An eight-year-old boy, with no significant history, underwent bilateral transtympanic drainage, hysterectomy and tonsillectomy, correctly vaccinated, who came to the Primary Care clinic for fever of up to 39.4 °C.
She had no rhinorrhea, cough, vomiting or diarrhea.
Tell her mother that she was seen two days before in the emergency room for pain in the left lower limb, without previous trauma or fever, and was diagnosed with biceps femoris contracture.
The examination showed good general condition, normal color, micropapular scarlatiniform exanthema in the cervical region, red lips, soft palate and hyperemic tonsils.
An important analgesic lameness was observed during gait, positive Lassègue sign in the left lower limb, pain on palpation of the lumbar region (L5-S1) and left glue.
fever, scarlatiniform rash and significant lumbosciatic pain not compatible with the previous diagnosis of biceps femoris contracture, it was decided not to prescribe antibiotics in the primary care consultation
In the emergency room, no deformity or hematoma was observed in the examination of the left lower limb, there was no increase in local temperature, pain on femoral biceps palpation, preserved mobility, and apophysis L5-S pain.
The rest of the examination was normal.
The laboratory tests showed 19 100 leukocytes, with 15 500 neutrophils, normal CK, C-reactive protein (CRP) 13.24 mg/dl and erythrocyte sedimentation rate (SGA) 13 mm/h.
Blood culture, throat swab culture, cytomegalovirus (CMV) and Epstein-Pugh (VEB) serology were performed.
After consultation with Traumatology, pelvic and lumbar spine radiographs were performed, these being normal.
She was admitted with initial diagnosis of pharyngitis and lumbar pain and left glue to study for magnetic resonance imaging (MRI), starting empirical treatment with intravenous cefazolin 100 mg/kg/day
The blood culture was negative, but Streptococcus pyogenes was isolated in the pharyngeal exudate.
Serology for CMV and EBV were negative.
MRI shows an increase in the volume of the external obturator muscle and, to a lesser extent, of the left internal muscle, with a slightly hyperintense signal with respect to the surrounding muscle tissue in T2 and isointense sequences.
There is contrast uptake in the most medial portion around the ischiopubic branch with bone edema, as well as mild contrast uptake in the periosteum of the most lateral portion.
Intramuscular or paramuscular stenosis, venous thrombosis or alterations of the hip joint, or in the lower region were not identified.
The diagnosis is pyomyositis of external and internal obturator with secondary inflammatory involvement of the adjacent ischiopubic branch.
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The rash on admission, scarlatiniform, extends on face and flexures.
Fever, lameness, and pain disappeared within 24 hours of admission.
In the analytical, CRP decreases to 0.41 mg/dl and ESR to 9 mm/h on the seventh day of treatment.
Cefazolin was maintained for seven days.
She was discharged after seven days of intravenous treatment and clinical and laboratory improvement was observed.
The patient was treated with cefuroxime-axlo oral outpatient treatment until completing four weeks of antibiotic therapy, with relative rest and complete disappearance of lameness.
Given the good evolution, the patient was discharged from the hospital four months after the admission episode.
