Diabetic demyelinating polyneuropathy responsive to intravenous immunoglobulin therapy.

BACKGROUND: There is growing evidence that idiopathic chronic inflammatory demyelinating polyneuropathy (CIDP) and polyneuropathy in patients with diabetes mellitus (DM) that meets the electrophysiological criteria for CIDP (DM-CIDP) have many similarities. OBJECTIVE: To evaluate whether DM-CIDP responds to intravenous immunoglobulin (IVIG) therapy. PATIENTS AND METHODS: Twenty-six patients (mean [SD] age, 64 [8.9] years; age range, 40-80 years) with type 2 DM (n = 25), who met the electrophysiological criteria for CIDP, were given IVIG therapy (400 mg/kg body weight per day for 5 days) in a prospective open-label pilot study. All patients had quantitative evaluation using the Neuropathy Impairment Score at baseline and at the end of 4 weeks from the initiation of IVIG therapy. RESULTS: The mean Neuropathy Impairment Score improved significantly from baseline (mean [SD], 61.5 [26.0] points) to the end of the fourth week (33 [29.6] points; P<.00l). This clinically significant improvement occurred in 21 (80.8%) of the 26 patients. Conduction block occurred in 11 (42.3%) of the 26 patients; improvement in the Neuropathy Impairment Score was more frequent in patients who had a conduction block (11 of 11 patients) than in those who did not (10/15 [66.7%]; P =.03). Adverse reactions to IVIG included reversible renal dysfunction in 3 patients, flulike symptoms in 5, headache in 5, and chest pain and shortness of breath in 1. CONCLUSION: Although IVIG therapy seemed to improve DM-CIDP in this uncontrolled trial, a controlled trial is required for confirmation of our findings.

Demyelinating neuropathy in diabetes mellitus.

BACKGROUND: Recent studies have reported that patients with diabetes mellitus (DM) have a predisposition to develop chronic inflammatory demyelinating polyneuropathy (CIDP). OBJECTIVES: To determine whether patients with DM have a polyneuropathy fulfilling electrophysiologic criteria for CIDP, and whether CIDP is more frequent in patients with type 1 than in patients with type 2 DM. METHODS: We prospectively studied the frequency of electrophysiologic changes meeting the criteria for CIDP in patients with DM seen in our electrophysiology laboratory during a 51-month period (period 1). To evaluate the relationship between DM and CIDP, we prospectively determined during a 14-month period (period 2) the frequency of DM in patients seen in our electrophysiology laboratory with other neuromuscular diseases, and the frequency of idiopathic CIDP. RESULTS: During period 1, 120 patients with DM met the electrophysiologic criteria for CIDP (DM-CIDP). The most frequent clinical features of DM-CIDP were those of a predominantly large-fiber sensorimotor neuropathy, with recent motor deterioration and a moderately increased cerebrospinal fluid protein concentration. Twenty-six of the 120 patients were given intravenous immunoglobulin (400 mg/kg per day for 5 days), and 21 patients (80.8%) had significant improvement in the neurologic deficit at the end of 4 weeks of therapy. The DM-CIDP occurred equally in type 1 and type 2 DM. During period 2, 1127 patients were seen. Of these, 189 (16.8%) had DM with various neurologic disorders, including 32 patients (16.9%) with DM-CIDP. Among the remaining 938 patients without DM, 17 (1.8%) had idiopathic CIDP. The odds of occurrence of DM-CIDP was 11 times higher among diabetic than nondiabetic patients (P<.001). CONCLUSIONS: Demyelinating neuropathy meeting the electrophysiologic criteria for CIDP occurred in both types of DM, and its occurrence was significantly higher in diabetic than in nondiabetic patients.

Incidence of acute femoral neuropathy following renal transplantation.

