Diabetic thoracoabdominal neuropathy: clinical and electrodiagnostic features

Focal and entrapment neuropathies

Of the many patterns of peripheral nerve disorders in diabetes mellitus (DM), isolated clinical involvement of single nerves, though less common than distal symmetric polyneuropathy and perhaps polyradiculoneuropathy, constitute an important collection of characteristic syndromes. These fall into four anatomical regions of the body: cranial, upper limb, truncal, and lower limb territories. Each of these groups of mononeuropathies has its own ensemble of epidemiologic patterns, clinical presentations, laboratory and radiologic findings, differential diagnosis, management principles and prognosis.

Intercostal neuralgia as a symptom of an osteoblastoma in thoracic spine

An osteoblastoma is a benign bone lesion most commonly affecting the spine; it is frequently found in the posterior elements of the vertebra. When an osteoblastoma originates in the spine, it usually causes dull and localised dorsal pain, but the period between symptom development and diagnosis can be long. MRI shows intense peritumoural oedema accompanying the osteoblastoma. We present a case of a 15-year-old boy with osteoblastoma at the level of the T8-9 left laminae causing intercostal neuralgia without direct invasion to the intercostal nerve. Immediately after surgery, intercostal neuralgia was diminished. To our knowledge, this is the first case of an osteoblastoma with intercostal neuralgia, which is possibly the key symptom for diagnosing an osteoblastoma in the thoracic spine.

Diabetic radiculoplexus neuropathies

Diabetic radiculoplexus neuropathies (DRPN) are neuropathies clinically and pathologically distinct from the neuropathy typically associated with diabetes (DPN). DRPN are usually subacute in onset, painful, and often demonstrate a monophasic course with incomplete recovery. Pathologically, these neuropathies are due to ischemic injury from altered immunity and often have features suggestive or diagnostic of microvasculitis. Unlike DPN, immune therapy may be helpful in treatment of these conditions given their pathological substrate and therefore are important to identify early and distinguish from other neuropathies that occur in patient with diabetes.

Diabetic neuropathy part 2: proximal and asymmetric phenotypes

Diabetic neuropathies consist of a variety of syndromes resulting from different types of damage to peripheral or cranial nerves. Although distal symmetric polyneuropathy is the most common type of diabetic neuropathy, many other subtypes have been defined since the 1800s, including proximal diabetic, truncal, cranial, median, and ulnar neuropathies. Various theories have been proposed for the pathogenesis of these neuropathies. The treatment of most requires tight and stable glycemic control. Spontaneous recovery is seen in most of these conditions with diabetic control. Immunotherapies have been tried in some of these conditions however are controversial.

Intravenous immunoglobulin therapy in proximal diabetic neuropathy

A 57-year-old man with type 2 diabetes mellitus for 10 years showed progressive loss of muscle strength in both legs, pain and muscle atrophy in the femoral region and significant weight loss. On admission, he could not stand alone and used a wheelchair. He also complained of severe pain in the lower extremities. He was diagnosed with proximal diabetic neuropathy (PDN) by characteristic clinical and electrophysiological features. Intravenous immunoglobulin therapy (IVIg 0.4 g/kg×5 days) markedly reduced the severe pain and muscle weakness in the legs. Eventually, pain assessed by the Visual Analogue Scale was relieved by 80% and muscle strength was also well recovered, thereby enabling the patient to walk with a cane. The present case suggests that IVIg therapy may be effective for the relief of pain in PDN.

Intravenous immunoglobulin therapy markedly ameliorates muscle weakness and severe pain in proximal diabetic neuropathy

A 57-year-old man with type 2 diabetes mellitus for 10 years showed progressive loss of muscle strength in both legs, pain and muscle atrophy in the femoral region and significant weight loss. On admission, he could not stand alone and used a wheelchair. He also complained of severe pain in the lower extremities. He was diagnosed with proximal diabetic neuropathy (PDN) by characteristic clinical and electrophysiological features. Intravenous immunoglobulin therapy (IVIg 0.4 g/kg x 5 days) markedly reduced the severe pain and muscle weakness in the legs. Eventually, pain assessed by the Visual Analogue Scale was relieved by 80% and muscle strength was also well recovered, thereby enabling the patient to walk with a cane. The present case suggests that IVIg therapy may be effective for the relief of pain in PDN.

