microbiology Flashcards
1
Q
cough + haemoptysis + fever + night sweats + weight loss + malaise for several weeks
A
TB
2
Q
what may induce reactivation a latent TB infection in patients?
A
immunosuppression chronic alcohol excess malnutrition ageing reinfection
3
Q
TB treatment 1st line
A
Rifampicin, Isoniazid (with B6 pyridoxine to prevent peripheral neuropathy), Pyrazinamide and Ethambutol for 2 months then Rifampicin and Isoniazid for the next 4 months
4
Q
Rifampicin Side effects
A
orange-red secretions (tears/ urine etc) induces cytochrome p450 - many drug interactions
5
Q
Isoniazid Side effects
A
peripheral neuropathy (give B6 pyridoxine) hepatotoxicity
6
Q
Pyrazinamide side effects
A
hyperuricaemia, neurotoxicity
7
Q
Ethambutol side effects
A
optic neuritis, visual disturbances
8
Q
TB meningitis tx?
A
all four drugs (RIPE) for 2 months then R+I for next 10 months
9
Q
Latent TB treatment?
A
Isoniazid alone for 6 months or Isoniazid + rifampicin for 3 months
10
Q
Ghon focus
A
TB - Ghon focus refers to a calcified tuberculous caseating granuloma - subpleural
11
Q
caveating granulomas in the lung, upper lobes usually affected. may progress rapidly to cavitation.
A
TB
12
Q
how to diagnose/ investigate a TB infection?
A
Imaging: CXR/ CT For diagnosis- Culture: sputum (x3) for microscopy (ZN/ aura mine staining showing gram +ve rods, acid fast, aerobic, intracellular)
13
Q
screening for TB infection?
A
Mantoux test (a type IV hypersensitivity) - but also positive in those with BCG vaccination/ latent TB IGRA (IFN gamma release assay) - cannot distinguish active and latent TB but no cross reaction w BCG vaccination
14
Q
Auramine- rhodamine stain
A
+ve for mycobactacterium helps visualise acid fast bacilli
15
Q
ziehl Neelson stain/ lowenstein-jensen medium
A
+ve for mycobacterium
16
Q
BCG vaccine contains an attenuated strain of?
A
mycobacterium bovis
17
Q
BCG vaccine used in?
A
at risk babies. e.g. from areas of high prevalence/ TB contacts contraindicated in HIV pts
18
Q
spinal TB disease
A
Potts disease fever, sweats, weight loss, back pain verterbral destruction + collapse + anterior extension (causing iliopsoas abscess)
19
Q
pneumonia, low Na, hepatitis, assoc w travel, air conditioning units and water towers
A
legionella pneumophlia
20
Q
most common cause of lobar pneumonia, rusty coloured sputum. what organism?
A
strep pneumoniae
21
Q
pneumonia associated with recent viral infection (e.g. post influenza) + cavitation on CXR what organism?
A
staph aureus
22
Q
pneumonia associated with heavy smoking and COPD what organism
A
haemophilus influenzae a gram -ve rod
23
Q
pneumonia associated with alcoholism, elderly people and usually presents w haemoptysis. what organism
A
klebsiella pneumonia gram -ve rod
24
Q
community acquired pneumonia associated with smoking. microscopy and staining shows a gram -ve coccus.
A
Moraxella catarrhalis
25
pneumonia associated with younger children to young adults, may trigger erythema multiforme (SJS), cold agglutinin test (AIHA).
mycoplasma pneumonia
26
most common cause of atypical pneumonia in adults
mycoplasma pneumonia
27
atypical pneumonia associated w birds, splenomegaly, rash and haemolytic anaemia
chlamydia psittaci
28
pneumonia with poor response to Abx, where CXR shows upper lobe cavitation. Dx on Auramine/ Zn stain
TB
29
pneumonia associated with farm animals and hepaitis
coxiella burneti (Q fever)
30
pneumonia/ whooping cough in those unvaccinated.
bordatella pertussis
31
what organisms cause Pneumonia assoc w HIV
Pneumocystis Jiroveci (PCP) esp if CD4\<200 TB Cryptococcus neoformans
32
most common causes of pneumonia in a 0-1 month old
e coli GBS listeria
33
most common causes of pneumonia in a 1-6 month old
chlamydia trachomatis staph aureus RSV
34
most common causes of pneumonia in a 6 month to 5 yr old
mycoplasma pneumonia, influenza
35
most common causes of pneumonia in a 16-30 yr old
mycoplasma pneumonia, strep pneumoniae
36
most common resp tract infection if one has neutropenia
fungal infection- aspergillus spp
37
silver GMS (Gomori methenamine silver) stain +ve, boat shaped organisms, bilateral ground glass shadowing on CXR
pneumocystis jiroveci PCP
38
post splenectomy- more at risk of which organisms?
n meningitidis s pneumonia h influenza
39
what organisms are associated with chronic infection in cystic fibrosis patients?
pseudomonas aeruginosa burkholderia cepacia (v high mortality)
40
post bone marrow transplant lung infection - what organisms
Aspergillus + CMV
41
what organisms can you test for with urine antigen test? (pneumonia)
strep pneumoniae legionella
42
in pneumonia, antibody tests - paired serum samples comparing values at presentation and 2 wks after- are useful with?
organisms that are difficult to culture. can show the rise of Ab over time. e.g. chlamydia, legionella
43
Community acquired pneumonia 1st line tx if mild-moderate severity?
Amoxicillin or Clarithromycin if penicillin allergic for 5-7 days
44
community acquired pneumonia 1st line if moderate-severe severity?
co-amoxiclav + clarithromycin for 2-3 wks if pen allergic: cefuroxime + clari
45
atypical pneumonia 1st line?
protein synthesis inhibitors clarithromycin + doxycycline
46
what Ix is useful in pneumonia?
FBC, WCC, CRP, U&Es Blood cultures, Sputum MCS ABG (Cap blood gas in children) CXR
47
CURB-65
if 2-5 admit to hospital. manage as severe
48
Pseudomonas pneumonia tx?
Piperacillin + tazobactam (Tazocin) or Ciprofloxacin +/- Gentamicin
49
MRSA pneumonia tx?
Vancomycin
50
Staph aureus pneumonia Tx?
flucloxacillin
51
Legionella Hosp acquired pneumonia Tx?
clarithromycin + rifampicin
52
Hospital acquired pneumonia 1st line tx?
Ciprofloxacin + Vancomycin
53
Hospital acquire pneumonia 2nd line/ in ITU?
Piptazobactam + Vancomycin
54
Aspiration pneumonia tx?
need gram +/ - and anaerobic cover cefuroxime + metronidazole
55
what causes genital ulcers?
painful- herpes simplex, chancroid painless- syphilis, donovanosis, LGV
56
what may cause rashes/ lumps/ growths in the genital area?
genital warts- HPV pubic lice scabies molluscum contagiosum
57
what is the most common cause of septic arthritis in a young adult?
neisseria gonorrhoea
58
complications of gonorrhoea
bartholins abscess salpingitis with irreversible tube damage, infected males - dysuria, frequency, mucopurulent discharge, prostatitis
59
disseminated gonococcal infection symptoms? who gets it?
pts with complement deficiencies present with fever, vasculitic rash, arthritis, septicaemia
60
Diagnosis of gonorrhoea
urethral / rectal smears MCS - gold standard gram -ve diplococcus
61
treatment for gonorrhoea
IM ceftriaxone if resistant- spectinomycin IM
62
what chlamydia serovars are associated with genital tract infection?
chlamydia trachomatis serovars D-K
63
how to diagnose chlamydia STI?
NAAT (nucleic acid amplification tests) are gold standard as chlamydia is an obligate intracellular pathogen and cannot be cultured on agar
64
complications of chlamydia STI
chronic pelvic pain ascending salpingitis-\> PID increased risk ectopic and infertility increased risk endometriosis epididymitis reiters syndrome adult conjunctivitis opthlalmia neonatorum
65
tx of chlamydia
doxycycline BD for 7 days or Azithromycin stat
66
tx of chlamydia in pregnancy
azithromycin
67
SEs of Doxycycline
photosensitivity, contraindicated in pregnancy due to disturbance of bone growth and discolouration of immature bones
68
Lymphogranuloma venereum - what organism?
chlamydia trachomatis serovars L1,2,3 causing a lymphatic infection
69
Lymphogranuloma venereum presentation
generally painless ulcer + balanitis, proctitis, cervicitis -\> painful inguinal buboes + inguinal lymphadenopathy (2/3 unilateral) -\> abscess formation rectal presentations - more common in MSM in developed world. pain, tenesmus, rectal bleeding, mucous discharge.
70
chlamydia: exists in two forms. which forms are stable and extracellular, and which are intracellular and metabolic active?
elementary bodies- stable and extracellular reticulate particles- intracellular and metabolically active
71
Lymphogranuloma venereum tx?
same as chlamydia but for longer doxycycline for 21 days or azithromycin once a wk for 3 wks/ erythromycin for 21 days
72
syphilis organism?
treponema pallidum an obligate gram -ve spirochaete
73
diagnosis of syphilis?
to diagnose: detect antibodies against T pallidum antigens e.g. TPHA (t palladium haemagluttinin test) TPPA (t pallidum particle agglutination test) tests
74
what test is useful to monitor response to treatment of syphilis?
RPR as titre falls in response to treatment
75
syphilis tx?
IM single dose benzathine penicillin if pen allergic doxycycline -monitor RPR, need a four fold reduction for tx to be considered successful
76
common side effect of syphilis tx that causes fever, headache, myalgia and usually clears within 24 hours?
JH (jarisch-heimer) reaction
77
primary syphilis presentation
painless genital ulcer often solitary. may persist for 4-6 wks. + bilateral lymph node enlargement
78
secondary syphilis presentation usually few months after infection
maculopapular rash on back, trunk, face, palms, soles mucosal lesions e.g. oral ulcers, genital warts low grade fever, malaise neuro involvement - cranial n palsies, optic neuritis, acute nerve deafness
79
latent syphilis?
no obvious signs but serology positive
80
neurosyphilis presentation
argyll-robertson pupil - accommodates but does not react to light. small, irregular pupils. CSF shows spirochaete. psychosis with muscular reflex abnormality, dementia and seizures.
81
pupils accommodate but do not react to light.
argyll-robertson pupil in neurosyphilis
82
congenital syphilis presentation?
hepatosplenomegaly, rash, fever, neurosyphilis and pneumonitis. often develops over the first 2 years of life.
83
neurosyphilis tx?
procaine penicillin
84
chancroid what organism responsible?
haemophilus ducreyi a gram -ve cocobacillus
85
tropical ulcer disease, frequently painful multiple ulcers. diagnosis via chocolate agar medium culture + PCR
chancroid.
