylococcus saprophyticus - only non-E-coli organism causing UTI in normal urinary stem
Staphylococcus epidermis
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113
Q

Routes of UTI

A

Ascending UTI or Haematogenous route (bacteraemia, endocarditis)

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114
Q

+ve nitrite indicates

A

Likely UTI

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115
Q

-ve nitrite AND +ve leukocyte

A

Urine culture

Treat if symptomatic

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116
Q

Nitrites are specific for

A

Coliform bacteria (have a reducing enzyme converting nitrates –> nitrites)

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117
Q

Urine leucocytes indicate

A

Inflammation

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118
Q

Definition of UTI

A

> 10,000 CFU / ml + urinary symptoms

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119
Q

DDx sterile pyruia

A

Chlamydia, TB

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120
Q

Urine microscopy showing squamous cells

A

Perineal contamination

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121
Q

Treatment of UTI

A

Trimethoprim or Nitrofurantoin

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122
Q

Treatment of Pyelonephritis

A

Co-amoxiclav +/- Aminoglycoside (Gentamicin)

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123
Q

Tx of complicated UTI (pregnancy, male)

A

Cefalexin or Co-amoxiclav

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124
Q

Candida UTI is associated with

A

Indwelling catheter

Tx: removal will cure

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125
Q

CSF: ↑WBC polymorphs, ↑↑protein, ↓glucose, turbid CSF

A

Bacterial meningitis

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126
Q

CSF: ↑WBC lmphocytes, ↑/ protein, glucose

A

Viral meningitis

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127
Q

CSF: ↑ WBClymphocytes, ↑↑Protein, ↓Glucose

A

TB meningitis

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128
Q

Meningitis, Gram +ve diplococci, α-haemolysis

A

Streptococcus pneumoniae

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129
Q

Meningitis, Gram -ve diplococci

A

Neisseria meningitidis

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130
Q

Meningitis, Gram +ve rods

A

Listera monocytogenes

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131
Q

India ink stain, MSM

A

Cryptococcus

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132
Q

Meningitis organisms

A

Neisseria meningitidis (Gram -ve diplococci)
Streptococcus pneumoniae (Gram +ve diplococci)
In neonates
—- GBS
—- Listeria
—- E coli

TB
Viral: Coxsackie, Mumps, HSV2
Fungal: cryptococcus

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133
Q

Tx for meningitis

A

IV Ceftriaxone

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134
Q

Tx for encephalitis

A

IV Aciclovir

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135
Q

Define Hospital acquired infection

A

infection > 48 hr of admission, 3 days discharge of 30 days of surgery, not present on admission

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136
Q

How common are HAI?

A

8%

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137
Q

Most common HAI

A

Hospital-acquired pneumonia

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138
Q

C. difficile - Gram, RF, Ix, Tx

A

Gram +ve, spore-forming anerobe
Risk factors: ABx
Ix: Pseudomembranous colitis
Tx: Metronidazole

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139
Q

E. coli - Gram

A

Gram -ve rod

Resistant to β-lactamases

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140
Q

Surgical site infection organisms

A

MRSA

Coagulase -ve Staphylococcus

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141
Q

Water-associated organisms

A

Legionella
Pseudomonas
Mycobacteria

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142
Q

Most common pathogens involved in surgical site infections

A

S aureus (MSSA, MRSA)
Less common
- E coli
- Pseudomonas

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143
Q

Tx for surgical site infection

A

Flucluoxacillin

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144
Q

Septic arthritis - organisms

A

Staph aureus (46%)
Streptococci (22%)
Less common: E coli

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145
Q

Septic arthritis - Sx

A

Fever
Red, hot, swollen joint
Unable to weight bear

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146
Q

Septic arthritis risk factors

A

RhA | OA | IVDU | DM | Immunosupression | Trauma

S aureus strain –> produces Panton-Valentine Leucocidin (PVL)

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147
Q

Septic arthritis - Ix

A

Blood culture
Joint aspirate > 50,000 WBC/mm3
ESR, CRP
Imaging: effusion

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148
Q

Osteomyelitis organisms

A 
S aureus (48%)
Less common: Gram -ve rods, Streptococcus
149
Q

Osteomyelitis - Ix for diagnosis

A

MRI - best imaging

Bone biopsy for culture/histology

150
Q

Osteomyelitis

A

ABx +/- debridement

151
Q

Prosthetic joint infection - organisms

A

Coagulase -ve Staph = Staphylococcus epidermidis ( > Staph aureus)
Streptococci spp.
Enterococci spp

152
Q

Prosthetic joint infection - Sx

A

Pain
Joint was ‘never right’ since operation
Early failure of jiont

153
Q

Prosthetic joint infection - Ix

A

X-ray: “Loosening”

