Body temperature is regulated primarily by the hypothalamus, which acts as the body's internal thermostat. Normal core body temperature typically ranges between 36.5°C and 37.5°C, fluctuating slightly throughout the day due to circadian rhythms, physical activity, and hormonal changes.
Thermoregulation involves a delicate balance between heat production and heat loss mechanisms.
When ambient temperatures or internal conditions shift, autonomic nervous system pathways trigger physiological responses like vasodilation to dissipate heat or vasoconstriction to conserve it.
Fever, medically known as pyrexia, is a temporary elevation in body temperature above the normal range, driven by an upward resetting of the hypothalamic set-point. This response is distinct from hyperthermia, where the body's set-point remains unchanged, but thermoregulatory mechanisms are overwhelmed by environmental heat or excessive metabolic production.
The pathophysiology of fever involves endogenous pyrogens, such as interleukins and tumor necrosis factor, released by immune cells in response to infection, inflammation, or tissue injury. These signaling molecules travel to the brain and stimulate the synthesis of prostaglandin E2 in the preoptic area of the hypothalamus. Prostaglandin E2 alters the firing rate of temperature-sensitive neurons, raising the thermal set-point. The body then perceives its normal temperature as too cold, triggering shivering and vasoconstriction to actively raise core temperature to the new target.
In Nigerian healthcare settings, fever is one of the most frequent presenting complaints across pediatric and adult wards. Infectious agents remain the leading cause, reflecting regional epidemiological profiles.
Documenting the pattern of a fever provides valuable diagnostic clues for the attending clinician.
| Fever Pattern | Description | Clinical Association |
|---|---|---|
| Sustained | Temperature remains continuously elevated with little fluctuation. | Typhoid fever, severe lobar pneumonia. |
| Intermittent | Temperature spikes daily but returns to normal baseline at some point. | Malaria, sepsis, localized abscesses. |
| Remittent | Temperature fluctuates throughout the day but never touches normal baseline. | Infective endocarditis, viral respiratory infections. |
| Relenting / Recurrent | Febrile episodes separated by days or weeks of normal temperature. | Malaria relapses, rat-bite fever, brucellosis. |
Assessing a febrile patient requires a systematic physical evaluation alongside frequent vital signs monitoring. Nurses must measure temperature using reliable routes—tympanic, oral, axillary, or core methods—while accounting for route-specific differences in accuracy.
Beyond the thermometer reading, evaluate hemodynamic parameters. Tachycardia frequently accompanies fever because every 1°C rise in body temperature typically increases the heart rate by about 10 beats per minute. Tachypnea may also develop as the body attempts to compensate for metabolic acidosis or increased oxygen demand. Monitor skin warmth, check for diaphoresis during the defervescence phase, and look for associated symptoms such as headache, muscle aches, rigors, or altered mental status.
Laboratory investigations help confirm the underlying etiology of a fever, guiding targeted antimicrobial or anti-inflammatory therapy.
Nursing care for a febrile patient focuses on comfort, safety, and supporting medical therapies prescribed by the physician.
Antipyretics such as paracetamol help reset hypothalamic control and alleviate discomfort, though they do not cure the underlying infection. Administer medications strictly according to calculated weight and dosage schedules. Encourage adequate oral hydration to replace fluid losses from sweating and increased metabolic rate, and monitor input and output.
Physical cooling measures, such as tepid sponging, are sometimes utilized, but aggressive ice-water immersion or alcohol rubs are avoided because they induce shivering, which paradoxically drives core temperature higher and causes vasoconstriction.
Prolonged or very high fevers can lead to significant clinical complications if left unmanaged. Dehydration is common due to increased fluid evaporation and diaphoresis. In vulnerable pediatric populations, rapid temperature spikes can trigger febrile seizures, which require calm nursing management to maintain airway patency and protect the child from injury.
Discharge education must empower patients and their families. Teach caregivers how to correctly administer prescribed antipyretics, measure temperature accurately, and recognize warning signs that necessitate prompt return to the health facility, such as persistent vomiting, severe headache, neck stiffness, or confusion.