Osteomalacia induced peripheral neuropathy after obesity reduction surgery
A 25-year-old lady from a good socio-economic background presented with generalised body pains, cramps in limbs, paresthesias, and difficulty in getting up and climbing stairs for 10 days. She had undergone gastric sleeve surgery for morbid obesity 3 months before presentation. She was having recurrent vomiting and reduced oral intake after the surgery. Her weight had reduced by 21 kg over 2½ months after surgery. She had no co-morbidities. At the age of 11 years, the patient had experienced difficulty in walking and climbing stairs associated with body pains for the 1st time. She had genu valgum deformity and was chair bound for 2-3 months. At that time also, she was diagnosed to have osteomalacia. Neurophysiological evaluation had revealed a myopathic pattern. She had recovered completely with vitamin D and calcium supplementation. A similar episode a few years later also recovered with the same treatment.\nAt the time of current admission, her general physical examination was unremarkable except for obesity and mild pedal edema. Cardiorespiratory and abdominal examination was normal. Neurological examination revealed a waddling gait, hypotonic limbs without wasting and upper and lower limb weakness. Power was: upper limbs-3-4/5 proximally, 4-/5 distally; lower limbs-3/5 proximally, 4+/5 distally. Deep tendon reflexes were normal in upper and sluggish - Medical Research Council (MRC) grade 1 in lower limbs. There was no cranial nerve weakness and sensory examination was normal. A provisional diagnosis of limb girdle weakness of probable inflammatory or nutritional etiology was made.\nLaboratory investigations including hemogram, vitamin B12 (938 pg/mL; reference range: 220-960 pg/mL), and folate levels (5 ng/mL; reference range: 3-17 ng/mL) were unremarkable. However, serum calcium was 7.8 mg/dL, alkaline phosphatase 214 IU/L and parathormone level was raised (232 pg/mL; reference range: 14-72 pg/mL). The level of 25-hydroxy vitamin D was significantly low (2.58 ng/mL; reference range: 30-100 ng/mL). X-ray pelvis showed Looser zones in the pelvic bones []. Bone densitometry testing by a Dual energy X-ray absorptiometry (DEXA) scan showed a Frisk score of 6.9 (normal: 4.7 ± 1.4) suggestive of osteoporosis []. The diagnosis of post-gastric sleeve surgery with osteomalacic limb girdle weakness and hypoalbuminemia was made. Electrodiagnostic test carried out 3 months after surgery revealed reduced conduction velocities in the motor nerves of the lower limbs with normal sensory potentials suggestive of symmetrical motor polyneuropathy []. Electromyography (EMG) showed more proximal involvement with active denervation in the form of positive sharp waves and fibrillations in both vastii lateralis, high amplitude, and long duration motor unit potentials with decreased recruitment in proximal and distal muscles of both lower limbs consistent with neurogenic pattern of involvement.\nShe was started on a high protein, calcium, and vitamin rich diet and vitamin D and calcium supplementation. On evaluation after 1 week of treatment initiation, she had subjective improvement of 40% with respect to cramps and general well-being and had improved clinically by 10-15%. Power in the limbs had increased by one grade and mobility was better. Three months later, pain had subsided and she had only distal numbness over tips of thumb and index fingers. Power and mobility had further improved and finally she regained complete recovery of strength after 7 months of initiation of treatment. Nerve conduction parameters also normalized []. Serum levels of albumin, calcium, alkaline phosphatase, 25-hydroxy vitamin D, and parathormone returned toward normal. X-ray pelvis on follow-up showed disappearance of the Looser's zones []. Thus, this young female who had presented with severe degree of proximal weakness due to osteomalacia unmasked after bariatric surgery, finally recovered with treatment with vitamin D and calcium therapy-clinically, biochemically and neurophysiologically.