THE YOUNG WOMAN WITH NUMB FEET. J.J. Silverman 1 ; 1 University of Pennsylvania, Philadelphia, PA (Tracking ID #75939) LEARNING OBJECTIVES: 1) Recount the most common causes of a symmetric polyneuropathy; 2) Perform the initial evaluation of a polyneuropathy 3) Recognize an uncommon presentation of hypothyroidism. CASE INFORMATION: A 28 year-old female with no significant past medical history presents complaining of bilateral foot and hand numbness for the past six weeks. The sensation begins mid-foot, occurs intermittently throughout the day, and she specifically notes worsening symptoms walking on the treadmill at the gym. She reports similar but milder symptoms in her hands, which are not related to activity. Review of systems is otherwise notable for chronic constipation and longstanding irregular menses (since menarche at age 14). Family history is negative for polyneuropathies, cancer and thyroid disease. She smokes two packs of cigarettes per week, does not drink alcohol or use drugs, and denies toxic exposures. She has no history of blood transfusions, reports regular condom use with her two prior sexual partners, and is not presently sexually active. She takes fexofenadine as needed for seasonal allergies. Physical exam revealed a well-appearing young woman, who was afebrile, with a blood pressure of 130/80 and a heart rate of 74. Neurologic exam was notable for decreased sensation to light touch and pinprick in the plantar aspect of her right foot, as well as decreased vibratory sense in her right foot. The remainder of the physical exam was unremarkable. Labs were notable for a TSH of 109, FTI of 2.9, Thyroxine of 2.7 and T3U of 1.06. IMPLICATIONS/DISCUSSION: Polyneuropathy is not an uncommon problem in the primary care setting. The differential diagnosis is quite broad, but chronic systemic disorders, hereditary causes and inflammatory diseases account for the majority of cases. Chronic medical conditions commonly associated with polyneuropathies include diabetes mellitus, malignancy, collagen vascular disease, organ failure, B12 deficiency, alcoholism, AIDS, toxic exposures and plasma cell dyscrasias. Though the history can direct the initial evaluation, for most cases it will include a CBC, basic metabolic panel, liver panel, ANA, SED rate, B12, folate, lead level, RPR, HIV, hepatitis serologies and TSH. If this initial evaluation is inconclusive, an EMG and neurology consult are warranted. Finally, it is important to realize that hypothyroidism is protean in its manifestations, and can present without its most commonly recognized signs and symptoms.