Joint aspirate

154
Q

Prosthetic joint infection - Tx

A

Remove metalwork

Joint replacement

155
Q

Classical causes of Pneumonia

A 
Streptococcus pneumoniae
Haemophilus influenzae
Moraxella catarrhalis
Staphylococcus aureus
Klebsiella pneumoniae
156
Q

Most common cause of CAP

A

Streptococcus pneumoniae

157
Q

Streptococcus pneumoniae

A

Gram +ve diplococci (αhaemolysis)
Rusty coloured sputum
Lobar pneumonia

158
Q

Haemophilus influenzae

A

Gram -ve cocco-bacilli
Smoking
Pre-existing lung disaese (e.g. COPD)
Chocolate agar plate

159
Q

Moraxella catarrhalis

A

Gram -ve coccus

Smoking

160
Q

Staphylococcus aureus

A

Gram +ve cocci - “grape-bunch clusters”
Recent viral infection
CXR: cavitation

161
Q

Klebsiella pneumoniae

A

Gram -ve rod (enterobacter)
Alcoholics
Elderly
Haemoptysis

162
Q

Classical vs Atypical pneumonia - presentation

A

Classical - signs on chest exam + CXR
Atypical has NO signs on chest exam and normal CXR +/- extrapulmonary features (e.g. ↓Na+) + do not respond to β lactams

163
Q

Causes of atypical pneumonia

A 
Legionella pneumophila
Mycoplasma pneumonia
Chlamydia pneumonia
Coxiella burnetii (Q fever)
Chlamydia psittaci (Psittacosis)
Bordatella pertussis
TB
164
Q

Legionella pneumophila

A 
Water (air conditioning) / Travel
Hyponatraemia
Hepatitis
↓ WBC
Confusion
Diarrhoea
Ix: Urinary legionella antigens
Charcoal agar
165
Q

Mycoplasma pneumonia

A 
Epidemics (every 5 years)
Cold agglutinin test
Erythema multiforme
Risk of SJS
Autoimmune haemolytic anaemia
Joint pain
166
Q

Chlamydia pneumonia

A

NAME?

167
Q

Coxiella burnetii (Q fever)

A

Farm animal: Goat / Sheep / Cattle –> aerollised / infected milk

168
Q

Chlamydia psittaci (Psittacosis)

A

Birds

169
Q

Bordatella pertussis

A

Whooping cough

Unvaccinated (travelling community)

170
Q

TB

A

Poor response to ABx
Auramine-Rhodamine stain
Ziehl-Neelson stain

171
Q

Ix for pneumonia

A 
CURB-65 score > 2 warrants admission
Confusion
Urea > 7
RR > 30
BP < 90
Age > 65 years old
172
Q

Bronchitis vs Pneumonia

A 
Bronchitis = inflammation of medium sized airways
Pneumonia = inflammation of alveoli
173
Q

Bronchitis - organisms

A

Viruses
Streptococcus pneumoniae
H. influenzae
Moraxella catarrhalis

174
Q

Bronchitis - Tx

A

Bronchodilation, Physiotherapy

175
Q

Causes of cavitation on CXR

A

Staphylococcus aureus
Klebsiella pneumoniae
TB
Haemophilius influenzae

176
Q

Hospital acquired pneumoniae organisms

A 
Gram -ve
---- E coli
---- Klebsiella
---- Pseudomonas
Staph aureus
Fungi
Protozoa
---- Pneumocystis jirovecii
177
Q

Pneumocystis jirovecii

A 
Protozoan
Immunosupressed
Silver stain
Immunofluorescence
AIDS-defining illness
CXR: "bat's wing" or "bilateral ground glass shadowing"
Ix: Walkings sats test (definitive test for PCP)
Tx: Co-trimoxazole
178
Q

Aspergillus fumigatus

A 
MC+S: Hypae with flower heads
Allergic bronchopulmonary aspergillosis
--- Chronic wheeze
--- Eosinophilia
Aspergilloma
--- In pre-existing cavity
Invasive aspergillosis
--- Immunocompromised
179
Q

HIV with LRTI

A

PCP, TB, atypical mycobacteria

180
Q

Neutropenia with LRTI

A

Fungi (aspergillius)

181
Q

Bone marrow transplant with LRTI

A

CMV

182
Q

Splenectomy with LRTI

A

Encapsulated organisms (N meningitis, H influenzae, S pneumoniae)

183
Q

Cystic fibrosis with LRTI

A

Pseudomonas aeruginosa, Burkholderia cepacia

184
Q

Tx for CAP (mild)

A

Amoxicillin OR Macrolide (Clarithromycin / Erythromycin)

185
Q

Tx for CAP (severe)

A

Co-amoxiclav AND Macrolide (Clarithromycin)