86
protein synthesis inhibitors - abx
30s subunit (AT) Aminoglycosides e.g. Gentamicin Tetracyclines e.g. Doxycycline 50s subunit (MOC) Macrolides- e.g. clarithromycin, erythromycin Oxazolidinone e.g. Linezolid Chloramphenicol
87
molluscum contagiosum, what organism?
pox virus
88
donovonasis = granuloma inguinale, what organism?
klebsiella granulomatis. gram -ve bacillus
89
large expanding ulcers starting as papule or nodule that breaks down. + beefy red appearance. diagnosis via Giemsa stain of biopsy + Donovan bodies
donovanosis
90
donovanosis tx
azithromycin
91
greenish gray offensive discharge in women. + vulval soreness. O/E strawberry cervix diagnosis shows flagellated protozoan
trichomonas vaginalis trichomoniasis
92
Trichomoniasis tx
metronidazole
93
clue cells, high pH, whiff test +ve
bacterial vaginosis tx with metronidazole. assoc w preterm delivery
94
white thick discharge, itching, soreness, redness. usually assoc w pregancy, diabetes mellitus, HIV, use of ABx, other immunosuppressive drugs
candidiasis candida albicans
95
candidiasis tx?
oral fluclonazole, topical clotrimoazole
96
facial molluscum contagiosum in adults?
HIV until proven otherwise
97
if tx required for molluscum contagiosum?
cryotherapy
98
genital warts tx?
1st line home tx: podophyllotoxin cream 2nd line: imiquimod or clinic tx- cryotherapy
99
seborrhoea dermatitis what organism?
malassezia furfur aka pityrosporum orbiculare
100
tinea/ pityriasis versicolor (depigmentation in those with dark skin) what organism?
malassezia furfur aka Pityrosporum orbiculare
101
athletes foot aka tinea pedis what organism?
most commonly - trichophyton rubrum caused by dermatophytes - fungi which inhabit dead layers of the skin and digests keratin
102
invasive candidiasis tx?
amphotericin B
103
often presents as pneumonia in immunocompromised, assoc with building work, cavitating lesion. also produces aflatoxin B1 which is carcinogenic and increases risk of Hepatocellular carcinom
aspergillus
104
tx for aspergillus
voriconazole
105
fungus that grows on czapek dox agar
aspergillus
106
insidious onset meningitis in HIV/ immunocompromised patients + associated with birds/ pigeons!
cryptococcus
107
tx of cryptococcal infection
amphotericin B
108
roseola infantum aka?
exanthem subitum
109
Roseola infantum - what causative organism?
HHV6
110
most common cause of febrile convulsions
Roseola infantum HHV6 infection
111
CMV complications in immunocompromised
pneumonitis (in post BMT patients) retinitis (AIDs) hepatitis
112
1st line tx of CMV infection
ganciclovir
113
Infant with IUGR, jaundice, hepatosplenomegaly, microcephaly, chorioretinitis, late progressive sensorineural deafeness, with periventricular calcification.
CMV congenital infection
114
Owls eyes inclusions highly specific for?
CMV infection !! different from owls eyes appearance of entire nucleus (pathognomonic of reed Sternberg cells of Hodgkins lymphoma)
115
diagnosis of CMV?
serology- IgM and IgG CMV (if primary infection, IgM will be dominant) Blood PCR
116
reactivation of CMV in post-transplant patients may cause?
encephalitis, bone marrow suppression, pneumonitis, hepatitis
117
what is a worrying complication of genital HSV infection
urinary retention
118
if pregnant woman gets primary HSV infection during third trimester, tx?
before treating, do check if this is primary infection - type specific HIV Ab test oral acyclovir 6 weeks before estimated delivery date. if primary infection and less than 6 wks til estimated delivery, c-section
119
neonatal HSV presentation
greatest risk of transmission from mother to fetus is if mother gets primary infection in third trimester (greatest at delivery) assoc w foetal loss, skin, eye, mouth lesions -\> long term ocular and neuro sequelae encephalitis disseminated disease + vesicles (high mortality rate due to fulminant hepatitis and multi organ failure)
120
neonatal HSV tx?
IV aciclovir
121
complications of HSV?
erythema multiforme eczema herpeticum herpetic whitlow - painful red finger herpes gladiators - painful blisters + inguinal LNapothy, rugby players/ wrestlers
122
what do you expect to see in a fetus with congenital varicella syndrome?
limb hypoplasia eye defects - cataracts, choreoretinitis skin scarring neuro defects - microcephaly, cortical atrophy disseminated haemorrhagic varicella infection if within 7 days of delivery - purpura fulminans (30% mortality)
123
chicken pox post exposure prophylaxis
VZIG, within 10 days of exposure.
124
in pregnant women, increased risk of which complications with chicken pox infection?
pneumonitis encephalitis hepatitis
125
complications of shingles (VZV reactivation)
painful rash in specific dermatome
post herpetic neuralgia
ramsay-hunt syndrome (reactivation in facial n near ear- vesicles in ear, hearing loss, facial n palsy)
Guillain-barre syndrome
126
infectious mononucleosis most common cause
EBV
127
fever, tonsillar enlargement + exudates, pharyngitis, lymphadenopathy + splenomegaly + maculopapular rash + atypical lymphocytosis
glandular fever, infectious mono
128
diagnosis of infectious mono?
blood film (atypical lymphocytes)
EBV antibodies (IgM EBV)
Paul Bunnell test/ monospot test
129
important risk/ complication of infectious mono?
risk of splenic rupture -\> may need abdo USS and splenectomy ask patients to avoid contact sports for next few wks
130
HHV8 assoc with?
Kaposis Sarcoma Castlemans disease (non cancerous growth in the Lymph nodes) Primary effusion lymphoma (HIV associated malignant effusions without tumour mass)
131
PUO? definition?
\>38.3 fever on several occasions persisting \>3/52 without diagnosis despite \>1/52 of intensive Ix
132
which malaria species causes a quartan fever?
a quartan fever is one every 72 h plasmodium malariae
133
which malaria species causes a tertian fever?
a tertian fever is one every 48h plasmodium falciparum p vivax p ovale
134
fever in returning traveller- always consider?
malaria, dengue, typhoid fever, bacterial diarrhoea etc
135
what organisms cause typhoid/ enteric fever?
salmonella typhi and paratyphi
136
infecting Peyer's patches. Rose spots, fever, headache, abdo pain, constipation, relative bradycardia, hepatosplenomegaly.
Typhoid fever -salmonella typhi/ paratyphi. - gram -ve rods
137
typhoid fever tx?
Iv fluids, IV/oral abx (Ceftriaxone)
138
diagnosis of typhoid fever?
blood cultures (usually bactaraemia present) stool culture shows gram - rod
139
which organism causes the most severe form of malaria
p falciparum
140
which organism causes a benign Malaria which may manifest more than 1 year after infection?
plasmodium malariae
141
which organisms cause the more indolent malaria, with hypnozoites in the chronic liver stage?
p vivax and p ovale
142
what is primaquine used for?
eradicates hypnozoites which are dormant forms in the life cycles of the plasmodium species. - useful in p vivax and p ovale
143
blood film shows young trophozoites (rings) in the absence of mature trophozoites and schizonts. crescent-shaped gametocytes. + Bloods show \>2% parasitaemia
p. falciparum malaria infection
144
blood film shows schuffners dots
p vivax and p ovale
145
blood film shows schuffners dots and \>20 merozites/ schizont
p vivax
146
p falciparum tx?
exchange transfusion if \>10% parasitaemia
if uncomplicated: Quinine + doxycycline or Clindamycin if pregnant or
Malarone (Atovoquone/ Proguanil) or
Riamet (artemether/lumefantrine)
if complicated: IV artesunate
medical emergency
Always admit!!!
147
p vivax and p ovale tx?
choroquine then primaquine
148
what is the thick and thin blood film used for?
thick blood film used to diagnose malarial infection
thin blood film to allow species identification
149
Primaquine - contraindications?
contraindicated in pregnancy and breastfeeding
and increases risk of haemolysis in G6PD deficiency
150
fever, splenomegaly, rigors, headache, flu-like illness, myalgia, n+v
+
thick blood film +ve
malaria
151
malaria ix?
70% patients have low Platelets,
50% deranged LFTs,
30% anaemia
if severe:
acidosis, renal impairment, hypoglycaemia, anaemia, DIC, shock, haemoglobinuria, jaundice
152
first line tx of UTI?
trimethoprim
nitrofurantoin in pregnancy
153
quinine side effects
nausea, deafness, tinnitus, monitor blood glucose
IV:
arrhythmogenic and causes hypoglycaemia
-\> cardiac and Blood gluc monitoring
154
fever, headache, myalgia, eschar (dark scab/ falling away of dead skin)
- \> vasculitis
- \> spread by vector: tick, mite, lice
Rickettsia
155
rickettsia tx?
doxycycline
156
what abx inhibit cell wall synthesis?
Beta lactams
- Penicillins e.g. Benzylpenicillin
- Cephalosporins e.g. Ceftriaxone
- Carbapenems e.g. meropenem
and
Glycopeptides
e.g. vancomycin, teicoplanin
157
e.g. of glycopeptide?
vancomycin for MRSA, 2nd line C.diff
teicoplanin
158
most common cause of UTI
e coli
159
chloramphenicol side effects?
given as eye drops for bacterial conjunctivitis e.g.
risk of aplastic anaemia, grey baby syndrome in neonates
160
what abx inhibit DNA synthesis?
Fluoroquinolones
e.g. Ciprofloxacin
for gram -ve
Nitroimidazoles
e.g. Metronidazole
for anaerobes
161
what UTI-causing organism is assoc with function/ anatomical abnormalities of the renal tract
klebsiella
162
what antibiotics inhibit RNA synthesis?
Rifamycin e.g. Rifampicin
indicated for mycobacteria e.g. TB
163
what antibiotics inhibit folate metabolism
sulfonamides
e.g. sulphamethoxazole
(indicated for PCP, forms co-trimoxazole with trimethoprim)
diaminopyrimidines
e.g. trimethoprim
164
what antibiotics target cell membranes?
polymxin
e.g. colistin
cyclic lipopeptide
e.g. daptomycin
165
what is the 2nd most common cause of uncomplicated UTI?
staph saprophyticus
166
GI infection + ate canned/ vacuum packed foods e.g. honey in kids, beans in students. -\> ingestion of preformed toxin.
