Want to learn more about malarial parasites? Here below and some pointers you need to take note of in order to recognize the serious and mild malaria diseases.
The classical (but rarely observed) malaria attack lasts 6–10 hours. It consists of
A cold stage (sensation of cold, shivering)
A hot stage (fever, headaches, vomiting; seizures in young children); and
Finally a sweating stage (sweats, return to normal temperature, tiredness).
Classically (but infrequently observed) the attacks occur every second day with the “tertian” parasites (P. falciparum, P. vivax, and P. ovale) and every third day with the “quartan” parasite (P. malariae).
More commonly, the patient presents with a combination of the following symptoms:
Nausea and vomiting
In countries where cases of malaria are infrequent, these symptoms may be attributed to influenza, a cold, or other common infections, especially if malaria is not suspected. Conversely, in countries where malaria is frequent, residents often recognize the symptoms as malaria and treat themselves without seeking diagnostic confirmation (“presumptive treatment”).
Physical findings may include the following:
Enlargement of the liver
Increased respiratory rate
Diagnosis of malaria depends on the demonstration of parasites in the blood, usually by microscopy. Additional laboratory findings may include mild anemia, mild decrease in blood platelets (thrombocytopenia), elevation of bilirubin, and elevation of aminotransferases.
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Severe malaria occurs when infections are complicated by serious organ failures or abnormalities in the patient’s blood or metabolism. The manifestations of severe malaria include the following:
Cerebral malaria, with abnormal behavior, impairment of consciousness, seizures, coma, or other neurologic abnormalities
Severe anemia due to hemolysis (destruction of the red blood cells)
Hemoglobinuria (hemoglobin in the urine) due to hemolysis
Acute respiratory distress syndrome (ARDS), an inflammatory reaction in the lungs that inhibits oxygen exchange, which may occur even after the parasite counts have decreased in response to treatment
Abnormalities in blood coagulation
Low blood pressure caused by cardiovascular collapse
Acute kidney injury
Hyperparasitemia, where more than 5% of the red blood cells are infected by malaria parasites
Metabolic acidosis (excessive acidity in the blood and tissue fluids), often in association with hypoglycemia
Severe malaria is a medical emergency and should be treated urgently and aggressively.
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In P. vivax and P. ovale infections, patients having recovered from the first episode of illness may suffer several additional attacks (“relapses”) after months or even years without symptoms. Relapses occur because P. vivax and P. ovale have dormant liver stage parasites (“hypnozoites”) that may reactivate. Treatment to reduce the chance of such relapses is available and should follow treatment of the first attack.