186
Q

Tx for atypical pnemonia

A

Macrolide

187
Q

Tx for HAP

A

Ciprofloxacin +/- Vancomycin

188
Q

Tx for MRSA

A

Vancomycin

189
Q

Tx for pseudomonas

A

Tazocin OR Ciprofloxacin +/- Gentamicin

190
Q

Tx for aspiration pneumonia

A

Cefuroxime + Metronidazole (need Gram +ve, -ve and anaerobic cover)

191
Q

Tx for Legionella

A

Macrolide + Rifampicin

192
Q

Tx for S aureus

A

Flucloxacillin

193
Q

Slow growing mycobacteria

A 
MTB complex
---- M bovis (cows, BCG vaccine)
---- M tuberculosis
---- M africanum (West Africa)
---- M marinum (swimming pool granuloma), aquarium owners, plaques/papules
---- M ulcerans (chronic painless ulcer)
M avium complex
---- M avium
---- M avium intracellulare (invades bronchial tree in those with prexisting lung disease, children with pharyngitis)
194
Q

Rapidly growing mycobacteria

A

M abscessus complex –> skin/soft tissue infection

195
Q

Ungrouped mycobacteria

A

M leprae –> Leprosy (spectrum from few skin lesion to multiple skin lesions with profound disfigurement and nerve damage)

  • Depigmentation, Macules, Plaques, Nodules, Ulcers
  • Sensory neuropathy
  • Keratitis
  • Periositis aseptic necrosis
196
Q

Stain for mycobacteria

A

Acid fast bacilli
Auramine-Rhodamine stain: fluorescent AFBs
Ziehl-Neelsen stain

197
Q

Non-TB bacteria commonly found in

A

Water and Soil (in nature)

No person to person transmission

198
Q

Vaccination against TB

A

Bacille Calmette-Guerin (BCG) = live attenuated M. bovis strain

199
Q

TB is associated with

A 
Erythema nodosum
Pulmonary TB: Caseating granuloma
Lymphadenitis (scrofula)
GI TB
Peritoneal TB (ascites)
GU TB (sterile pyruia)
Spinal TB = Pott's disease (+/- Iliopsoas abscess)
Meningeal TB
Miliary TB (millet seeds on CXR)
200
Q

Histology of TB

A

Caseating granuloma

201
Q

Culture for TB

A

Lowenstein-Jense (LJ) medium (gold standard)

202
Q

Ix for speciation / drug resistance of TB

A

NAAT / PCR

203
Q

Tuberculin skin test +ve

A

Latent TB, Active TB or Vaccination

204
Q

IGRA = interferon γ release assay = ELISpot = Quantiferon

A

+ve in Latent TB and aactive TB

205
Q

S/E of TB treatment

A

Rifampicin - orange secretions, liver enzyme inducer
Isoniazid - peripheral neuropathy (Tx: Vitamin B6 / Pyridoxine)
Pyrazinamide - Hepatotoxic
Ethambutol - loss of colour vision, optic neuritis
Risk of immune reconstitution inflammatory syndrome (IRIS) in HIV patients

206
Q

% of world infected with TB

A

30%

207
Q

Risk of reactivation of latnet TB

A

10% lifetime risk

If HIV +ve –> this increases to 10% yearly risk

208
Q

Road to pandemic

A

Acquire mutations to break down species barrier / cross-over into humans
—- PB2 switch
—- Reassortment = ANTIGENIC SHIFT (co-infection between Bird flu and human flu –> viral proteins recombine –> allow infection of humans)
—- ANTIGENIC DRIFT = mutation in HA/NA to give new strains
Survive longer in environment (remain airbounr in mildly acidic resp droplets
Overcome barriers to infection (physical, chemical, receptor)

209
Q

Natural reservoir for Influenza A

A

Ducks

210
Q

Respiratory tropism is the result of

A

Influenza virus requires activation by host cell proteases only expressed in respiratory tract

211
Q

Infection by influenza

A

Attachment to sialic acid cell surface receptor –> endosome –> release viral DNA
HA must be cleaved for viral fusion to occur (airway tryptase only found in the lung)
Viral DNA to nucleus –> mRNA synthesis –> viral proteins –> virus buds off

212
Q

Most common cause of death from pandemics

A

Cytokine storm (hypercytokinaemia) –> acute respiratory distress syndrome –> pulmonary oedema –> death

213
Q

Influenza virus - number of genetic segments

A

8 RNA segments
Encodes for
- Neuraminidase (NA): cleaves sialic acid residues –> exposures receptors on host cell, disrupts mucus barrier
- Haemogglutinin (HA): binds sialic acid receptors –> viral entry (named for causing agglutination fo RBCs)

214
Q

Anti-virals for Influenza

A

Amantadine: targets M2 ion channel, most viruses already resistant
Oseltamavir (Tamiflu): neuraminidase inhibitor
Zanamivir (Relenxa)
(Favipiravir, Baloxavir): polymerase inhibitors [NEW]
Sialic acid

