MICRO: Fever in the returning traveller Flashcards
- PVI - presumed viral infection
- 70% of those returning from Africa had a tropical illness
- Risk of tropical infection higher among VFRs (visiting friends and relatives)
- Non-tropical were common among returnees from SE Asia (45%)
- but enteric fever (34%) and dengue (20%) remain important
Fever and Rash - Dengue, Chikungunya, rickettsial, enteric fever (rose spots), acute HIV, measles
Fever and abdominal pain - Enteric fever, amoebic liver abscess
Undifferentiated fever and normal/ low blood count - Dengue, malaria, rickettsial, enteric, Chikungunya
Fever and haemorrhage - Viral haemorrhagic fevers (dengue and others), meningococcaemia, letposiprosis, rickettsial
Fever and eosinophilia - Acute schistosomiasis, drug hypersensitivity, fascioliasis, other parasitic
Fever and pulmonary infiltrates - Bacterial/ viral pathogens, legionellosis, acute schistosomiasis, Q fever
Fever and altered mental status - Cerebral malaria, viral or bacterial meningoencephalitis, African trypanosomiasis
Mononucleosis syndrome - EBV, CMV, Toxoplasma, acute HIV
Fever persisting >2 weeks - Malaria, enteric fever, EBV, CMV, toxoplasmosis, acute HIV, acute schistosomiasis, brucellosis, TB, Q fever, visceral leishmaniasis (rare)
Fever with onset >6 weeks after travel - vivax malaria, acute hepatitis (B,C,E), TB, amoebic liver abscess
RDT = rapid diagnostic test
Malaria paracites look like “headphones”, there are two of them in the cell so it’s more likely falciparum
Case 1:
High prasitaemia - most helpful for guiding treatment
IV artesunate gives 30% reduction in mortality vs IV quinine in severe malaria
NB: 20% means that 20% of erythrocytes have been infected with malaria parasites
What % of African children deaths are caused by Malaria?
20%
African child may have 5 episodes of malaria per year affecting growth and development
How many cases of Malaria is seen in the UK per year?
~1500
What are the 5 types of Plasmodium species?
P. falciparum - MOST SEVERE - increased drug resistance, infects erythrocytes of all stages
P. vivax and P. ovale
P. malariae
P. knowlesi - behaves like falciparum
What is the life cycle of malaria?
NB: vivax and ovale have a hypnozoites stage in the liver (parasites are asleep in the liver) so targeted malarials need to be given for that
In humans: erythrocytic and exoerythrocytic stages
Describe techniques for prevention of malaria.
Repellants/nets
Prophylaxis - malorone/mefloquine/doxycycline
Take note of region (may recommend different medication by region), individual characteristics (e.g. pregnancy) etc
How does malaria present?
Fevers – cyclical or continuous with spikes
Malaria paroxysm – chills, high fever, sweats
Severe Malaria:
- High parasitaemia* or schizont
- Altered consciousness with/ without seizures
- Respiratory distress or ARDS
- Circulatory collapse
- Metabolic acidosis
- Renal failure, haemoglobinuria (blackwater fever)
- Hepatic failure
- Coagulopathy +/-DIC
- Severe anaemia or massive intravascular haemolysis
- Hypoglycemia
What is a schizont an indication of?
Even one schizont indicates a severe malaria
Schizont is a cell with multiple parasites which could burst and cause a rapid rise in parasitaemia
What is the % parasitaemia used in the UK for treatment cut-off?
2% is usually the cut-off used in guidelines to treat.
What laboratory tests are used for malaria?
Thick and thin blood smears x3
- Field’s or Giemsa* stain
- Thick: screen parasites (sensitive)
- Thin: identify species & quantify parasitaemia
Malaria antigen detection tests
- Paracheck-Pf® (detect plasmodial HRP-II)
- OptiMAL-IT (parasite LDH)
*Giemsa for better detection of species
Summarise the management of malaria.
- Decide whether falciparum or not
- If falciparum check if severe or mild
- If non-falciparum check for G6PD deficiency
Milf falciparum malaria:
Not vomiting, Parasitaemia <2%, Ambulant = Oral Malarone ™ (atovaquone and proguanil), 4 tablets daily with food for three days
ACT – artemisinin combination therapies =
- E.g Riamet/ Co-artem – Artemisinin & Lumefantrine,
- Oral quinine 600mg tds (salt)
- then doxycycline 100mg od for 1 week
Severe falciparum malaria:
- ABC
- Correct Hypoglycamia
- Cautious rehydration (avoid overload)
- Organ support as necessary
IV Artesunate in preference to IV Quinine
Daily parasitaemia then PO follow on eg with ACT
What is a side effect of IV quinine vs artesunate?
Artesunate side effects: delayed haemolysis
Quinine side effects: cinchonism, arrhythmias, hyperinsulinaemia
Case 2: Some conjunctival injection, travelled abroad to SE Asia, arthralgia, thrombocytopenia,, no anti-malarials but told not needed.
Dengue
Dengue
Aedes mosquito
What type of disease is Dengue caused by? How many serotypes?
Flavivirus
4 main serotypes - reinfection can occur and may be worse
Mostly URBAN
How common is Dengue in the UK?
Seen in ~340/year mostly from SE Asia
What is the presentation and onset of Dengue?
- Short incubation
- Fever, retro-orbital headache, myalgia, erythrodermic rash
- Severe - bleeding, hepatitis, encephalitis, myocarditis
- Rash in 50%
What is the spectrum of disease in Dengue?
Usually mild self-limited illness - mild febrile/ dengue haemorrhagic/ dengue shock.
DHF and shock syndromes rare in travellers - Occur in those previously infected with a different Dengue serotype
What is the treatment for Dengue?
Supportive only
Identify those at high risk - high Hct, low platelets
How do you prevent Dengue?
DEET = insecticide
What serology is done for Dengue? What PCR can be done?
IgM will be positive after 5-7 days - BUT can cross react with IgG for other flaviviruses (JE, yellow fever)
PCR is preferred - may be done on blood or urine
“Fever apperance of Himalaya peaks” are characteristic of…?
Typhoid fever
Sphygmothermic dissociation (relative bradycardia) in relation to the fever
33yo lady born in India, travelled to UK - what is the diagnosis?
- PC – fever, sweats, constipation, dry cough
- HPC
- –Fortnight in India 2/52 prior
- –Anorexia, 5kg weight loss, diarrhoea before constipation
- –Confused/ vacant
- PM – Ix for nephrotic syndrome at HH
- Examination
- –T 39 C. 110/70 P=130 Sats 98% RR=30
- –HS = I+II Gallop rhythm JVP-angle of mandible
- –Chest – fine bibasal inspiratory creps
- –Abdomen – mild suprapubic tenderness
•Investigations:
- –Malaria negative
- –HIV negative
- –Blood culture – gram negative rods on day 3
•Management:
- –Initially ceftriaxone 2g IV OD
- –Changed to Meropenem at day 3
- –Careful monitoring and supportive care
Typhoid fever
What causes typhoid fever?
Salmonella typhi or paratyphi
How does typhoid fever present?
Clinical Presentation:
- High prolonged fever
- Headache
- Rose spots (rare)
- Constipation
- Dry cough
Incubation: 7-18 days (up to 60 days)
What are the complications of typhoid fever?
- GI bleeding
- perforation
- encephalopathy
What is the treatment for typhoid fever?
Empiric Ceftriaxone (2g IV OD) then Azithromycin (500mg BD 7 days)
