A 15-month-old boy was admitted to the hospital because of prolonged and persistent fever for fifteen days. The patient was delivered at full term weighing 3,100 g and did not require admission to the neonatal intensive care unit (NICU). He was previously healthy without recurrent respiratory infections, cough, wounds, admissions, or surgeries. Additionally, he was up-to-date with vaccinations.
The patient experienced fever for fifteen days before he visited the pediatric infectious department of our hospital. He had initially developed a high fever of 39 C, two or three times daily, without chills, lethargy, cough or vomit. The patient was treated at home with only oral antipyretic drugs. He was admitted to the local hospital four days later as he developed a high fever of 42 C, two or three times daily, accompanied by chills, lethargy, decreased appetite, tachycardia, tachypnea, and mild cough. Physical examinations revealed enlarged tonsils with yellow discharge, 0.5 cm x 2 cm lymphadenopathy on the right side of the neck and few rales in bilateral lungs. Laboratory tests showed a normal white blood cell count (WBC, 9.82 x 109/L; normal range, 4-10 x 109/L) and elevated levels of C-reactive protein (CRP, 206.6 mg/L; normal range, <0.5 mg/L) and procalcitonin (PCT, 10.831 ng/ml; normal range, <0.5 ng/ml). The first sample of blood culture collected on admission was negative for bacterial growth. Radiograph of the chest revealed bilateral bronchopneumonia. The doppler echocardiography was normal and ultrasound of the neck did not find any obvious mass or liquid anechoic area. Even after intravenous administration of cefuroxime (25 mg/kg, q6h) for two days and cefoperazone sodium and sulbactam sodium (20 mg/kg, q6h) for three days (Table 1), the patient's fever persisted. Subsequently, the second sample of blood culture, collected five days after admission, revealed the growth of S. aureus which was demonstrated to be methicillin-susceptible. Computed tomography (CT) of the chest showed bilateral scattered infiltrates in lungs (Figure 1A), an enlarged mediastinum, some pleural effusion, and pericardial effusion (Figure 1B). Moreover, the WBC count and CRP levels increased to 14 x 109/L and 295.1 mg/L, respectively. Physicians considered the occurrence of SAB and modified the antibiotic treatment to intravenous vancomycin (50 mg/kg, q6h) after excluding central nervous infection. The symptoms alleviated after four days of intravenous vancomycin therapy. Nine days after admission to the local hospital, contrast-enhanced CT of the chest revealed scattered infiltrates in the bilateral lungs (Figure 2A) and encapsulated MA (Figure 2B), and the patient was transferred to the pediatric surgery unit of another hospital for abscess incision and drainage.
The patient received intravenous oxacillin (50 mg/kg, q6h) and vancomycin (10 mg/kg, q6h) treatment in the surgical ward before surgery. With this therapy regimen, the symptoms improved gradually and contrast-enhanced CT of the chest obtained after eleven days suggested partial absorption of MA. Afterwards, the patient was transferred to our hospital for continuous conservation treatment.
Physical examination of the patient at our hospital on admission revealed the vital signs were normal. He had pharyngeal hyperemia, with bilateral tonsil hypertrophy without exudate. The rest of the physical parameters were normal. Laboratory tests showed that the WBC count was 6.6 x 109/L and the CRP level was less than 0.5 mg/L. Tests for immune function and tuberculosis yielded normal results.
The patient was diagnosed to be septic, by methicillin-susceptible S. aureus (MSSA) and non-traumatic MA. After fourteen consecutive days of intravenous oxacillin (50 mg/kg, q6h) treatment, the blood culture was negative for MSSA twice, and MA disappeared (Figure 2C). The patient fully recovered and was discharged. He did not show any untoward symptom during the one-month follow-up.
Contrast-enhanced CT scan of chest. (A). CT showing scattered infiltrates in the bilateral lungs.