FEVER OF UNKNOWN ORIGIN

General Information

DEFINITION--Prolonged temperature above 101F (38.3C) on at least four occasions over a 14 day period for which no cause is evident and illness of 14 days duration without an obvious cause.

BODY PARTS INVOLVED--Any body organs or system may be the source of a fever-producing condition.

SEX OR AGE MOST AFFECTED--Both sexes; all ages.

SIGNS & SYMPTOMS--Fever (measured rectally) for at least 2 weeks. Fever may be intermittent.

CAUSES

In infants and children:

• Infections.
• Collagen or autoimmune diseases.
• Tumors and cancer, especially leukemia.

In adults:

• Infections.
• Collagen or autoimmune diseases.
• Tumors and cancer, especially kidney cancer and leukemia.
• Self-induced in some psychologically unstable persons.

RISK INCREASES WITH

• Poor nutrition.
• Illness that has lowered resistance.
• Chemical or environmental exposure to polluted water or air.
• Travel in areas with unsanitary conditions.
• Exposure to others with contagious diseases.
• Elderly person.
• People in AIDS risk group.
• Drug abuse.

HOW TO PREVENT--No specific preventive measures.

What To Expect

DIAGNOSTIC MEASURES--

• Your own observation of symptoms.
• Accurate daily temperature chart.
• Medical history and physical exam by a doctor.
• Because fever may be the first evidence of a serious condition (in its early stages), thorough diagnostic testing may be recommended. This may include laboratory studies, such as blood studies and a urine culture, x-rays of the chest, CT scan, ultrasound, echocardiogram (See Glossary for all), thyroid studies, liver function tests, HIV antibody test and others.

APPROPRIATE HEALTH CARE

• Self-care after diagnosis.
• Doctor's treatment.

POSSIBLE COMPLICATIONS--Depends on the underlying condition causing fever.

PROBABLE OUTCOME--Spontaneous recovery in about 10% of cases. In other cases, the outcome depends on successful detection and treatment of the underlying disorder.

How To Treat

GENERAL MEASURES--

• Until the fever's cause has been diagnosed, keep a daily temperature chart. Rectal temperatures are most accurate.
• Treatment will be determined by underlying cause that is found.

MEDICATION--

• For minor discomfort, you may use non-prescription drugs such as acetaminophen. Until the underlying cause is determined, your doctor may withhold prescription drugs to avoid masking symptoms of the underlying disorder.
• Occasionally, in critically ill patients awaiting results of laboratory studies, the doctor may recommend a therapeutic trial of antibiotics or other drugs.

ACTIVITY--As tolerated. Encourage bed rest.

DIET--No special diet.

Call Your Doctor If

• You have unexplained fever that lasts longer than 24 hours.
• New symptoms develop. They may provide a clue about the underlying cause of the fever.