Descending paralysis
clostridia botulinum
167
clostridia botulinum tx
antitoxin
168
pseudomembranous colitis caused by abx use (usually cephalosporins/ ciprofloxacin/ clindamycin). releases 2 exotoxins A and B.
c difficile
169
c difficile pseudomembranous colitis tx
metronidazole
2nd line- vancomycin
170
reheated rice and sudden vomiting.
heat stable emetic toxin and heat labile diarrhoeal toxin. watery non bloody diarrhoea.
bacillus cereus
171
what organism causes gas gangrene?
clostridia perfringens
gas gangrene is a bacterial infection that produces gas in gangrenous tissues - medical emergency caused by exotoxin - alpha toxin.
172
reheated meats, superantigen enterotoxin, watery diarrhoea + cramps, lasts 24 hours
+ may cause gas gangrene
clostridia perfringens
173
gram + cocci in clusters, beta haemolytic. Catalase, coagulase +ve
produces entertoxin that acts as superantigen -\> causing prominent vomiting and watery, non bloody diarrhoea.
Main virulence factor: protein A.
staph aureus
174
most common cause of travellers diarrhoea
e coli
175
Anaemia, thrombocytopenia, renal failure following diarrhoea + recent visit to farm
Haemolytic Uraemic Syndrome (E. coli strain 0157)
176
rice water stool
enterotoxin with A/B subunit -\> efflux of Cl- to lumen and loss of H2O and electrolytes
massive diarrhoea
vibrio cholera
tx: supportive, fluids and electrolytes
177
ingestion of raw undercooked seafood, shellfish. comma shaped organism.
vibrio parahaemolyticus
178
cellulitis in shellfish handlers,
fatal septicaemia with diarrhoea and vomiting in HIV patients.
comma shaped organism
vibrio vulnificus
179
Tx of vibrio parahaemolytics and vibrio vulnificus
doxycycline
180
unpasteurised milk/ food e.g. poultry
headache, fever + abdo cramps + bloody foul smelling diarrhoea.
curved, s shaped, motile bacteria
assoc w guillain barre syndrome, reactive arthritis
campylobacter jejuni
181
Beta haemolytic, aesculin +ve, tumbling motility
GI: watery diarrhoea, cramps, headache, fever
assoc with immunocompromised patients, perinatal infection
unpasteruised dairy, veggies
listeria monocytogenes
182
motile trophozoite in diarrhoea. histology shows flask shaped ulcer.
dysentery, wind, tenesmus
chronic weight loss + RUQ pain due to \*liver abscess + swinging fevers
assoc w MSM
entamoeba histolytica
183
what organism is associated with recurrent aseptic lymphocytic meningitis?
HSV type 2
184
Pear shaped trophozoite
trophozoites/ cysts in stool
assoc w travellers/ hikers/ MSM
malabsorption of protein and fat + foul smelling non bloody diarrhoea. may be of very long duration
giardia lamblia
185
tx for giardia lamblia
metronidazole
186
causes severe diarrhoea in the immunocompromised. e.g. HIV
profuse, water diarrhoea
oocytes seen in stool
Kinyoun acid fast stain +ve
cryptosporidium parvum
187
most common cause of gastroenteritis in \<6 yrs. assoc w outbreaks
rotavirus
188
what is a prion disease?
protein-only infectious disease
rare transmissable spongiform encephalopathies resulting in rapid neuro degeneration and death in months
untreatable
due to variant PrP protein (PrPsc) abnormally folding to form insoluble configurations
189
hospital actuired surgical site infection: consider which organisms?
MRSA
Coagulase negative staphylococcus
190
CSF: 14-3-3 protein +ve
sporadic CJD
191
what biopsy is 100% specific and sensitive in diagnosing variant CJD?
tonsillar biopsy
192
rapid, progressive dementia with myoclonus, cortical blindness, akinetic mutism and LMN signs
mean onset 45-75 yrs
mean survival time 6 months
EEG shows periodic triphasic changes.
Genetics: most have 129 codon MM polymorphism
Post mortem shows spongiform vacuolation on brain biopsy, and PrP amyloid plaques
Sporadic CJD
193
exposure to bovine spongiform encephalopathy.
young age of onset. mean survival 14 months.
psychiatric symptoms (anxiety, paranoia, hallucinations)
followed by
neuro symptoms (peripheral sensory symptoms, ataxia and myoclonus)
then dementia, chorea, ataxia
variant CJD
194
which CJD has the lowest mean age of onset?
variant CJD - around 30
sporadic - 45-75
familial CJD - around 50
195
which type of CJD is linked to exposure of bovine spongiform encephalopathy?
variant CJD
196
which type of CJD has the lowest survival time?
sporadic CJD - mean survival time is 6 months from when symptoms start
197
which type of CJD sees patients who ALL have a 129 codon Methionine-Methionine polymorphism?
variant CJD
198
inherited prion disease - what mutation?
autosomal dominant
PNRP mutation - diagnostic
causes familial CJD, GSS (Gerstmann-Straussler-Scheinker syndrome), fatal familal insomnia
199
which type of CJD has EEG changes showing perioding triphasic changes?
sporadic CJD
200
posterior thalamus highlighted on MRI - pulvinar sign positive
All patients have codon 129 MM polymorphism
Tonsillar biopsy diagnostic
Post mortem- PrPsc detectable in CNS + lymphoreticular tissue
variant CJD
201
CJD tx
symptomatic: clonazepam for myoclonus
delaying prion conversion: quinacrine, pentosan, tetracycline
202
do psychiatric or neurological symptoms appear first in variant CJD?
pyschiatric first
paranoia, anxiety, hallucinations
203
progressive ataxia, dementia and myoclonus.
history of neurosurgery in the past
Most are homozygous at codon 129 MM or VV
iatrogenic CJD
- due to inoculation with human prions most commonly from surgery
204
exposure to human prions from cannibalistic feasts
progressive cerebellar syndrome and death within 2 years
45 yr incubation
kuru
205
autosomal dominant condition
PRNP mutation +
mean survival- 5yrs
presents w dysarthria progressing to cerebellar ataxia ending in dementia
Gerstmann-Straussler-Scheinker syndrome
GSS
206
autosomal dominant condition
insomnia and paranoia progressing to hallucinations and weight loss. then a mute period.
death 1 month to 1.5 years after start.
PRNP mutation +
fatal familial insomnia
207
gram -ve aerobic bacilli
consumption of untreated dairy products/ contaminated food/ animal contact
undulant fever (peaks in evening)
+ malaise, rigors, sweating, myalgia/ arthragia, tiredness, bone pain
Serology- shows anti-O-polysaccharide antibody
Brucellosis
208
Brucellosis Ix?
WCC usually normal
Culture Bone Marrow (\>90% +ve)
Blood cultures (70% +ve)
serology- anti-O-polysaccharide antibody
significant no neutropenic
209
Brucellosis tx?
Doxycycline combined with Streptomycin
for 4-6 wks
or Doxycycline + rifampicin
210
fatal encephalitis with prodrome of fever, sore throat
Negri bodies
following animal bite
rabies
rhabdovirus
211
Rabies tx?
PEP Rabies IgG
212
Negri bodies pathognomonic of?
Rabies
213
Following flea bite,
swollen LNs (Bubo)
+ acral gangrene
yersinia pestis
tx: streptomycin, doxycycline, gentamicin, chloramphenicol (in meningitis)
214
red currant jelly sputum
alcoholics
upper lobe consolidation w marked carvitation
more likely to lead to lung abscesses/ empyemas than pneumonias caused by strep pneumo
klebsiella pneumoniae
215
swimming in contaminated water.
organism is a gram -ve, obligate, motile spirochaete
High spiking temp + headache + conjunctival haemorrhages + jaundice + malasie + myalgia + haemolytic anaemia
Leptospirosis
tx- amoxicillin, erythromycin, doxycycline or ampicillin
216
painless round black lesions + rim of oedema
bacillus anthracis -anthrax
tx: ciprofloxacin/ doxycycline
217
bullseye rash - erythema chronicum migrans
+ tick bite +
cyclical fevers, malaise, LNopathy + arthritis, nerve palsies, hepatitis, carditis
Lyme disease
-borrelia burgdoferi
218
acrodermatitis chronic atrophicans (ACA)
+ focal neurology + arthritis + neuropsychiatric disturbance
late persistent lyme disease
219
Lyme disease Ix and Tx?
Ix- biopsy edge of ECM +
Lyme Abs ELISA
Tx: Doxycycline for 2-3 wks
if CNS issues: IV ceftriaxone for 2-4 wks
220
zoonosis
that looks like atypical pneumonia
fever, dry cough, fatigue, pleural effusion, diarhhoea, NO rash
Q fever
- coxiella burnetti
221
sandfly bite
skin ulcer at site of bite - may be single or multiple painless nodules whcih grow and ulcerate
cutaneous leishmaniasis
222
zoonosis
usually young malnourished child, abdo discomfort + distension, anorexia and weight loss,
invasion of reticuloendothelial system -\> hepatosplenomegaly, BM invasion
later disfiguring dermal disease, skin hyperpigmentation and dry warty skin
visceral leishmaniasis
aka
Kala Azar
223
antiviral that inhibits neuraminidase
oral oseltamivir (tamiflu)
inhaled/ iv zanamivir (relenza)
224
2-4 wks after group A strep throat infection
rash
chorea
heart valve involvement (most often mitral stenosis- MDM)
rheumatic fever
225
risk factors of infective endocarditis
structural heart disease
prosthetic valves
poor dentition
long term lines
prior bacteraemia
bowel/GI issue
226
most common cause of subacute bacterial endocarditis
strep viridans
tx: benzylpenicillin + gentamicin
227
mild-moderate illness progressing over weeks- months. often PUO
fever, malaise, weight loss
heart murmur that changes
clubbing, splinter haemorrhages, osler's nodes, janeway lesions, Roth spots, splenomegaly, haematuria
subacute bacterial endocarditis
(subtype of infective endocarditis)
228
fulminant illness in days
fever, anorexia, weight loss, malaise, rigors, night sweats
new onset heart murmur
acute infective endocarditis
229
most common cause of acute infective endocarditis in general?
in IVDU?
in general/ IVDU: staph aureus
in prosthetic valves: still staph aureus, but 2nd most common- coagulase negative staphylococci
230
tx of MSSA endocarditis? and MRSA?
