Nusinersen Initiation After Onset of Weakness Does Not Prevent Progression of Hip Instability.

BACKGROUND: We report changes in the natural history of hip instability with nusinersen treatment among patients with spinal muscular atrophy (SMA) type II after onset of weakness, historically wheelchair-bound but now potentially ambulatory in the era of disease-modifying therapy. METHODS: Patients with genetically confirmed diagnoses of SMA type II who received intrathecal nusinersen from January 1, 2018, to June 30, 2022, were screened for inclusion. Patients with less than 6 months of follow-up, or prior hip surgeries were excluded. Primary clinical outcome measures included scores from Hammersmith motor functional scale expanded (HMFSE), revised upper limb module (RULM), 6-minute walk test (6MWT), and ambulatory status. Radiographic outcomes, including Reimer migration index, the presence of scoliosis, and pelvic obliquity, were also assessed. Secondary outcomes involved comparisons with a historical cohort of SMA type II patients treated at our institution who never received nusinersen. RESULTS: Twenty hips from 5 boys and 5 girls were included in the analysis, with a mean follow-up of 3 years and 8 months. The median age at time of nusinersen initiation was 6.8 years old, ranging between 2.5 and 10.3 years. All patients developed lower limb motor weakness before nusinersen initiation. After treatment with nusinersen, 1 previously stable hip (5%) developed subluxation, 15 hips (75%) remain subluxated, 3 hips (15%) remain dislocated, and 1 hip (5%) remained stable, with a statistically significant difference between the pretreatment and posttreatment groups (P<0.01). Six patients (60%) were ambulatory at latest follow-up. Six patients (60%) had improved ambulatory ability; 2 had static ambulatory ability (20%); and 2 had deterioration in their walking ability. The median HFMSE score improved from 18.5 (range 0 to 46) to 22 (range 0 to 49) (P=0.813), whereas the median RULM score improved from 17 (range 2 to 28) to 21.5 (range 5 to 37), which was statistically significant (P=0.007). CONCLUSIONS: Hip instability persists despite treatment with nusinersen among patients with SMA type II who received nusinersen after onset of lower limb weakness. LEVEL OF EVIDENCE: Therapeutic Level IV.

A child with acute myeloid leukemia complicated by calcaneal osteomyelitis due to Mycobacterium abscessus infection after induction chemotherapy successfully salvaged with bedaquiline and clofazimine.

Our patient was a 4-year-old female with acute myeloid leukemia complicated with right calcaneal osteomyelitis due to Mycobacterium abscessus with subcutaneous abscesses extending to the popliteal and groin regions after two courses of induction chemotherapy according to NOPHO-AML 2012 protocol. She required multiple operations and prolonged anti-mycobacterial therapy. A high index of suspicion for mycobacterial infection is required for immunocompromised patients with prolonged fever or unusual presentation. Mycobacterial osteomyelitis is rare, difficult to diagnose and treat, and may necessitate prolonged interruption of anti-leukemic therapy. Multidisciplinary collaboration in patient management is crucial. Long-term toxicity of antimicrobials with uncertain efficacy should not be overlooked.