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

Review article: Abdominal pain and diabetes mellitus in the emergency department

This manuscript seeks to describe diagnostic considerations in individuals with diabetes mellitus presenting to the ED with abdominal pain. It highlights the importance of early investigation with computerised tomography to differentiate aetiologies that compel early surgical intervention from those which may be treated conservatively.

A Comprehensive Review of Neuronal Changes in Diabetics

There has been an exponential rise in diabetes mellitus (DM) cases on a global scale. Diabetes affects almost every system of the body, and the nervous system is no exception. Although the brain is dependent on glucose, providing it with the energy required for optimal functionality, glucose also plays a key role in the regulation of oxidative stress, cell death, among others, which furthermore contribute to the pathophysiology of neurological disorders. The variety of biochemical processes engaged in this process is only matched by the multitude of clinical consequences resulting from it. The wide-ranging effects on the central and peripheral nervous system include, but are not limited to axonopathies, neurodegenerative diseases, neurovascular diseases, and general cognitive impairment. All language search was conducted on MEDLINE, COCHRANE, EMBASE, and GOOGLE SCHOLAR till September 2021. The following search strings and Medical Subject Headings (MeSH terms) were used: "Diabetes Mellitus," "CNS," "Diabetic Neuropathy," and "Insulin." We explored the literature on diabetic neuropathy, covering its epidemiology, pathophysiology with the respective molecular pathways, clinical consequences with a special focus on the central nervous system and finally, measures to prevent and treat neuronal changes. Diabetes is slowly becoming an epidemic, rapidly increasing the clinical burden on account of its wide-ranging complications. This review focuses on the neuronal changes occurring in diabetes such as the impact of hyperglycemia on brain function and structure, its association with various neurological disorders, and a few diabetes-induced peripheral neuropathic changes. It is an attempt to summarize the relevant literature about neuronal consequences of DM as treatment options available today are mostly focused on achieving better glycemic control; further research on novel treatment options to prevent or delay the progression of neuronal changes is still needed.

Neurological Causes of Chest Pain

PURPOSE OF REVIEW

Chest pain is a very common presenting complaint among patients in the hospital, a large proportion of whom have non-cardiac chest pain (NCCP). Neurological causes of NCCP have not been previously reviewed although several causes have been identified.

RECENT FINDINGS

Chest pain has been reported as a symptom of multiple neurological conditions such as migraine, epilepsy, and multiple sclerosis, with varying clinical presentations. The affected patients are often not formally diagnosed for long periods of time due to difficulties in recognizing the symptoms as part of neurological disease processes. This paper will briefly summarize well-known etiologies of chest pain and, then, review neurological causes of NCCP, providing an overview of current literature and possible pathophysiologic mechanisms.

Diabetic thoracic radiculopathy: a case of a young woman with clinical improvement following immunotherapy

Thoracic radiculopathy is a rare cause of thoracic-abdominal or abdominal pain in subjects with poorly controlled diabetes. We present a case of a young woman with type I diabetes and a severe abdominal pain in both lower quadrants. An extensive diagnostic gastroenterological and gynaecological workup did not disclose abnormalities. Electromyography revealed an initial polyneuropathy and significant neurogenic abnormalities in the T10-T12 paravertebral muscles. Following the hypothesis that the radiculopathy-related abdominal pain might have an immuno-mediated pathogenesis, the patient underwent a complex trial of immunotherapy, which was accompanied by a sustained improvement over months to full recovery. This report would support the hypothesis that immune-mediated mechanisms are still active even months after onset of symptoms.

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.

Diabetic neuropathy

Neuropathies related to diabetes mellitus can affect 60-70% of patients with diabetes. These can include peripheral polyneuropathies, mononeuropathies, and autonomic neuropathies. Control of glucose, lipids, and hypertension and cessation of smoking can limit onset and progression of these neuropathies. Besides control of the above listed risk factors, we do not have effective medications to treat the pathophysiologic mechanisms of diabetic neuropathies. Treatment is limited to ameliorating pain and correcting the end organ consequences of the neuropathic processes.

