Various peripheral neuropathies are associated with the different endocrinopathies (Table 21-1). In particular, peripheral neuropathy associated with diabetes mellitus (DM) is one of the most common causes worldwide.
TABLE 21-1.NEUROPATHIES ASSOCIATED WITH ENDOCRINOPATHIES
DM is the most common endocrinopathy and can be separated into two major subtypes: (1) insulin-dependent DM (IDDM or type 1 DM) and (2) non–insulin-dependent DM (NIDDM or type 2 DM). DM is the most common cause of peripheral neuropathy in developed countries. DM is associated with several types of polyneuropathies: distal symmetric sensory or sensorimotor polyneuropathy, autonomic neuropathy, diabetic neuropathic cachexia (DNC), polyradiculoneuropathies, cranial neuropathies, and other mononeuropathies (Table 21-1).1,2 The exact prevalence of each subtype of neuropathy among diabetic patients is not accurately known, but it has been estimated that between 5 and 66% of patients with diabetes develop a neuropathy.3 Diabetic neuropathy can occur in children and adults.4
Long-standing, poorly controlled DM, and the presence of retinopathy and nephropathy are risk factors for the development of peripheral neuropathy in diabetic patients.5 In a large community-based study, 1.3% of the population had DM (27% type 1 DM and 73% type 2 DM).5 Of these, approximately 66% of individuals with type 1 DM had some form of neuropathy: generalized polyneuropathy, 54%; asymptomatic median neuropathy at the wrist, 22%; symptomatic carpal tunnel syndrome, 11%; autonomic neuropathy, 7%; and various other mononeuropathies alone or in combination (3%) such as ulnar neuropathy, peroneal neuropathy, lateral femoral cutaneous neuropathy, and diabetic polyradiculoneuropathy. In the type 2 DM group, 45% had generalized polyneuropathy, 29% had asymptomatic median neuropathy at the wrist, 6% had symptomatic carpal tunnel syndrome, 5% had autonomic neuropathy, and 3% had other mononeuropathies/multiple mononeuropathies. Considering all forms of DM, 66% of patients had some objective signs of neuropathy, but only 20% of patients with DM were symptomatic from neuropathy.
DIABETIC DISTAL SYMMETRIC SENSORY AND SENSORIMOTOR POLYNEUROPATHY
Distal symmetric sensory polyneuropathy (DSPN) is the most common form of diabetic neuropathy.1,2 It is a length-dependent neuropathy in which affected individuals develop sensory loss beginning in the toes, which gradually progresses over time up the legs and into the fingers and arms.6,7 When severe, a patient may also develop sensory loss in the trunk (chest and abdomen) in the midline that spreads out laterally toward the spine. Sensory loss is often accompanied by paresthesia, lancinating ...