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FUO: Introduction

FUO: Fever of unknown origin (fever without known cause). See detailed information below for a list of 165 causes of FUO, Symptom Checker, Assessment Questionnaire, including diseases and drug side effect causes.

» Review Causes of FUO: Causes | Symptom Checker » | Assessment Questionnaire »

Causes of FUO:

The following medical conditions are some of the possible causes of FUO. There are likely to be other possible causes, so ask your doctor about your symptoms.

» Review Causes of FUO: Causes | Symptom Checker » | Assessment Questionnaire »

Home Diagnostic Testing and FUO

Home medical tests possibly related to FUO:

FUO: Symptom Checker

Listed below are some combinations of symptoms associated with FUO, as listed in our database. Visit the Symptom Checker, to add and remove symptoms and research your condition.

Symptom Checker

Symptom Checker

FUO Treatments

Some of the possible treatments listed in sources for treatment of FUO may include:

Review further information on FUO Treatments.

Stories from Users for FUO

Real-life user stories relating to FUO:

Message Boards for FUO

Symptom specific forums: The following patient stories in our interactive forums and message boards relate to FUO or relevant symptoms:

Diagnostic tests for FUO:

Various tests are used in the diagnosis of FUO. Some of these are listed below :

  • Physical examination
    • Temperature - Fevers can be due to infection, malignant disease; metabolic disorders e.g. gout; blood disorders e.g. hemolytic anemia; vascular disorders e.g. stroke, brain hemorrhage; immunological disorders e.g. lupus.
    • Examine the heart for a heart murmur which would suggest bacterial endocarditis
    • Examine the lungs for noises that suggest pneumonia or bronchiectasis
    • Examine the abdomen for enlarged liver - enlarged liver without jaundice may suggest amoebic abscess.
    • Examine the nervous system for abnormalities - may suggest brain abscess, sinus thrombosis, encephalitis or epidural abscess.
  • more tests...»

FUO: Animations

Medications or substances causing FUO:

The following drugs, medications, substances or toxins are some of the possible causes of FUO as a symptom. Always advise your doctor of any medications or treatments you are using, including prescription, over-the-counter, supplements, herbal or alternative treatments.

FUO: Comorbid Symptoms

Some of the comorbid or associated medical symptoms for FUO may include these symptoms:

Causes of General Symptom Types

Research the causes of these more general types of symptom:

Causes of Similar Symptoms to FUO

Research the causes of these symptoms that are similar to, or related to, the symptom FUO:

Assessment Questionnaire: Questions your doctor may ask (and why!)

During a consultation, your doctor will use various techniques to assess the symptom: FUO. These will include a physical examination and possibly diagnostic tests. (Note: A physical exam is always done, diagnostic tests may or may not be performed depending on the suspected condition) Your doctor will ask several questions when assessing your condition. It is important to openly share any pertinent information to help your doctor make an accurate diagnosis.

It is also very important to bring an up-to-date list of all of your all medical conditions, medications including dosages, and names of numbers of any specialist you see.

Create your printable checklist here.

See FUO Assessment Questionnaire (15 listings)

FUO: Deaths

Read more about causes and FUO deaths.

Misdiagnosis and FUO

Sinusitis is overdiagnosed: There is a tendency to give a diagnosis of sinusitis, when the condition is really a harmless complication of another infection, such as a common more »

Whooping cough often undiagnosed: Although most children in the Western world have been immunized against whooping cough (also called " more »

FUO: Research Related Doctors & Specialists

Other ways to find a doctor, or use doctor, physician and specialist online research services:

Causes of FUO listed in Disease Database:

Other medical conditions listed in the Disease Database as possible causes of FUO as a symptom include:

Definitions of FUO:

Fever in which the etiology cannot be ascertained.
- (Source - Diseases Database)

Organs affected by FUO:

The list of organs typically affected by FUO may include, but is not limited to:

  • General constitution

Detailed list of causes of FUO

The list below shows some of the causes of FUO mentioned in various sources:

How Common are these Causes of FUO?

This information refers to the general prevalence and incidence of these diseases, not to how likely they are to be the actual cause of FUO. Of the 165 causes of FUO that we have listed, we have the following prevalence/incidence information:

  • 5 causes are "very common" diseases
  • 9 causes are "common" diseases
  • 5 causes are "uncommon" diseases
  • 2 causes are "rare" diseases
  • 26 causes are "very rare" diseases
  • 130 causes have no prevalence information.

Conditions listing medical symptoms: FUO:

The following list of conditions have 'FUO' or similar listed as a symptom in our database. This computer-generated list may be inaccurate or incomplete. Always seek prompt professional medical advice about the cause of any symptom.

Select from the following alphabetical view of conditions which include a symptom of FUO or choose View All.

View All A B C D E F G H I J K L M N O P Q R S T U V W X Y




  • Lupus ... unexplained fever






Join in at the forums

Ask or answer a question about symptoms or diseases at one of our free interactive user forums.

Medical story forums: If you have a medical story then we want to hear it.

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Causes of FUO Based on Risk Factors

This information shows analysis of the list of causes of FUO based on whether certain risk factors apply to the patient:

  • Travel - has the patient travelled recently?
  • Diabetes - history of diabetes or family history of diabetes?

    Doctors and specialists: Who should I consult about FUO?

    Depending on the seriousness of the onset of FUO, you may want to consult one of the following medical professionals.

    Important:In extreme cases, always seek advice from emergency services :

    What are the alternative names for FUO:

    - (Source - Diseases Database)

    Classifications of FUO:

    Medical Conditions associated with FUO:

    Fever (2274 causes), Common symptoms (8589 causes), Temperature symptoms (2497 causes), Sick (5751 causes), Body symptoms (5672 causes), Pain (6458 causes), Sensations (6520 causes), Skin symptoms (5992 causes), Brain symptoms (2787 causes), Neurological symptoms (9575 causes), Skin problems (3422 causes), Sensory symptoms (7134 causes), Nerve symptoms (9132 causes), Head symptoms (10192 causes)

    Symptoms related to FUO:

    Fever (2274 causes), Infection (1293 causes), High fever (84 causes), Chronic low-level infection, AIDS, Tuberculosis, Leukemia, Subacute bacterial endocarditis (SBE), Cancer, Abscess (44 causes), Drug side effect, Malaria, Amebiasis

    Medical articles on signs and symptoms:

    Doctor-patient articles related to symptoms and diagnosis:

    These general medical articles may be of interest:

    Related medical articles from our Disease Center for Fever of Unknown Origin:

    More Ways To Research Medical Signs and Symptoms:


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