Subinternship Medicine · Year 4 · from Subinternship Medicine
Case 3: Diagnostic Uncertainty and Watchful Waiting
Clinical Image
Source: Wikimedia Commons - Medical Imaging - CC BY-SA 3.0
Case Presentation
A 45-year-old man presents with 3 weeks of intermittent low-grade fever (maximum 38.3 degrees Celsius), fatigue, and 5-pound weight loss. He has no localizing symptoms: no cough, no urinary symptoms, no diarrhea, no joint pain, no rash. Physical examination is unremarkable except for possible splenomegaly. Initial workup shows mild normocytic anemia (hemoglobin 11.2 g/dL), elevated ESR (65 mm/hr), elevated LDH (280 U/L), and mildly elevated alkaline phosphatase. Chest X-ray is normal. CT of chest, abdomen, and pelvis shows borderline splenomegaly (14 cm) but no lymphadenopathy or masses. Blood cultures are negative. The team considers the broad differential for fever of unknown origin: infection (endocarditis, occult abscess, tuberculosis), malignancy (lymphoma, leukemia), and autoimmune disease (Still's disease, vasculitis). Echocardiography shows no vegetations. ANA and RF are negative. Peripheral smear is unremarkable. The attending suggests a "diagnostic time-out" to reformulate the problem. Rather than ordering more tests immediately, the team decides on watchful waiting with close follow-up in 1 week. At follow-up, the patient reports night sweats and notices a new enlarged lymph node in his left axilla. Repeat examination confirms 3 cm rubbery lymphadenopathy. Excisional biopsy reveals Hodgkin lymphoma. The 1-week delay allowed the disease to declare itself, avoiding unnecessary invasive testing while the diagnosis was evolving.
Key Learning Points
- Time can be a diagnostic tool; watchful waiting with close follow-up allows evolving presentations to declare themselves
- Fever of unknown origin (greater than 38.3 degrees Celsius for greater than 3 weeks without diagnosis) has classic categories: infection, malignancy, and autoimmune/inflammatory conditions
- A "diagnostic time-out" forces reconsideration of the working diagnosis and prevents reflexive test ordering
- When the diagnosis is unclear, focus on the "most likely," "most dangerous," and "most treatable" conditions while monitoring for new clinical clues