215
Q

Recent change in vaccination strategy since 2009 pandemic

A

Vaccinate children (intranasal flu vaccine) with live attenuated virus
Vaccinate healthcare works
Vaccinate elderly

216
Q

Link between Pandemic and Seasonal flu

A

Pandemics may drift and transform into seasonal influenza

217
Q

3 seasonal flus

A 
Influenza A (H1) - peaks in Jan
Influenza A (H1N1) - peaks in Dec
Influenza B (peaks in March)
218
Q

Most common cause of meningococcal disease in the UK

A

MenB

MenC / Hib / Pneumococcus now rare as vaccainated against

219
Q

TORCH screen

A 
Toxoplasmosis
Other - Syphilis, HIV, Hepatitis B/C
Rubella
CMV
Herpes
220
Q

TORCH infection - Sx

A 
Thrombocytopaenia
Other (cataracts, choroidoretinitis)
Rash
Cerebral abnormality (microcephaly)
Hepatosplenomegaly
221
Q

Toxmoplasmosis

A 
Cats --> Mice/Birds 
Cat litter
Asympatomatic at birth (60%)
40% symptomatic
- Choroidoretinitis
- Microcephaly
Long term: deafness, ↓IQ
222
Q

Congenital Rubella syndrome

A

Only risk if < 20 weeks’ gestation

Triad of cataracts, sensorineural deafness, congenital heart defects

223
Q

HSV

A

Lies in mother’s genital tracts

Congenital HSV - blistering rash, disseminated HSV, meningoencephalitis

224
Q

Early vs Late onset neonatal infection =

A

Early < 48 hours since birth

Late > 48 hours since birth

225
Q

Group B strep

A

Gram +ve coccus
Catalase -ve
β-haemolytic

226
Q

E coli

A

Gram -ve rod

227
Q

Listeria monocytogenes

A

Gram +ve rod

228
Q

Risk factors for early onset neonatal sepsis

A

PROM | PPROM | Chorioamniotis | Meconium staining | Acidosis | Hypoglycaemia | Jaundice

229
Q

Early onset neonatal sepsis - organisms

A

GBS - most common
E coli
Listeria monocytogenes

230
Q

Early onset neonatal sepsis - Tx

A

benzylpenicillin (covers GBS + Listeria) + Gentamicin (covers E coli)

231
Q

Late onset neonatal sepsis - organisms

A

Coagulase -ve Staphylococci
GBS | E coli | Listeria
S aureus
Gram -ve (Klebsiella, Enterobactera | Pseudomonas)

232
Q

Late onset neonatal sepsis - Tx

A

Cefotaxime + Vancomycin

233
Q

Neisseria meningitidis

A

Gram -ve diplococci

234
Q

Streptococcus pneumoniae

A

Gram +ve diplococus, α-haemolytic, optochin sensitive

235
Q

Haemophlius influenzae

A

Gram -ve rod, Chocolate agar (grows on haemolysed blood)/

236
Q

Meningitis organisms based on age

A

< 3 months: GBS, E coli, Listeria, N meningitis, S pneumoniae, Hib if unvaccinated
> 3 months: N meningitis, S pneumoniae, Hib if unvaccinated
> 6 years: N meningitis, S pneumoniae

237
Q

Respiratory infection organisms in children

A

Viruses
Then, S pneumoniae
Then, Mycoplasma (>4yr)

238
Q

Ix for ? Rubella infection in mothers

A 
Look for evidence of seroconveresion
Rubella IgM as marker of infection
PCR - gold standard (respiratory seretions, blood, urine)
Tx: < 20 weeks --> TOP
No documented risk > 20 weeks' gestation
239
Q

Congenital CMV - Ix

A

Prenatal Ix: amniocentesis
PCR, cell culture, DEAFF (cell culture), Serology (IgM, IgG)
Post-natal: urine + saliva swabs (CMV is shed in urine and saliva)

240
Q

Congenital CMV - Tx

A

Valganciclovir or Ganciclovir

241
Q

Congenital CMV - SX

A

90% asympatomatic at birth (10% will become symptomatic)

10% symptomatic at birth - hearing loss, microcephaly, choroidoretinitis, jaundice

242
Q

HSV infection has highest risk when

A

In 6 weeks before EDD ∴C-section is recommended

243
Q

Congenital HSV infection - Sx

A

Skin, Eye, Mouth disease - scarring, hypopigmentation
CNS disease - microcephaly
Disseminated infection

244
Q

Congenital HSV - Tx

A

IV Aciclovir

245
Q

VZV in early gestation cause

A

Congenital varicella syndrome

246
Q

VZV in late gestation lcauses

A

Neonatal varicella syndrome

247
Q

Tx for VZV exposure

A

VZIG within 10 days of exposure

Aciclovir if > 10 days post-exposure

248
Q

Measles infection in pregnancy

A

↑ risk of miscarriage

No congenital measles syndrome

249
Q

Parvovirus in pregnancy - Sx

A 
Slapped cheek syndrome
Aplastic crisis
Hydrops foetalis
Tx: intrauterine transfusion
No risk > 20 weeks gestation
250
Q

Congenital Zika syndrome

A

Microcephaly
Seizures
Retinopathy, Deafness

251
Q

Tx for HSV and VZV

A

(1) Aciclovir
(2) Valaciclovir (prodrug of AC)
(3) Famciclovir
Act Very Fast!

