Tropical Gastroenterology Flashcards
What are key findings on examination on a returned traveller with symptoms?
Fever Rash Hepatosplenomegaly Lymphadenopathy Insect bites Wounds
What are possible causes of fever in a returned traveller?
Respiratory tract infections – pneumonia/influenza
Travellers diarrhoea
Malaria
Enteric fever (typhoid/paratyphoid fever)
Arboviruses – Dengue/Chikungunya
What is traveller’s diarrhoea defined as?
3 loose stools in 24 hours
What typically causes travellers diarrhoea?
What are other reasonably common causes?
Enterotoxigenic E. coli
Also Campylobacter, Salmonella, Shigella
What is a likely cause of diarrhoea if the patient has been on a cruise ship?
Norovirus and rotavirus
What is a likely cause of bloody diarrhoea?
E coli 0157
Amoebic colitis
What is a likely cause of profuse watery diarrhoea often associated with outbreaks in refugee camps?
Cholera
What investigations are carried out for traveller’s diarrhoea?
Stool culture
Stool wet prep on recently passed stool for amoebic trophozoites
How is traveller’s diarrhoea treated?
Supportive: fluid rehydration
Bloody diarrhea with systemic upset may warrant treatment
In those travelling a fluoroquinolone (ciprofloxacin) single dose can stop worsening (a three day course is often recommended - simple gastroenteritis will resolve without treatment)
Antibiotic resistance – now very common especially in Asia where a macrolide (azithromycin) may be more useful
What are the possible types of enteric fever?
What causes them?
Typhoid fever caused by Salmonella typhi
Paratyphoid fever caused by Salmonella paratyphi
Which patients is enteric fever most common in?
Most common in those returning from Indian subcontinent and SE Asia
Often in people visiting family or friends
What is the incubation period for enteric fever?
Incubation period 7-18 days (though occasionally up to 60 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
Where can the pathogens be isolated from in enteric fever?
Blood, stool or urine
Sometimes bone marrow
How are patients with enteric fever managed?
In hospital they should be isolated immediately if the diagnosis is considered.
If the patient is septic, treat empirically with IV ceftriaxone.
What are prehepatic/haemolytic causes of jaundice, associated with GI infection?
Malaria
HUS as a complication of diarrhoeal illness- E.coli 0157/Shigella
Sickle cell crisis triggered by infection
What are hepatic causes of jaundice associated with GI infection?
Hepatitis A and E – acute (occasionally Hepatitis B)
Leptospirosis – Weils diseases (Icteric, haemorrhagic and renal failure)
Malaria
Enteric fever
Typhus
Viral haemorrhagic fever
What are post-hepatic causes of jaundice associated with GI disease?
ascending cholangitis – and helminths
What investigations are done in 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 is the management and treatment for fever with jaundice?
Appropriate isolation and infection control procedures
Supportive – may need dialysis if acute kidney injury
If acute liver failure – hepatology/transplant unit
Directed to pathogen isolated
Discussion with infectious diseases
How does amoebic liver abscess present?
Incubation period 8-20 weeks – symptoms develop over 2-4 weeks - Fever, cough, aching abdominal pain, hepatomegaly, sometimes a history of GI upset (dysentery) – usually male
How is amoebic liver abscess investigated?
CXR – raised right hemi-diaphragm. Abnormal LFTs. USS/CT scan. Serology. Stool microscopy often negative. Exclude hydatid disease before aspiration if from high risk country (Middle East, Central Asia)
What is the management for amoebic liver abscess?
–metronidazole
If pyogenic abscess a possibility then treat with
appropriate antibiotics whilst awaiting
diagnostic investigations.
Need to clear the gut lumen of parasites
Paramomycin/diloxanide
What are helminth infections?
Where are they found?
What are they associated with?
Parasites
Found in the gut and in the tissues.
Often associated with eosinophilia
How are Helminth infections often diagnosed?
Often diagnosed by the adult worm passed or the eggs in stool
Give examples of Helminths
Nematodes (Roundworms):
Intestinal roundworms
Tissue roundworms (filariasis)
Trematodes (Flukes)
Cestodes (Tapeworms):
Intestinal
Larval
What is the most common intestinal nematode (roundworm)?
What is its lifecycle?
Ascariasis
Life cycle:
Egg ingested – hatch in small intestine – invade gut wall into venous system and via liver and heart reach lungs – break into alveoli – ascend tracheobroncial tree then swallowed and in the gut develop into adult worm where they start to produce eggs.
Give 2 examples of trematodes (flukes)
Trematodes (flukes)
Schistosomiasis – fresh water exposure
Acute infection
Chronic infection
Adult worms located in portal venules which can lead to hepatolmegaly and liver fibrosis and portal hypertension
Liver flukes – Clonorchis/Fasciola – SE Asia
Give examples of cestodes or tapeworms and where they come from
Taenia solium (Pork) or saginatum (Beef) – acquired by eating undercooked meat containing infectious larval cysts Taenia solium eggs (autoinoculation or from human faeces) can cause – cysticercosis – tissue cysts muscle and brain
Give two examples of protozoan infections
Giardia lamblia
Trypanasoma cruzi – Amercian Trypanosmiasis, Chagas’ Disease
What are the symptoms of Giardiasis?
diarrhoea
chronic diarrhoea
malabsoprtion
weight loss
How is Giardiasis diagnosed?
look for cysts or parasites in stool
How is Giardiasis treated?
Metronidazole
How is Trypanasoma cruzi transmitted?
By the kissing bug- Triatome
What does Trypanasoma cruzi cause?
Causes parasymphathetic denervation affecting the colon and or oesophagus
Megaoesophagus
