Acute inflammatory demyelinating polyneuropathy in a diabetic patient: predominance of vesicular disruption in myelin sheaths

Evaluation of the efficacy of pulsed electromagnetic field in the management of patients with diabetic polyneuropathy

AIM

The study was carried out to evaluate and compare the effect of low power, low frequency pulsed electromagnetic field (PEMF) of 600 and 800 Hz, respectively, in management of patients with diabetic polyneuropathy.

SETTINGS AND DESIGNS

The study was a randomized controlled trial performed in Guru Nanak Dev University and Medical College, Amritsar, India with different subject experimental design.

MATERIALS AND METHODS

Thirty subjects within an age group of 40-68 years with diabetic polyneuropathy stages N1a, N1b, N2a were randomly allocated to groups 1, 2, 3 with 10 subjects in each. Group 1 and 2 were treated with low power 600 and 800-Hz PEMF for 30 min for 12 consecutive days. Group 3 served as control on usual medical treatment of diabetic polyneuropathy (DPN). The subjects with neuropathy due to any cause other than diabetes were excluded. The pain and motor nerve conduction parameters (distal latency, amplitude, nerve conduction velocity) were assessed before and after treatment.

STATISTICAL ANALYSIS

Related t-test and unrelated t-test were used for data analysis.

RESULTS

Significant reduction in pain and statistically significant (P<0.05) improvement in distal latency and nerve conduction velocity were seen in experimental group 1 and 2.

CONCLUSIONS

Low-frequency PEMF can be used as an adjunct in reducing neuropathic pain as well as for retarding the progression of neuropathy in a short span of time.

Inexcitability of nerves in a fulminant case of Guillain-Barré syndrome

A 45-year-old woman presented with a recent sensorimotor deficiency in all 4 limbs, and the next day she was totally paralyzed. A slight motor improvement began on day 27. The cerebrospinal fluid had normal cellularity, but the protein varied from 90 mg/dL on the first day to 800 mg/dL on day 15, and then 290 mg/dL on day 33. Electrophysiologic studies performed on days 15 and 23 revealed a universal peripheral nerve inexcitability. A superficial peroneal nerve biopsy was performed on day 23. Nine fascicles were examined on semi-thin sections and myelinated fiber damage varied greatly from one fascicle to another. At ultrastructural examination, certain axons were severely damaged, but the others were quite well preserved and were naked or wrapped in a myelin sheath presenting a multivesicular degeneration. A few fibers had a better-preserved myelin sheath that was sometimes dissociated by elongated processes from an invading histiocyte. Six cases of fulminant Guillain-Barré syndrome with inexcitability of nerves and ultrastructural examination of nerve fragments have been reported. Electrophysiologic study is often ambiguous and cannot determine the precise origin of such an axonal degeneration. Therefore, ultrastructural analysis of a nerve biopsy is mandatory in this setting.

Ultrastructural effects of Guillain-Barré serum in cultures containing only rat Schwann cells and dorsal root ganglion neurons

Serum from patients with the acute form of the Guillain-Barré syndrome was applied to cultures containing only rat dorsal root ganglion neurons and Schwann cells. Serum taken from 4 of 10 patients during the first 1-3 weeks of clinical onset had previously been shown to have significant demyelinating activity in this culture system when observed at the light microscopic level. More detailed assessment made at the ultrastructural level showed that: (1) wide-spread myelin-related Schwann cell lysis occurred in concert with vesicular myelin breakdown; (2) non-myelin-related Schwann cells avidly phagocytized necrotic cell debris and fragments of compact myelin; and (3) neurites and non-myelin-related Schwann cells remained structurally undamaged. Cultures treated with convalescent phase serum from patients whose acute phase serum had cytolytic activity displayed no significant ultrastructural damage to either neurites or Schwann cells. This is the first electron microscopic study to provide direct evidence that acute Guillain-Barré serum can be cytolytic for myelin-related Schwann cells and peripheral myelin in an experimental setting free of leukocytes, lymphocytes and mononuclear phagocytes.

Demyelination in vivo by Guillain-Barré syndrome and other human serum

Serum from patients with acute inflammatory polyneuropathy (the Guillain-Barré syndrome, GBS) demyelinates peripheral nerves in vivo more intensely than control human serum. To clarify the processes leading to demyelination we injected rat sciatic nerves with serum from GBS and control subjects in the presence of complement and examined the sequential morphologic changes over 7 days. One day after injection, five of six GBS sera but none of seven control sera caused vesicular demyelination; 3-5 days after injection both GBS and control sera produced macrophage-mediated demyelination. These observations suggest that GBS serum can initiate acute myelin injury through a humoral mechanism that is disease associated. This response appears to be distinct from delayed cell-mediated serum-induced demyelination that is not disease specific.

Relapsing inflammatory demyelinating polyneuropathy in a diabetic patient

Inflammatory demyelinating polyradiculoneuropathies exhibit well-known ultrastructural lesions of the peripheral nerve, both in acute cases, i.e., Guillain-Barré syndrome, and in relapsing, sub-acute and chronic cases. We present a case of relapsing inflammatory demyelinating polyradiculoneuropathy in a diabetic patient with a biopsy exhibiting these lesions, as well as a widening of the outermost myelin lamellae in some fibers. Such associated lesions are classic in experimental inflammatory demyelinating polyradiculoneuropathies, but have not been reported in human pathology.