(2nd line) = Foscarnet or Cidofovir

252
Q

MOA of Aciclovir

A

Guanosine analogue –> activated by viral thymidine kinase –> ACP-PPP –> binds to viral DNA polymerase

253
Q

CMV - Histology

A

Owl’s eye inclusions

254
Q

CMV - Sx

A

Bone marrow suppression
Retinitis
Pneumonitis

255
Q

CMV - Tx

A

(1) Ganciclovir
(2) Foscarnet
(3) Cidofovir
Different as CMV does not have same enzymes

256
Q

MOA of Gancliclovir

A

Requires activation by viral UL97 kinase
Inhibits viral DNA synthesis
S/E: BM supression

257
Q

MOA of Foscarnet

A

Non-competitive inhibitor of viral DNA polymerase (does not require activation)

258
Q

MOA of Cidofovir

A

Nucleoside analogue -> competitive inhibitor of viral DNA synthesis

259
Q

MOA of Miribavir

A

Inhibits viral kinase

260
Q

MOA of Letermovir

A

CMV DNA terminase inhibitor

261
Q

EBV infects

A

B cells (lifelong low grade viral replcication)

262
Q

EBV is associated with

A

Post-transplant lymphoproliferative disease –> classical HL, Burkitt’s lymphoma
- Latently infected B cells –> polyclonal activation
Tx: ↓immunosuppression, Rituximab (Anti-CD20 Ab)”

263
Q

Tx for Bronchiolitis (RSV)

A

Ribavirn (Guanosine analogue –> inhibit viral RNA synthesis)
IVIG

264
Q

Prophylaxis for Bronchiolitis (RSV)

A

Palivizumab (mAb against RSV)

265
Q

BK virus - Sx

A

Only sympatomtic in immunocompromised

  • In bone marrow transplant –> Haemorrhagic cystitis (Tx: Cidofovir)
  • In renal transplant –> BK nephritis (Tx: IVIG)
266
Q

Most common cause of HSV drug resistance to ACV

A

Mutation in viral thymidine kinase

Tx: Foscarnet

267
Q

Most common cause of CMV drug resistance to GCV

A

Mutation in protein kinase gene (UL97)

Tx: Foscarnet

268
Q

Indications for treating chickenpox

A

Immunocompromised, Pregnant, Adults with pneumonitis

269
Q

Basic reproductive rate (R0)

A

Average number of individuals infected by infectious case during their infectious period
If R0 < 1 –> transmission is stopped

270
Q

Herd immunity threshold (HIT)

A

= 1 - (1/R0)

Percentage required to stop the spread of disease

271
Q

Inactivated vaccine

A

Pathogen destroyed by heat, chemicals, radiation or ABx
Unable to cause infection
e.g. Influenza, Polio

272
Q

Attenuated vaccine

A

Live organisms grow in un-natural host –> less virulent
Risk of reversion to virulence
Contraindicated in pregnancy and immunosuppressed patients
e.g. MMR

273
Q

Toxoid vaccines

A

Inactivated toxic component

e.g. Tetanus, Diphtheria

274
Q

Subunit vaccine

A

Protein component of pathogen

e.g. Hepatitis B, HPV

275
Q

Conjugate vaccine

A

Poorly immunogenic antigen with adjuvant

e.g. Hib

276
Q

Heterotypic vaccines

A

Pathogens that infect other animals but only cause mild disease in humans
e.g. BCG

277
Q

Contraindications for influenza vaccine

A

Anaphylactic hypersensitivity to egg

278
Q

Contraindications for MMR

A

Immunocompromised, Pregnant, Anaphylactic reaction to egg

279
Q

HIV fusion inhibitor

A

Enfuvirtide

280
Q

CCR5 co-receptor antagonist

A

Maraviroc

281
Q

NRTI

A

Zidovudine, Tenofovir

282
Q

NNRTI

A

Efavirenz

283
Q

Integrase inhibitor

A

Raltegravir

284
Q

Protease inhibitor

A

Ritonavir

285
Q

Yeast vs Mould

A

Yeast = individual cells (divide by budding from one another)
—- Candida
—- Cryptococcus
Mould = filamentous fungi
—- Aspergillus
—- Dermatophytes
N.B. Dimorphism (yest during infection, mould in nature)

