2009 Southern Regional Meeting Abstracts

Case Report: A 16yo male track athlete presented with syncope, bradycardia, hypotension and hypothermia. He presented with 1 month of progressive lower limb weakness, salt craving, cold intolerance, constipation and a 30 pound weight loss. No trauma, viral illness or drugs. PMH/FH neg. PE: T94, P25, BP 96/71, RR16 Sao2 100(RA), BMI:18.2, lungs:clear; heart:bradycardia without murmurs; abdomen:normal; muscle tone/joints:normal, nonfocal neurologic exam except patellar and ankle reflexes 1+ and 3/5 strength in lower extremities. He required an isoprotrenolol drip to keep his heart rate over 40/minute during extensive testing by cardiology, endocrinology, rheumatology, oncology and neurology consultants. Labs: CBC, CMP, TSH, ACTH stimulation test and lumbar puncture were all normal. Viral titers, drug screen, rheumatology and endocrine tests - negative except testosterone 124. EKG: sinus bradycardia; Echocardiogram and MRI: unremarkable. Autonomic testing showed an abnormal valsalva manuever/failure of sympathetic nervous system. He went home on midodrine/caffeine but continued with significant symptoms. 2 weeks later his anti-acetylcholine-receptor(AchR) antibody returned high and he was given a trial of IVIG. PET/CT scan were negative for tumor.
DISCUSSION:
This case immediately raised suspicion of severe hypothyroidism or adrenal crisis as well as Guillain-Barre but these were quickly ruled out. Only weeks of extensive consultation and testing revealed the diagnosis: autoimmune autonomic neuropathy. This is an extremely rare disorder affecting the sympathetic and parasympathetic systems with manifestations ranging from abnormal GI motility and sexual dysfunction to life-threatening disturbances in heart rate and blood pressure as seen in our patient. The antibody mediated attack directed against the acetylcholine receptors of the autonomic ganglia is often triggered by an occult neoplasm that expresses the autoantigen but no obvious cause is found in more than a third of patients. Immunomodulatory therapy may ameliorate the severity of the disease but is not curative. This case illustrates the importance of the relentless pursuit of an elusive diagnosis through collaboration with the patient, fellow pediatricians and subspecialists.