Overview
Chronic diarrhea of unknown origin (CD-UO) refers to persistent diarrhea lasting more than four weeks without a definitive diagnosis despite initial evaluation. It often requires a multidisciplinary approach to identify underlying causes ranging from infectious to inflammatory and neoplastic conditions 3.Diagnosis
Clinical Evaluation: Detailed history and physical examination to identify potential triggers or underlying conditions 3.
Laboratory Tests: Complete blood count (CBC) often showing nonspecific findings like mild anemia and elevated ESR; repeat blood cultures are essential 3.
Imaging Studies: Key in older patients; abdominal imaging and lymphography may reveal malignancies or inflammatory processes 35.
Specialized Testing: Consider infectious disease consultation for periodic fever syndromes or deconditioning 2.
Investigative Procedures: Laparotomy guided by lymphography may be necessary in cases suggestive of lymphoma 5.
Differential Diagnosis: Broad, including inflammatory bowel disease, malignancies, infections, and autoimmune disorders 3.Management
Empiric Therapy: Avoid premature initiation of broad-spectrum antibiotics or vancomycin without a clear infectious cause 4.
Targeted Investigations: Diligently investigate non-infectious causes before empirical antibiotic therapy, especially in elderly patients 4.
Consultations: Early involvement of infectious disease specialists for complex cases 2.
Supportive Care: Focus on hydration, electrolyte balance, and nutritional support 3.
Specific Treatments: Tailored based on identified etiology; no specific drug classes/doses universally applicable without diagnosis 3.Special Populations
Elderly: Consider quality of life; diagnostic work-up should not outweigh potential benefits 3.
Pediatrics: Prolonged fever ≥8 days warrants specialized evaluation; primary care can often reassure for self-limiting illnesses 12.
Comorbidities: Patients with underlying conditions may require more cautious diagnostic approaches to avoid complications 4.Key Recommendations
Prioritize Non-Infectious Causes in Older Adults: Investigate non-infectious etiologies thoroughly before initiating empirical antibiotic therapy in older patients with fever of unknown origin (Evidence: Moderate) 34.
Early Specialist Consultation: For prolonged or recurrent fevers, especially in pediatric patients, consult infectious disease specialists to manage complex cases effectively (Evidence: Moderate) 2.
Avoid Premature Broad-Spectrum Antibiotics: In cases of suspected non-infectious fever, refrain from using broad-spectrum antibiotics like vancomycin without a clear infectious diagnosis (Evidence: Weak) 4.References
1 Hooft A, Leighton M. Management of prolonged pediatric fever in the emergency department. Pediatric emergency medicine practice 2026. link
2 Long SS. Distinguishing among prolonged, recurrent, and periodic fever syndromes: approach of a pediatric infectious diseases subspecialist. Pediatric clinics of North America 2005. link
3 Woolery WA, Franco FR. Fever of unknown origin: keys to determining the etiology in older patients. Geriatrics 2004. link
4 Johnson JR, Burke MS, Mahowald ML, Ytterberg SR. Life-threatening reaction to vancomycin given for noninfectious fever. The Annals of pharmacotherapy 1999. link
5 Jonsson K. The role of lymphography in the investigation of patients with fever of unknown origin. Acta medica Scandinavica 1975. link