How to Manage and Treat Fever of Unknown Origin?

fever of unknown - kjohealth

Fever of unknown origin is a fever of at least 101°F (38.3°C) that lasts for more than three weeks or happens on a regular basis without a known cause. It’s important to get a diagnosis even if you don’t know what’s causing the fever.

Major types of fever of unknown origin:


Those who were previously healthy are affected by classic FUO. It’s characterized as a three-week-long fever without a known cause. Leukemia, an infectious disease, or another type of cancer can all contribute to the development of typical FUO. Diseases of the connective tissue, for example, can potentially be a cause. In a few cases it can also be dengue, reach out to a dengue specialist doctor to avoid complications.


As a result of being hospitalized, people with a nosocomial FUO appear to develop a fever. Initially, they’re admitted for an unrelated condition, and then they develop a fever for no apparent reason. Some of the common causes are:

  • pulmonary embolism
  • enterocolitis
  • sinusitis
  • deep vein thrombosis
  • septic thrombophlebitis, a kind of inflammation that affects the veins


People with weakened immune systems are more likely to get FUO. Consequently, they are more susceptible to infection. Chemotherapy treatment frequently results in a weakened immune system.


A fever can be caused by HIV itself. A person living with HIV is more vulnerable to illnesses that can result in high fevers.

Causes that can indicate the onset of fever of unknown origin:

Identifying the sort of FUO a patient has aids general physician Coimbatore in determining what’s causing it. Any of the following may be a contributing factor to FUO:

  • Infection: Other diseases include tuberculosis, mononucleosis, Lyme disease, cat scratch fever, and endocarditis.
  • Inflammation: Lupus, rheumatoid arthritis, inflammatory bowel disease, as well as other autoimmune diseases
  • Malignancy: Lymphoma, leukaemia, pancreatic carcinoma, and other malignancies and sarcomas
  • Miscellaneous: substance misuse, hyperthyroidism, hepatitis, and other reasons that don’t fall into any of the other categories are examples of fevers.

Signs that indicate the presence of fever of unknown origin:

If other symptoms are present, they can help doctors identify the underlying cause of the condition.

A fever’s most common symptoms include:

  • Babies and children should not be exposed to temperatures more than 100.4°F (37.5°C)
  • Sweating
  • Chills
  • Headaches
  • Body or joint aches
  • Weakness
  • Sore throat
  • Fatigue
  • Cough
  • Rash
  • Sinus congestion

How Does The Body Temperature Rise?

Body temperature is controlled by the hypothalamus, a tiny gland in the brain. Biochemical substances known as pyrogens are released in response to some type of injury or microorganism. The hypothalamus transmits signals based on this biochemical response. Due to their inability to grow or replicate in such settings, microbes are reduced in number as a result of elevated body temperatures. Shivering is caused by the flow of blood to the centre of the body being diverted away from the peripheral body parts.

Diagnostic procedures for FUO:

In other circumstances, a wait-and-see approach is often adopted for short-term fevers that aren’t accompanied by any red flag symptoms. Once a fever lasts long enough to be categorized as a fever of unknown origin, your general physician Coimbatore may run several tests to determine the underlying reason to determine the fever of unknown origin.

Blood and physical examination:

In order to rule out less evident disorders, such as autoimmune diseases, your doctor may order blood testing. Pallor, rashes, and jaundice are all things they’ll be looking for when they examine your skin at a fever hospital .

If the general physician notices anything suspicious during the physical examination or the results of the blood work, he or she will likely prescribe additional diagnostic testing.

Culture testing:

Cultures of bodily fluids (blood, urine, sputum) can help rule out infectious agents like bacteria and fungi. Atypical bacterial, fungal, or viral infections can also be detected with the use of specialized tests.

Imaging tests:

If your general physician notices a murmur or has reason to suspect endocarditis, he or she may order an endocardiogram to assess your heart. One of the heart’s valves is infected. X-rays of the chest can sometimes be used to examine the lungs.

Managing and treating fever of unknown origin:

To what extent will depend on the diagnosis. In stable, non-critically ill patients, antibiotic medication should be recommended until the cause of the fever has been confirmed so that treatment for viral fever can be recommended to a specific diagnosis. This strategy stems from the realization that PUO is notoriously difficult to treat, and that using a blanket approach risks delaying a proper diagnosis. The following are three significant deviations from the norm:

  • A diagnosis of culture-negative endocarditis must be made in these cases.
  • Cases that may be cryptic spread tuberculosis (or other granulomatous infections).
  • Vision loss cases where temporal arteritis is suspected.

People whose fevers are suspected to have an immune-deficient origin may be treated with broad-spectrum antibiotics. These concentrate on the most dangerous germs. Between 20% and 40% of all cases of unexplained fever are caused by infections. Reach out to the general physician Coimbatore to undergo fever treatment

Fever caused by HIV is typically treated with antiviral medication. Subsequently, any subsequent issues or symptoms will be dealt with.

Outlook of the condition:

It is often impossible to determine the cause of a fever, and in many cases, the fever goes away on its own. However, a fever that lasts for three weeks or more may be a sign of a more serious condition. You should see your doctor to check for underlying issues, especially if you have other symptoms.

Seek quick medical assistance if you have a fever and any other symptoms that could indicate an emergency. Signs and symptoms include:

  • Stiff neck
  • Confusion
  • Difficulty staying awake
  • Chest pain
  • Difficulty breathing
  • Difficulty swallowing
  • Repeated vomiting

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