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see also http://www2.ncid.cdc.gov/travel/yb/utils/ybBrowseO.asp

Illness in returned travellers

The information below gives an overview of the complexity of investigating adequately the returned traveller and also highlights the urgency to investigate and refer the febrile patient. This information was taken from a travel seminar in October 1996 with the authors permission. ( added information in italics )
Dr. M. Oldmeadow
Sub-Dean, Monash Medical School, Melb,Vic

In a study of 10,000 Swiss travellers it was found that after return, a total of 15% developed health problems. Eight percent consulted a medical officer and 3% were off work for an average of 15 days.
It is likely that this approximately reflects the situation with respect to Australian travellers. If so, it underlines the fact that tens of thousands of consultations with family practitioners in Australia each year will be for medical illness and/or advice in returned travellers.
Most commonly encountered problems are those relating to enteric infections contracted in S.E. Asia. These include salmonella, shigella, giardia and amoebic infections as well as helminthic infestations. These are followed by an array of other diseases including hepatitis, malaria, STD's and pulmonary infections. Finally, non infectious travel complications are also common. Drug reactions, cardiac and respiratory disorders and thrombo-embolic events may occur.
As some of these disorders may be associated with serious consequences if diagnosis is delayed, it is important that the medical practitioner is familiar with the various ways in which they may present.
In this regard, travellers presenting with fever and/or jaundice require the most care and vigilance. Malaria and bacterial infections including those involving salmonella organisms may be the underlying cause and appropriate initial steps must therefore be taken to ensure an early diagnosis. Viral Hepatitis and amoebiasis are other common serious infections to be considered in this clinical setting.
Persisting gastrointestinal symptoms following travel in S.E. Asia, in particular, is a common and frustrating problem requiring understanding, patience and support from the attending doctor. The extent of diagnostic investigations required in this situation is sometimes difficult to judge and the "therapeutic trial is an important tool in management.
Range of presenting problems

• Most will present within 2 weeks of return :- Common infections encountered;
  giardiasis>amoebiasis>hepatitis>gonorrhoea >malaria and helminthic infestations
• Travel associated problems not caused by infection:
  jet lag (west to east>east to west), thromboembolism, scopolamine toxicity,
  other drug reactions (antimalarials, antibiotics),
  hypoxia associated cardiac and pulmonary problems

Important principles in management
Fever:-

• refer immediately if unwell
• beware of malaria, typhoid, meningitis, septicaemia never delay active treatment or referral beyond 48hrs.
• if > 50 yo consider septicaemia, & malaria if no focal signs and always before hepatitis if patient icteric.
• in children, malaria may masquerade as gastro-enteritis (fever & diarrhoea) or respiratory infections (fever & cough)
• associated thrombocytopaenia - consider malaria

Diarrhoea:- Clinically important pathogens include
(10% symptoms last 1 week, 3% last 2 weeks or more, 1-2% 1 month or more)

• Bacterial - Enterotoxigenic E. coli (ETEC) account for >80% of cases, Campylobacter, Salmonella, Yersinia, Aeromonas
  - Less common - Campylobacter, Salmonella, Shigella, Yersinia, Aeromonas
  - Single Faeces M & C usually will detect these (Nb. ETEC not detected with routine culture)
  - Treat Norfloxacin 800mg stat then 400mg BD for 3 days or Azithromycin (To hospital if unwell)
• Other - Giardia, Plesiomonas, Entamoeba histolytica, Hookworm, Strongyloides, Schistosomiasis, Cryptosporidium, Clostridium difficile and Vibrio cholerae (especially if watery diarrhoea).
• always request for Clostridium difficile toxin if previous antibiotic use.
• Reportable but not clinically significant or treatable Entamoeba coli, Endolimax, Iodamoeba butschlii.

• Eosinophilia on blood film:-
  • absolute counts, not percentages, are required. - normal < 400/cmm
  • consider non-infective associations - particularly with low level counts (500-1000)
    drugs - sulphas, penicillin, cephalosporins, beta blockers, NSAIDs, aspirin, quinine.
    atopic disease, inflammatory bowel disease, connective tissue disease, some malignancies,
    scabies, pulmonary syndromes (higher counts)
  • giardia, amoebae and helminths (tapeworms, adult ascaris) DO NOT cause eosinophilia.
  • Isospora belli and other helminths are a cause. degree of eosinophilia relates to amount of tissue invasion occurring at the time. counts > 3000/cmm
  • ascaris, angiostrongyliasis, strongyloides, hookworm, filaria, schistosomiasis, other.
  • commonest when investigations negative over 3 months are :- hookworm and strongyloides
• Investigation of Infective cause
  • stool M+C x 3 - include strongyloides culture.
  • faeces immunoassay for Giardia & Crytosporidium antigens
  • persisting diarrhoea: collection of faeces using preservative may detect D.fragilis parasite
  • terminal urine (MD-2pm), rectal biopsy for shistosome eggs
  • duodenal juice (string test) for strongyloides, hookworm eggs, ascaris larvae, liver flukes.
  • CXR - if respiratory symptoms
  • serology (see next section) - strongyloides, schistosomiasis, filariasis, hydatid, fasciola.
• Management
  • consider empirical therapy according to exposure
    mebendazole - roundworm.
    praziquantel - schistosomiasis, fasciola (drug is easy and safe to use).
    thiabendazole - strongyloides (drug has high toxicity; therefore pursue diagnosis actively).
    diethyl carbamazine - filariasis
  • observe without treatment
    many raised eosinophil counts will resolve spontaneously over 3-6 months.
    counts persisting over 1-2 years suggest -hookworm, strongyloides, filariae, flukes, hydatids, cysticerosis.
  • nb: eosinophil count may increase in initial weeks of treatment and resolve over months

