Ultrasound-guided corticosteroid injection of the subtalar joint for treatment of juvenile idiopathic arthritis.

BACKGROUND: The subtalar joint is commonly affected in children with juvenile idiopathic arthritis and is challenging to treat percutaneously. OBJECTIVE: To describe the technique for treating the subtalar joint with US-guided corticosteroid injections in children and young adults with juvenile idiopathic arthritis and to evaluate the safety of the treatment. MATERIALS AND METHODS: We retrospectively analyzed 122 patients (age 15 months-29 years) with juvenile idiopathic arthritis who were referred by a pediatric rheumatologist for corticosteroid injection therapy for symptoms related to the hindfoot or ankle. In these patients the diseased subtalar joint was targeted for therapy, often in conjunction with adjacent affected joints or tendon sheaths of the ankle. We used a protocol based on age, weight and joint for triamcinolone hexacetonide or triamcinolone acetonide dose prescription. We describe the technique for successful treatment of the subtalar joint. RESULTS: A total of 241 subtalar joint corticosteroid injections were performed under US guidance, including 68 repeat injections for recurrent symptoms in 26 of the 122 children and young adults. The average time interval between repeat injections was 24.8 months (range 2.2-130.7 months, median 14.2 months). Subcutaneous tissue atrophy and skin hypopigmentation were the primary complications observed. These complications occurred in 3.9% of the injections. CONCLUSION: With appropriate training and practice, the subtalar joint can be reliably and safely targeted with US-guided corticosteroid injection to treat symptoms related to juvenile idiopathic arthritis.

Cranial nerve and cervical root enhancement in an infant with polymerase gamma mutation mitochondrial disease.

BACKGROUND: Nuclear polymerase gamma (POLG) mutations are the most common cause of inherited mitochondrial disease. POLG mutation diseases have a broad spectrum of clinical manifestations; the lethal infantile form is myocerebrohepatopathy spectrum. PATIENT: A 4-month-old boy was referred for poor feeding, emesis, failure to thrive, and hypotonia. RESULTS: Brain computed tomography was normal. Brain magnetic resonance imaging with and without contrast demonstrated bilateral enhancement of cranial nerves III, V-X, and the upper and midcervical nerve roots. Liver biopsy revealed early cirrhosis, steatosis, and focal necrosis. Muscle biopsy did not demonstrate specific abnormalities of mitochondrial morphology or number. Electron transport chain analysis of both fibroblasts and muscle demonstrated deficiencies. Because of suspected mitochondrial depletion disorder, testing was performed for mitochondrial abnormalities including analysis of the POLG gene, which revealed two pathogenic mutations, c.1399G>A (p.A467T) and c.3285C>G (p.S1095R). CONCLUSIONS: We report abnormal gadolinium enhancement of multiple cranial nerves and cervical nerve roots in an infant with myocerebrohepatopathy spectrum disease whose brain MRI otherwise revealed only mild atrophy. Mitochondrial disease should be included in the differential diagnosis of cranial nerve enhancement. Contrast-enhanced MRI aids in the diagnostic evaluation of infants with developmental delay and suspected neurological disease.