Post-Transplant Pain and Paralysis: Neurologic Amyotrophy as an Atypical Cause of Shoulder Dysfunction Following Hematopoietic Stem Cell Transplant

Between August 2020 and July 2022, nine patients (44% male, median age 60) were diagnosed with NA following autologous (n = 4) or allogeneic (n = 5) HSCT. The onset of severe shoulder pain occurred at a median of 9 days post-transplant (range 1-21 days), with the majority of patients experiencing unilateral pain, predominantly affecting the right shoulder (55%). Neurologic weakness developed on average 5.1 days after pain onset, and sensory deficits were observed in all but one patient. MRI findings revealed muscle edema, atrophy, and enhancement in six patients, while electromyography confirmed NA in five. Due to the small sample size, statistical analyses, including <i>p</i>-values, confidence intervals, and trend comparisons, were not performed, and thus no conclusions can be drawn regarding associations between variables such as early onset and worse outcomes. Shoulder pain resolved after a median of 23 days (range 8-40 days). Long-term follow-up (>1 year) showed that three patients achieved full or near-full recovery, four partially recovered, and two showed minimal improvement. <b>Conclusions</b>: NA should be highly suspected in patients with acute shoulder pain and neurologic symptoms post-HSCT. To improve diagnostic accuracy and clinical outcomes, we recommend enhanced clinician awareness, the implementation of targeted diagnostic protocols (such as MRI and electrodiagnostic studies), and the establishment of standardized long-term follow-up protocols.