MSSA endocarditis
IV flucloxacillin for 4 wks
MRSA- Vancomycin + Gentamicin/ Rifampicin/ Fucidin
231
in IVDU, which valve is most commonly affected (infective endocarditis)
tricuspid
232
alpha haemolytic Gram + cocci in pairs (chains) - diplococci
strep pneumoniae
233
how to differentiate strep pneumoniae from strep viridans?st
strep pneumoniae is optochin sensitive
and strep viridans is optochin insensitive
234
beta haemolytic gram positive cocci in grape like clusters
staph aureus
all staphylococci are catalase positive
whereas all streptococci are catalase negative
235
aerobic gram negative diplococci that is particularly problematic in patients with chronic lung disease and causes exacerbations of COPD.
also infects ears, eyes and CNS
moraxella catarrhalis
236
beta haemolytic Gram + rod
outbreaks of non invasive gastroenteritis
sources include refrigerated food and unpasteurized dairy products.
clinical features include watery diarrhoea, abdo cramps, headaches and fever.
'tumbling motility' as a result of flaggelar- driven movements
Neonates and immunocompromised patients are particularly susceptible
Listeria Monocytogenes
237
pear-shaped trophozoite
transmission occurs via ingestion of a cyst from faecally contaminated water and food.
Trophozoites attach to the duodenum but do not invade. Instead, protein absorption is inhibited, drawing water into the lumen of the GI tract.
so clinically: foul smelling non bloody diarrhoea produced (like coeliac)
Assoc w travellers, hikers, homosexual men
Microscopy shows stool containing cysts
giardia lamblia
238
which gastroenteritis causing bacteria produces the exotoxin TSST-1
which acts as a superantigen causing non specific activation of T cells and subsequent release of IL1, IL2, and TNFa.
-\> massive shock and organ failure.
the enterotoxin produced by the bacteria causes vomiting and diarrhoea 12-24 hours after the culprit food has been consumed
staph aureus
239
slow onset fever, constipation, splenomegaly
multiplies in Peyers patches of the small intestine
Rose spots are pathognomonic (red macules 2-4 mm in diameter)
salmonella typhi
240
motile trophozite
ingestion of the cysts leads to colonization of the caecum and colon
which may cause a flask shaped ulcer to develop
clinical features include dysentery, chronic weight loss, liver abscess formation
entamoeba histolytica
241
oxidase positive, non motile bacteria
causing watery, foul smelling diarrhoea
complications include guillain barre and reiters syndrome
campylobacter jejuni
242
subacute or chronic meningitis
symptoms include fever, headache, confusion
focal signs may be present as a result of a cerebral granuloma
\* Rich focus
Mycobacterium tuberculosis
Rich focus: a tuberculous granuloma that occurs in the cortex of the brain subsequently rupturing into the subarachnoid space
CSF usually appears colourless and characteristically has high protein, low glucose, raised lymphocytes. Nucleic acid amplification tests + CT/MRI may be useful in the diagnostic work up
243
first stage of infection: sudden fever, accompanied by chills, intense headache, severe myalgia, abdo pain, conjunctival suffusion (red eye) + skin rah.
asymptomatic for 3-4 days before second phase
where another episode of fever, meningitis\*.
if severe, weil's disease develops, compromising of liver damage (jaundice), kidney failure and bleeding
Leptospirosis
- leptospira interrogans
transmission via contact w animals
CSF will show a raised WCC
gold standard for diagnosis - microscopic agglutination test (serological test)
244
2 causes of subacute/ chronic meningitis in HIV patients?
TB
Cryptococcus neoformans
245
subacute / chronic meningoencephalitis
CSF india ink staining reveals yeast cells w a surrounding halo
cryptococcus neoformans
source: pigeon droppings
cryptococcal antigen test is a more sensitive test than CSF staining
246
what serovars cause genital chlamydia?
chlamydia trachomatis serovars D-K
247
what serovars cause lymphogranuloma venereum?
chlamydia trachomatis serovars L1, L2, L3
248
tabes dorsalis
- what is it
- what condition is it seen in
aka syphilitic myelopathy
occurs in tertiary syphilis
tabes dorsalis is the slow demyelination of the dorsal columns of the spinal cord -\> affected one's proprioception, vibration and discriminative touch
leads to argyll roberston pupil
- eventually may lead to paralysis, dementia and blindness
249
chancroid vs syphilis presentation?
chancroid: painful genital ulcer that leads to unilateral painful swollen inguinal LNs
syphilis: painless ulcer w bilater painless lymphadenopathy
250
what medium is used to culture neisseria gonorrhoea?
Thayer-Martin VCN medium
251
donavonosis
- what organism
- what stain
klebsiella granulomatis
a gram + rod
diagnosed via Giemsa stain of biopsy, showing Donovan bodies
252
trimethoprim side effects, contraindications
trimethoprim is an inhibitor of folate metabolism
should be used in caution w patients w megaloblastic anaemia due to its interaction w folate
side effects include thrombocytopenia, megaloblastic anaemia and hyperK
253
what is cotrimoxazole?
trimethoprim + sulphamethoxazole
used in treatment of pneumocystis jirovecii
both are from classes of abx that inhibit folate metabolism
254
side effects of vancomycin
ototoxicity
renal failure
blood disorders
rash
anaphylaxis
255
meningitis in community: immediate treatment
IM benzylpenicillin until transferred to secondary care unit
cefotaxime/ ceftriaxone then started
256
what else is cefotaxime useful for?
apart from meningitis
tx of pyelonephritis
sepsis secondary to hospital acquired pneumonia
soft tissue infections
257
EBV infects what cells?
B lymphocytes
258
influenza
- what components of the virus bind to which parts of the host?
infleunza virus is a spherical virion with haemagglutinin and neuramindase glycoproteins on the surface
HA binds to sialic acid receptors present in the upper resp tract
viral RNA is subsequently inserted into the host cell and HA is cleaved by clara cell tryptase
NA cleaves neuraminic acid, a component of protective mucin. protective barrier is thus disrupted exposing the sialic acid receptor sites beneath
NA also has a role facilitating the release of newly formed influenza virions
259
how does IFN alpha work in the treatment of hep B/C?
IFN alpha potentiates the immune system to fight active viral infection.
IFN alpha acts on the JAK-STAT pathway eventually leading to the synthesis of anti viral proteins.
A NRTI and IFNa is the std tx for hep B infection
in Hep C, pegylated IFN a is used. (half life of the drug increased with the addition of polyethylene glycol)
260
how does oseltamivir work?
a viral neuraminidase inhibitor
-\> prevents further viral replication
261
gancyclovir
used for?
common SE?
used for CMV, EBV and HHV6 infection
can cause bone marrow toxicity
hence may be prescribed together with G-CSF (granulocyte colony stimulating factor
262
acyclovir
what is it?
how is activated in the body?
a guanosine analogue anti-viral drug
it is converted to acycl-GMP by viral thymidine kinase.
then further phosphorylated to acyclo-GTP
Acyclo-GTP is the active form, which is incorporated into the viral DNA strand, terminating the chain and stopping DNA polymerase from functioning.
263
what is the active form of acyclovir?
acyclo-GTP
acyclo- guanosine triphosphate
264
what is amantadine
an M2 ion channel inhibitor preventing the uncoating of influenza virions and therefore inhibiting entry into susceptible cells
265
oral thrush - creamy white patches with red base over mucous membranes of mouth
can lead to oesophagitis, characterized by odynophagia
what organism?
what treatment?
candida albicans
oral thrush - treat with nystatin
can be diagnosed by testing for blood beta-D-glucan (a component of fungal cell wall)
266
complications of cryptococcal meningitis
fatal without treatment
due to associated cerebral oedema
and brainstem compression
267
hypopigmentation in patients w dark skin,
hyperpigmentation in patients w pale skin
spots affect back, arms, legs, chest, underarm, neck
what organism is causing this?
whats the name of the condition?
pityriasis versicolor
- malassezia furfur
\*microscopy reveals 'spaghetti w meatballs' appearance
woods light may reveal an orange fluoresence
268
rose gardeners disease
prick by thorns cause nodular lesions to appear on the surface of the skin.
Initially the lesions will be small and painless, left untreated they become ulcerated.
infection may spread to joints, bone and muscle.
inhalation of spores may lead to pulmonary disease
what organism?
a fungus - Sporothrix Schenckii
causing sporotrichosis
tx: itraconazole, fluconazole and oral potassium iodide
269
aspergillus flavus may produce which carcinogen?
assoc w?
aflatoxin
hepatocellular carcinoma
270
aspergillus can cause which few diseases?
ABPA allergic broncho-pulmonary aspergillosis
allergic reaction in the airways due to an IgE mediated type I hypersensitivity reaction leading to bronchospasm and eosinophilia.
Aspergilloma:
infection in pre-formed lung cavitiy e.g. TB may lead to fungal ball visible on CXR
Invasive aspergillosis:
chronic necrotizing infection that may occur in neutropenic (chemotx) patients or patients with AIDS (CD4\<50)
271
cutaneous dermatophyte fungal infection of the scalp leading to scaly red lesions with loss of hair
primarily affecting children
infection is characterised by an expanding ring on the scalp
tinea capitis
272
raised red rings
cutaneous dermatophyte fungal infection affecting the trunk, arms and legs
ring worm
tinea corporis
273
rocky mountain spotted fever
caused by Rickettsia infection
transmitted to humans by ticks
rickettsia bacteria invade the endothelial lining of capillaries causing a vasculitis.
clinical features include headache, fever, mylagia, vomiting and confusion
late signs include a rash that is maculopapular and or petechial on the distal parts of the limb which then spreads to the trunk and face.
may lead to thrombocytopenia, hypoNa, and or elevated liver enzymes
274
contact with birds
severe pneumonia + splenomegaly + epistaxis
hepatitis
haemolytic anaemia, rash (horder's spots)
psittacosis
chlamydia psittaci
275
what is pathognomonic of Rabies
cerebral negri bodies
276
bite or scratch
leading to progressive and incurable encephalitis, hydrophobia and muscle spasm
Rabies
Cerebral negri bodies (inclusion bodies) are pathognomonic
277
cat scratch leading to tender and swollen lymph nodes with headache and backache.
atypically may cause parinaud's oculoglandular syndrome- granulomatous conjunctivitis in one eye and swollen LNs in front of the ear on the same side
Cat scratch disease
caused by Bartonella spp
278
fever, malaise, transient hearing loss
parotitis with unilateral or bilateral swelling and pain on chewing
plasma amylase levels elevated
complications such as viral meningitis, orchitis/ oophoritis, mastitis and arthritis may result
Mumps infection
MMR vaccine normally given at 12-13 months and again as a preschool booster
279
if abx fails to tx pneumonia, consider:
· Empyema / abscess
· Proximal obstruction (tumour)
· Resistant organism (incl. Tb)
· Not receiving / absorbing Abx
· Immunosuppression
Other diagnosis - Lung cancer, cryptogenic organising pneumonia
280
how to detect legionella pneumophila
- buffered charcoal yeast extract culture
- **urine serology** for antigen
281
contact with domestic/ farm animals
flu-lie symptoms, fever, malaise, sweats
less often: granulomatous hepatitis, retinal vasculitis,
chronic endocarditis
dx by serology
Q fever
-coxiella burnetti
282
a hospital acquired pneumonia is when?
any pneumonia contracted by patient in a hospital at least 48-72 h after being admitted
283
being neutropenic makes one more susceptible to what type of pneumonia?
aspergillus
284
empiric antibiotic therapy for mod-severe community acquired pneumonia
co-amoxiclav + clarithromycin
if allergic: cefuroxime + clarithromycin
285
glycopeptides
- how does it work
- e.g.?
