A 13-day-old neonate was presented with a swelling and bluish discoloration on the left thigh and groin (Fig. 1a). There was reduced movement of the left lower limb. The baby was born by normal vaginal delivery at 37 weeks of gestation with a birth weight of 2.3 kg. There was no history of maternal fever or premature rupture of membrane. USG revealed left-sided large hydrocele and a collection in the left flank area, measuring about 2.5 mm × 3 mm. Needle aspiration from the flank swelling revealed clear fluid. The aspirated fluid from the iliopsoas region showed glucose of 121 mg/dl, protein of 2.5 g/dl, albumin of 1 g/dl and cholesterol of 45 mg/dl, but no microorganism. Blood investigations demonstrated anemia (hemoglobin 9.4 g/dL), total leucocyte count (TLC) of 13,800/cumm with 32% neutrophils and 64% lymphocytes, mild thrombocytopenia (platelet 1.3 lakhs/cumm), and C-reactive protein (CRP) value of 3.9 mg/dL (normal ≤1 mg/dL). We started intravenous antibiotics in the form of Piperacillin-Tazobactam, Amikacin, and Linezolid as possibility of an abscess could not be ruled out. The patient responded to supportive medical management and we were about to discharge the patient. Surprisingly, the patient developed fever and refusal to feed after three weeks of admission. We shifted the patient in the pediatrics intensive care unit (PICU). The swelling became tense and tender. The child was irritable and started crying with the movement of the left lower limb. Repeat laboratory examinations revealed hemoglobin 8.7 g/dL, erythrocyte sedimentation rate (ESR) 8 mm/1st hour, an elevated total leucocyte count (TLC) of 34,000/cumm with 42% neutrophils, 55% lymphocytes, and C-reactive protein (CRP) of 5 mg/dl.
New USG showed a hypoechoic space-occupying lesion (40 mm × 24 mm) in the left iliopsoas region with internal moving contents. We tried another aspiration from the swelling but nothing came out. As the swelling progressed with associated high-grade fever, an MRI of lower abdomen and pelvis was performed which suggested an extremely large, thick-walled abscess measuring 59.7 mm × 31.9 mm size along the left psoas muscle extending from the level of lower border of the left kidney superiorly up to proximal thigh inferiorly (Fig. 2). In the upper thigh, the abscess was seen to extend from the anterior compartment in to the posterior compartment insinuating in between the muscles. Considering the condition, we discussed with the concerned pediatric surgeon and planned for surgical drainage of the abscess.
Initially, an incision was made in the medial aspect of the thigh where aspiration revealed frank pus. Another counter incision was made under finger guidance in the left flank, piercing the left psoas muscle (Fig. 1b). The whole cavity was then irrigated with normal saline and packed with roller gauze. Pus culture showed growth of methicillin-resistant Staphylococcus aureus (MRSA). However, the result of blood culture was negative. The patient was given meropenem and vancomycin initially which were changed to linezolid for 14 days according to the sensitivity of pus culture. The child responded well with the given treatment. At 3 months follow-up, the patient was doing well and there was no asymmetry in appearance of movements.
