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 ...