I am writing you an initial answer. We can discuss it further once you review this. The commonest cause for pain and coldness in legs are;
1) Nerve disease (termed neuropathy)
2) Arterial diseases; This is investigated by colored doppler study, arteriography and arterial biopsy.
Following are the causes of neuropathy (many times cause is not known);
2) An underactive thyroid gland
3) Excessive use of alcohol
4) Thiamine deficiency
5) Vitamin B 12 deficiency (pernicious anemia)
6) Vitamin B 6 (pyridoxine) taken in excessive amounts
7) Drugs, medications, herbs
8) Autoimmune diseases
9) Heavy metals such as lead and mercury.
Following investigations are done (many of which had been done for you);
1) Electromyography/nerve conduction studies (EMG/NCS)
2) MRI of the spine and brain
3) blood glucose and glycosylated hemoglobin
4) serum B12 level with methylmalonic acid (with or without homocysteine),
5) serum protein electrophoresis
6) Anti-nuclear antibody
7) Lyme testing
8) Rheumatoid factor
9) Sjogren's syndrome testing (Anti-Ro, Anti-La Antibodies)
Skin and nerve biopsy are recommended after the results of these investigations.
This should give the diagnosis and guidelines for the management.
Supplements and alternative integrative therapy protocols for neuropathy are;
1) Evening primrose oil
3) Alpha-lipoic acid
4) Benfotiamine (Milgamma), 100 mg, is a lipid-soluble vitamin B1 analogue
5) Vitamin E
Your physician may consider to start Gabapentin or Pregabalin, if symptoms are significant and persistent.
Investigations to ascertain the nutritional neuropathy are;
Thiamine (vitamin B 1 ) deficiency: A serum thiamine (vitamin B 1 ) level
Pyridoxine (vitamin B 6 ) level
Folate deficiency: Serum folate levels .
Niacin (vitamin B 3 ) deficiency: Urinary excretion of N -methylnicotinamide
Cyanocobalamin (vitamin B 12 ) level
Pantothenic acid deficiency: Excretion is less than 1 mg/d.
Alpha-tocopherol (vitamin E) deficiency: The serum α -tocopherol (vitamin E) level
Hypophosphatemia: Serum phosphate level
There are metabolic causes of neuropathies too and following investigations may help in diagnosing them;
Aminolevulinic acid synthase in urine (porphyria)
Arylsulfatase A and B (leukodystrophies)
Urine oxalate levels
Serum lactate, ammonia, and pyruvate
Enzyme assays of muscle, blood, and fibroblast
Leukocyte glycogen levels to detect acid maltase deficiency
Leukocyte, DNA analyses (McArdle disease)
Please feel free for your follow up questions.
I would be happy to assist you further, if you need any more information.
Thanks for using Just Answer.