286
Q

Fungal - superficial vs deep (definition, Ix)

A

Superficial (skin, hair, nails) vs Deep (systemic)
Ix for superficial - Woods Lamp for diagnosis (Tinea, Pityriasis)
Ix for deep - clinical Hx, Ix, Imaging for diagnosis (Candida, Aspergillus)

287
Q

Types of Candida

A

Candida albicans
Candida glabrata - resistant to 1st line azoles
Candida krusei - resistant to 1st line azoles
Candida tropicalis
Candida dubliniensis

288
Q

Candida microscopy

A 
Discrete colonies
Germ tubes (indicates likely C albicans)
289
Q

Candida culture

A

Chromogenic agar
MALDI-TOF technique
Sabouraud’s dextrose agar

290
Q

Candida - Ix

A

Microscopy
Blood cultures - candidaemia
Serology - β-D-Glucan assay

291
Q

Candida - Tx

A

Echinocandin (anidulafungin) - covers C albicans + non-albicans
+/- Fluconazole - covers C albicans

292
Q

Cryptococcus types

A

Cryptococcus neoformans
Cryptococcus gattii

Cryptococcus life cycle between Bird excrement and Eucalyptus trees
Often affects immunocompromised (esp HIV)

293
Q

Cryptococcus - Ix

A

India Ink staining –> Halo appearance
—- capsule protects cryptotoccus from being stained black
Enzyme immunoassay for Cryptoccocal antigen (gold standard)
CXR: pulmonary cryptococcoma

294
Q

Cryptococcus - Tx

A

Amphotericin B

295
Q

Aspergillus - microscopy

A

Filaments
Hyphae
Spores

296
Q

Aspergillus types

A 
Aspergillus fumigatus
Aspergillus flavus
Aspergillus niger
Aspergillus nidulans
Aspergillus terreus
297
Q

Aspergillus - Sx

A

Mycotoxicosis - ingestion
ABPA
Aspergilloma
Invasive aspergillosis

298
Q

Aspergillus - risk factor

A

Building work

299
Q

Aspergillus - Ix

A

Microscopy - mainstay of Dx
Culture
Galactomannan Ag
Aspergillus PCR

300
Q

Aspergillus - Tx

A

Amphotericin

301
Q

Dermatophtes

A 
Tinea pedia
Tinea cruris (groin area)
Tinea corporis (ringworm)
Tinea capitis (scalp)
Onychomycosis
Pityriasis versicolour - discolouration of skin (malassezia furfur)
302
Q

Mucormycosis - Sx + Tx

A

Black eschar (black pus)
Due to Rhizopus spp, Rhizomucar spp, Mucor spp
Tx: Surgical debridement + Amphotericin

303
Q

Types of anti-fungals

A 
Cell membrane anti-fungals
---- Azoles (Ketoconazole)
---- Polyene (Amphotericin B)
DNA synthesis anti-fungals
---- Flucytosine
Cell wall antifungals
---- Echinocandin (caspofungin)
304
Q

MOA of Azoles

A

Affects cell membrane synthesis
Bind to lanosterol 14 αdemethylase –> prevents conversion of lanosterol to ergosterol –> build up of toxic sterol –> cell death

305
Q

MOA of Polyenes

A

Affects cell membrane integrity

Forms transmembrane channels in fungal cell wall –> electrolyte leaks –> cell death

306
Q

MOA of Flucytosine (DNA synthesis antifungal)

A

Inhibits DNA synthesis in fungal cells

307
Q

MOA of Echinocandin (Caspofungin)

A

Affects cell WALL

Inhibits β(1,3) D-glucan synthase –> loss of cell wall glucan –> osmotic fragility –> lysis

308
Q

Pyrexia of unknown origin

A

Fever > 38.3 lasting > 3 weeks without diagnosis OR uncertain diagnosis after 7 days in hospital OR after sensible set of Ix

309
Q

Durack and Street criteria for PUO

A 
Classical PUO: PUO after > 3 days in hospital
- Infection
- Malignancy
- Connective tissue disorders
Healthcare-associated PUO: PUO after 24 hours in hospital
- Surgery
- Drugs
- Medical devices
- LRTI
Neutropenic PUO: Fever with neutropenia (medical emergency)
- Chemotherapy
- Haematology malignancy
HIV-associated PUO: HIV +ve patient with PUO
- Seroconversion
- TB
- Kaposi's sarcoma
310
Q

Routine Ix for PUO

A 
FBC, U&E, Protein, LFTs, CRP
HIV test
Blood culture x3
Urine culture
CXR
311
Q