Diabetic thoracic polyradiculopathy

Diabetic thoracic polyradiculopathy usually causes severe, chronic abdominal pain in patients with type 2 diabetes of variable duration. Other diabetic complications, weight loss and paretic abdominal wall protrusion are common. Sensory, motor and autonomic functions are affected. The diagnosis can be made from the characteristic history, physical examination findings, paraspinal electromyography, and other procedures. The differential diagnosis includes postherpetic neuralgia, abdominal wall pain, malignancy, and other spinal disorders. The pathology appears to be immune-mediated neurovasculitis resulting in ischemic injury. Traditional therapy is symptomatic, but recent pathological findings and clinical experience suggest that immunotherapy may be effective.

Diabetic thoracic radiculopathy: an unusual cause of post-thoracotomy pain

Persistent pain is common following thoracotomy. A 64-year-old retired electrician with Type 2 diabetes presented with chest wall and abdominal pain 3 months following video-assisted thoracoscopic surgery (VATS). Postoperatively the patient had suffered pain despite a functioning thoracic epidural catheter. Following investigation, his persistent pain was due to diabetic thoracic radiculopathy (DTR). The disorder is characterized by pain, sensory loss, abdominal and thoracic muscle weakness in patients with diabetes. As in this patient, the pain and sensory loss usually resolve within one year after onset. The disorder may be distinguished from intercostal neuralgia based upon clinical and electromyographic features.

Focal and multifocal neuropathies

The focal and multifocal neuropathies affect only a minority of patients with diabetes; however, they form a major clinical problem in terms of diagnosis, development of significant symptoms and signs, and often inadequate therapy. Diagnosis requires accurate and detailed clinical history and neurologic examination combined with targeted neurophysiologic tests, which differ considerably from those carried out in day-to-day practice. Because of their relatively infrequent occurrence, treatment is not evidence based.

Diabetic Lumbosacral Polyradiculoneuropathies

The pathogenic basis and treatment of diabetic polyradiculoneuropathy is a source of recent controversy as there may be two or more distinct forms of diabetic polyradiculoplexopathy. We believe that the following two categories of diabetic polyradiculoneuropathy can be made on the basis of clinically differences: 1) the more common asymmetric, painful polyradiculoneuropathy; and 2) the rare symmetric, painless, polyradiculoneuropathy. The asymmetric, painful form (also known as diabetic amyotrophy) may have an autoimmune basis, but the etiology is not clear. The natural history for diabetic amyotrophy is spontaneous improvement. Nevertheless, various immunotherapies (eg, corticosteroids and intravenous immunoglobulin (IVIg) have been tried with subsequent improvement in symptoms. Treatment is reserved only for patients with severe ongoing pain, given the significant side effects of these medications in those patients with diabetes. Prednisone and IVIg may help alleviate the pain associated with diabetic amyotrophy. Relief of pain can help patients begin physical therapy earlier, however, there are no prospective, blinded, controlled studies that demonstrate that these treatments lead to an earlier and better recovery of muscle strength compared with the natural history of the disorder. The symmetric, painless form of diabetic polyradiculoneuropathy may in fact represent chronic inflammatory demyelinating polyneuropathy (CIDP) occurring in a patient with diabetes mellitus (DM). Patients with idiopathic CIDP may improve various immunomodulating therapies, including corticosteroid treatment, plasma exchange (PE), and IVIg. In this regard, patients with the symmetric, painless, proximal diabetic polyradiculoneuropathy may also respond to corticosteroids, plasma exchange, IVIg, azathioprine, or cyclophosphamide. However, as with diabetic amyotrophy, some patients improve spontaneously without treatment. In still other patients, the neuropathy appears unresponsive to immunotherapy. In such patients, this polyradiculoneuropathy might be caused by metabolic dysfunction associated with DM. Unfortunately, from a clinical, laboratory, and electrophysiologic standpoint, it is impossible to distinguish the patients with a symmetric, painless diabetic polyradiculoneuropathy who might respond to therapy. A trial of PE can be useful in identifying patients who might have a polyradiculoplexopathy that is responsive to immunotherapy. If patients respond to PE, they may continue to receive intermittent exchanges or be switched over to prednisone or IVIg.

