Unexplained fever is also referred to as "fever of unknown origin (FUO)." Under normal circumstances, when fever occurs, it is accompanied by cough, pain, sore throat, and other abnormal symptoms. In such cases, the cause can be easily identified. However, this is not the story with this case of fever, wherein the person has an elevated body temperature, but without exhibiting any other symptoms which can give a clue to the cause of the problem. Typically, such a fever goes over than 38.3 °C (101 °F). However, this reading fluctuates over a period of more than three weeks, and without any signs of the cause. That is why, doctors usually continue their tests until the fever persists, so that they can narrow down the possible causes, and determine the right approach to treat the problem. Reports say, in about 50 out of 100 people, no causes are found despite continued attempts to diagnose it.
Although, doctors are not able to find the exact cause of the condition, they suspect certain factors which are closely linked to the same. These may include:
» Infections are known to be responsible for about 30% of cases of unexplained fever in adults and children. And such infections could be of several kinds; especially those which do not cause any physical signs or symptoms other than the fever. According to scientists, infections which could be more closely associated with this condition may include extrapulmonary tuberculosis (bacterial infection in places other than in the lungs), atypical tuberculosis, and yellow fever.
» When infections are not in the line of the suspects, cancer may come in the question. The cancerous disease known as lymphoma could explain a fever of unknown origin.
» Another possible cause of unexplained fever could be linked with an adverse reaction to certain types of medication. This is known as drug-induced hyperthermia.
» A disease of the heart called endocarditis is also considered while diagnosing the case of this near-idiopathic condition. The disease affects the inner lining of the heart (endocardium).
Tests and Diagnosis
As said earlier, despite undertaking various tests, doctors come up with no strong explanation as to why the person has an increased body temperature. That is why, most doctors follow the principle of elimination. Here, several factors are considered which show close association with the condition. And after narrowing down to the most possible cause, treatment is initiated. The different procedures that may be included in the test may include:
- Examination of blood, urine, and other bodily fluids
- Studies such as X-rays, Computerized Tomography (CT) scan, Magnetic Resonance Imaging (MRI) scan, and ultrasound imaging
- Endoscopic studies of the stomach, digestive system, sinus cavities and lungs
According to doctors, treating a fever without determining the cause, is not considered as a proper approach. Fever is one of the body's natural responses to fight off infections. And suppressing it without knowing the cause, may make the unknown infection worse or more potent. However, there might be an exception to this, when it comes to small kids, or people suffering from heart or lung problems. Children may develop seizures due to high fever and patients with heart or lung problems may experience difficulty in breathing. So for them, the doctor may be in a position to prescribe fever-reducing medication. In situations wherein, the doctor does not prescribe any medication, he/she usually advises the patient to concentrate more on his/her diet
- Antioxidants foods such as various vegetables and fruits help in reducing fever
- Lean meats must be preferred over red meats
- Foods with trans fatty acids must be avoided
- Beverages such as coffee, alcohol must be avoided, and so should tobacco products
- Drinking plenty of water helps in flushing out toxins from the body
- Although 30 minutes of exercises everyday is a must, during times of fever, simply stretching the body is also good enough
- Fish rich in omega-3 fatty acids may help in reducing the severity of the unknown cause of fever
- Taking a multivitamin is also helpful