Fever caused by malaria can have any pattern, and falciparum infections often present with a constant fever. The classic paroxysm typically has three stages, and is preceded in some patients by an initial period of nonspecific symptoms. Those symptoms include fatigue, muscle aches, loss of appetite, headache, and a slight fever of 2-3 day's duration. There is minimal sweating and the patient is at risk of febrile seizures or hyperthermic brain damage. Clinical signs and symptoms include tachycardia, hypotension, cough, headache, backache, nausea, abdominal pain, vomiting, diarrhea, and altered consciousness.
Paroxysms occur in regular intervals, but take several days to emerge.
As previously stated, the classic paroxysm described above is generally not how P. falciparum infections present. P. falciparum malaria is more severe and qualitatively different from the other plasmodia that infect humans, and is the only type that causes microvascular disease. For those reasons, it will be discussed separately and in more detail. This stickiness causes parasitized red blood cells to adhere to endothelial cells, lining capillaries and postcapillary venules of brain, kidneys, and other organs, obstructing blood flow. Lack of oxygen and increased concentrations of toxic metabolites cause capillaries to become more permeable, allowing leakage of protein and fluids.