Cervicobrachial involvement in diabetic radiculoplexopathy

Diabetic radiculoplexopathy is commonly viewed as a condition affecting the lower extremities. However, other regions may also be affected and the presence of upper extremity involvement has rarely been emphasized. Our goal was to illustrate the clinical features of arm involvement in this condition. Of 60 patients with diabetic lumbosacral radiculoplexopathy, we identified 9 who also had upper extremity involvement. The study included 8 men and 1 woman, ranging in age from 36 to 71 years. Upper limb involvement developed simultaneously with the onset of lower limb disorder in 1 patient, preceded it by 2 months in another patient, and occurred between 3 weeks and 15 months later in the remaining 7. In 5 cases, arm involvement developed after symptoms in the legs began to improve. The upper extremity weakness affected the hands and forearms most severely. It was unilateral in 5 patients and bilateral but asymmetric in 4. Pain was often present, but it was not a prominent feature. In most patients, neurologic deficits in the arms improved spontaneously after 2-9 months. We conclude that diabetic radiculoplexopathy may involve the cervical region before, after, or simultaneously with the lumbosacral syndrome. The upper limb process is similar to that in the legs, with subacutely progressive weakness and pain followed by spontaneous recovery.

Neuropathological alterations in diabetic truncal neuropathy: evaluation by skin biopsy

OBJECTIVES

To describe the neuropathological features in skin biopsies from patients with diabetic truncal neuropathy.

METHODS

Three patients with diabetic truncal neuropathy underwent skin biopsies from both symptomatic and asymptomatic regions of the chest and trunk. After local anaesthesia, biopsies were performed using a 3 mm diameter punch device (Acupunch). Intraepidermal nerve fibres (IENFs), the most distal processes of small myelinated and unmyelinated nerve fibres, were identified after staining with PGP 9.5 as previously described.

RESULTS

Diabetes was diagnosed at the time of the neurological presentation in two, and one was a known diabetic patient. All three had associated sensory-motor polyneuropathy. In all, skin biopsies showed a marked reduction of both epidermal and dermal nerve fibres in the symptomatic dermatomes, compared with skin from asymptomatic truncal areas. In one patient, a follow up skin biopsy when symptoms had improved showed a return of IENFs.

CONCLUSIONS

In diabetic truncal neuropathy, skin biopsies from symptomatic regions show a loss of IENFs. After clinical recovery, there is a return of the IENF population, suggesting that improvement occurs by nerve regeneration. These findings suggest that sensory nerve fibre injury in diabetic truncal neuropathy is distal to or within the sensory ganglia. Skin biopsy provides a possible tool for understanding the pathophysiology of the disease.

Peripheral neuropathies in diabetes

Peripheral neuropathy in diabetes remains a difficult management dilemma. The clinical manifestations may vary widely. Polyneuropathies develop with increasing duration of disease, and a thorough understanding of the clinical manifestations, including sensory, motor, and autonomic deficiencies, helps guide diagnosis and treatment. A multidisciplinary approach emphasizing preventive care and timely intervention can decrease morbidity significantly and improve the quality of life for the patient. Properly fitting shoes and avoidance of foot trauma are cornerstones of preventive management. Strict control of serum glucose can alter the course of peripheral neuropathies. This control can be accomplished with a strict insulin regimen or pancreatic transplant. Further research is needed to increase knowledge about peripheral neuropathies in diabetes and aid the physician with new treatment options.

Autoimmune diabetic neuropathy

Recent work has shown that inflammatory vasculopathy is commonly seen in biopsies of diabetic patients with neuropathy. Most of these patients have had syndromes consistent with proximal diabetic neuropathy or amyotrophy. This suggests that inflammatory vasculopathy is important in the pathogenesis of these disorders. Immunosuppressive therapy may benefit many of these patients.