Criteria for bacterial endocarditis

A

Duke’s criteria

312
Q

Macrophage activation syndrome

A

Associated with systemic-onset juvenile idiopathic arthritis
Sx: Fever, hepatosplenomegaly, pancytopenia, ↑ IFN-γ, GM-CSF
↓Hb, ↓Plt, ↓Neutrophils

313
Q

DDx Fever with Rash

A 
Dengue
Chikungunya
Rickettsial
Enteric fever (rose spots)
Measles
314
Q

DDx Fever with haemorrhage

A

Viral haemorrhagic fever (Dengue)

Meningococcaemia

315
Q

DDx with Eosinophlia

A

Acute schistosomiasis, Drug hypersensitivity

316
Q

DDx Fever with onset > 6 weeks after travel

A

Malarix vivax
Acute hepatitis
Amoebic liver abscess

317
Q

Types of malaria

A

Protozoa, Anopheles mosquito

  • P falciparum
  • P vivax
  • P ovale
  • P malariae
  • P knowlesi
318
Q

Malaria Sx

A 
Cyclical fever
Severe when parasitaemia > 2%
- Altered consciousness
- Metabolic acidosis
- Haemoglobinuria --> black water fever
- Anaemia
- Jaundice
- Coagulopathy
319
Q

Malaria - Ix

A

Thick blood film –> screen for parasites
Thin blood film –> identification of species
—- Falciparum is typically headphone shaped (cresent shaped) and RBCs have >1 intracellular parasite
Giemsa stain

320
Q

Malaria - Tx

A

Non-falciparum malaria –> Chloroquine, Primaquine (if G6PD normal)
Falciparum malaria
- Mild –> Atovaquone, Proguanil, Riamet (Artemisinin + Lumefantrine), Quinine
- Severe –> IV Artesunate

321
Q

Dengue fever - Sx

A

Fever
Sunburn-appearing rash - blanching
Tourniquet test +ve (mark left where skin was squeezed)
Retro-orbital headache

322
Q

Dengue fever - Ix

A

Dengue PCR

Serology IgM +ve

323
Q

Chikungunya virus

A

↑arthralgia (c.w. dengue)

324
Q

Enteric fever = Typhoid fever

A 
Salmonella typhi / paratyphi
High, prolonged fever
Rose spots
Constipation
Tx: IV Ceftriaxone + Azithromycin
325
Q

Infectiuos mononucleosis

A

EBV or CMV
Fever
Tonsillitis
Ix: atypical lymphocytosis, monospot test

326
Q

Campylobacter jejuni

A

Gram -ve rod
Chicken
Sx: Diarrhoea
Ix: Stool MC&S

327
Q

Salmonella

A

Gram -ve rod
Chicken, contaminated food, poor hand hygiene
India
Salmonella typhi/paratyphi –> enteric fever (rose spots, constipation)
Other strains –> enteritis

328
Q

Bartonella henselae

A

Gram -ve rod
Cat scratches
Cat scratch disease (immunocompetent) –> Macule, Fever, Night sweats,Weight loss
Bacilliary angiomatosis (immunocompromised) –> Skin papules, disseminated multi-organ involvement (hepatitis)

329
Q

Toxoplasmosis

A 
Toxoplasma gondii (parasiteº
Cats, Faecal contamination
Fever
Pregnant women --> fetal abnormalities
Immunocompromised --> CNS --> Seizures
330
Q

Brucellosis

A 
Gram -ve cocco-bacilli
Cattle, Unpasteurised milk
Fever, Sweats, Weight loss
Back pain,
Orchitis
331
Q

Coxiella burnetii (Q fever)

A

Goats, Unpasteurised milk/Aerolisation
Atypical pneumonia
NO RASH

332
Q

Rabies (LYSSA VIRUS)

A 
Dogs, Cats, Bats
Bites, Scratches, Infected fluid
Fever
Headache
Salivation
Agitation
Negri bodies (pathognomonic)
333
Q

Rat bite fever

A 
Streptobacillus moniliformis (Gram -ve rod)
Spirillum minus (Gram -ve rod)
Fever
Polyarthralgia
Maculopapular rash
334
Q

Hantavirus pulmonary syndrome

A

Deer mouse - Sin Nombre virus
Infected urine/droppings
Acute respiratory distress syndrome

335
Q

Viral haemorrhagic fever

A 
Includes
- Ebola (bats)
- Marburg (bats)
- Lassa (rats)
- CCHF (Ticks)
Thrombocytopaenia --> bleeding
Fever
336
Q

sCJD - Ix

A

Brain biopsy

337
Q

vCJD - Ix

A

MRI: Pulvinar sign

Tonsillar biopsy - only done for vCJG (NOT for sCJD)

