You arrive in the ED for a late shift. It’s early Autumn and not that busy. You’re stationed in majors, and pick up your first patient. A 23 year old final year medical student. They’ve self-presented and the triage sheet says the following:
2/7 fever, diarrhoea and a rash.
You head to see the patient in his cubicle to get more information.
He mentions that he’s been on elective in Uganda over the summer period, working in a rural clinic close to Lake Victoria. All other members of his travel party are well.
He attended his GP travel clinic prior to his elective and is up to date with all vaccinations. Apart from this trip, he has not left northern Europe in the previous 5 years.
During this trip he swam in Lake Victoria and had no sexual partners abroad – he has a long-term girlfriend in the United Kingdom. He has never taken drugs, drinks minimal alcohol and doesn’t smoke. He has no past medical problems or allergies, and is not on any regular medication. All his household contacts are well.
- Hb 123g/L WCC 12.1 x 103 /µL Neutrophils 6.5 x 103 /µL Eosinophils 1.3 x 103 /µL (0.04-0.4) Lymphocytes 3.8 x 103 /µL
- GGT 68 ALT 56 Bilirubin 22
- Urea & Electrolytes normal
- INR 1.1
Urinalysis: Blood 1+
CXR: no obvious abnormality
A mildly elevated WCC with a marked eosinophilia and mildly elevated LFTs with preserved synthetic function.
The main points in the history and initial investigations are sudden onset of fever, diarrhoea and a rash. The young man has recently returned from sub Saharan Africa with an eosinophilia but otherwise unremarkable bloods.
This leaves a broad differential diagnosis:
- Viral: HIV sero-conversion, hepatitis A, other non-specific viral illness
- Parasitic: Malaria, schistosomiasis
- Bacterial: atypical pneumonia, typhoid
Allergic reaction to unknown allergen,
Fever in a returned traveller with non specific symptoms or ‘flu-like illness’ has a broad differential diagnosis (with many others not mentioned here). It is vital to take a very detailed travel history including rural or urban locations, whom they stayed with, source of drinking water, and whether the traveller ate local food. Remember to enquire about recreational activities, including sexual history.
Any patient with fever and a compatible travel history should have malaria excluded. This can be done with either rapid diagnostic test (RDT) or thick and thin blood films. HIV can also be rapidly excluded via serology testing.
Schistosomiasis mansoni is endemic to sub Saharan Africa with a prevalence approaching 100% in some areas. Known areas with infected water include Lake Victoria, Lake Malawi and the upper end of the Nile – but all freshwater in sub Saharan Africa should be treated as a potential source. It is a small, highly contagious trematode with a life cycle moving through water and fresh water snails, before trans-dermal penetration to the human host. It colonises in the portal vein or arterial supply to the large bowel (see diagram below). Eggs are excreted in stool to continue the life cycle. In chronic, repeated infection the patient is predisposed to portal hypertension with oesophageal varicies, splenomegaly and hepatocellular carcinoma. Children with infection show short stature, poor performance at school and anaemia.
‘Katayama fever’ is the initial symptoms of Schistosomiasis infection; as described above with fever, rash, dry cough and GI upset. It is thought to be a hypersensitivity reaction to the movement of the parasite giving non-specific, multi-system symptomatology.
Diagnosis relies on a high index of suspicion in travellers or immigrants who have been to an area with a known high prevalence, especially when in contact to fresh water. The gold standard is microscopy of stool for eggs shed into the GI tract. Serology performed in travellers with primary infections can initially be negative. Ectopic eggs can cause granulomas in any tissue, including the central nervous system and lungs. Skin biopsies can be taken to confirm an eosinophilic rash. A chest X-ray may show sparse nodular changes.
Treatment of Katayama fever is supportive, with steroids and a single dose of praziquantel (40mg/kg). If praziquantel is given early in the disease process a second dose may be needed as it is only effective on adult parasites. Travellers should be reminded to avoid swimming and bathing in water that is likely to be infected.
Human schistosomiasis. Gryseels B, Polman K, Clerinx J et al. Lancet 2006; 368: 1106–18
Manson’s Tropical diseases 23rd edition 2008
An approach to fever in the returning traveller. GK Brink et al.South African Family Practice. 2008; 50:1, 23-27, DOI: 10.1080/20786204.2008.10873662