· Large molecules, unable to penetrate Gram –ve outer cell wall, only active against Gram +ve
· Inhibit cell wall synthesis
· Important for treating serious MRSA infections (iv only)
e.g. vancomycin, teicoplanin
\*nephrotoxic - impt to monitor drug lvls
286
tetracyclines
- how does it work
- e.gs
· Broad-spectrum agents with activity against intracellular pathogens (e.g. chlamydiae, rickettsiae & mycoplasmas) as well as most conventional bacteria
· Bacteriostatic, inhibit protein synthesis by preventing binding of aminoacyl-tRNA to the ribosomal acceptor site
287
when do you use oxazolidinones e.g. linezolid?
VRE
MRSA
should only be used with consultant ID approval
neuro side effect - dont give for \>4 wks
288
how does salmonella enteritidis cause pathology in an affected person?
Enterocolitis
**·** loose stool, diarrhea type of presentation
· transmitted from poultry, eggs,meat
· invasion of epi-and sub-epithelial, tissue of small and large bowel
· No fever, bacteraemia infrequent
· self limited, non-bloody diarrhoea, usually no treatment
289
cellulitis in shellfish handlers (get cut by shellfish corals in sea divers)
fatal septicaemia with D+V in immunocompromised eg HIV patients
Treat with doxycycline
vibrio vulnificus
290
Transmitted via food contaminated with domestic animals’ excreta (farming activities)
Enterocolitis, mesenteric adenitis
associated with extra GI symptoms - reactive arthritis, Reiter’s
yersinia enterocolitica
291
· motile trophozoite in diarrhoea
· non-motile cyst in non-diarrhoeal illness
· Killed by boiling, removed by water filters
“flask shaped” ulcer
· dysentery, flatulence, tenesmus
if chronic: can cause weight loss +/- diarrhoea
liver abscess
diagnosis: stool micro to look for procytes and serology in invasive disease
entamoeba histolytica
tx: metronidazole for the stool + paromomycin in luminal disease
292
infects the jejunum
severe diarrhoea in the immunocompromised
oocysts seen in stool by modified kinyoun acid fast stain
cryptosporidium parvum
293
what are the 3 factors that contribute to surgical site infection risk?
host defence
wound environment
pathogen
294
negative pressure isolation vs positive pressure isolation
· Negative pressure isolation – protection of others from an infectious patient with airborne infection
· Positive pressure isolation – protection of transplant patients from organisms from outside the room
295
3 levels of surgical site infection
1. superficial incisional - affect skin and subcut tissue
2. deep incisional - affect fascial and muscle layers
3. organ/ space infection- any part of anatomy other than the incision
296
What are some patient-dependent risk factors of surgical site infections?
age \>65
any underlying illness e.g. diabetes, malnutrition, rheumatoid
obesity - adipose tissue is poorly vascularised
smoking - nicotine itself delays primary wound healing. + may have peripheral vascular disease
297
what are some measures taken prior to surgery to prevent surgical site infections?
**pre-operative showering**
**hair removal**: use electric clippers instead of razor if hair needs to be removed (microabrasions caused by razor shaving may lead to multiplication of bacteria)
**nasal decontamination**: e.g. staph aureus risk factor for SSI following cardiothoracic surgery
**abx prophylaxis**
298
what measures to take during the surgery to reduce risk of surgical site infection?
mx of infected/ colonised surgical personnel
reduce theatre traffic to a minimum
ventilation of theatre: maintain positive pressure ventilation. consider laminar flow for orthopaedic implant surgery
sterilise all surgical instruments
skin prep: using antiseptic iodine or chlorhexidine
aseptic surgical technique
normothermia: mild hypothermia appears to increase risk of SSIs by causing vasoconstriction, decreased delivery of oxygen to wound space and subsequent impairment of neutrophil function
maintain optimal oxygen during surgery
299
why is staph aureus so effective at causing joint infection?
s aureus has receptors such as fibronectin binding protein that allows binding to synovial membrane (e.g. fibronectin found when joint is damaged)
s aureus produces the cytotoxin PVL Panton valentine leucocidin which have been associated with fulminant infections
300
septic arthritis investigations
Blood culture before antibiotics are given
Synovial fluid aspiration for M&C
ESR, CRP - traditionally a synovial count\> 50,000 WBC cells/mm3 used to suggest septic arthritis
(Negative culture does not exclude septic arthritis)
Imaging:
US - confirm effusion and guide aspiration
CT - erosive bone change, periarticular soft tissue extension
MRI (done if osteomyelitis is suspected) - joint effusion, articular cartilage destruction, abscess, contiguous osteomyelitis
301
mx of septic arthritis
antibiotics- up to 4-6 wks of IV antibiotics may be given (flucloxacillin or cephalosporin)
if MRSA- vancomycin
drainage- washout of joint
302
what are some routes of infection in vertebral osteomyelitis
acute haematogenous
local spread
303
most common organism causing osteomyelitis
staph aureus
salmonella in sickle cell anaemia
304
vertebral osteomyelitis
- common locations
- symptoms
- diagnosis/ investigations
- treatment
most common lumbar, then cervical, cervico-thoraco
symptoms- back pain, fever, neuro impairment
diagnosis via MRI, blood cultures.
Tx: 6 wks of antibiotics, longer if undrained abscesses / implant associated.
2nd line- debridement, remove sequestra and infected bone
305
Brodie's abscess
a localized area walled off by fibrous and granulation tissue
intraosseous abscess
occurs in osteomyelitis
306
Chronic osteromyelitis
pain, brodie's abscess (intraosseous abscess), sinus tract between bone to skin which releases exudates
MRI showing dead bone and new bone (involucrum). Bone biopsy for culture and histology. +ve for bacterial growth.
tx
radical debridement down to living bone
remove sequestra (dead bone tissue within diseased bone), infected bone and soft tissue
307
prosthetic joint infection
- diagnosis
radiology - 'loosening' bone loss in Xray
if CRP \> 13.5 for prosthetic knee infection, CRP \>5 for prosthetic hip joint infection
Joint aspiration - for MCS. be careful as there is risk of introducing infection if joint is not already infected
intraoperative microbiological sampling: tissue specimens taken from at least 5 sites around the implant (if 3 or more yield identical organisms, this is highly predictive of infection)
308
treatment of prosthetic joint infection
single stage revision:
· Remove all foreign material and dead bone
· Change gloves, drapes etc
· Re-implant new prosthesis with antibiotic impregnated cement and give iv antibiotics.
two stage revision:
Remove prosthesis, take samples for microbiology and histology
Patient given a spacer in place of the prosthesis
· Period of iv Abx (6weeks). Stop Abx for 2 weeks
· Re-debride and sample at second stage
· Re-implantation with Abx-impregnated cement
· No further antibiotics if samples clear
· Involve OPAT
309
Routes of infection in meningitis:
Four routes of entry:
haematogenous spread (pneumococcas, herpes)
direct implantation – through surgery
local extension – through the ears from swimming
PNS into CNS – rabies virus at the legs
The most frequent route is haematogenous.
310
infection of the spinal cord, causing a myelitis.
and disturbance of nerve transmission
progressing to paralytic disease. the weakness most often involves the legs, but may also affect the muscles of the head, neck and diaphragm
what organism?
Poliovirus
311
neurotoxins causing rigid paralysis
- what organism?
and
flacid paralysis
- what organism?
clostridium tetani causes rigid paralysis.
c tetani produces a potent biological toxin, tetanospasmin, acting on several sites in the CNS. Causes painful muscular spasms, that can lead to respiratory failure and in some cases, death.
clostridium botulism causes flaccid paralysis
common with canned food
usually descending paralysis
beginning with blurred vision, trouble speaking then weakness of arms, chest, muscles and legs.
312
what pathology lies behind septicaemia?
Capillary leak - albumin and other plasma proteins leads to hypovolemia.
Coagulopathy - leads to bleeding and thrombosis. (endothelial injury results in platelet-release reactions, the protein C pathway, plasma anticoagulants)
Metabolic derangement, particularly acidosis
Myocardial failure leading to multi-organ failure
313
most common causes of aseptic meningitis
coxsackie group B and echoviruses - 80-90% of cases
herpes simplex
314
what bacterial infection may also cause encephalitis?
listeria monocytogenes
315
empiric treatment for meningitis
ceftriaxone
if elderly/ immunocomp
+ amoxicillin to cover listeria
316
empiric tx for meningoencephalitis
aciclovir
ceftriaxone
if \>50/ immuno comp
add amoxicillin
317
why does influenza virus only affect the respiratory tract?
Influenza virus infection causes respiratory disease because the influenza virus requires activation by host cell proteases (tryptase) that are only expressed in the respiratory tract.
tryptase cleaves the influenza haemagglutinin
318
ingredients for a pandemic virus:
A pandemic virus will have novel antigenicity.
A pandemic virus will replicate efficiently in human airway.
A pandemic virus will transmit efficiently between people. (influenza cannot transmit through air between people hence havent led to pandemics)
319
features of Haemagglutinase and Neuramindase that affect influenza transmission
HA and NA are viral surface proteins of influenza
Receptor binding (HA) – able to bind to respiratory cell surfaces
Virion stability – to heat and mildly acidic pH
NA stalk length – able to chew through human mucus to penetrate through the barrier
NA required for release of new virus to propagate infection.
320
what gene mutation is linked with severe influenza?
IFITM3
321
what antiviral only works against Influenza A?
amantidine
322
which vaccine has dramatically reduced the incidence of meningitis since it was introduced
Hib vaccine
323
congenitally transmitted
hepatosplenomegaly, rash, fever, neurosyphilis in the first few years
long-term complications include saddle nose deformity, Higoumenaki's sign (unilateral enlargement of the clavicle) and Clutton's joints (symmetrical joint swelling)
Syphilis
324
what human herpes viruses are in the alpha subfamily?
what are the characteristics?
HSV1, HSV2
VZV
rapid growth + latency in sensory ganglia
325
what human herpes viruses are from the beta subfamily?
