Everything You Need to Know About Treating Pyrexia of Unknown Origin

symptoms of pyrexia - Sriramakrishnahospital

Pyrexia, also called “fever”, is a condition in which a person’s body temperature rises above what is considered normal. Even though a rise in body temperature can be worrying. Pyrexia is a normal way for the human boy to fight off diseases.

Fatigue, headaches, cough or cold, can sometimes accompany pyrexia of unknown origin

What is referred to as pyrexia?

Pyrexia is the immune system’s natural response to germs that cause disease and to serious illnesses. The temperature of the human body is usually taken from the mouth, armpit, and rectum.

Understanding the different types of pyrexia of unknown origin:

As there are various causes of fever of unknown origin, categorizing them can be difficult, and the classification is not always helpful. Here are the major types of pyrexia,

Intermittent fever:

Throughout the day, the normal temperature and the level of fever change with this fever.

Remittent fever:

This kind of fever comes and goes, and the temperature can change, but it never returns to normal.

Hectic fever:

Hectic fever is identified when the body temperature varies considerably throughout the day, with a difference between the peak and lowest temperature of at least 1.4 degrees Celsius.

Continuous fever:

A continuous or sustained fever is characterized by minimal or no fluctuation in temperature throughout the day.


This kind of intermittent fever comes back after a time when the temperature is normal. Mosquito bites and diseases like malaria cause, most of the time, this kind of fever. 

The significant symptoms that people with pyrexia can experience:

FUO may come with other symptoms that help doctors figure out what might be the cause. Some of the most common signs of fever are:

  • Headaches 
  • Sweating
  • High temperature
  • Chills 
  • Fatigue 
  • Joint aches and pains
  • Sore throat 
  • Weakness 
  • Rashes
  • Sinusitis 
  • Fatigue 
  • Cough 

The following are the several causes of fever of unknown origin:

Understanding the causes of pyrexia of unknown origin can assist a physician in determining the origin. Pyrexia of uncertain origin may be caused by any one or all of the following:


Rheumatoid arthritis, inflammatory intestinal disease, lupus, etc.


Cat scratch fever, tuberculosis, endocarditis, dengue fever and a few more.


Pancreatic cancer, leukaemia, different types of cancers.b


Fever caused by drug use or misuse, hyperthyroidism, hepatitis, chronic fatigue syndrome, and other reasons not classified elsewhere.

A person with FUO must undergo several clinical tests to determine the cause and get treatment for a fever of unknown origin. If FUO is diagnosed, it could be a sign that you need to treat a condition that has not been diagnosed. 

The different diagnostic procedures that help determine FUO:

Sometimes, people with short-term fevers that don’t come with any red-flag symptoms are told to wait and see. If you have a fever that lasts long enough to be called a “fever of unknown origin”,  your general physician may do some tests to determine the cause.

The tests can include:

Physical examination:

  • The doctor can also do blood tests to diagnose conditions without evident symptoms, such as autoimmunity. 
  • The physician will inspect your skin for evidence of skin pallor rash. 
  • Also, they may search for jaundice symptoms.
  • If the blood tests or a physical examination reveal positive results, the physician requests additional testing to confirm the diagnosis.

Culture examinations:

Cultures of urine, blood, and sputum can be performed to identify the sources of infections, such as bacteria and fungi. Moreover, case-specific testing can aid in detecting unusual bacterial, fungal, and viral diseases. 

Imaging procedures:

If your physician detects a murmur or strongly suspects endocarditis, an echocardiogram may be used to assess your heart. X-rays of the chest can be used to inspect the lungs. 

Options for treating fever of unknown origin (FUO):

According to health doctors, up to fifty per cent of patients with FUO lack a precise diagnosis. Yet, in many cases, FUO resolves itself with time. 

FUOs that don’t seem to have a clear cause could also be treated with FUO medications. Many people may find that the drugs help ease the symptoms of the FUO.

Antibiotics with a broad spectrum of activity can be used to treat fevers believed to be caused by an immunological deficiency. They focus on some of the pathogens most likely to cause them. Infections cause twenty to forty per cent of fever cases with an uncertain course. 

The pyrexia treatment is an unclear course for patients with HIV-related fevers focused on HIV management using antiviral medicines. After that, any potential complications or symptoms will be addressed. 

The signs to recognize that might indicate FUO in children:

Fever is most common in young children and toddlers. It can happen at any age but is common in young children and toddlers. 

Possible causes of your child’s fever include:

  • Staying less active and loud than normal
  • Are either less hungry or thirst 
  • Are easily irritated

At times, this may be due to dengue fever. For a proper diagnosis, consult  dengue fever treatment in Coimbatore for immediate treatment.

Outlook of the condition:

Many fevers of unknown origin are difficult to identify and can resolve independently. On the other hand, a fever that lasts three weeks or longer can suggest a major health problem. If you have any symptoms, you should consult a doctor to rule out any underlying problems. Getting childhood vaccines for children can prevent FUO from rising.

Get medical assistance immediately if you have any emergency symptoms besides a temperature. Some of the important indications are as follows:

  • Confusion 
  • Unable to stay awake
  • Stiff neck
  • Trouble in swallowing
  • Trouble in breathing
  • Repeated vomiting

Reach out to a high fever treatment in Coimbatore if you notice any of the above signs.

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