Infectious Disease Flashcards
How does Cholera present
Painless watery diarrhoea
severe dehydration
Diagnosis: - DARK GROUND MICROSCOPY
gram negative bacillus
comma shaped
Pathogenesis:
endotoxin cholera release
stimulates small bowel fluid secretion
What is the management of cholera
FLUIDS
CIPROFLOXACIN MAY REDUCE INPATIENT STAY
ALSO MACROLIDES AND COTRIMOXAZOLE
What causes bloody diarrhoea
Giardia lambides
Gardenella
Entaemoeba
Clostridium
What causes watery diarrhoea
Cholera
Cryptosporidium - parasitic - treat nitazoxanide
tropical sprue - metro + fluids + folic acid
post abx
coeliac
SBS
What is the treatment of cyrptosporidium diarrhoea
- Supportive management
- anti-helminth
- Praziquantel
- Nitazoxanide - blocks iron reduction in bacteria and therefore interferes with normal metabolism
How does Hookworm present
- microcytic anaemia
- eosinophilia
740million people affected greatest SS Africa
burden of 40-60 = Hb<11
treat:
Albendazole
mebendazole
praziquantel
What is Lyme disease
Caused by:
BORRELIA BURGDORFEI - Spirochete (as trypanoma palladum)
spread by:
tick bites
Erythema migrans - Bullse eye from infection site onwards Mutli-organ involvement \: fever / malaise + mylagia encephalitis cardiomyopathy AV block
What is Chagas Disease
Chagas disease is caused by Trypanosoma Cruzi
- Typically S American e.g. bolivia
- KISSING BUG - bites and excretes feces near bite
- localised histamine reaction - pruritic - host infects itself with feces
Chagas 1. oedema 2 D+V 3. mega oesophagus - PATHOGNOMIC 4. mega colon - PATHOGNOMIC 5. Cardiomyopathy
Remember as CHUGA DISEASE - BIG OESOPHAGUS BIG BOWEL
Treatment:
nitroheterocycles
What is Whipples Disease
Parasitic infection of the small bowel - jejunum
caused by T. Whippelei
GASTRO WHIPPLES
CNS WHIPPLES
OCULOMASTICATORY MYORHYTHMIA IS PATHOGNOMIC
only occurs in 20% of cases
smooth convergent divergent nystagmus of both eyes
simultaneous rhythmic dystonia of masseter and buccalis
Upgaze palsy - (IV)
+/-rhythmic movements of arms and legs
Signs
B12 and folate malabsorption
sensory neuropathy
weight loss
Symptoms: bile salt malabsorption and steatorrhoea confusion depression behavioural changes
Diagnosis: jejunal biopsy Acid alcohol fast bacillus - periodic acid Schiff stain stains infected macrophages PCR analysis
Differentials: rule out Coeliac - TTG / endomysial rule out porphyria - acute abdo pain / confusion AIP +ADP +VP + HC / PCT EPP CEP Tropical sprue (no CNS) Crohns (no CNS) malnutrition + alcohol
What is Meliodosis?
Respiratory infection caused by burkholderia psuedomallei
Endemic to Thailand / N Australia
- cavitating pulmonary abscess
- pleural effusions
- vesicular eruptions over the shins
- LFT derangement
not contagoius
transmitted from sea water and rural buildings
MORT 20-50% even with treatment
gram neg bacteria
treatment:
meropenem + cotrimoxazole
What is Typhoid fever
Caused:
Salmonella Typhi
Infected / contamined food from contaminated water
ROSE SPOTS = PATHOGNOMIC (25% present)
2-4mm raised erytheamatous maculopapular rash
presentation: abdmoinal pain lethargy + fatigue weight loss \+/- diarrhoea
Signs:
BRADYCARDIA - Faget’s sign
ROSE SPOTS - 25%
Diagnosis:
blood culture
fecal culture
Rx:
azithromycin
ceftriaxone if severe
-QUINOLONE RESISTANCE INCREASING
What is Lyme disease
Spirochete borrellia burgholderia Causes erythema migrans chronicum endocarditis arthralgia seizures and depressed GCS
Treat:
Doxy
How does Dengue Fever present?
Dengue virus
4 subtypes
Australia
fever
arthralgia
rash
headache
1st presentation = self limiting
May remit and then recur with secondary infection causing dengue haemorrhagic fever
What causes Hairy Oral Leukoplakia?
Reactivation of EBV in immunosuppressed individuals
e.g. HIV / steroids / infliximab / azathioprine
What is Katayama fever?
Schistosomiasis
high worm and egg count lead to serum sickness
i.e. IC formation and deposition
hepatosplenomegally
Treatment:
praziquantel
What is Weil’s disease
Leptospirosis - spirochaete
Fever and cough with malaise phase 1
Liver failure and renal failure
also hepatosplenomegally / meningism etc
Classically spread via rat urine from infected water
e.g. river thames
Dengue Fever
First exposure self limiting
Second exposure with a different isotype leads to rapid onset heamorrhagic fever
fever
headache
flushing
haemorrhage
Supportive measures only
research ongoing for vaccination
what is the difference between schistosomiasis mansoni and haematobium infection?
S.Mansoni predominantly causes hepatitis and increases the risk of HCC developing via chronic inflammation
Also causes CLD and CLF due to portal HTN / congestion / varices / fibrosis
S. Haematobium infests bladder plexus leading to chornic haematuria and renal failure - eggs in urine (typical hook)
All other schistos are region specific and cause liver damage
What is Jarisch-Herxheimer reaction?
What is it specific for?
Akin to tumour lysis syndrome
Occurs post treatment of spirochete infection
Lyme - syphillis -
Death of parasites leads to massive release of endotoxin triggering and SIRS response
Supportive management usually
What is classically associated with proteus UTI
Staghorn calculus
Proteus splits urea = styruvite crystals - magnesium ammonium phosphate
very difficult to eradicate infection
What does Wucheria bancrofti cause?
How is it treated?
Lymphatic filiarisis
Treat with diethyl carbamazine
How is HSV2 managed in pregnancy?
400mg acyclovir TDS for 7 days
restart treatment after 36 weeks to reduce chance of neonatal transmission - would need C-section
