Cerebral Malaria
Cerebral malaria should always be considered as a cause of unconsciousness in a person that comes from a malaria endemic region.
Causes
Malaria can be an uncomplicated disease for some people, causing flu like symptoms only, but for others it can develop into a severe disease. The most severe complication of severe malaria is cerebral malaria.
Malaria is caused by a parasite that is spread through the bite of a mosquito. Although there are various species of the parasite, the one that causes cerebral malaria is called Plasmodium falciparum. Cerebral malaria occurs when the parasites in the blood block the small capillaries in the brain.
Risk Factors
Risk factors for developing cerebral malaria are extremes of age (children and the elderly), pregnant women, the malnourished, and those who have HIV infection.
Signs and Symptoms
Impairment of consciousness is the main symptom of cerebral malaria, which can progress to deep coma. This often leads to permanent brain damage or death. The patient with malaria would likely have a history of fevers, fatigue, muscle ache and headache.
Complications
In severe malaria there may also be:
- anemia, due to the fact that the parasites destroy red blood cells
- a disorder in blood clotting (coagulopathy)
- hypoglycemia
- pulmonary edema and shortness of breath
- multi-organ failure, such as liver failure (resulting in jaundice) and renal failure (resulting in low urine output)
- cerebral malaria can also cause seizure which could be a full body seizure (tonic clonic) or a more subtle seizure such as repetitive eye or hand movements
Investigations
Rapid diagnostic test are available that can diagnose malaria with a small sample of blood from a finger prick. These tests enable quick diagnosis of Plasmodium falciparum malaria.
Another way to diagnose malaria is by sending a blood sample to be examined under a microscope. The benefit of this method is that different malaria parasites can be identified, and also the amount of parasites can be identified. The disadvantage is that it takes a skilled laboratory technician to perform.
The blood glucose level should be checked frequently because severe malaria can cause hypoglycemia.
Routine blood tests include kidney function, liver function and coagulation studies. Hemoglobin level should also be checked.
Treatment
Plasmodium falciparum malaria must always be treated aggressively as cerebral malaria has a high mortality rate.
Treatment consists of an Artemisinin (such as Artemether) in combination with another antimalarial. If unavailable, then an intravenous Quinine infusion can be administered. However care should be taken with Quinine as it is toxic if given in excessive dosages, and has dangerous side effects such as cardiac arrhythmias. Quinine is therefore given according to the patient’s weight and must be monitored closely. Medications can be changed to oral if the patient regains consciousness.
As with any unconscious patient, it is important to maintain an open airway, and provide oxygen if required.
Hypoglycemia must always be treated if present. Restoration of blood sugar level however does not usually improve the level of consciousness. Blood sugar levels should be especially monitored closely if administering Quinine, as Quinine further lowers blood glucose.
If seizures occur then they must be treated with benzodiazepines (such as diazepam) and the dose repeated as required. If seizures continue then other anti-seizure medications can be administered, such as Phenytoin or Phenobarbitone.