What characteristics?
CMV, HHV6, HHV7
slow growth
326
what human herpes viruses are from the gamma subfamily?
what characteristics?
EBV
HHB8
oncogenic
327
2nd line tx for chicken pox resistant to aciclovir?
foscarnet or cidofovir
328
how is aciclovir selective for viral cells?
has to be phosphorylated by viral thymidine kinase
affinity to herpesvirus DNA polymerase is 10-30x higher than for cellular DNA
329
tx for herpes simplex encephalitis?
aciclovir IV for 21 days
330
CMV presentation in immunosuppressed
can cause
pneumonitis, encephalities, retinitis, gastroenteritis, marrow suppression
dx: PCR for viral load
331
tx of CMV infection
Ganciclovir IV 1st line
oral valganciclovir - prophylaxis
2nd line: iv foscarnet
3rd line: IV cidofovir
332
Foscarnet
- how does it work
- what is it used for
- side effects
non competitive inhibitor of viral DNA polymerase
activity against CMV, occasionally used for HSV e.g. if aciclovir resistant
side effects: nephrotoxic. keep pt well hydrated and monitor electolytes
333
what antiviral may be used to treat RSV in immunocompromised?
Ribavarin
Inhibits viral RNA synthesis – broad activity in vitro – effective for Lassa fever and HEV, used in combination with other drugs for HCV
Clinical efficacy for RSV is unclear
334
tx for CMV pneumonitis
Ganciclovir + IVIG
335
what is the monoclonal antibody against RSV used prophylactically
pavilizumab
in high risk group: preterm, congenital heart/ chronic lung disease, SCID, long term ventilation
336
BK virus
- what problems does it cause?
problematic in the immunocompromised
BMT: haemorrhagic cystitis, less commonly nephritis
Renal transplant: ureteric stenosis, nephritis
tx: bladder washouts for haemorrhagic cystitis
reduce level of immunosupression if possible
IVE cidofovir if significant morbidity
337
Adenovirus
- what impt group of patients does this virus affect?
- tx?
Paediatric post BMT patients
causes fever, encephalitis, pneumonitis, colitis, haemorrhagic cystitis
do weekyly PCR surveillance
Tx: reduce immunosuppression
+ IV cidofovir 1st line
338
hep B tx
combined antiviral + immunomodulatory effect:
IFNa or PefIFNa-2a
= nucleoside/nucleotide RTI - lamivudine, tenofovir
339
Tx for EBV driven PTLD
post transplant lymphoproliferative disease
rituximab anti-CD20
340
uncomplicated vs complicated UTI? whats the difference?
· Uncomplicated UTI refers to infection in a structurally and neurologically normal urinary tract.
· Complicated UTI refers to infection in a urinary tract with functional or structural abnormalities (including indwelling catheters and calculi).
341
causes of sterile pyuria
· Prior treatment with antibiotics, catheterisation
· Calculi, bladder neoplasm, TB
· Sexually Transmitted Disease – gonorrhoea and chlamydia won’t grow on typical agar used.
342
1st line treatment for UTI (imperial guidelines)
due to resistance to trimethoprim.
1st line cefalexin for 7 days
for men, women, breastfeeding
343
tx for pyelonephritis or urosepsis
IV co-amoxiclav
+ amikacin/ gentamicin
344
what is herd immunity
· Form of immunity that occurs when vaccination of a significant proportion of a population provides a measure of protection for individuals that are not immune.
345
advantages & disadvantages of live vaccines
Single dose often sufficient to induce long-lasting immunity, strong immune response evoked, local and systemic immunity produced
Disadvantages:
· Potential to revert to virulence, poor stability
· Contraindicated in immunosuppressed patients
· Interference by viruses or vaccines and passive antibody, p otential for contamination
346
advantages and disadvantages of inactivated vaccines
Advantages: Stable, constituents clearly defined, unable to cause the infection
Disadvantages:
· Need several doses, local reactions common
· Adjuvant needed tokeep vaccine at injection site and activate APCs, shorter lasting immunity
347
established risk of measles vaccine
thrombocytopenia
348
established risk of rubella vaccine
acute arthritis
349
prerequisites for successful disease eradication
· No animal reservoir
· Antigenically stable pathogen with only one (or small number of) strains
· No latent reservoir of infection and no integration of pathogen genetic material into host genome
· Vaccine must induce a lasting and effective immune response. High coverage required for very contagious pathogens
350
mycobacterium leprae
- what condition
leprosy aka hansen's disease
incubation 2-10 yrs
symptoms that develop include granulomas of the nerves, resp tract, skin and eyes.
may result in lack of ability to feel pain, thus loss of parts of extremities due to repeated infections due to unnoticed wounds/ injuries
weakness/ poor eyesight
split into paucibacillary (\<5) and multibacillary (\>5 poorly pigmented, numb skin patches)
dx by skin biopsy showing acid fast bacilli or PCR
tx involves dapsone and rifampicin for 6 months
+ clofazimine (for multibacillary- all 3 for 12 months)
\*dapsone causes oxidant damage in G6PD deficiency
351
multidrug resistant TB -resistant to?
rifampicin + isoniazid
352
Extremely drug resistant TB
resistant to?
rifampicin, isoniazid
+ at least 1 injectable
and fluoroquinolones
353
CMV in pregnancy tx
none
· If maternal CMV infection suspected check serology (compare with booking bloods)
· If suspected seroconversion during pregnancy refer to fetal medicine unit for USS +/- amnio
354
measles in pregnancy
causes?
o Fetal loss (miscarriage, IUD), preterm delivery
o Increased maternal morbidity
o No congenital abnormalities to fetus
355
parvovirus B19 in pregnancy- results in?
o 9% risk of infection overall
o 3% risk of hydrops fetalis (oedema) if infection from 9-20/40
o Risk of fetal anomalies less than 1%
Maternal infection after 20/40 – no risk
mx:
· Refer to fetal medicine for monitoring
· Intrauterine transfusion improves fetal outcome
356
coxsackie virus (hand foot mouth disease) in pregnancy:
o early onset neonatal hepatitis, congenital myocarditis, early onset childhood IDDM, & abortion or intrauterine death
357
zika virus in pregnancy: consequences
· Miscarriage/stillbirth/microcephaly
**congenital zika syndrome**:
· Severe microcephaly + skull deformity
· Decreased brain tissue, seizures, hypertonia
· Retinopathy, deafness, talipes
358
what are some AIDS-defining illnesses?
· Cervical cancer, invasive
· CMV disease (other than liver, spleen, or nodes)
· Cytomegalovirus retinitis (with loss of vision)
· Encephalopathy, HIV related
· HSV: chronic ulcer(s) (\>1 month in duration); or bronchitis, pneumonitis, or esophagitis
· EBV: severe candidiasis, hairy oral leukoplakia
· Kaposi sarcoma
· Lymphoma, Burkitt's (or equivalent term)
Progressive multifocal leukoencephalopathy - JC
359
what cells do CMV and HHV6 infect?
stay in lymphocytes
360
VZV infection in immunocompromised: complications
o Pneumonitis, encephalitis, hepatitis
o Purpura fulminans in neonate
o Shingles-often late complication post-transplant
· Shingles can be early sign of HIV infection-indicate HIV testing particularly in young person
· Multidermatomal or disseminated zoster (signs of losing control) is associated with high mortality, need quite aggressive treatment
· Acute retinal necrosis (ARN)
· Progressive outer retinal necrosis (PORN)
· VZV-associated vasculopathy
361
Post transplant prophylaxis measures to reduce opportunistic viral infection/ reactivation:
Aciclovir for HSV and VZV
Ganciclovir - but this causes BM suppression so avoid in BM transplant pt.
Valganciclovir (100 days) for CMV in a solid organ transplant pt
362
post transplant lymphoproliferative disease
latently infected B cells (EBV) - polyclonal activation
predisposes to lymphoma
suspicion on rising EBV viral load and CT scan
confirmation w biopsy of LNs
mx: reduce immunosuppression
antiCD20 rituximab
363
progressive multifocal leukoencephalopathy
what virus?
JC virus
364
Progressive multifocal leukoencephalopathy
JC virus
seen in immunosuppressed hosts
· Cognitive disturbance, personality change, motor deficits other focal neurological signs
· The main pathological feature of PML is a demyelination of white matter with neurological deficits corresponding to the area(s) of the brain affected.
Diagnosis: MRI and PCR on CSF
365
BK cystitis
BK virus
Risk of BK cystitis post SCT and BK nephropathy post Renal Tx
· Present with fever, cystitis, haematuria
· Tx: bladder irrigation, modulation of immunosuppression with cidofovir
366
tx of influenza A and B
oseltamivir for 5 days
if severely immunosuppressed: IV zanamivir
367
congenital toxoplasmosis
· May be asymptomatic at birth – 60% but may still go on to suffer long term sequelae – deafness, low IQ, microcephaly
· 40% symptomatic at birth: choroidoretinitis; microcephaly/hydrocephalus; **intracranial calcification**; seizures; jaundice; hepatosplenomegaly
368
risk factors for early onset sepsis in neonate;
Maternal: PROM/prem. labour (increased risk of ascending infection before labour due to early rupture of membrane), fever, foetal distress. meconium staining, previous history
Baby: Birth asphyxia, resp. distress, low BP, acidosis, hypoglycaemia (good marker for sepsis), neutropenia, thrombocytopenia, rash, hepatosplenomegaly, jaundice
369
tx of early onset neonatal sepsis
Supportive: ventilation, circulation, nutrition – TPN
· Antibiotics: e.g. benzylpenicillin for GBS & gentamicin for E. coli (also consider Listeria)
370
late onset sepsis- after 48h of birth tx
## Footnote
o 1st line: Flucloxacillin & gentamicin
o 2ndline: Pipericillin/tazobactam & vancomycin
o Community acquired late onset infections: cefotaxime, amoxicillin +/-gentamicin
o 1st line: Flucloxacillin & gentamicin
o 2ndline: Pipericillin/tazobactam & vancomycin
o Community acquired late onset infections: cefotaxime, amoxicillin +/-gentamicin
371
what are some risk factors for infective endocarditis?
rheumatic fever
structural heart disease
prosthetic valves
poor dentition
Bowel/ GI problem - diverticular, bowel lesion
lines, esp long term
· Prior bactereamias, especially Staphylococcus aureus, enterococcus, rare gram negatives
372
signs of Infective endocarditis
Heart murmur 85%, changing murmur 5-10%, embolic lesions \>50%, osler’s 10-23%, splinter haemorrhages 15%, splenomegaly 20-57%, clubbing 10-20%, PR interval on ECG
373
what are some symptoms of Infective endocarditis?
