Fever and Chills

INTRODUCTION

Facts and figures

• Fever plays an important physiological role in the defence against infection

• Normal body temp. (measured orally) is 36–37.3°C (av. 36.8°C); there is considerable diurnal variation in temperature so that it is higher in the evening by ~0.6°C

• Normal average values (morning):

  • – oral 36.8°C

  • – axilla 36.4°C

  • – rectum 37.3°C

• Fever (pyrexia):

  • – morning oral >37.2°C

  • – evening oral >37.8°C

• Fevers due to infections have an upper limit of 40.5–41.1°C (105–106°F)

• Hyperthermia (temp. >41.1°C) and hyperpyrexia appear to have no upper limit

• Infection remains the most important cause of acute fever

• Symptoms associated with fever include sweats, chills, rigors and headache

• Drugs can cause fever (e.g. allopurinol, antihistamines, barbiturates, cephalosporins, cimetidine, methyldopa, penicillins, isoniazid, quinidine, phenolphthalein, incl. laxatives, phenytoin, procainamide, salicylates, sulfonamides)

• Features of a true chill are teeth chattering and bed shaking lasting 10–20 minutes, with absence of sweating; a feature of bacterial infection and malaria

FEVER OF LESS THAN 3 DAYS DURATION

• Usually due to self-limiting viral URTI

• Watch out for an infectious disease, UTI, pneumonia or other infection

• Consider routine urine examination

• Most can be managed conservatively

FEVER PRESENT FOR 4–14 DAYS

If fever persists beyond 4–5 days, a less common infection should be suspected since most common viral infections will have resolved by about 4 days (e.g. Epstein–Barr mononucleosis, PID, drug fever, zoonosis, travel acquired infection, abscess incl. dental abscess).

FEVER IN CHILDREN

Fever is usually a response to a viral infection. Consider a fever of ≥38.5°C as significant and warranting close scrutiny. Fever itself is not harmful until it reaches 41.5°C. Temperatures >41°C are usually due to CNS infection or the result of human error, e.g.:

• shutting a child in a car on a hot day

• overwrapping a febrile child

Complications include dehydration (usually mild) and febrile convulsions.

All febrile neonates should be considered for a full septic work-up and admitted for parenteral antibiotics. Not to be missed conditions include meningitis/encephalitis, sepsis, pneumonia, septic arthritis, urinary infection and pertussis.

Management

• Treatment of low-grade fevers should be discouraged.

• Treatment of high-grade fevers includes:

  • – treatment of the causes of the fever (where appropriate) + adequate fluid intake

  • – paracetamol (acetaminophen) is the preferred antipyretic since aspirin is potentially dangerous in young children. The usual dose of 10–15 mg/kg every 4–6 h may represent undertreatment. Use 20 mg/kg as loading dose and then 15 mg/kg maintenance.

Evidence favours tepid sponging for 30 mins + paracetamol.

Advice to parents

• Dress the child in light clothing (stripping off is unnecessary)

• Do not overheat with too many clothes, rugs or blankets

• Give frequent small drinks of light fluids, esp. water

• Sponging with cool water and using fans ...