Tropical Infection of the GI tract Flashcards
What is the definition of travellers diarrhoea?
3 loose stool in 24h
What are the usual microorganisms causing Travellers diarrhoea?
Typically enterotoxigenic E. coli
But also – Campylobacter, Salmonella, Shigella
Cruise ships – Norovirus and rotavirus
Others – Amoebic diarrhoea (Entamoeba histolytica)
What are the investigations for acute travellers diarrhoea?
Stool culture
Stool wet prep on recently passed stool for amoebic trophozoites
What are the treatments for acute travellers diarrhoea?
Supportive – fluid rehydration (oral/IV)
Bloody diarrhea with systemic upset may warrant treatment
In those travelling:
- fluoroquinolone (ciprofloxacin) single dose can stop worsening
Antibiotic resistance – now very common especially in Asia where a macrolide (azithromycin) may be more useful
What is enteric fever?
Typhoid or paratyphoid fever
Most common in those returning from Indian subcontinent and SE Asia – due to sanitary conditions
Food borne illness
What is the incubation time for enteric fever?
7-18 days
What are the symptoms of enteric fever?
Fever
Non-specific
- Headache
- Constipation or diarrhoea
- Dry cough
Complications
- GI bleeding
- GI perforation
- Encephalopathy
- Bone and joint infection
(i. e. dont need to have diarrhoea)
What is enteric fever caused by?
Salmonella typhi or paratyphi
Usually isolated from blood, stool, or urine
What is the empirical treatment of enteric fever?
IV Ceftriaxone
What can cause pre-hepatic fever and jaundice?
Malaria
HUS as complication of diarrhoeal illness – E.coli 0157, Shigella
Sickle cell crisis triggered by infection
What can cause hepatic fever and jaundice?
Hepatitis A and E – acute (occasionally Hepatitis B)
Leptospirosis – Weils diseases (Icteric, haemorrhagic and renal failure)
Malaria
Enteric fever
Rickettsia (scrub typhus, Rocky Mountain spotted fever etc)
Viral haemorrhagic fever
What can cause post hepatic fever and jaundice?
ascending cholangitis and helminths
What are the investigations for fever and jaundice?
Malaria blood film and rapid antigen Blood film for red cell fragmentation FBC/UE/LFT/coagulation Blood cultures USS abdomen Serological testing for viruses
What are the treatments for fever and jaundice?
Appropriate isolation and infection control procedures
Supportive – may need dialysis if acute kidney injury
If acute liver failure – hepatology/transplant unit
What is Amoebic dysentry caused by?
Faecal-oral spread
strong association with poor sanitation
Entamoeba histolytica, a protozoa
Asymptomatic carriage - shed cysts in stools chronically
What are the symptoms of Amoebic dysentry?
Abdominal pain
Fever
Bloody diarrhoea / colitis (can perforate)
Toxic and unwell, abdominal tenderness, peritonism
What are the investigations of Amoebic dysentry?
Stool microscopy for trophozoites or cysts (distinguish between E. histolytica and E. dispar)
AXR - possible toxic megacolon
Endoscopy for biopsy (not if evidence of toxic dilatation)
What is Amoebic liver abscess?
Subacute presentation over 2-4 weeks
- Fever, sweats
- Upper abdominal pain
- Sometimes history of GI upset (dysentery)
- Hepatomegaly
- Point tenderness over right lower ribs
What organism causes Amoebic liver abscess?
Entamoeba histolytica
What is the management of Amoebic liver abscess?
metronidazole or tinidazole
What is the presentation of Gardiasis?
Watery, malodorous diarrhoea
Bloating, flatulence
Abdominal cramps
Weight loss
How is Gardiasis spread?
Giardia intestinalis (lamblia), flagellated protozoa
Invades duodenum and proximal jejunum
Faecal-oral spread (contaminated water most commonly)
Incubation usually around 7 days
Name some times of helminth infections (worms)?
Trypanasoma cruzi – Amercian Trypanosmiasis
Cestodes – Tapeworms
Schistosomiasis – fresh water exposure
Clonorchis/Fasciola – SE Asia