Fever 80%, chills 40%, weakness 40%, dyspnoea 40%, weight loss
374
complications of Infective endocarditis
splenic infarcts 44%, cerebral abscesses 20%, glomerulonephritis (look for blood in urine dipstick!)
375
most common valve affected in IVDU endocarditis
tricuspid valve
most common s aureus
most common in IVDU w HIV
polymicrobial infection is more common
376
most common group of pathogens causing infective endocarditis
strep viridans
e.g. strep oralis, strep bovis
377
Organisms that may be found on Prosthetic valve endocarditis
CNS (staph epidermiditis), staph aureus
378
Culture negative endocarditis?
Most commonly due to cultures taken afterantibiotics!
Brucella, coxiella, chlamydia, mycoplasma, bartonella, HACEK organisms
379
investigations for infective endocarditis
· Multiple blood cultures: at least 3 blood cultures in the first 24hrs off antibiotics
· Echo and ECG (?carditis), FBC (anaemia), ESR (usually raised), CRP ( useful to monitor therapy)
· Serology if culture negative - brucella, bartonella, chlamydia, coxiella
Dukes criteria
380
dukes criteria for Infective endocarditis
clinical criteria- 2 major criteria/ 1 major and 3 minor criteria/ 5 minor criteria
Major criteria: Positive Blood culture for IE (a typical microorganism consistent with IE), evidence of endocardial involvement (echo, new valvular regurgitation)
Minor criteria:
o Predisposing heart condition or iv drug use
o Fever \> 38ºC
o Vascular phenomena: major arterial emboli, septic pulmonary infarcts etc
o Immunological phenomena eg. oslers nodes, glomerulonephritis, janeway lesions
o Microbiological evidence: positive blood culture but does not meet a major criterion
o Echo findings consistent with endocarditis but do not meet major criterion
381
tx of strep viridans endocarditis
benzylpenicillin and gentamicin
382
tx of enterococcal endocarditis
ampicillin and gentamicin
383
tx of MSSA endocarditis
flucloxacillin for 4-6 wks at least
384
tx for MRSA endocarditis
vancomycin and gentamicin or rifampicin or fucidin
385
indications for surgical therapy in Infective endocarditis
· More than 1 serious systemic emboli
· Uncontrolled infection
· Significant valve dysfunction
· Lack of response to antibiotics
· Local suppurative complications e.g perivalvular abscesses
· Congestive heart failure
386
diagnosis of brucellosis
culture of Bone marrow (\>90% positive)
blood cultures (70% +ve)
serological diagnostic tests
387
tx of brucellosis
4-6 wks of doxycycline + IM streptomycin
or
Oral doxycycline and rifampicin
388
louse borne relapsing fever
fever, rigors, headache, myalgia
transmitted by body louse
mortality rate is 30-70% without treatment. 1% w treatment
occurs in epidemics amid poor living conditions, famine and war in the developing world
pathogens: rickettsia prowazekii
389
tonsillar biopsy for variant CJD
what is seen?
florid plaques and vacuolation
390
diagnostic test for Hep C
HCV RNA
Anti-HCV antibodies - if immunocompromised, may not even develop antibodies
391
severe falciparum tx
medical emergency
· WHO 1stline: - IV Artesunate: BM monitoring, better tolerated, more rapid clearance of parasitaemia,
· IV Quinine, arrhythmogenic and causes hypoglycaemia, require cardiac & BM monitoring
392
what does mycobacterium tuberculosis look like on lowenstein-jensen medium?
appears as brown coffee-colored (buff), granular bread crumb-like colonies (rough) which often stick to the bottom of the growth plate are are hard to remove (tough)
'buff, rough and tough'.
393
how does mycobacteria tuberculous appear on the ziehl-neelson stain?
bright red against a blue background.
the stain contains carbofuchsin, a pink dye which binds to the unique mycolic acids found in the mycobacterium cell wall
394
how does mycobacterium tb or other acid fast bacilli
appear on auramine stain
yellow fluorescence
395
acid fast bacilli on skin biospy/ nasal smear
hypopigmented skin lesions, nodules and loss of sensation
what condition
and what organism?
mycobacterium leprae
396
Coxiella burnetti- Q fever
first described by abbatoir workers
obligate intracellular gram - bacteria found in animals and pets
manifests as flu like symptoms but can progress to atypical pneumonia or less often a granulomatous hepatitis.
typical CXR- ground glass appearance
397
Mantoux test results:
when is an induration of 5mm or more considered positive
HIV pts, recent contact with TB, ppl w fibrotic changes on CXR consistent w prior TB, pts w organ transplants, ppl who are immunosuppressed
398
Mantoux test
when is an induration of 10mm or more considered positive
recent immigrants (\<5 yrs) from high prevalence countries
IVDU
residents and employees of high-risk congregate settings
mycobacteriology laboratory personnel
persons w clinical conditions that place them at high risk
children \<4 yrs of age
infants, children, adolescents exposed to adults in high-risk categories
399
Mantoux test
when is an induration of \>15mm considered positive
considered positive in any person, including those with no known risk factors for TB
400
what are the alpha haemolytic streptococci?
how do you differentiate the two?
strep pneumoniae
strep viridans
s. pneumoniae is optochin sensitive
and
s viridans is optochin resistant
401
what are some beta haemolytic streptococci?
Group A Strep
e.g. strep pyogenes
scarlet fever, strep throat, impetigo, rheumatic fever, post strep glomerulonephritis
Group B Strep
e.g. in O&G
groups C/D/E etc
402
gram -ve rod
atypical pneumonia
frequently in alcoholics
can result in sudden, v severe systemic upset in these patients, and the production of thick, purulent, and sometimes blood stained sputum said to resemble redcurrant jelly
klebsiella pneumoniae
haemoptysis occurs most frequently with this organism
radiological features include upper lobe consolidation, w marked cavitation as described in the question.
it is more likely to lead to complications such as lung abscesses and empyemas than pneumonias caused by strep penumoniae
403
subacute infective endocarditis most common cause
strep viridans
+ usually on damaged valves
insidious onset of fever, night sweats and weight loss
404
signs of infective endocarditis?
hand: clubbing, splinter haemorrhages
abdomen: splenomegaly, microscopic haematuria
new or changing heart murmurs
eponymous signs: Oslers nodes (immune complex deposition), janeway lesions (septic emboli which deposit bacteria, forming microabscesses), roth spots (immune complex mediated vasculitis)
405
strep bovis infective endocarditis - assoc w?
colonic malignancy
- must do a colonoscopy
406
what is the active form of acyclovir ?
acyclovir triphosphate
acyclovir -\> acyclovir-monophosphate by viral thymidine kinase
acyclovir-monophosphate-\> di -\> triphosphate by cellular tyhymide kinase
407
why is e coli so good at causing UTI?
a flagellum enabling it to move upstream
fimbriae so that it can adhere to the urothelium
haemolysin to form pores in WBCs
it also has a protective capsure called the K antigen
408
proteus mirabilis UTI predisposes to what complication
formation of phosphate stones, particularly staghorn calculi
409
entamoeba histolytic memory aid
four runners ent-ering a race and the winner gets a silver flask
entamoeba cysts classically have **four** nuclei
**entamoeba**
**flask** shaped ulcers
410
mnemonic for important oxidast positive organisms
PuNCH Me Very Lightly
Pseudomona
Neisseria
Campylobacter
Helicobacter
Moraxella
Vibrio
Legionellaa
411
Visceral leishmaniasis
aka
Kala Azar
- clinical features?
Fever, splenomegaly
Hepatomegaly, skin hyperpigmentation and dry warty skin
bone marrow invasion can result in pancytopenia
transmitted by phlebotomine sandflies and occurs in africa, america and the middle east
leishmania donovani and l infantum
412
cutaneous leishmaniasis
features
most common form of leishmaniasis is cutaneous
itchy papule develops at bite site and develops into an ulcer with raised edges
local LNpathy can also occur
but the lesion usually heals within 8 months leaving a depigmented scar
l. major and l. tropica.
diagnosis by giemsa staining of skin smears
cultured on novy-macneal-nicolle medium
1st line drug - pentavalent antimonial such as sodium stibogluconate
413
mucocutaneous leishmaniasis
- features
the most feared form of cutaneous leishmaniasis
can produce destructive and disfiguring facial lesions
may begin as the cutaneous form but years later ulceration can appear in mucous membranes leading to mutilation of those areas
most often caused by leishmania braziliensis.
414
toxoplasmosis
toxoplasma gondii
can infect humans by eating undercooked meat or from contact w cat faeces
trophozites in the gut and spread to brain, eyes and lungs
in AIDs pts it can have neurological manifestations such as cranial n palsies, meningo-encephalitis and focal neuro deficits secondary to space occupying lesion
in the eye- chorioretinitis
CT scan shows ring enhancing lesions w surrounding oedmea
tOxOplasmosis - rmb the rings on the CT scan
415
vector for lyme disease
Ixodes tick
416
Lyme disease memory aid
PEACH
Peripheral neuropathy
Erythema chronicum migrans
Arthritis
Cranial n palsies
Heart block
late stage - persistent arthritis and chronic encephalitis
417
what rash is assoc w rheumatic fever
erythema marginatum
418
tx of neisseria gonorrhoea septic arthritis
IV cefotaxime for 4-6 wks
419
HBsAg +ve after 6 months - what are you?
hepatitis carrier
420
Anti-HBs Ab
+ve
what does this mean
IgG antibody that appears after the host has cleared the infection and indicates recovery
also +ve in those who have been vaccinated
421
HBeAg +ve
what does this mean
found when virus is actively replicating
e for EEK
highly infective!!
422
Anti-HbC IgM
what does this mean
patient has been recently infected w hep B
and is a marker of acute infection
423
Anti-HBc IgG +ve
what does this mean
core antigen- for chronicity
has been infected before
if HBsAg -ve and HbsAb +ve then this person would be immune from natural infection
424
if someone has had C difficile pseudomembranous colitis before and been treated and presents again, what tx?
repeat course of metronidazole for 10-14 days for trx of recurrent c difficile infection
425
which antibiotic may cause red man syndrome
vancomycin
sudden onset erythematour pruritic rash over face, neck and upper torso
rmb driver of red cross van emerging very angry w bright red face
426
sporadic CJD memory aid
demented LAMB
dementia - v rapid
LMN signs
Akinetic mutism
Myoclonus
cortical Blindness
427
in variant CJD what do u see in MRI
positive pulvinar sign (enhanced signal of nuclei in the thalamus)
428
BG of portal hypertension and chronic liver disease
fever, tachycardia, abdo tenderness and ascites
nausea vomiting, general malaise or features of hepatic encephalopathy
what condition?
how to diagnose?
spontaneous bacterial peritonitis
diagnostic paracentesis: ascitic fluid WCC / neutrophil count
most common organisms in SBP are e coli, gram + cococi and enterococci
tx: cefotaxime
429
with Hep C, what determines how likely someone is to cleart he virus?
virus strain/ genotype
genotype 1 assoc w poorer response to anti viral (IFN and ribavarin)
430
431
Human African trypanosomiasis aka Sleeping Sickness
-an infection transmitted by the **tsetse fly**
two main types:
1) trypanosoma brucei gambiense - responsible for \>95% of cases. causes chronic infection that takes months-years to appear.
