A Paralyzing Case of Myalgias

Patient: Male, 70-year-old Final Diagnosis: Succinylcholine-induced myalgias Symptoms: Myalgia Medication:— Clinical Procedure: Lymph node biopsy Specialty: General and Internal Medicine OBJECTIVE: Challenging differential diagnosis BACKGROUND: Myalgia, which describes muscle pain or soreness, is a common presenting complaint encountered in the Emergency Department, in inpatient settings and in outpatient settings. Its differential diagnosis is broad and includes benign as well as more serious clinical entities. Some of the common causes of myalgias include viral infections, strenuous exercise, and medications. Succinylcholine is a well-known neuromuscular blockade agent that is frequently used for rapid sequence intubation and short surgeries. CASE REPORT: We present the case of a 70-year-old male who presented to the Emergency Department with a chief complaint of acute, severe onset diffuse myalgia leading to the inability to mobilize. He was being investigated for recent onset generalized lymphadenopathy and had undergone a diagnostic lymph node biopsy under general anesthesia 2 days prior to his presentation. He was diagnosed with presumed succinylcholine-induced myalgias after other etiologies were deemed less likely with thorough history, physical examination, and laboratory investigations. Succinylcholine binds nicotinic acetylcholine receptors of the neuromuscular junction and produces prolonged depolarization during which activation of the muscle is blocked. Initial depolarization of the neuromuscular junction induces hectic fasciculation of the muscle fibers, which in turn may be responsible for the occurrence of post-operative myalgias (POM). This entity can be severe and debilitating and is self-limited. CONCLUSIONS: Succinylcholine remains a commonly used agent in anesthesia and succinylcholine-induced myalgia should remain in the differential diagnosis of acute, non-inflammatory myalgia. Its recognition can help avoid unwar-ranted, possibly invasive investigations and their associated additional healthcare costs.