Fever of unknown origin resident survival guide

Fever of unknown origin Resident Survival Guide
Diagnostic Criteria
Classification
Causes
Focused Initial Rapid Evaluation
Empiric Therapy
Dos
Don'ts

Main article: Fever of unknown origin

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Synonyms and keywords: febris continua e causa ignota; febris e causa ignota; febris E.C.I.; FUO; PUO; pyrexia of unknown origin

Diagnostic Criteria

In 1961, Petersdorf and Beeson suggested the following criteria:

• Fever higher than 38.3°C (100.9°F) on several occasions
• Persisting without diagnosis for at least 3 weeks
• At least 1 week's investigation in hospital

Classification

In 1991, Durack and Street proposed a revised definition in which cases of FUO are categorized into four subclasses: classic FUO, nosocomial (health care-associated) FUO, neutropenic (immune-deficient) FUO, and HIV-related FUO.

Classic FUO

Fever (>38.3° C or >100.9° F) for >3 weeks with no identified cause after 3 days of hospital evaluation or ≥3 outpatient visits

Nosocomial (health care-associated) FUO

Fever (>38.3° C or >100.9° F) in hospitalized patients receiving acute care and with no infection present or incubating on admission if the diagnosis remains uncertain after 3 days of appropriate evaluation

Neutropenic (immune-deficient) FUO

Fever (>38.3° C or >100.9° F) in patients with immunodeficiencies if the diagnosis remains uncertain after 3 days of appropriate evaluation, including negative cultures after 48 hours

HIV-related FUO

Fever (>38.3° C or >100.9° F) for >3 weeks in outpatients with confirmed HIV infection or >3 days in inpatients with confirmed HIV infection if the diagnosis remains uncertain after appropriate evaluation

Causes

• Infections

Localized

Endocarditis

Intraabdominal infections Urinary tract infections Osteomyelitis

Upper respiratory tract infections Infected peripheral vessels

Generalized

Bacterial

Mycobacterial

Fungal

Viral

Parasitic

• Neoplasia

Lymphoproliferative disorders Leukemia

Myelodysplastic diseases Solid tumors

• Rheumatologic disorders

Adult Still's disease

Giant cell arteritis

Polymyalgia rheumatica

Other forms of vasculitis (e.g., polyarteritis nodosa, Wegener's granulomatosis, Takayasu's arteritis)

Other rheumatologic disorders (e.g., systemic lupus erythematosus, rheumatoid arthritis, Sjogren's disease)

• Miscellaneous

Granulomatous disorders

Alcoholic hepatitis

Vascular disorders (pulmonary embolism, hematoma)

Drug fever

• Hereditary (e.g., familial Mediterranean fever)
• Endocrine

Hyperthyroidism

Thyroiditis

Adrenocortical insufficiency

• Factitious fever

FIRE: Focused Initial Rapid Evaluation

Focused Initial Rapid Evaluation (FIRE) should be undertaken to identify patients requiring urgent intervention.

Abbreviations: CBC, complete blood count; CI, cardiac index; CK-MB, creatine kinase MB isoform; CVP, central venous pressure; DC, differential count; ICU, intensive care unit; INR, international normalized ratio; LFT, liver function test; MAP, mean arterial pressure; PCWP, pulmonary capillary wedge pressure; PT, prothrombin time; PTT, partial prothrombin time; SaO2, arterial oxygen saturation; SBP, systolic blood pressure; ScvO2, central venous oxygen saturation; SvO2, mixed venous oxygen saturation; SMA-7, sequential multiple analysis-7.

Suspected FUO

Empiric Antibiotic Therapy

Dos

Don'ts

References