BACKGROUND: Case reports exist of femoral neuropathy following renal transplantation (RTSP) with possible pathophysiology, including direct compression and nerve ischemia. However, the occurrence of acute femoral neuropathy (AFN) following RTSP has not been studied prospectively. OBJECTIVE: To determine the occurrence of AFN following RTSP. METHODS: We prospectively studied the occurrence of AFN following RTSP from June 1, 1998, to October 31, 1999. A total of 184 RTSPs were performed during this period. All the patients had end-stage renal failure and had effective hemodialysis before RTSP. All patients with AFN underwent neurologic examination, nerve conduction and electromyographic studies (5 to 7 days after the onset of symptoms), and magnetic resonance imaging or computed tomography of pelvis and lumbosacral spine within 24 hours of onset of symptoms. RESULTS: Four (2.2%) of 184 patients developed AFN (ipsilateral to the RTSP surgery) postoperatively between 24 (3 patients) and 48 hours. All the patients achieved good renal function after RTSP. All the patients had excellent recovery of motor function in 4 to 9 months. CONCLUSION: We believe that AFN following RTSP is an uncommon (2.2%) complication from which patients have an excellent chance of recovery.

Chronic inflammatory demyelinating polyradiculoneuropathy associated with multiple sclerosis.

OBJECTIVE: To describe temporal profile of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) in patients with definite, relapsing multiple sclerosis (MS). BACKGROUND: Peripheral demyelinating neuropathy has been rarely reported in association with central nervous system demyelinating disorder indistinguishable from MS. METHODS: In addition to usual diagnostic studies for CIDP and MS in all 5 patients, we studied proximal segments of nerves using deep tendon reflex latency measurements of biceps reflex, patellar reflex, and ankle reflex. RESULTS: All patients with MS subsequently (4-22 years) developed definite CIDP. Two of these patients developed multiple cranial nerve and spinal root enhancement on subsequent imaging without new intraparenchymal enhancement after a diagnosis of CIDP. The deep tendon reflex latencies were prolonged at more than 2 sites in all patients. Cerebral spinal fluid protein increased (70 +/- 19 to 144.8 +/- 17.4 mg/dL, P = 0.0001) at time of diagnosis of CIDP. Clinical improvement was observed in all patients after intravenous immunoglobulin therapy. CONCLUSIONS: When patients with MS develop CIDP, manifestations of central and peripheral disease involvement seem to respond to intravenous immunoglobulin. These cases suggest that there may be common antigenic targets in central and peripheral nervous system in this subset of patients.

Diagnostic role of deep tendon reflex latency measurement in small-fiber neuropathy.

Small-fiber neuropathy (SFN) is diagnosed on the basis of clinical features and specialized tests of small-fiber function because standard nerve conduction studies are normal. Thus, the objective of this study was to determine the value of deep tendon reflex (DTR) latency measurement in the diagnosis of SFN in patients with preserved DTR on clinical examination. We prospectively examined electromyographic reflexes from the biceps brachii [biceps brachii reflex (BR)], patellar [patellar reflex (PR)], and ankle [ankle reflex (AR)] using a manually operated electronic reflex hammer attached to electromyography machine and recorded by means of surface electrodes in 18 patients with SFN and 38 controls. Intra- and inter-evaluator reliability was good (intraclass correlation coefficient: 0.80-0.91, p < 0.01). In controls, the latencies at all sites were correlated to the height (R= 0.6, p < 0.01). Compared with controls, in patients with SFN, the mean latency in milliseconds was prolonged at all sites (BR: 12.8 +/- 1.6 vs. 8.9 +/- 1.9, p < 0.01; PR: 23.0 +/- 5.8 vs. 17.4 +/- 2.4, p < 0.01; and AR: 34.5 +/- 4.8 vs. 30.0 +/- 2.4, p < 0.01). The sensitivity [61.1% (95% CI: 51-94.9)] and specificity [92% (95% CI: 73-97.3)] of BR latency were roughly equal to those of PR and AR. We conclude that DTR latencies were significantly abnormal in the majority of the patients with SFN, suggestive of subclinical involvement of large myelinated fibers. DTR latency measurement is a reproducible, valuable, sensitive tool in the evaluation of mild subclinical involvement of large fibers.

Chronic inflammatory demyelinating polyradiculoneuropathy in diabetes mellitus.

There is a higher incidence of demyelinating peripheral neuropathy responsive to immunomodulating treatment in patients with diabetes mellitus. The diagnosis is often overlooked and the patients are given the label of "diabetic neuropathy." Progressive symmetric or asymmetric motor deficit, progressive sensory neuropathy in spite of optimal diabetic control, and unusually high cerebrospinal fluid protein level in "diabetic neuropathy" should alert the clinician to the possibility of an underlying treatable demyelinating peripheral neuropathy masquerading as "diabetic neuropathy."