Fever in the returned traveller — branching viva

Opening question

Examiner: The registrar asks what the single most important action is. What is it, and why? [2]

Candidate: The single most important action is to recognise that this child has possible severe falciparum malaria and to send a same-day thick and thin malaria blood film in the first blood draw. The frame is that a febrile child who has been in a malaria-endemic area has falciparum malaria until a competent film proves otherwise — and this child is drowsy, acidotic and splenomegalic, so he is not just possibly infected, he is possibly severe. The film is part of the resuscitation, not a downstream test. [11]

Examiner: What else will you do in the first hour? [6]

Candidate: A structured ABC assessment with a paediatric early-warning score, high-flow oxygen for the respiratory distress, and intravenous access. In the same first draw I send a full blood count and film, venous gas and lactate, glucose, urea and electrolytes, liver function tests, C-reactive protein, blood cultures and a urinalysis. I give empiric ceftriaxone because bacterial sepsis cannot be excluded and dual pathology occurs, and I hold IV artesunate ready, because if the film confirms malaria and he is severe, he receives it immediately. [11] [6]

Branch 1 — the single negative film

Examiner: The first film comes back negative. What do you do? [6]

Candidate: I do not exclude malaria. A single negative film never excludes malaria, because parasitaemia fluctuates, the sensitivity depends on the microscopist, and low-level infection is missed. I repeat the film at twelve- to twenty-four-hour intervals — and sooner if he deteriorates — until either malaria is found or an alternative diagnosis is secured and the clinical course is clearly consistent with it. A child sent home after one negative film, without a repeat, is the classic and lethal error. [6] [11]

Examiner: And if the repeat film is positive at two per cent parasitaemia but the child remains drowsy and acidotic? [5]

Candidate: That is severe malaria, and the parasitaemia percentage is not the sole determinant of severity — the clinical severity is. Drowsiness and acidotic breathing are severity criteria, so he receives intravenous artesunate regardless of the two per cent figure. The AQUAMAT trial showed a relative reduction in mortality with artesunate over quinine in African children with severe falciparum malaria, so artesunate is the standard, and it is faster-acting and safer than quinine. [5]

Branch 2 — the dengue differential

Examiner: Suppose the malaria films stay negative and on day five the fever falls, but the child becomes lethargic, vomits persistently, and the haematocrit has risen. What are you thinking now? [7]

Candidate: Dengue, and specifically the transition into the critical phase. The paradox of dengue is that the child looks better as the fever falls, exactly when the capillary leak peaks and the shock risk is highest. The rising haematocrit signals plasma shift, and the persistent vomiting and lethargy are warning signs of severe dengue. I would send dengue NS1 antigen and serology, measure the pulse pressure and perfusion serially, and manage with careful titrated isotonic crystalloid through the leak — not aggressive boluses, because the lesion is capillary leak and excessive crystalloid worsens the plasma shift. [7]

Examiner: Why does the leak happen at defervescence? [7]

Candidate: In a secondary infection, pre-existing antibody enhances viral uptake through Fc-γ receptors — antibody-dependent enhancement — and the NS1 viral protein with complement activation injures the endothelium, producing capillary permeability. The leak is time-limited, peaking around defervescence, and the management discipline is to titrate fluid through a window the child will pass, watching the haematocrit fall back and the perfusion improve as the leak resolves. [7]

Branch 3 — typhoid and resistance

Examiner: Now imagine a different child: two weeks of stepwise fever, abdominal pain and constipation, back from visiting family in Pakistan. Blood cultures are pending. What is your empiric antibiotic and why? [10]

Candidate: Azithromycin is often the safer empiric oral choice while the cultures return. Extensively drug-resistant Salmonella Typhi is now prevalent in South Asia and is resistant to ampicillin, chloramphenicol, co-trimoxazole, fluoroquinolones and often third-generation cephalosporins, so a fluoroquinolone or even ceftriaxone may not cover it. I would reserve ceftriaxone for severe disease or for a confirmed susceptible isolate, and I would treat the empiric antibiotic as a travel-history decision, not a generic one. [10]

Examiner: What confirms the diagnosis? [10]

Candidate: Blood culture, or bone marrow culture, which is the gold standard but rarely needed. A single negative blood culture does not exclude enteric fever, because bacteraemia is intermittent. The clinical features in children are less classical than the textbooks imply — the rose spots and relative bradycardia are insensitive — so I would not be reassured by an atypical picture. [10]

Branch 4 — public health and isolation

Examiner: A third child arrives: three days of fever, malaise and gum bleeding, two weeks after returning from an area with an active viral haemorrhagic fever outbreak. Walk me through your first actions. [2]

Candidate: I isolate the child first and contact the public-health and infectious-diseases teams before any further assessment, blood test or aerosol-generating procedure. The decision to isolate is made on the travel history alone — a child febrile within twenty-one days of a VHF risk zone — because an unrecognised case is a serious nosocomial hazard to staff and other patients. The specific therapy, where one exists, is delivered within that protocol. [2]

Examiner: And the non-VHF infectious diseases you must notify? [2]

Candidate: Malaria, enteric fever, dengue and the arboviral infections are notifiable in most jurisdictions, as are tuberculosis and the viral haemorrhagic fevers. Notification triggers public-health follow-up, and for the visiting-friends-and-relatives family it is an opportunity to ensure the whole family has pre-travel advice for future visits — prophylaxis, vaccination, and a plan for febrile illness abroad. [1]

Branch 5 — the visiting-friends-and-relatives family

Examiner: These children keep coming back with imported infection. What is the systemic fix? [1]

Candidate: The visiting-friends-and-relatives traveller is the single highest-risk group for imported malaria and typhoid, and the one most often missed by pre-travel services. The fix is twofold. In the acute setting, ask the travel history of every febrile child so the group is surfaced. In primary care, target pre-travel advice to migrant families planning a return visit — prophylaxis, vaccination, and a clear plan for febrile illness abroad — because the next visit will happen and the risk will recur. [1] [10]

Wrap

Examiner: Summarise the approach to fever in the returned traveller in one sentence. [2]

Candidate: Ask the travel history of every febrile child, send the same-day malaria film and never believe a single negative result, hold the five must-not-miss causes with their time-critical therapies, and escalate to artesunate for severe malaria, careful fluids for dengue at defervescence, doxycycline for the eschar, travel-guided antibiotics for typhoid, and immediate isolation for the viral haemorrhagic fevers. [2] [5]