Neurologic infections in diabetes mellitus

Even at a time when HIV/AIDS and immunosuppressive therapy have increased the number of individuals living with significant immunocompromise, diabetes mellitus (DM) remains a major comorbid disorder for several rare but potentially lethal infections, including rhino-orbital-cerebral mucormycosis and malignant external otitis. DM is also a commonly associated condition in patients with nontropical pyomyositis, pyogenic spinal infections, Listeria meningitis, and blastomycosis. As West Nile virus spread to and across North America over a decade ago, DM appeared in many series as a risk factor for death or neuroinvasive disease. More recently, in several large international population-based studies, DM was identified as a risk factor for herpes zoster. The relationships among infection, DM, and the nervous system are multidirectional. Viral infections have been implicated in the pathogenesis of type 1 and type 2 DM, while parasitic infections have been hypothesized to protect against autoimmune disorders, including type 1 DM. DM-related neurologic disease can predispose to systemic infection - polyneuropathy is the predominant risk factor for diabetic foot infection. Because prognosis for many neurologic infections depends on timely institution of antimicrobial and sometimes surgical therapy, neurologists caring for diabetic patients should be familiar with the clinical features of the neuroinfectious syndromes associated with DM.

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.

The spectrum of diabetic neuropathies

Diabetes mellitus is associated with many different neuropathic syndromes, ranging from a mild sensory disturbance as can be seen in a diabetic sensorimotor polyneuropathy, to the debilitating pain and weakness of a diabetic lumbosacral radiculoplexus neuropathy. The etiology of these syndromes has been studied extensively, and may vary among metabolic, compressive, and immunological bases for the different disorders, as well as mechanisms yet to be discovered. Many of these disorders of nerve appear to be separate conditions with different underlying mechanisms, and some are caused directly by diabetes mellitus, whereas others are associated with it but not caused by hyperglycemia. This article discusses a number of the more common disorders of nerve found with diabetes mellitus. It discusses the symmetrical neuropathies, particularly generalized diabetic polyneuropathy, and then the focal or asymmetrical types of diabetes-associated neuropathy.

"A girdle-like tightening sensation" misapprehended as abdominal splanchnopathy in a sarcoidosis patient

We describe a 53-year-old man with the isolated manifestation of girdle-like tightening sensation of the trunk due to polyradiculopathy at the beginning of sarcoidosis which was first misapprehended as abdominal splanchnopathy. Late development of other neurological and systemic symptoms led to the final diagnosis of sarcoidosis. Segmental dysesthesia at the trunk in neurosarcoidosis is unique and may mimic a splanchnic pain. Such a dysesthesia may be solely manifested at the beginning of sarcoidosis and may continue for days without other symptoms. When patients complain of a girdle-like tightening with unknown etiology, sarcoidosis should be suspected as the possible cause.

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.

Electrophysiology of radiculopathies

The anatomy, pathophysiology, and clinical evaluation of radiculopathies are discussed. Defining whether root injury is present and which roots are involved can be difficult but critical for patient management. In conjunction with clinical and radiological information, studies that establish physiological abnormalities of roots should be helpful and important. Clinical neurophysiological studies for radiculopathies are performed frequently but have yet to achieve a universally accepted role in the evaluation of these patients. Electrophysiological techniques for the evaluation of radiculopathies are reviewed. Needle electromyography is the best established of these procedures but has the disadvantage of requiring injury to motor fibers of both a certain degree and distribution. Nerve conduction studies may rarely be abnormal in radiculopathies but are needed to be certain other conditions that may produce similar symptoms and signs are not present. H reflexes and F waves probably have roles in the evaluation of radiculopathies but published reports about F waves in radiculopathies have been marred by inadequate methodology. There is evidence based on large series of patients that somatosensory evoked potentials can be helpful for evaluating patients with multilevel injury such as spinal stenosis, patients where electrophysiological studies may have their greatest clinical utility. Further work using either electrical stimulation with needles or magnetic stimulation of roots seems warranted. The demonstration of meaningful electrophysiological changes with activities that reproduce radicular symptoms may be a promising experimental approach. Available information does not necessarily answer critical questions about the role of electrophysiology in patients with radiculopathies. This cannot be done using analyses based on current ideas about evidence based medicine given the absence of a 'gold standard' for defining radiculopathies as well the absence of blinded studies. The available information provides strong arguments for further investigations evaluating different clinical neurophysiological techniques in the same patient, and for evaluating the value of these techniques by concentrating on their clinical import.

