Hello and welcome.
This can be mixed connective tissue disorder which is an autoimmune disorder. But if you have not be investigated for deficiency and metabolic neuropathy; you doctor may get work up for following;
Investigations to ascertain the nutritional neuropathy;
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.
Investigations for metabolic neuropathy:
Hypophosphatemia: Serum phosphate level
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.
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