Diabetic neuropathy

The most common form of diabetic neuropathy is chronic, distal symmetrical sensorimotor, or predominantly sensory neuropathy; the latter is invariably associated with some degree of autonomic dysfunction. There are, however, other neuropathic patterns in diabetes mellitus that are uncommon but are important to recognize, since they may mimic many other non-neurologic diseases. This article discusses a variety of forms of mononeuropathies and diabetic proximal motor neuropathy, commonly known as diabetic amyotropy.

[Abdominal neuropathy of motor expression of diabetic origin. Apropos of a case]

Authors report a case of diabetic truncal neuropathy presenting as a painful abdominal swelling. This entity, which frequently is probably under estimated, may mimic abdominal visceral pathology and patients may be subjected unnecessary to extensive diagnosis procedures.

Sixteenth annual AAEM Edward H. Lambert Lecture. Electrodiagnostic aspects of diabetic neuropathies: entrapments. American Association of Electrodiagnostic Medicine

A MEDLINE review suggested a lack of recent studies about the entrapments seen with underlying diabetic neuropathy. Suggested protocols for research in diabetic peripheral neuropathy have not included the concepts of entrapments as an early--indeed, first manifestation of the neuropathy. Carpal tunnel syndrome is a frequent accompaniment of diabetic peripheral neuropathy. Assessment of the degree of entrapment superimposed on the generalized peripheral neuropathy can be clarified by analysis of the CMAP and the SNAP--particularly with respect to duration of the negative spike of the action potential. Also, analysis of the action potentials elicited by stimulation of the ulnar and radial nerves and their comparison with the median nerve is often helpful. Finally careful inspection of the action potential when stimulating proximal and distal to the entrapment will establish the degree of nerve compromise relative to the underlying diabetic neuropathy.

Intercostal nerve conduction study in man

A new surface technique for the conduction study of the lower intercostal nerves has been developed and applied to 30 normal subjects. The problem of the short available nerve segment of the intercostal nerves and the bizzare compound motor action potential (CMAP) of inconsistent latency while recording over the intercostal muscles, is overcome by applying recording electrodes over the rectus abdominis muscle and stimulating the nerves at two points at a fair distance away. With the use of multiple recording sites over the rectus abdominis, the motor points for different intercostal nerves were delineated. CMAP of reproducible latencies and waveforms with sharp take-off points were obtained. Conduction velocity of the intercostal nerves could be determined.

Diabetic truncal neuropathy: topography of the sensory deficit

The distributions of sensory abnormalities in 17 episodes of diabetic truncal neuropathy among 7 patients with diabetes mellitus are described. The patterns are highly variable: the distribution of adjacent main spinal nerves may be involved, resulting in a complete dermatomal band of dysesthesia, but almost two-thirds of the episodes were restricted to the distribution of the ventral or dorsal rami of the spinal nerves or branches of these rami or varying combinations of these distributions.

Peripheral diabetic neuropathy

Diabetic neuropathy is a common complication of diabetes mellitus with significant morbidity and mortality. Hyperglycemia with its secondary metabolic, vascular, and enzymatic consequences is most likely to be the predominant cause. The clinical manifestations includes a wide range of somatic and autonomic syndromes. Painful diabetic neuropathy may require symptomatic treatment. The precise role of therapies such as continuous subcutaneous insulin therapy and aldose reductase inhibitors remains to be clarified.

Diabetic thoracic radiculopathy: electrodiagnostic study

We investigated the diagnostic value of electromyographic (EMG) examination of the anterior abdominal wall muscles (AWMS) in thoracic radiculopathy and compared it with examination of thoracic paraspinal muscles (TPSM). Technically, examination of AWMS was much easier compared to TPSM. In eight patients with thoracic diabetic radiculopathy at the level of T7-T12, AWMS was abnormal in all and was considered to be diagnostic, whereas AWMS was normal in diabetic lumbar radiculopathy, patients with diabetes mellitus without radiculopathy, patients with unspecified gastrointestinal pain, and patients with musculoskeletal-type back pain. We conclude that EMG evaluation for possible thoracic radiculopathy should include examination of AWMS, and if abnormal, would be of great diagnostic help in patients with unspecified gastrointestinal symptoms.

