Malaria

Last Updated on by FRCEM Intermediate

Overview

malaria is a protozoan infection caused by Plasmodium species that are transmitted by female Anopholes mosquito

Species of malarial parasite

  • Plasmodium falciparum (most common cause of malaria presenting in the UK, most likely to result in severe illness/death)
  • Plasmodium vivax and Plasmodium ovale (may cause relapsing malaria)
  • Plasmodium malariae (less commonly seen in the UK, may present late years after the person has left an
    endemic area)

life cycle
mosquito bite -> blood stream -> RBCs -> haemolysis and release

Risk groups

  • Young children and infants.
  • Pregnant women (especially primigravidae).
  • Elderly people.
  • Non-immune people (eg, travellers, foreign workers).

History

Travel history

  • Which countries?
  • Urban/rural environment – Visits to rural locations
  • Types of accommodation – Staying in cheap backpacker accommodation
  • Climate – Travel to areas of high humidity and ambient temperature between 20-30°C/Travel at times of high seasonal rainfall
  • Dates of entering each country/returning home-Longer durations of travel

Timing of symptoms

  • Onset – exactly when did the symptoms start?
  • What was the course of the symptoms e.g. prodrome, relapsing, progressive
  • Duration

Clinical symptoms and Findings

  • ever and rigors
    • may be continuous in the first week
    • classically described cyclical fever (every 2-3 days) is often absent, but is said to be due to release from liver and reticuloendothelial system
  • non-specific constitutional symptoms: malaise, anorexia, headache, lethargy, myalgia
  • cough and diarrhoea may occur (may mimic LRTI or gastoenteritis)
  • splenomegaly

Severe malaria

  • CNS: Altered consciousness, (+/- meningism) seizures, focal deficits (cerebral malaria)
  • GI: Vomiting, jaundice
  • RESP: Respiratory distress +/- ARDS
  • RENAL: AKI
  • CVS: Shock
  • HAEM: Severe hemolytic anaemia with jaundice, coagulopathies and spontaneous haemorrhage
  • METABOLIC: acidosis and hypoglycemia
  • high parasite load

Other presentations

hemoglobinuria (“black water fever”)
nephrotic syndrome (P. malariae only)

Complications

  • Impaired consciousness or seizures (cerebral malaria).
  • Renal impairment.
  • Acidosis.
  • Hypoglycemia.
  • Pulmonary oedema or acute respiratory distress syndrome.
  • Anaemia.
  • Splenic rupture.
  • Disseminated intravascular coagulopathy.
  • Shock secondary to complicating bacteraemia/sepsis (algid malaria).
  • Haemoglobinuria (‘black water fever’).
  • Multiple organ failure.
  • Death.

Investigation

General

  • glucose
  • FBC: hemolysis, normochromic normocytic anemia
  • UE
  • LFTs
  • Coags and cross match,
  • Haemolysis screen
  • Septic screen to exclude other causes (e.g. blood culture, throat swab, urine MCS, LP as needed)
  • CT head +/- LP +/-
  • EEG if suspected seizures
  • CXR

Specific

  • Thick and thin blood smears stained with Giemsa stain remain the ‘gold standard’.
  • Nucleic acid-based tests including polymerase chain reaction (PCR)
  • Rapid diagnostic tests (RDTs) which detect parasite antigens

Treatment

Treatment of non-falciparum malaria

  • Chloroquine (against P. malariae and P. ovale and most strains of P. vivax.)

Treatment for uncomplicated falciparum malaria

  • Oral quinine sulfate 600 mg/8 hours for 5-7 days plus doxycycline 200 mg daily (or clindamycin 450 mg/8 hours for pregnant women) for seven days.
  • Atovaquone-proguanil (Malarone®): four standard tablets daily for three days.
  • Artemether with lumefantrine (Riamet®): if weight >35 kg, four tablets stat and then a further four tablets at 8, 24, 36, 48 and 60 hours.

Treatment of severe or complicated falciparum malaria

  • IV quinine dihydrochloride is the first-line antimalarial drug. A loading dose of 20 mg/kg (to a maximum of 1.4 g) over four hours, followed by 10 mg/kg (to a maximum of 700 mg) every eight hours for the first 48 hours or until the patient can swallow is usual to reach high therapeutic blood levels quickly, although alternative regimens exist. ECG monitoring is required.

Cerebral malaria signs

Patients may present with either of the following:

Cortical signs: 

  • Drowsiness or confusion
  • Seizures
  • Decorticate rigidity

OR

Brainstem signs:

  • Decerebrate rigidity
  • Opisthotonos
  • Pupillary changes
  • Absent corneal reflexes
  • Abnormal respiratory patterns
  • Gaze abnormalities

Most deaths occur within 24 hours of diagnosis, and most of those who survive recover fully within 48 hours of starting treatment.Profound coma, repeated or prolonged seizures, metabolic acidosis and hypoglycaemia are associated with poor outcomes

Causes of fever in the returned traveler

  Short (< 10 days) Medium (< 1 month) Long (> 3 months)
Bacterial Leptospirosis

Typhoid and paratyphoid

Meningococcal disease

Rickettsial infections

Anthrax

Brucellosis

 

Syphilis

Amoebic liver abscess

Lyme disease

Viral Influenza

Viral haemorrhagic fevers

Dengue

Yellow fever

Acute HIV

Japanese encephalitis

Zika

Hepatitis A

CMV

EBV

 

HIV

Hepatitis B and C

TB

Rabies

Parasitic Malaria (> 7 days) Malaria

Visceral Leishmaniasis

Fascioliasis

Schistosomiasis (acute)

African trypansomiasis

 

Filariasis

Fungal Toxoplasmosis Histoplasmosis

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