Approach to the adult with fever of unknown origin

Approach to the adult with fever of unknown origin =
INTRODUCTION
Clinicians commonly refer to a febrile illness without an initially obvious etiology (sometimes called fever without localizing signs) as fever of unknown origin (FUO). This usage is not accurate. Most febrile illnesses either resolve before a diagnosis can be made or develop distinguishing characteristics that lead to a diagnosis. FUO refers to a prolonged febrile illness without an established etiology despite intensive evaluation and diagnostic testing.
Petersdorf and Beeson defined pyrexia of unknown origin (PUO) in 1961[1]. It is defined as:
  • A temperature greater than 38.3°C on several occasions.
  • Accompanied by more than three weeks of illness.
  • Failure to reach a diagnosis after one week of inpatient investigation.
This timing allowed exclusion of patients with protracted but self-limited viral illnesses, giving time for studies to be completed. This has now been modified to include patients who are diagnosed after two outpatient visits or three days in hospital.
The term 'fever of unknown origin' (FUO) is also sometimes used. PUO and FUO are used 
Most cases are unusual presentations of common diseases - eg, tuberculosis, endocarditis, gallbladder disease and HIV infection, rather than rare or exotic diseases[7].
  • In adults, infections and cancer (25-40% of cases each) account for most PUOs[8]. Autoimmune disorders account for 10-20% of cases[9].
  • In children, a systematic review found that infectious disease (37.6%) was the main cause of PUO, followed by malignancy (17.2%), miscellaneous disease (16.1%) and collagen vascular disease (14.0%)[5].

Bacterial

  • Abscesses:
    • There may be no localising symptoms.
    • Previous abdominal or pelvic surgery, trauma or history of diverticulosis or peritonitis increases the likelihood of an occult intra-abdominal abscess.
    • They are most commonly in the subphrenic space, liver, right lower quadrant, retroperitoneal space or the pelvis in women.
  • Tuberculosis - when dissemination has occurred (eg, in patients who are immunocompromised) the initial presentation is more likely to consist of constitutional symptoms than localising signs. CXR may be normal.
  • Urinary tract infections (UTIs) - these are rare causes. Perinephric abscesses occasionally fail to communicate with the urinary system, resulting in a normal urinalysis.

Viral

  • Herpes viruses (such as cytomegalovirus (CMV) and Epstein-Barr virus (EBV) - these can cause prolonged febrile illnesses with constitutional symptoms and no prominent organ manifestations, particularly in the elderly.
  • HIV:
    • Prolonged febrile episodes are frequent in patients with advanced HIV infection.
    • Approximately 60% of the cases are infectious in nature. The remainder of them are mainly due to lymphomas and a small fraction of them are due to HIV itself[7].
    • Patients with AIDS and lymphoma often have extranodal involvement, particularly CNS, gastrointestinal tract, liver and bone marrow[

Fungi

Immunosuppression, the use of broad-spectrum antibiotics, the presence of intravascular devices and total parenteral nutrition all predispose people to disseminated fungal infections.

Parasites

  • Toxoplasmosis - this should be considered in patients who are febrile with lymph node enlargement.
  • Trypanosoma, leishmania and amoeba species - these may rarely cause PUO.

Rickettsial organisms

Coxiella burnetii may cause chronic infections, chronic Q fever or Q fever endocarditis may be identified in patients with a PUO.

Psittacosis[11]

Infection by the causative organism, Chlamydophila psittaci should be considered in a patient with PUO who has a history of contact with birds.

Lymphogranuloma venereum[12]

This should also be considered but is rare.

Neoplasms


Comments

Post a Comment

Popular posts from this blog

Image
Generalized Anxiety Disorder: Causes and Risk Factors                                           There is no singular cause of  generalized anxiety disorder  that has been identified. Evidence has shown that multiple factors are usually at play, influencing the development of GAD. Some of the common factors include things like genetic predisposition, brain chemistry, family background, social influence, and life experiences.                                Brain Structure The limbic system is a collection of brain structures that, among other functions, is involved in the regulation of many of our basic emotional reactions. Although it is generally under the control of the "thinking" part of our brain, it can respond to stimuli on its own as well. Genetics...
Read more

Dandruff? There Are 5 Types, So You Might Just Be Treating It Wrong!

Image
Dandruff? There Are 5 Types, So You Might Just Be Treating It Wrong!                                                                It starts slowly. Your black clothes are the first to be banished. Then comes the embarrassment. The awkward dance of your hands with your hair – tucking it behind your ears, rolling it up in a bun, spreading it out strategically to conceal those pesky white flakes that lay beneath. Dandruff. And there are several types of dandruff. Read on. Diagnose Your Dandruff “Eczema, dryness of scalp, infrequent shampooing and a yeast-like fungus are all common causes of the itchiness and dry flakes that define dandruff. To treat this unfortunate condition, it’s best to identify the type of dandruff that may be getting you down,” explains Dr Gray. 1)Dry-skin related dandruff Dandruff caus...
Read more