Case Presentation: This is a case of a 53 year old female with past medical history of hypertension, anxiety and gastric bypass surgery in 2001. She presented to the hospital acutely ill, complaining of inability to ambulate along with leg weakness that had started two years ago and was associated with progressive numbness and tingling. It was gradual in onset but had progressed to the point where she could not walk anymore. She also reported fatigue, anorexia and depressed mood. She denied any history of alcohol or substance abuse and had discontinued her vitamin supplements many years ago. When her symptoms initially started, she had an MRI Brain done which was unremarkable. On examination, she appeared emaciated and malnourished. She had stage 1 pressure ulcers in the sacral region. Neurological exam showed 2/5 motor strength in bilateral lower extremities with absent deep tendon reflexes. Sensory testing showed diminished perception to light touch and vibration below L1 level. Pain and temperature sensations were grossly intact. On admission, neurology was consulted. MRI of brain along with cervical, thoracic and Lumbar spine was ordered. A lumbar puncture was done and autoimmune and infectious tests were sent. Furthermore, vitamin and heavy metal screening was also requested. MRI of Brain showed enhancement of the mammillary bodies with hyperintense signals in the thalamus. Autoimmune and infectious tests came back negative. Thiamine(B1) Level was ordered which came back extremely low at 29 nmol/L (Normal 75-180nmol/L). She also had folate, B6 and Vitamin D deficiencies.  She was diagnosed with Dry Beriberi and started on IV thiamine 500mg daily for 5 days followed by oral supplementation. Other supplements including Pyridoxine(B6), Vitamin D, Calcium and folate were also started. Patient had a prolonged hospitalisation for three weeks due to severe malnutrition, major depression and poor oral intake and required enteral nutrition with Nasogastric tube followed by gastrostomy tube placement to meet nutritional requirements. Her neurological deficits improved and at the time of discharge to acute rehab she was able to lift both her legs against gravity.

Discussion: Thiamine deficiency presents as two different phenotypes. Beriberi and Wernicke-Korsakoff syndrome. Beriberi is further subdivided into two types, Wet and dry Beri-Beri. While wet beriberi affects the heart, dry Beriberi presents as motor and sensory impairments, usually of the lower extremities. The common causes of thiamine deficiency are alcohol abuse and malnutrition. However, with growing utilization of bariatric surgical procedures, incidence of thiamine/vitamin deficiencies due to malabsorption has increased. These deficiencies are relatively easy to diagnose and can be treated in the outpatient clinical settings. Therefore, in patients with a history of bariatric procedures, clinicians should always have a high index of suspicion for these vitamin deficiencies.

Conclusions: With the increased incidence of gastric bypass, thiamine deficiency due to malabsorption is becoming more common. Due to the delay in diagnosis of this patient, she not only underwent expensive and unnecessary testing including multiple MRIs and an LP, she was also so weak malnourished, she had to undergo PEG tube placement. A procedure that may have been prevented. Therefore, increased recognition and early diagnosis is imperative in patients with gastric bypass. This will not only improve health care burden but save patients a prolonged hospital course.