Fever : Causes

Human being is a warm-blooded animal, that is, body temperature is maintained regardless of the environmental temperature. The normal temperature of the body is maintained at 37°C or 98.6°F by the hypothalamus, a small but important part situated just below the brain. A slight variation of 0.5°C or 0.9°F occurs during the day.

Fever is defined as a before-noon temperature of more than 37.2°C or 98.9°F or an after-noon temperature of more than 37.7°C or 99.9°F. Fever is an elevation in normal body temperature that occurs in connection with a raised hypothalamic set point.

Body temperature is measured using a thermometer. The reading is obtained either by placing a thermometer in the mouth, in the rectum (especially in children), from the ear near the ear drum or in the armpit. Rectal temperatures are usually 0.5°C or 0.7°F higher than oral temperatures. Temperatures taken in the armpit are usually not very reliable.

Very high temperature of more than 41.5°C or 106.7°F is called hyperpyrexia. It occurs due to brain hemorrhage or severe infections.

Some causes of fever are listed below:

(1) Viral, bacterial, fungal or protozoal infections often cause fever.
(2) Fever of short duration without specific symptoms may be due to influenza

(3) Fever with throat pain and difficulty in swallowing could be due to sore throat infection, diphtheria or infectious mononucleosis (infection by a virus called Epstein-Barr virus)

(4) Fever with cough, chest pain and rusty sputum may be due to pneumonia

(5) Fever with rigors and burning while passing urine indicates a urinary tract infection

(6) An alternate day fever with rigors indicates malarial infection

(7) Fever with swelling of feet with rigors and a raised eosinophil count may indicate filariasis

(8) An increasing fever with pain in abdomen, small red spots on the skin and a slow heart rate could be due to typhoid

(9) Fever with neck stiffness, headache and vomiting may be due to meningeal infection (infection of the covering of the brain)

(10) Fever with cough over a long duration and weight loss may indicate tuberculosis

(12) Fever with rashes may be due to a viral infection

(13) Short-duration fever with progressive weight loss and a high-risk behavior could possibly be due to HIV infection

Other causes of fever include:

(1) Drugs and Biological Agents: Drugs like beta-lactam antibiotics, procainamide, isoniazid, alpha-methyldopa, quinidine and diphenylhydantoin are associated with fever. Biological agents like interferons and interleukins used in therapy could also cause fever. Vaccines could also result a temporary rise in temperature. Fever caused by drugs is often associated with a rash.

(2) Tissue injury: Heart attack, burns, trauma and injections into muscles damage tissues and can cause fever.

(3) Cancers: Blood cancers like leukemia and lymphoma, and liver cancer can cause fever. The liver, spleen and lymph nodes may be enlarged and easily felt in these conditions.

(4) Inflammatory diseases: Rheumatoid arthritis, systemic lupus erythematosus and inflammatory bowel disease are some inflammatory diseases that could cause a rise in body temperature.

(5) Hormonal diseases: Thyrotoxicosis (a condition in which the thyroid gland is hyperactive) and pheochromocytoma (a condition in which the adrenal gland is affected) can cause fever.

(6) Metabolic diseases: Gout and increase in blood urea can sometimes raise the body temperature.

(7)Genetic diseases: Familial Mediterranean fever is a genetic disease with fever as one of its symptoms.

doctor may examine based on the infections cause of the fever.the tests for diagnosis mainly include the following:
1.blood test
2.x –rays and physical examination.

Acetaminophen or ibuprofen: use these drugs as per prescription.avoid long term usage of these drugs as they may cause liver ,kidney damage and acute over doses can fatal.
Aspirin ,for adults only:itshould not be prescribed to children as it may lead to reye’ssyndrome.
Prescription drugs : depending on the infecton doctor may prescribe the drugs . Antibiotics don’t treat viral infections, such as stomach infection (gastroenteritis) and mononucleosis. There are a few antiviral drugs used to treat some specific viral infections. However, the best treatment for most viruses is often rest and plenty of fluids.

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