: 103  Hyperthermia is not to be confused with hyperpyrexia (which is a very high fever). : 102 Clinically, it is important to distinguish between fever and hyperthermia as hyperthermia may quickly lead to death and does not respond to antipyretic medications. The distinction may however be difficult to make in an emergency setting, and is often established by identifying possible causes. : 103

Types
Various patterns of measured patient temperatures have been observed, some of which may be indicative of a particular medical diagnosis:
Continuous fever, where temperature remains above normal and does not fluctuate more than 1 °C in 24 hours (e.g. in bacterial pneumonia, typhoid, infective endocarditis, tuberculosis, or typhus. Intermittent fever is present only for a certain period, later cycling back to normal (e.g., in malaria, leishmaniasis, pyemia, sepsis, or African trypanosomiasis. Remittent fever, where the temperature remains above normal throughout the day and fluctuates more than 1 °C in 24 hours (e.g., in infective endocarditis or brucellosis). Pel–Ebstein fever is a cyclic fever that is rarely seen in patients with Hodgkins lymphoma. Undulant fever, seen in brucellosis. Typhoid fever is a continuous fever showing a characteristic step-ladder pattern, a step-wise increase in temperature with a high plateau.Among the types of intermittent fever are ones specific to cases of malaria caused by different pathogens.
Fever has been described in teaching texts as assisting the healing process in various ways, including:

increased mobility of leukocytes;: 1044 
enhanced leukocyte phagocytosis;: 1030 
decreased endotoxin effects;: 1029  and
increased proliferation of T cells. : 1030 : 212

Advantages and disadvantages
Having a fever response in response to an infectious disease is generally regarded as protective, whereas fever in non-infections may be maladaptive. Studies have not been consistent on whether treating fever generally worsens or improves mortality risk. Benefits or harms may depend on the type of infection, health status of the patient and other factors. Studies using warm-blooded vertebrates suggest that they recover more rapidly from infections or critical illness due to fever. In sepsis, fever is associated with reduced mortality. Pathophysiology of fever induction
Hypothalamus
Temperature is regulated in the hypothalamus. The trigger of a fever, called a pyrogen, results in the release of prostaglandin E2 (PGE2). PGE2 in turn acts on the hypothalamus, which creates a systemic response in the body, causing heat-generating effects to match a new higher temperature set point. There are four receptors in which PGE2 can bind (EP1-4), with a previous study showing the EP3 subtype is what mediates the fever response. Hence, the hypothalamus can be seen as working like a thermostat. When the set point is raised, the body increases its temperature through both active generation of heat and retention of heat. Peripheral vasoconstriction both reduces heat loss through the skin and causes the person to feel cold.