Tropical GI Flashcards
What is the most important thing to aid diagnosis in tropical GI problems?
A really detailed and accurate history.
Important for incubation periods and identifying likely pathogens.
What are the common examination findings in an unwell returned traveller?
Fever, rash, hepatosplenomegaly, lymphadenopathy, insect bites and wounds
What are the most common diseases in returned travellers?
RTI- international air travel and circulating air systems
Travellers diarrhoea
Malaria
Enteric fever- typhoid and paratyphoid fever
Arboviruses- Dengue/Chikungunya/Zika (more common in cities)
What infection control precautions do you take with returned travellers?
Isolate until infectious disease ruled out
What is acute travellers diarrhoea?
3 loose stolls per day associated with low fever in 30%
What causes travellers diarrhoea?
Normally Enterotoxigenic e coli (different water => different E coli than the e coli in our gut)
Sometimes campylobacter, salmonella, shingella (longer incubation of a couple of days)
Cruise ships = norovirus and rotavirus
Rarely (associated with dysentery/blood in stool) amoebic diarrhoea, e coli 0157 cholera (very watery diarrhoea and dehydrated)
What investigations if you suspect acute travellers diarrhoea?
Stool culture and Stool wet prep for microscopy to look for amoebic trophozoites
What is the treatment for acute travellers diarrhoea?
Supportive- fluid rehydration
Ciprofloxacin can be used in those still travelling but high antibiotic resistance in Asia- use azithromyicin
Where is enteric fever most common?
Indian subcontinent.
What are the symptoms of enteric fever?
Long incubation 1-8 weeks.
Fever, headache, constipation/diarrhoea, dry cough.
What are the complications of enteric fever?
GI bleeding/perforation
Encephalopothy
Bone and joint infections
What causes enteric fever?
Salmonella typhi or paratyphi
How is eteric fever diagnosed?
Blood cultures as usually bacteraemic.
Stool or urine sample or bone marrow.
Lab precautions taken.
What is the treatment for enteric fever?
Empirical if serve = IV Ceftriaxone
Otherwise wait for sensitivities and use ciprofloxacin (high resistance), azithromycinor ceftriaxone.
Fever can take days to reduce. Be patient. All patients isolated
How effective is the typhoid vaccine?
70% against salmonella typhi and does not protect against paratyphi
What can cause fever and pre-hepatic jaundice?
Malaria- break down of RBCs.
HUS as a complication of diarrhoeal illness from Ecoli 0157 or Shigella.
Sickle cell crisis triggered by infection.
What can cause fever and hepatic jaundice?
Hepatitis A and E (occasionally B) Leptospirosis => haemorrhagic and renal failure) Malaria- damage hepatocytes Enteric fever Viral haemorrhagic fever (ebola)
What can cause fever and post hepatic jaundice?
Ascending cholangitis and helminths
What investigations are important for travellers returning with jaundice?
Malaria test FBC/UE/LFT/coagulation Blod cultures USS abdomen to rule out obstruction Serological testing for viruses eg Hepatitis
What is amoebiasis?
Infection with entamaeba histolytica- protozoa.
How is amoebiasis spread?
Faecal oral- associated with poor sanitation
WHat are the symptoms of amoebiasis?
Asymptomatic carriage Amoebic dysentery (abdo pain, fever, bloody diarrhoea, toxic megacolon, puritanism)
What are the investigations for amoebiasis?
Stoll microscopy
AXR for toxic megancolon
Endoscopy for biopsy- not in toxic megacolon
Amoebic liver abscess is a complication of amoebiasis but may not have had dysentery symptoms. It is more common in men. T or F?
True
How is amoebic liver abscesses/amoebiasis treated?
Metronidazole or tinidazole
What is giardiasis?
Infection with giadia intestinalis (a flagellated protozoa)
Invades the duodenum and proximal ileum . Faecal oral spread. Incubation 7 days
What is the presentation of giadia?
Watery diarrhoea, bloating, flatulence, abdominal cramps, weight loss
What are the investigations for giadia?
Stool microscopy for cycts
PCR tests
OGD for duodenal biopsy occasionally
What is the treatment for giadia?
Tinidazole or metronidazole
What are the 3 main types of helminths?
Round worms (Nematodes)
Flukes (Trematodes)
Tapeworms (Cestodes)
How are helminth infections diagnosed?
Adult wor or eggs passed in the stool
What is the life cycle of Intestinal nematodes (round worms) the most common helminth infection in the world?
Eggs ingested
Hatch in small intestine and invade gut wall and venous system
Travel via venous system to liver and heart to reach lungs.
Break into alvioli and ascend tracheobronchial tree where they are swallowed in to the gut and mature into adult worms and produce eggs.
What are the features of severe schistosomiasis?
Adult worms in portal venuloes leading to hepatomegaly and liver fibrosis and portal hypertension
Where doe infection with tape worms come from?
Undercooked meat. Some tapeworms can produce extra intestinal symptoms
Trypanasoma cruzi is transmitted by the kissing bug and can cause mega colon and oesophagus. T or F?
True