Serologic tests of value

• Schistosomiasis: early seroconversion within weeks but may be delayed for up to 3 months
  few false negatives after 3 months
  some false positives occur
• Amoebiasis: highly specific.
  sensitivity:- extra intestinal disease - 95%
  invasive intestinal disease - 85%
  asymptomatic carrier - 10%
• Strongyloides: sensitivity & specificity - 80-90%
  (in comparison, stool microscopy = 80% sensitive)
• Filariasis: up to 30% false positives
  low positive results difficult to interpret
• Hydatid: sensitivity:
  active liver cysts 90%
  dead/calcified cysts 50%
  specificity: - poor at low titre IHA
  good at high titre IHA
• HIV most positive by 3 months
  if high risk check at 6 & 12 months

Management of Individual travellers
Asymtomatic
1.Exposure but without illness whilst away
1.1 STD

• HIV, HBsAg -allow for "window" period of 3 mnths
• VDRL - if negative, repeat in 6 -10 weeks
• direct smears for microscopy a) urethral (include culture) for chlamydial antigen + gonococci b) any genital, ano-rectal or oral lesion
• empirical treatment - ? doxycycline

1.2 Schistosomiasis

• Swimming exposure in Africa (including Lake Malawi), Middle -East & S.E. Asia
• serology should be performed after 1 month
• investigations otherwise low yield if asymtomatic and not useful if < 3 months
  consider empirical therapy as treatment is safe and long term illness may occur.:- praziquatel 20mg/kg for 3 doses (total 60mg/kg ) 4 hours apart.

1.3 Rabies

• post exposure vaccine indicated following scratches or bites (especially if unprovoked) from animals in endemic areas. (list on previous page).
• best given early, but should be administered if event is within the last 2 months
• if pre-exposure immunisation has been given, an abbreviated course of vaccine is still indicated.

1.4 Malaria
thick and thin blood films only if clinical signs eg: splenomegaly or FBE shows thrombocytopenia.

1. Exposure plus clinical illness whilst away
   Careful history and examination required ( ? icterus, rash, lymphadenopathy, splenomegaly, hepatomegaly.

1.1 Febrile Illness
consider malaria, salmonella, schistosomiasis (Katayama fever) and investigate if these may have been responsible.

1.2 Malaria

• If clinical illness likely - eradicative therapy warranted after excluding G6PD deficiency
• Primaquine 7.5 mg t.d.s. for 14 days

1.3 Gastrointestinal illness

• mild illness - no further investigation
• moderate to severe, or prolonged diarrhoea: consider Giardia lamblia, Campylobacter, Salmonella, Entamoeba histolytica, others.
• Consider: FBE, stool M+C X3, serology
• Treat if pathogens identified or if symptoms develop
• If eosinophilia (see special section)

1.4 ? Schistosomiasis

• 3 clinical entities (all or none may occur)
  i) dermatitis - local - within days
  ii) acute febrile illness (Katayama fever) - within weeks
  iii) chronic illness - after 3 months
• may have diarrhoea, abdominal pain, haematuria
• investigations (see serology & eosinophilia sections)

B). Symptomatic at the time of review
1. Gastrointestinal Symptoms
1.1 persisting abdominal discomfort

• Bloating, borborygmi & intestinal hurry is very common (may persist for many months, up to a year or more) in those contracting a diarrhoeal illness in India or S.E. Asia in particular
• All should have
  stool M+C x3 (including C. difficile toxin & culture)
  FBE (? eosinophilia), LFT, U+E
• if no pathogens, all should have trial of
  metronidazole 400mg tds for 7 days
  mebendazole 100mg bd for 3 days
  exclusion of dairy products
  exclusion of alcohol
• many will continue to experience mild symptoms, despite no cause being found & having had empirical treatment. The label of "Post infective irritable bowel syndrome" is then appropriate. Reassurance rather than reinvestigation may be required.
• reasses if weight loss or new symptoms
• consider non infective causes

1.2 Persisting mild - moderate diarrhoea

• investigate as above & include serology
• May warrant proctoscopy with rectal biopsy, string test (or duodenal aspiration: see eosinophilia notes), faecal fat, colonoscopy.
• eosinophilia: investigate as per notes consider therapeutic trial: (see 1.1) & include norfloxacin.

1.3 Severe diarrhoea and/or associated fever
(or patient clinically unwell) :- referral appropriate

2. Fever

• see section on important principles
• most common are malaria, typhoid, hepatitis, dengue
• If not unwell: FBE, thick & thin films, LFT, blood culture, MSU, + or - stool culture and/or CXR
• refer if fever more than 48 hours
• no role for empirical therapy outside hospital

3. Malaria

• most present within 2 months of infection, but may be up to 2 years or later
• Beware of modified infection
• deaths may occur any time from 3 days after initial symptoms
• order thick & thin blood films on ALL febrile patients returning from a malarial area
• treatment is best carried out in hospital

Information mostly taken from: "International Travel and Health" (WHO year book - internet only)
Australian Immunisation Handbook, 8th Edition - 9/2003 - Part1 - Part 2 & Part 3 (large pdf files)
Centre for Disease Control, USA -  www.cdc.gov/travel Travel Health Seminar Oct 96, June 97,Feb 98, March 99, May 2000, August 2002 & March 2005 - Victorian Medical Postgraduate Foundation.
Manual of Travel Medicine, Melbourne, Oct 2004. Updated 18/09/2005.  Additional references & disclaimer.