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.

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.

Neuropathies associated with diabetes

Diabetic neuropathy is the most frequent complication of diabetes and the leading cause of polyneuropathy in the Western world. A distal symmetric predominantly sensory polyneuropathy is the most common of the diverse neuropathies that occur secondary to diabetes. Pain is often the most bothersome and difficult to treat symptom of diabetic neuropathy. Autonomic neuropathy is a frequent feature of diabetic neuropathy and the source of many significant problems including postural hypotension, gastroparesis, diarrhea, constipation, neurogenic bladder, and male impotence. Physicians need to be familiar with the multiple, less common forms of diabetic neuropathy, as these often mimic other medical or neurologic conditions. The cause of diabetic neuropathy is not determined, but abundant evidence suggests that both metabolic and ischemic nerve injury are likely factors. These should not be considered mutually exclusive causes of diabetic neuropathy as both factors likely operate to different degrees to produce the clinical spectrum of neuropathies that are seen in diabetes. Although no effective treatment exists to cure diabetic neuropathy, improvement is possible with glycemic control and symptomatic therapy.

Diabetic neuropathy. Helping patients cope with their pain

Diabetic neuropathy may have a metabolic or an ischemic origin, and the pattern of nerve damage varies by cause. Treatment should address the underlying cause. Patient reassurance, relaxation techniques, glucose control, use of tricyclic antidepressants or anticonvulsants, and surgical decompression for entrapment neuropathy are currently the mainstays of treatment. Physicians must reassure these patients that neuropathic pain is temporary.

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.

Assessment of thoracic paraspinal muscles in the diagnosis of ALS

The distribution of muscle involvement, assessed clinically and electromyographically, was analyzed prospectively in 55 consecutive amyotrophic lateral sclerosis (ALS) patients and in 54 patients with other predominantly motor syndromes, some of whom were referred with suspected ALS. In ALS patients, distal limb muscles and thoracic paraspinal muscles were affected most frequently, more so than proximal limb and cranial muscles. The incidence of bulbar symptoms in ALS was greater in women than in men. These patterns suggest selective vulnerability of specific neuronal populations. The vulnerability of truncal muscles, illustrated by thoracic paraspinal wasting or head and shoulder drooping, was a helpful differential sign in diagnosing ALS. Thoracic paraspinal electromyography was especially valuable in distinguishing ALS from other disorders, such as combined cervical and lumbar spondylotic amyotrophy or polymyositis, which may masquerade as ALS. The finding of denervation atrophy on biopsy of thoracic paraspinal muscles was diagnostic in difficult cases. Because the thoracic paraspinal muscles are frequently affected in ALS and spared in spondylotic amyotrophy, their assessment provides a practical strategy in differentiating ALS from other motor syndromes.

Proximal sensory conduction in diabetic patients

A study of segmental conduction along the peripheral afferent pathway of the upper limbs was carried out in 44 diabetic patients and 44 controls. An abnormal proximal conduction (Erb-cervical) was observed in 9 patients (20.4%). A similar incidence of abnormalities appeared at the most distal segment (digit III-wrist). A significant relationship between the alterations of proximal conduction and the presence of clinical signs of diabetic polyneuropathy was found. A common pathogenic mechanism underlying both these disorders is suggested.

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

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Diabetic thoracic polyradiculopathy presenting as abdominal swelling

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