A 50-year-old Filipino gentleman with a medical history of stroke, hypertension, diabetes, and diabetes-related kidney disease (baseline serum creatinine 150-200 micromol/L) presented to the emergency department with a history of fever of 5 days and low-back pain of 10 days. Low-back pain was worse with movement. On examination, he was afebrile, with tenderness in the lumbar area and no features of spinal cord or root compression.
Routine laboratory tests showed Hgb 12.8 g/dL, WBC count 26x103/microL, ALP 356 U/L, serum creatinine 211 micromol/L, CRP 189.3 mg/L, and sterile blood cultures. Medications administered regularly during his hospital stay were amlodipine 10 mg daily, atorvastatin 20 mg daily, carvedilol 6.25 mg twice daily, enoxaparin 40 mg daily, esomeprazole 40 mg daily, linagliptin 5 mg daily, sodium bicarbonate 1200 mg three times daily, paracetamol-orphenadrine 450/35 mg and tramadol 50 mg as needed for pain. His spine MRI showed an epidural collection at L5-S1 that measured approximately 40x10x8 mm maximum, meningeal thickening, and edematous changes involving L5 and S1 vertebrae, along with L4/5 paraspinal and psoas abscess. He was started on ceftriaxone 2 g once daily, which was continued for 6 days, and then escalated to piperacillin-tazobactam as fever persisted. He underwent L1/2 and L5/S1 right-side laminotomy and drainage of epidural abscess. Pus and tissue were sent for culture, which turned out to be sterile and negative for TB.
Four days after the surgery, antibiotics were optimized to cefepime 2 g every 12 hours in view of the meningeal involvement seen on MRI and operation. Dosage was calculated based on adjusted body weight and creatinine clearance (48 mL/min). The plan was to continue cefepime for 6 weeks and then repeat imaging studies. His fever subsided after the surgery. CRP decreased to a quarter of the peak value and WBC count normalized in 1 week postsurgery (Table 1). After 4 weeks on cefepime, his WBC count started to decrease, reaching a nadir of 1400 cells/mm3 with ANC of 200 cells/mm3 (14%). These were accidental findings during routine blood tests, and the patient reported no symptoms associated with the marked changes in his WBC count. No changes in red blood cell count, Hgb, or platelet count were noted (Table 1). A diagnosis of CIN was considered, cefepime discontinued, and meropenem 2 g every 8 hours initiated. Dosage was calculated based on creatinine clearance (53 mL/min). Withdrawal of cefepime showed an immediate effect on lab results: WBC count increased to 2000 cells/mm3 and normalized to 4200 cells/mm3 within 4 days, with a similar response from neutrophils (Table 1, Figure 1). His treatment course was completed with meropenem, with no further adverse events.