Fièvre Prolongée: Diagnostic Approche

Introduction

• This document provides a guide for managing prolonged fever.
• It outlines a diagnostic approach.

Objectives

• Define prolonged fever.
• List the main causes of prolonged fevers.
• Establish a diagnostic approach.

Definitions

• Prolonged fever (classic): Temperature ≥ 38°C on multiple occasions, lasting ≥ 3 weeks, and no clear diagnosis after appropriate investigations (3 days in hospital or 3 consultations).
• Nosocomial prolonged fever: Fever ≥ 38°C on multiple occasions in hospitalized patients without a confirmed infection at admission, and no diagnosis after 3 days of tests.
• Prolonged fever in neutropenic patients: Fever ≥ 38°C on multiple occasions in neutropenic patients (PNN < 500/mm3), with no diagnosis after 3 days.
• Prolonged fever in HIV patients: Fever ≥ 38°C on multiple occasions in HIV patients, lasting ≥ 4 weeks in ambulatory care or ≥ 3 days in hospital, and no diagnosis after 3 days of tests.
• Prolonged fever in children: Definition depends on the child's age; the duration varies.

Context of discovery

• Asymptomatic: Prolonged fever discovered during a routine check-up.
• Symptomatic: Prolonged fever arises in context of another condition (e.g., general health check-up, signs of infection, or general state deterioration).

Etiologies in adults

• Infections: Bacterial, viral, or parasitic.
  • Bacterial: Endocarditis (especially right-sided), deep-seated infections, dental problems, tuberculosis
  • Viral: Cytomegalovirus (CMV), Epstein-Barr virus (EBV), HIV infections, hepatitis B and C.
  • Parasitic: Toxoplasmosis (especially in pregnant women), hepatic amoebiasis, malaria, leishmaniasis, schistosomiasis, trypanosomiasis.
  • Fungal: Candidiasis, cryptococcosis, histoplasmosis (especially in HIV patients), aspergillosis.
• Neoplasms: Cancers (kidney, ovary, liver, pancreas, lung, colon, thyroid, neuroblastoma, lymphoproliferative disorders - lymphomas, leukemia, myeloma, myelodysplasia, Castleman's disease).
• Non-infectious inflammatory conditions: Connective tissue disorders (lupus, polymyositis, Sjögren's syndrome), vasculitis (giant cell arteritis, Takayasu's arteritis, polyarteritis nodosa, ANCA-associated vasculitis, Behçet's disease), granulomatous diseases (sarcoidosis, Crohn's disease, ulcerative colitis).
• Other conditions: Endocrine disorders (thyroiditis, pheochromocytoma), deep vein thrombosis (DVT), hematomas, drug-induced fever, central nervous system disorders (e.g., factitious fever), Münchhausen syndrome, autoimmune diseases

Etiologies in children

• Similar causes to adults, but with varying frequencies.
• Frequent causes include viral infections, and cancer (leukemia more frequent).
• Other conditions include dehydration and Kawasaki disease.

Prolonged fever under antibiotics

• Treatment ineffectiveness: Causes include incorrect treatment, wrong treatment, inadequate dosage or duration, drug resistance in microorganisms, secondary infections, presence of the initial infection's source, or allergic reactions.

Diagnostic Steps

• History: Treatments, timelines of use, history of cancer, immune deficiency, allergies, or autoimmune diseases
• Physical exam: Thorough physical exam focusing on infection sites, lymph node enlargement, and palpable masses.
• Investigations:
  • Complete blood tests (CBC) to assess infection markers
  • Blood cultures
  • Urine culture (or culture from other specimens)
  • Serologic tests (to assess different infections)
  • Radiographic imaging (CXR, abdominal ultrasound)
  • Other specialized investigations as necessary