Malaria (I) Flashcards
Define malaria.
Parasitic infection caused by protozoa of the genus Plasmodium
What is the most life-threatening species causing malaria?
Plasmodium falciparum
What type of disease is malaria?
Notifiable
Where in the world is malaria prevalent?
Through topical and subtropical regions - travellers account for majority of disease in Western countries
How is malaria transmitted? (3)
- via a bite by an infected female Anopheles mosquito
- potentially blood transfusion
- potentially organ transplant
What are some protective features for malaria? (2)
- sickle cell anaemia
- G6PD deficiency
Where does the protozoa (Plasmodium) grow in malaria?
Red blood cells
What are the clinical features of malaria? (9)
- headache
- weakness
- myalgia
- arthralgia
- anorexia
- diarrhoea
- splenomegaly
- haemolytic anaemia - jaundice, dark urine
- cyclical (alternating days) fevers with chills and rigors (shivering)
What is important to check in suspected malaria?
Travel Hx (incubation period can be up to a year)
What might you find on examination in malaria? (5)
- pyrexia
- haemolytic anaemia
- jaundice
- hepatosplenomegaly
- hypotension
What are some risk factors for malaria? (9)
- travel to endemic area
- inadequate/absent chemoprophylaxis
- insecticide-treated bed net not used in endemic area
- low host immunity
- immunocompromised
- pregnancy
- malnutrition
- age<5
- older age
What are the first-line investigations for malaria?
- Giemsa-stained thick and thin blood smears
- rapid diagnostic tests (RDTs)
- FBC
- clotting profile
What is the main first-line investigation for malaria?
Giemsa-stained thick and thin blood smears:
- detection of asexual or sexual forms of parasites inside erythrocytes
- thick detects parasites
- thin detects species
- 2% is a sign of severe disease
- thick films more sensitive, headphone-like sign
- smears should be repeated daily on three occasions
Why do we do rapid diagnostic tests (RDTs) in malaria?
Rapid detection of parasite antigens or enzymes
Why do we do FBC in malaria?
To look for anaemia
What are some differential diagnoses for malaria?
- dengue fever (abrupt onset of Sx, headache, retrobulbar pain that worsens with eye movements, leukopenia, thrombocytopenia, PCR)
- Zika virus - unprotected sexual contact with infected individual
- chikungunya virus
- yellow fever
- South American haemorrhagic fevers
- pneumonia
- influenza
- enteric fever (typhoid infection)
- pyogenic infection
- leptospirosis
- infectious mononucleosis
- HIV seroconversion
- amoebic liver abscess
- African trypanosomiasis
- Rickettsia infection
- Legionnaire’s disease
- pulmonary TB
- COVID-19
What drugs do we give for malaria?
- chloroquine (okay during pregnancy) or hydroxychloroquine
- once Sx resolved to prevent relapse: primaquine
What do we do in malaria if complicated and parasitaemia >2%, evidence of organ dysfunction, pregnancy, child or >65 years?
Admission
What do you do in malaria before starting medication?
Confirm which type of malaria before starting medication unless concurrent bacterial infection with life-threatening sepsis
What do we give for complicated case of malaria? (3)
- IV artesunate
- strict fluid balance
- early ITU
What do we give for Plasmodium falciparum (uncomplicated) malaria?
Artemether, lumefantrine OR artenimol, piperaquine phosphate
What do we give for Plasmodium ovale or vivax malaria?
- artemether-lumefantrine
- in areas which are known to be chloroquine-sensitive then WHO recommend either artemisinin-based combination therapy (ACT) or chloroquine
- in areas which are known to be chloroquine-resistant an ACT should be used
- ACTs should be avoided in pregnant women
- patients should be given primaquine (following acute Rx with chloroquine to destroy liver hypnozoites and prevent relapse)
How do we monitor malaria? (3)
- blood films daily
- follow-up of complications or HIV (2-4 weeks after starting Rx to check for haemolysis)
- primaquine - 14 days
What do we give for malaria prevention? (2)
- avoid exposure (nets/repellent/protective clothing)
- prophylaxis
