Fever in the returning traveller Flashcards
What are key elements of a travel history?
- Where did you go? → Be specific Include stop-overs Rural or urban
- When did you go? → Exact dates Timing of symptoms
- Why did you go? → Visiting friends and relatives etc.
- What did you do? → Activities
- What pre-travel vaccines/malaria prophylaxis did you take?
What is the epidemiology of tropical diseases in London?
What are the differentials for fevers with clinical findings?
Most likely diagnosis?
Malaria
Rapoid diagnostic test = RDT
How can you tell its falciparum?
What other information would you like?
- Glucose
- Lactate
- LDH
- Parasitaemia
- Something else
Parasitaemia - helps guide tx
IV Artesunate
Describe the epidemiology of malaria?
How many cases of Malaria do we see in the UK? What type are they?
1500/ year
Usually falciparum but also vivax
What are the different species of plasodium?
-
Plasmodium falciparum - Double-dotted rings
- Invades erythrocytes of all ages
- Can be life-threatening
- Can be drug-resistant
- Plasmodium vivax “Schaffner’s” dots
- Plasmodium ovale Enlarged red cells, comet forms, “Schaffner’s” dots
- Plasmodium malariae Daisy-head appearance; square ring-forms
- Plasmodium knowlesi
Describe the life cycle of malaria?
Vivax and oval also have a liver stage
- Within humans, there is an erythrocytic stage and an exo-erythrocytic stage
- Malaria breaks down red cells haemolysis
- There is also a liver stage (where the parasite lies dormant in the liver)
What is the prevention and pre-travel advice for malaria?
How does malaria present?
- Fevers – cyclical or continuous with spikes
- Malaria paroxysm – chills, high fever, sweats
-
SEVERE malaria → end-organ damage:
- High parasitaemia (>2%) or schizont
- Altered consciousness with/without seizures
- ARDS
- Circulatory collapse
- Metabolic acidosis
- Renal failure, haemoglobinuria (blackwater fever)
- Hepatic failure
- Coagulopathy ± DIC
- Severe anaemia
- Hypoglycaemia
How do we diagnose malaria?
-
3 thick and thin blood smears:
- Field’s or Giemsa (better for species identification) stain
- Thick: screen for parasites (sensitive)
-
Thin: identify species and quantify parasitaemia
- Quantifying involves looking at the proportion of red cells that are parasitised
-
Parasitaemia:
- Child, severe = >2%
- Adult, severe = >10%
- Malaria antigen detection tests (rapid antigen test):
- Paracheck-PF (Detect plasmodial HRP-II (Histidine-Rich Protein II))
- OptiMAL-IT (Detect parasite LDH=
Summarise : How do we treat malaria?
- Chloroquine – 3 days
- Eradicate hypnozoites → Primaquine – 14 days (if G6PD normal)
- If G6PDD, primaquine causes cell haemolysis
- Effective in the hypnozoite/liver stage
- Complications = splenic rupture 80% fatality
How do we treat mild falciparum?
- Adults Oral malarone (atovaquone and proguanil), QDS, 3 days
- Children Artemisinin Combination Therapy (ACT)
- Artemisinin; AND
- Lumefantrine Mild if not vomiting**, parasitaemia <2%/<10% and ambulant
- Oral quinine, TDS doxycycline, OD, 7 days
- Not used frequently
How do we treat severe falciparum?
- ABC approach
- Correct hypoglycaemia
- Cautious hydration (avoid overload)
- Organ support is necessary
-
IV Artesunate > IV quinine
- Quinine SEs = cinchonism (tinnitus, dizziness, N&V), arrhythmias, hyperinsulinaemia
- Hyperinsulinaemia → worst hypoglycaemia
- Daily parasitaemia monitoring
- Follow on with oral antimalarials
- 53yo male, returned from Thailand (n.b. city travel > rural)
- PC – 1/52 fever, headache, joint pain, rash
-
HPC:
- Return from Thailand 5/7 before admission
- Similar symptoms 1/52 prior to these – unwell for 3 days then got better. Had Amoxicillin.
- Painful joints
- No malaria prophylaxis
-
Examination:
- T 39 BP 130/80 HR 90
- Conjunctival injection
- Cardiorespiratory, abdominal examination – unremarkable
-
Further examination:
- CXR – clear WCC 2.3 (lymphopenia – i.e. virus)
- Plts 40 Hb 140 Alb 28, ALT 15 CRP 30
Impression: Undifferentiated fever with a rash (‘sun-burn’-like)
Dengue
How is dengue transmitted?
Aedes mosquito
What type of virus is dengue? Where can you get it? How serious is it? What is the incubation period? What is try most common symptom?
How do we prevent dengue?
What are the clinical features, ix and management of dengue?
What is the clinical course of dengue?
- 33yo, Indian lady, born in the UK
- PC – fever, sweats, constipation, dry cough
- HPC:
- Fortnight in India 2/52 prior
- Anorexia, 5kg weight loss, diarrhoea before constipation
- Confused/ vacant
- PMHx – Ix for nephrotic syndrome at HH
- Examination:
- T 39C BP 110/70 P: 55, Sats 98%, RR=30
- HS = I+II, Gallop rhythmJVP-angle of mandible
- Chest – fine bibasal inspiratory creps
- Abdomen – mild suprapubic tenderness
- Further tests:
- WCC 5.7 Plts 150 ALT 66, Alb 18
- CRP 330 Hb 130 Cr 140, Ur 15
- CXR – clear
- ECG – peaked p-waves (‘p pulmonale’
-
Impression: a high fever with a relatively (to the fever) normal HR
- A fever should send the HR much higher
- If this does not occur → “Faget Sign”
- Investigations:
- Malaria negative; HIV negative
- Blood culture – gram negative rods on day 3
- Diagnosis: Typhoid fever / Enteric Fever (from Salmonella typhi)
Why causes typhoid? What is the incubation? What is the vaccine? Where is it more common?
- Caused by Salmonella typhi or paratyphi
- Gram-negative rod
- Insidious onset (incubate 7-18 days; up to 60d)
- Most imported from South Asia (Indian Subcontinent)
- Vaccine is only partially protective against S. typhi and offers no protection against S. paratyphi
What are the clinical features? incubation period? Complications? Ttre ament?
