β-Lactam-Induced Fever Mimicking Post-caesarean Infection: A Diagnostic Dilemma.

Fever after a caesarean section is often believed to be caused by infections, which usually require an escalation of antimicrobial treatment. Although caesarean delivery can be lifesaving for both mother and baby, the procedure carries risks, with emergency caesarean sections being associated with a higher chance of complications, including infection and haemorrhage, compared to elective caesarean sections.  Drug-induced fever is an important yet often overlooked alternative diagnosis in obstetrics and can be difficult to recognise in patients receiving antibiotics for suspected postoperative infection. Persistent fever in a postoperative patient is a significant concern, as it may indicate ongoing or worsening infection and require systematic evaluation and a multidisciplinary approach. We report a case of a 31-year-old woman in her first pregnancy who developed a fever of 39.8°C, abdominal pain, and cough on day two following an emergency caesarean section. Her blood culture, urine culture, high vaginal swab, and viral panel were negative. Her white cell count (WBC), lactic acid, and procalcitonin levels were within normal limits, but C-reactive protein (CRP), a non-specific inflammatory marker, was the only elevated inflammatory marker. Pelvic ultrasound showed a small hematoma at the surgical site, and a chest X-ray indicated bilateral bronchopneumonia. A diagnosis of bronchopneumonia and pelvic haematoma was made. She was started on intravenous β-lactam antibiotics. Her cough resolved within two days, and she remained relatively well, but her high-grade fever persisted.  Despite escalating her antibiotics, she continued to experience a high-grade fever, which led to her transfer to a tertiary hospital. There, she was managed by a multidisciplinary team (MDT) of infectious disease specialists (ID team), pharmacists, physicians, and obstetricians, but her high-grade fever persisted. Repeat blood cultures, urine cultures, and high vaginal swabs were all negative. Similarly, her WBC, lactic acid, and procalcitonin levels, markers of infection, were within normal limits, but her CRP remained elevated. A further CT scan to exclude infected pelvic vein thrombosis or retained products of conception was negative, but raised concerns about worsening abdominal infection and possible peritonitis, even though the patient felt well with no abdominal pain or tenderness on examination. The CT report created diagnostic and management dilemmas. The MDT discussed the report extensively and recommended an exploratory laparotomy, which was explained to the patient and her family, but she declined. The next day, she developed jaundice and drug-induced hepatitis, leading to suspicion of drug-induced fever. All her antibiotics were stopped, and she became fever-free within days. The worsening ultrasound and CT scan findings are most likely due to an unusual response to a systemic hypersensitivity immune complex reaction to drug-induced fever rather than infection.  This case underscores the challenges of managing patients with persistent fever and highlights the importance of vigilance and awareness of drug-induced fever as a potential cause. Regular comprehensive assessments, including clinical examinations and investigations, are essential to identify infectious causes. A delayed diagnosis can lead to longer hospital stays, unnecessary tests, increased healthcare costs, and possible harm to the patient.