INTRODUCTION: Community-Acquired Methicillin-Resistant Staphylococcus Aureus (CA-MRSA) is an emerging clinical problem. It mostly causes skin and soft tissue infections but may cause osteomyelitis, septic arthritis, pyomyositis, and pneumonia with empyema. We present a child with disseminated CA-MRSA.
CASE PRESENTATION: A previously healthy 15-year-old male presented with right groin pain with no known trauma. He was seen in clinic where a hip x-ray showed no abnormality and was treated with naproxen for pain. A week later, he presented to an emergency department with worsening groin pain, difficulty walking, myalgia, headache, blurred vision, slurred speech and difficulty hearing. His physical exam demonstrated decreased mentation, tachycardia, hypotension, right hip tenderness and a swollen right knee. Pertinent lab findings included: white blood cell count (WBC)- 6x103/mm3 with 22% bands, HCO3- 14mmol/L, blood urea nitrogen- 32mg/dL, creatinine - 1.1mg/dL. Cerebral spinal fluid (CSF) was hazy, colorless with 300 WBC. The patient received vancomycin and ceftriaxone. Due to decreased mental status, he was intubated, rehydrated and transported to our institution (8 days after the initial presentation). He was comatose and in refractory shock- managed with crystalloids, colloids, dopamine, norepinephrine, epinephrine, vasopressin and stress dose steroids. A generalized papular rash with tiny pustules was noted. Ultrasound and x-rays of the hip were negative. His chest x-ray showed scattered small nodularities throughout the lungs consistent with septic emboli. Computer tomography (CT) scan of the head showed multiple abscesses and abdominal CT showed ascites and lesions suggestive of septic emboli with small abcesses in the spleen and kidneys. A peritoneal drain was placed and fluid was sent for culture. Blood, urine, CSF and peritoneal cultures grew MRSA. His antibiotics were changed to linezolid and daptomycin. However, he developed multi-organ failure and died within 48 hours. Orthopedics was consulted but joint aspiration was not attempted before the patient's demise. Multiple small abscesses were found in the lungs, heart, liver, kidneys, adrenals, spleen, thyroid, skeletal muscles, bowel wall and peritoneum at autopsy. Aspiration of the right hip at autopsy revealed pus and grew MRSA.
DISCUSSIONS: MRSA was initially associated with healthcare facilities, now known as healthcare-acquired MRSA (HCA-MRSA). HCA-MRSA is characterized based on risk factors including: hospitalization or surgery in previous 2 years, presence of indwelling devices or catheters, a household member hospitalized during the previous 2 years or employed in a healthcare facility, underlying chronic illness, immunosuppression or injecting narcotic use. CA-MRSA is associated with strains arising de novo in the community and no risk factors. About 77% of CA-MRSA carry the Panton-Valentine leukocidin gene. Compared with HCA-MRSA, CA-MRSA has been reported as causing more necrosis and pus formation, frequently requiring surgical intervention. In our patient, septic arthritis is clearly in the differential diagnosis. An elevated WBC, C-reactive protein or sedimentation rate may have prompted a more aggressive workup and earlier initiation of antibiotics. Plain radiographs and ultrasound of joints have limited use in early septic arthritis or osteomyelitis. Magnetic resonance imaging is more sensitive and shows muscle involvement.Initiation of the appropriate antibiotic is essential for successful treatment therefore up to date information on current antimicrobial susceptibilities is crucial. CA-MRSA strains are generally susceptible to vancomycin, trimethoprim/sulfamethoxazole, clindamycin, doxycline, linezolid and daptomycin. Multi-drug therapy should be started on individuals with a high index of suspicion for life-threatening MRSA infections. A vital part of successful treatment is drainage of abscesses or purulent collections, in this case the right hip to decrease the risk of hematogenous spread.
CONCLUSION: CA-MRSA is becoming more prevalent. Where there is a high suspicion for MRSA, appropriate antibiotics, even multi-drug therapy, should be initiated. Every effort to promptly drain purulent collections and isolate the organism should be made.
DISCLOSURE: Mac Wayment, None.