338
Q

CJD - Tx

A

Symptomatic only

  • Clonazepam - for myoclonus
  • Quinacrine (anti-malarial) - delay prion conversion
  • Pentosan
  • Tetracycline
  • Anti-prion Ab
339
Q

vCJD vs sCJD

A

vCJD has younger age of onset + Psychiatry symptoms first (before neuro Sx)

340
Q

Sx of CJD

A 
Rapid progress dementia
Myoclonus
Cortical blindness
Akinetic mutism
LMN signs
341
Q

Sx of Kuru

A

Progressive cerebellar syndrome

342
Q

Sx of GSS

A

Dysarthria –> Cerebellar ataxia –> Dementia

343
Q

Sx of FFI

A

Insomnia –> Hallucinations

344
Q

Epidermodysplasia verruciformis

A

EVER1/2 mutation –> ↑risk of HPV infection

345
Q

AIDS defining conditions

A 
Oesophageal candidiasis
Cervical cancer (invasive)
CMV retinitis
Kaposi sarcoma (HHV8)
Burkitt's lymhoma
PCP
PML (JC virus)
346
Q

HIGH to LOW risk of opportunistic viral infections

A 
Allogenic stem cell transplant
Advanced HIV
Solid organ transplant
monoclonal antibody therapy
Cytotoxic chemotherapy
Steroids
347
Q

Progressive multifocal leukoencephalopathy

A

JC virus
Demyelination of white matter tracts
Focal neurological signs
Cognitive disturbance

348
Q

BK virus - Sx

A

Post-stem cell transplant –> BK cystitis
Post-renal transplant –> BK nephropathy
Tx: Cidofovir

349
Q

Types of helminths

A 
Cestodes = tapeworms
Trematodes = Flukes = no body cavity, gut
Nematodes = Roundworms = earthworm-like, body tubes ends in anus
350
Q

Pork tapeworm

A

Taenia solium

  • Eggs seen in faeces
  • Risk of cystericerosis (headache, seizures, confusion, major changes)
  • —— Faecal-oral transmission, not from uncooked meat
351
Q

Beef tapeworm

A

Taenia sagina

- Segments fall out of rectum

352
Q

Poor and Beef tapeworm - Sx

A

Onset after 2-3 months
D&V
White rice grains in stools

353
Q

Hyatid lifecycle

A

Normally Dog Sheep
Humans eat dogshit contaminated food
Tx: praziquantel +/- aspiration of cysts

354
Q

Schistosomiasis types

A 
S mansoni (Africa, S America) --> GI 
S haematoium (Africa) --> Bladder (haematuria)
S mekongi
S japonicum (China, Philippines) --> GI
355
Q

Schistosomiasis life cycle

A

Contaminated freshwater
Snails
Release into water
Infect through skin –> bladder or GI tract
Ix: Stool/urine microscopy (look fro eggs), Biopsy (bladder, rectum) granulomatous lesions with eggs
Tx: Praziquantel

356
Q

Ascaris

A

Contaminated soil

357
Q

Strongyloides

A

Contaminated mud –> foot –> lungs –> cough and swallowed –> SI –> eggs –> perianal skin
Walking barefoot

358
Q

Filariasis

A 
Blackflies vector
Lymphatics --> elephantiasis
SC tissues
Serous cavity
USS: Dance sign
359
Q

Myiasis

A 
Bot fly OR Tumbu fly
Non-healing skin lesion
Itchiness
Discharge from central punctum
Fly larve lies in skin and bursts out and flies away
NOT a worm
360
Q

Most common cause of adult-onset seizures

A

Cystericerosis

361
Q

Mechanism of cysticerosis

A

Contaminated pork eaten by Human 1 (asympatomatic, GI tapeworm, eggs excrete in faeces)
Faecal-oral transmission to Human 2 –> CYSTICERCOSIS (eggs mature, invade tissue –> form cysts)
Cysts may form in Brain, Muscles , Tongue

362
Q

Gram +ve rod (branches)
Alcoholics
Lung abscess
Microscopy: Basophilic granules, Grocott stain

A

Actinomyces

363
Q

Leishmania

A

Cutaneous - Sandy fly bite, skin ulcer
Diffuse cutaneous - nodular skin lesions
Muco-cutaneous - dermal ulcer
Visceral - Kala Azar, malnourished child, abdo discomfort, BM invasion, splenomegaly

364
Q

Leptospirosis

A

Dog/Rat urine, Swimming, Fever, Jaundice, Meningism, Carditis, Haemolytic anaemia

365
Q

Incubation period (1-6 hours)

A

S aureus, Bacillus cereus

366
Q

Incubation period (12-48 hours)

A

Salmonella, Escherichia coli (watery)

367
Q

Incubation period (48-72 hours)

A

Shigella (bloody), Campylobacter (flu prodrome)

368
Q

Incubation period (7 days hours)

A

Amoebiasis (bloody), Giardiasis (non-bloody)

RW Pathology (9 decks)

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