Pain relief in diabetic neuropathy: the effectiveness of imipramine and related drugs

Experience of treating 80 consecutive patients with painful diabetic neuropathy and a double-blind study of imipramine in acute painful neuropathy are reported. A standard stepwise protocol was used, based on imipramine as the drug of first choice, substitution of amitriptyline or mianserin as second choice, and, thirdly, addition of phenothiazine or clonazepam if necessary. Sixty per cent were satisfied with imipramine alone and all but 3 (5%) were improved by the stepwise scheme. Paradoxically, the most effective analgesia was obtained in those with the most severe and unpleasant pain. Often 150 mg of imipramine or amitriptyline was necessary. The onset of analgesia and relapse after withdrawal of treatment were rapid, facilitating clinical use, and suggesting a peripheral rather than central drug action.

Diabetic neuropathy of the lateral cutaneous nerve of the calf. A case report

We report a case of neuropathy of the lateral cutaneous nerve of the calf in a patient with inadequately controlled diabetes mellitus. The painful syndrome was controlled with carbamazepine.

Accumulation of midazolam after repeated dosage in patients receiving mechanical ventilation in an intensive care unit

Images

Diabetic thoracic polyradiculopathy presenting as abdominal swelling

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Evaluation of radiculopathies by segmental stimulation and somatosensory evoked potentials

Thirty-six patients with suspected or myelographically proven radiculopathies were investigated with motor and sensory conductions, F-waves, needle electromyography, and somatosensory evoked potentials (SEPs). SEPs were elicited by cutaneous nerve stimulation representative of input from individual cervical and lumbosacral dorsal roots. A myelographic defect was present in 83% of 30 patients who had myelograms. Overall 78% of patients had one or more abnormal electrophysiologic tests, the needle EMG giving the best diagnostic yield (75%). F-waves and SEPs were abnormal in 43% and 57% of cases respectively. Motor deficit correlated best with abnormal EMGs, whilst abnormal SEPs occurred most frequently when sensory deficit predominated. Prolonged latency of the SEP occurred rarely, reduced amplitude or abnormal morphology being the most useful characteristics. SEPs evoked by cutaneous nerve stimulation are a useful addition to conventionally available electrophysiological methods of evaluating radiculopathies, especially in the absence of motor deficit.

Segmental demyelination and remyelination in lumbar spinal roots of patients dying with diabetes mellitus

Morphometric evaluations of histopathological changes in postmortem materials from three patients with diabetes mellitus with neuropathy, nephropathy, and retinopathy were made on the sural nerve, lumbar spinal roots, lumbar dorsal root ganglion (2 cases), and fasciculus gracilis. In all three patients there was a marked decrease in densities of both the large and the small myelinated fibers in the sural nerves. In the lumbar spinal roots, segmental demyelination and remyelination with or without decrease in the number of myelinated fibers per root was the main finding in both dorsal and ventral roots, being more common in the dorsal roots. At the third cervical segment of the fasciculus gracilis, the myelinated fiber density was slightly decreased in one patient and moderately decreased in the other two. The number of cell bodies of the fifth dorsal root ganglion was within normal limits in the two patients where this was examined, although the median diameters approximated the lower limit found in controls. The potential presence of segmental demyelination and remyelination in dorsal and ventral spinal roots should be considered especially when assessing electromyographic changes and nerve conduction in diabetic patients.

Thoracic root pain in diabetes: the spectrum of clinical and electromyographic findings

Diabetic thoracic radiculopathy has been reported rarely. Fifteen new cases, seen in an equal number of patients over a 3-year period and confirmed by electromyographic findings, have been analyzed. All patients presented with severe abdominal or chest pain, which often was not radicular in character. The presence of dysesthesias and an abnormal sensory examination of the trunk aided diagnosis. The pain was frequently associated with marked weight loss but carried a good prognosis for recovery. Six additional patients with negative electromyographic examinations were considered to have the disorder. Diabetic thoracic radiculopathy produces a distinct syndrome and may be more common than is generally recognized.