**G**ambiense for **gradual**
2) trypanosoma brucei rhodesiense - \<5% causes acute infection, appearing over wks-months
**R**hodesiense for **rapid** infection
A subcutaneous chancre can develop at the site where the tsetse fly bites and symptoms such as fevers, weakness, arthralgia and headache can then appear. + posterior cervical lymphadenopathy (winterbottom's sign)
Later the parasite crosses the BBB to cause disturbance of the sleep cycle, ataxia, behavioural changes and psychiatric disturbance.
Tx is w drugs such as pentamidine and suramin in early stages
432
Sleeping sickness-
organism responsible for a rapid infection
occuring over a few wks or months
trypanosoma brucei rhodesiense
- fevers, weakness, arthralgia, headache
posterior cervical lymphadenopathy
disturbance of sleep cycle, ataxia, behavioural changes, psychiatric disturbance
433
sleeping sickness
what organism is responsible for majority of the infections.
and causes a chronic infection
showing up months - years later
Trypanosoma brucei gambiense
- fevers, weakness, arthralgia, headache
posterior cervical lymphadenopathy
disturbance of sleep cycle, ataxia, behavioural changes, psychiatric disturbance
434
what vector transmits the sleeping sickness? (trypanosoma)
tsetse fly
435
Chagas Disease
carried by the reduviid bug
- what presentation
*trypanosoma cruzi*
'kissing bugs' aka reduviid bugs
a red nodule, called a chagoma, can appear at the site of the bite
acute phase: fever, lethargy, diarrhoea and vomiting. characteristic feature is a purplish swelling of the eyelids (called Romana's sign)
to put this all together, picture Tom Cruise (Trypanosoma cruzi) starring in a gladiator film as a roman (romana's sign) wearing purple sunglasses (swollen eyelids) and being kissed (kisisng bugs) by lots of fans 'ready w their video cameras' (reduviid bug)
436
Chagas Disease
trypanosoma cruzi (Tom Cruise)
spread by reduviid bugs
what does the chronic phase present w?
can occur years after the initial bite, and typically affects the heart and GI tract.
Both dilation and dysfunction in three organs:
heart (dilated cardiomyopathy and arrhythmias)
colon (megacolon and constipation)
oesophagus (megaoesophagus and dysphagia)
Tx: bennzimidazole and nifurtimox
437
what vector transmits dengue fever
Aedes mosquito
438
**Maurer's clefts** on Malaria thin blood film
Plasmodium falciparum
these are disc-like granulations seen at the edge of the cell using an electron microscope.
they are larger and coarser than the Schuffner's dots seen w P vivax and P ovale.
439
Schuffner's dots on thin blood film
P ovale and P vivax
these are punctuate granulations seen under the microscope in erythrocytes invaded by the tertian malaria parasite
440
Severe malaria tx?
V severe malaria?
IV Quinine
if v severe: IV artesunate +/- IV quinine
441
tx of uncomplicated malaria
ALWAYS ADMIT
Oral quinine and doxycycline for 5-7 days
Co-artem (artemetherelumefantrine) for 3 days
Malarone (atovaquone-proguanil) for 3 days
442
tx of non-falciparum malaria
chloroquine + 2 wks of primaquine
chloroquine to treat the parasites in the erythrocytes and primaquine to kill the hypnozoites that remain latent in the liver
443
malaria life cycle
an infected mosquito injects ______ from its saliva into a persons blood stream when it bites
sporozites
444
malaria life cycle
sporozites enter the blood stream where they are taken to the ____ where they infect \_\_\_\_\_
liver
hepatocytes
445
Malaria life cycle
In the liver, they multiply for a varying period of time, and then differentiate to form haploid \_\_\_\_\_\_. These have a 'signet ring' appearance
\_\_\_\_\_\_ are oval-shaped inclusions that contain the \_\_\_\_\_\_.
Haploid merozites
shizonts are oval shaped inclusions that contain the merozoites.
\*P vivax and P ovale sporozites may not develop into merozites immediately, but can form hypnozoites that remain dormant in the liver
446
P vivax and P ovale sporozites may not develop into merozites immediately, but can form ______ that remain dormant in the liver
hypnozoites
447
malaria life cycle
merozites escape from the liver into the blood stream and infect RBCs.
they multiply further in the erythrocytes and will be released from them at intervals. the waves of fever the patient experiences correspond to when the merozites are released from the erythrocytes.
some of the merozoites develop into sexual forms of the parasite called _________ which can be taken up by the next mosquito.
male and female gametocytes
448
what malaria parasite causes daily (quotidian) fevers
Plasmodium knowlesi
mainly occus in SEA, and not in africa
449
side effects of ethambutol
renal impairment (avoid in pts w impaired renal fn)
pts renal function should be checked routinely before
ocular toxicity
- changes in visual acuity, colour blindness and restriction of visual fields
450
why should liver function be tested in everyone before starting antituberculous therapy?
isoniazid, rifampicin and pyrazinamide are all hepatotoxic
Rifampicin can commonly cause a transient disturbance to LFTs for the first 2 months, but this does not usually necessitate any changes to the tx regimen.
451
gram -ve diplococci
pneumonia
esp in smokers
chronic lung disease
and causes exacerbations of COPD
other targets of infection include ears, eyes and CNS
moraxella catarrhalis
452
what causes threadworm infection?
roundworm - enterobius vermicularis
453
presentation of hydatid disease
tapewarm causing cysts in liver, lungs
abdo discomfort, biliary obstruction or incidental finding on USS
cyst rupture may result in anaphylaxis
454
hydatid disease
what organism
tapeworm
echinococcus granulosus
455
mx of hydatid disease
long term albendazole/ praziquantel
PAIR (puncture-aspirate-injection-reaspirate) for inoperable cysts
surgical removal of cysts
456
Ascariasis
presentation
large roundworms, growing up to 35cm
symptoms when worm burden is high - bloody sputum, cough, fever, abdo discomfort, intestinal ulcer, passing worms
sometimes see TONS of worms in intestine
457
mx of ascariasis
albendazole.
keep NMB, natural peristalsis usually expels worms
may need surgery - if bowel obstruction.
458
itchy migrating painful rash on foot
hx involves barefoot walking on beach
cutaneous larva migrans
hook worm
heals spontaneously over weeks to months
cant get beyond the subcut tissues
459
mx of cutaneous larva migrans
oral albendazole/ Ivermectin can speed up process
topical / oral thiabendazole halts migration of larva/ relieves itching in \<48h
460
strongyloides
usual presentation
asymptomatic
or mild GI symptoms/ skin rash (larva currens)
can be lifelong infection
diagnosis via stool/ serology
461
strongyloides
severe presentation
strongyloides hyperinfestation syndrome
when immune system fails
e.g. steroids/ biologics
bowel breakdown -\> gram - bacteraemia
-\> CNS meningitis, encephalitis, lung disease, death
462
mx of strongyloides
Ivermectin x2
463
schistosomiasis mx
praziquantel
464
water snails vector
causes eosinophilia, haematuria, Katayama fever (cough, wheeze, urticaria, eosinophilia)
schistosomiasis
migrates via lungs (causing Katayama fever)
colonises colon, bladder, liver
complications: bladder SCC, portal HTN
465
diagnosis of schistosomiasis
egg microscopy
serology
466
what vectors for leishmaniasis?
sandflies
467
what is the vector for trypanosomiasis
tsetse flies
468
trypanosomiasis
presentation
aka chagas disease
red chancre
aggressive fulminant infection:
fever, swollen LNs, bloody urine, myalgia, headache, irritability and death
also causes sleeping sickness: presents months to years later
Tom cruise: trypanosoma cruzi
469
loa loa presentation
conjunctiva of the eye
eye worm
- visual disturbance
calabar swellings
dx: seeing the worm, blood film for microfilariae
470
GI infection- watery diarrhoea, abdo cramps
fever, headaches
unpasteurized dairy products
**tumbling motility**
listeria monocytogenes
471
profuse watery diarrhoea
no inflammatory cells on microscopy
vibrio cholera
active secretion of NaCl
water lost due to osmotic pull of NaCl
472
fever, constipation, splenomegaly
rose spots
salmonella typhi
enteric fever
multiplies in Peyers patches of Small intestine
473
flask shaped ulcers
dysentery
chronic weight loss
liver abscess
entamoeba histolytic
motile trophozite
-\> colonization of colon and caecum
474
26 yr old man has recently returned to the UK from a year of working in Africa where he was taking part in a charity farming project.
he presents to A+E with signs of meningism.
a serological microscopic agglutination test is positive
Leptospirosis (weils syndrome)
A microscopic agglutination test is gold standard for diagnosis
475
most common cause of viral meningitis
of the herpes family
herpes simplex type 2
type 1 - encephalitis more common
476
what organism causes donovanosis
klebsiella granulomatis
gram + rod
477
pegylated-IFNa
how is it different from IFNa
addition of polyethylene glycol - increases the half life of the drug
used in tx of Hep C
IFNa acts on the JAK-STAT pathway
478
a 48 yr old man presents to his GP with flu like symptoms
OE the pt has a maculopapular rash on his trunk
the patient also shows an area where a vague bite mark is visible
rocky mountain spotted fever
caused by Rickettsia infection
harboured in small wild rodents and domestic animals.
-\> rickettsia bacteria cause vasculitis
features include headache, fever, myalgia, vomiting, confusion
late signs: rash maculopapular/ petechial
RMSF may lead to hypoNa, thrombocytopenia and elevated liver enzymes
479
congenital syphilis symptoms/signs
hepatosplenomegaly, rash, fever, neurosyphilis.
later on- saddle nose deformity, higoumenaki's sign (unilateral enlargement of the clavicle) and Cluttons joints
480
response to antiviral tx depends on viral genotype
Hepatitis C:
what genotypes are associated w poorer response.
genotype 1 poor response.
genotype 2 /3 better response so only need 24 weeks
