> - suspect Malaria in any febrile illness and recent travel to region where malaria is endemic. > - most important tropical disease: half world's population at risk, with over **200 million cases** annually, with **> 400,000 deaths/year**, most in sub-saharan africa > - eradicated in Australia in 1981, but ~ 400-500 cases/year from travelers and migrants . risk of coming back, nearby PNG, indonesia are endemic **vector**: anopheles mosquito # varieties of malaria | bug | incubation | features | region | | ---- | ---- | ---- | ---- | | p falciparum | shorter<br>8-25 days | - *most severe*, main thing that causes death and severe cases<br>- unfortunately, also causes majority of cases (75%)<br>- fairly unpredictable fevers<br>- anaemia | Africa, South america, SE asia | | p malarie | 15-30 days | Quartan malaria (rigors/fever recur after 64 hours) | Africa, SE asia, pacific, S american | | p ovale | | | W Africa, SE asia | | p vivax | | relatively benign | US, S america, Asia, Africa | # pathogenesis **Liver stage** - sporozoites **blood stage:** - merozoites infect blood cells and develop into trophozoites # diagnosis - thick and think blood smears - *thick* blood films to detect parasites - *thin* blood films to identify the species - can obtain every 8 hours if malaria suspected, since **one negative smere does not exclude malaria** usually need three sets - anaemia - thrombocytopenia - elevated AST/ALT - elevated bilirubin - elevated urea/creatinine # Malaria symptoms - paroxysmal fevers/chills -- fevers >40 deg C - **rigours** - tachycardia/tachyponea - fatigue/malaise - headache/cough - nausea/vomiting/abdo pain , sometimes diarhoea - arthralgias/myalgia - *splenomegaly* - in non-falciparum malaria, death due to splenic rupture can occur # uncomplicated malaria - fever, malaise, headache, headache, chills - +/- splenomegaly , abdo tenderness, enlarged liver # Severe malaria > A patient with severe malaria is at risk of dying even with optimal case management. Case fatality rates range between 5% and 30% in patients receiving treatment for severe malaria according to the complications present and their intensity - defined as altered consciousness, jaundice, oliguria, severe anaemia, severe hypoglycaemia - ​parasites in > 5% of RBCs - parasite count > 100,000/mm3 - vomiting and acidosis - **​treat immediately**; ​assume chloroquine resistant P falciparum - [[Seizures]] - ARDS/shock - metabolic acidosis - #hypoglycaemia - [[Acute Renal Failure]] - liver failure - anemia/coagulopathy | feature | cause | signs/symptoms | | ---- | ---- | ---- | | cerebral malaria | microvascular obstruction w/ parasite-containing RBCs | drowsy, confused, delirium, coma | | Respiratory distress | [[ARDS]] (direct capillary damage), resp compensation in metabolic acidosis, anaemia, chest infection | increase WOB<br>Kussmaul breathing | | Severe anaemia | increased RBC clearance, hypersplenism, haemolysis, bone marrow failure | pallor, fatigue, jaundice, haemoglobinuria | | Acute renal failure | pre-renal (dehydration), renal (microvascular obstruction, [[glomerulonephritis]]) | oliguiria, anuria | # Treatment > **treatment is based on known geographical patterns of resistance** ## Supportive therapies - rehydration + fluid replacement - cooling - treat hypoglycaemia, renal failure, anaemia, seizures, etc ## antimalarial drugs (grain of salt given geographical variation) - **Artesunate 2.4 mg/kg IV on admission** - Antimalarial drugs (**chloroquine** and **sulfadoxine-pyimethamine**), but there is worldwide resistance to these drugs. - **Artemisinin** / **Artesunate** (derived from wormwood) combined with another agent is the best current treatment for falciparum malaria per Camerons - **primaquine** 15mg for falciparum as single dose after exclude G6PD per ETG ETG regimens: - artemether + lumefantrine 20+120mg with fatty foods - atovaquone + proguanil 250+100mg w/ fatty foods (don't use if atovaquone was used for ppx) - quinine + doxycycline # prevention # Related Questions ## malaria - [ ] 21Q: [Fever in returned traveller](x-devonthink-item://8AAAF35C-CCF4-4157-9551-5B05727AA0CD?page=7) -- [Answer](x-devonthink-item://FDFBA3A1-6207-4204-AB6D-7483D80C5B5C?page=7) - [ ] DUPLICATE Q: [Malaria](x-devonthink-item://8AAAF35C-CCF4-4157-9551-5B05727AA0CD?page=7) -- [Answer](x-devonthink-item://FDFBA3A1-6207-4204-AB6D-7483D80C5B5C?page=7) - [ ] 22Q: [Fever in Returned Traveller](x-devonthink-item://87BC05C2-0A6B-436D-B51A-75E14AA5EA7E?page=13) -- [Answer](x-devonthink-item://98D17FA0-225B-4E94-B21C-4E36D5C76A7C?page=67)