What would cause hyper-sensitive patella reflex?

Several posibilities: Anxiety, an overactive thyroid, medications, an electrolyte imbalance, spinal cord injury, upper motor neuron diseases like ALS or a stroke. Some people just are born with more hyperactive reflexes than the norm.

Neuropathy: Neuropathy from metabolic diseases are the first consideration, and often associated abdominal obesity and adult onset diabetes. If you have your physician order a b-6 (vitamin) level, it most likely will be markedly elevated, and therefore inactive and toxic. There are other reasons, and if the b-6 is normal conside vitamin B12 deficiency, heme deficiency, and then discs or tumors of the spine.