What is the appropriate evaluation and management approach for a patient with continuous fever?

Clinical Vignette: Patient with Continuous Fever

Case Presentation

A 68-year-old man is admitted to the medical ICU on post-operative day 5 following an open colectomy for colon cancer. He develops a temperature of 39.2°C (102.6°F) that has persisted for the past 48 hours despite initial empiric antibiotic therapy with ceftriaxone started 24 hours ago. 1

Patient Background

• Past Medical History: Type 2 diabetes mellitus (poorly controlled, HbA1c 9.2%), chronic obstructive pulmonary disease, hypertension 1
• Surgical History: Open right hemicolectomy 5 days ago with primary anastomosis; surgical drain placed intraoperatively 1
• Current Devices: Central venous catheter (placed day 1 post-op), Foley catheter (placed intraoperatively), surgical drain 1
• Medications: Ceftriaxone (started 24 hours ago), insulin sliding scale, albuterol nebulizers, lisinopril, and recently added phenytoin for seizure prophylaxis after a brief post-operative seizure 2

Clinical Presentation at Time of Fever Evaluation

Vital Signs:

• Temperature: 39.2°C (102.6°F) via bladder catheter thermistor 1
• Heart rate: 118 beats/min 3
• Blood pressure: 98/62 mmHg 1
• Respiratory rate: 24 breaths/min 1
• Oxygen saturation: 91% on 4L nasal cannula 1

Physical Examination Findings:

• General: Lethargic but arousable, appears uncomfortable 1
• Cardiovascular: Tachycardic, regular rhythm, no murmurs appreciated 1
• Pulmonary: Decreased breath sounds at bilateral bases, dullness to percussion on right lower lobe, coarse crackles heard posteriorly 1
• Abdominal: Surgical incision with mild erythema extending 2 cm from wound edges, tenderness to palpation in right lower quadrant, surgical drain in place with serosanguinous output 1
• Extremities: Central line site without erythema or purulence, but mild tenderness on palpation 1
• Skin: No rashes, no pressure ulcers 1
• Neurological: Alert and oriented to person only, follows simple commands 1

Initial Laboratory Results

• White blood cell count: 18,500/μL with 85% neutrophils and 10% bands 3
• Hemoglobin: 9.2 g/dL (baseline 11.5 g/dL pre-operatively) 1
• Platelet count: 245,000/μL 1
• Serum creatinine: 1.8 mg/dL (baseline 1.1 mg/dL) 1
• Blood glucose: 285 mg/dL 1
• Procalcitonin: 4.5 ng/mL 3
• C-reactive protein: 185 mg/L 2
• Urinalysis: 50-100 WBCs/hpf, positive leukocyte esterase, positive nitrites, many bacteria 2

Imaging Obtained

• Portable chest X-ray: New right lower lobe infiltrate with possible small pleural effusion, compared to post-operative day 1 film 1
• Abdominal CT (from 2 days prior): Post-surgical changes, small fluid collection near anastomosis site, no abscess identified at that time 1

Clinical Course Leading to Presentation

The patient had an uncomplicated intraoperative course but developed decreased urine output on post-operative day 3. 1 On post-operative day 4, he had a brief generalized tonic-clonic seizure lasting approximately 45 seconds, attributed to metabolic derangements, and phenytoin was initiated. 2 Temperature elevation to 38.8°C was first noted 36 hours ago, prompting initiation of ceftriaxone empirically. 1 Despite antibiotic therapy, fever has persisted and increased to current levels, with development of hypotension and increased oxygen requirements over the past 12 hours. 1

Key Risk Factors Present

• Multiple indwelling devices: Central venous catheter (5 days), urinary catheter (5 days), surgical drain (5 days) 1
• Recent surgery: Major abdominal surgery with bowel anastomosis 1
• Immunocompromising conditions: Poorly controlled diabetes mellitus, malignancy 1
• Aspiration risk: Altered mental status, recent seizure activity 1
• Recent antibiotic exposure: Ceftriaxone for 24 hours, perioperative prophylaxis 1

Diagnostic Dilemma

This patient presents with continuous fever and multiple potential sources of infection, including healthcare-associated pneumonia, catheter-related bloodstream infection, complicated urinary tract infection, surgical site infection, and possible intra-abdominal abscess. 1 The persistence of fever despite 24 hours of antibiotic therapy, combined with hemodynamic instability and elevated procalcitonin, suggests severe bacterial infection requiring urgent source identification and treatment modification. 3 Drug-induced fever from phenytoin must also be considered given recent initiation, though the clinical picture is more consistent with infectious etiology. 2