Syndrome of opsoclonus-myoclonus in hyperosmolar nonketotic coma

Movement disorders in patients with diabetes mellitus

Movement disorders are not infrequent in patients with diabetes mellitus. These may occur on the basis of both central and peripheral nervous system dysfunction and can be secondary to severe hyperglycemia, complications of diabetes or its treatment and less often to diseases in which both diabetes and a movement disorder are primary manifestations of the same underlying disease. We present a typical case of a severe movement disorder complicating diabetes as a springboard to review the spectrum of disorders associated with this condition.

An update on opsoclonus

PURPOSE OF REVIEW

The aim of this article is to review opsoclonus, with particular emphasis on its immunopathogenesis and pathophysiology.

RECENT FINDINGS

Infections (West Nile virus, Lyme disease), neoplasms (non-Hodgkin's lymphoma, renal adenocarcinoma), celiac disease, and allogeneic hematopoietic stem cell transplantation can cause opsoclonus. Newly identified autoantibodies include antineuroleukin, antigliadin, antiendomysial, and anti-CV2. Evidence suggests that the autoantigens of opsoclonus reside in postsynaptic density, or on the cell surface of neurons or neuroblastoma cells (where they exert antiproliferative and proapoptotic effects). Most patients, however, are seronegative for autoantibodies. Cell-mediated immunity may also play a role, with B and T-cell recruitment in the cerebrospinal fluid linked to neurological signs. Rituximab, an anti-CD20 monoclonal antibody, seems efficacious as an adjunctive therapy. Although changes in synaptic weighting of saccadic burst neuron circuits in the brainstem have been implicated, disinhibition of the fastigial nucleus in the cerebellum, or damage to afferent projections to the fastigial nucleus, is a more plausible pathophysiologic mechanism which is supported by functional magnetic resonance imaging findings in patients.

SUMMARY

There is increasing recognition that both humoral and cell mediated immune mechanisms are involved in the pathogenesis of opsoclonus. Further studies are needed to further elucidate its immunopathogenesis and pathophysiology in order to develop novel and efficacious therapy.

Opsoclonus-myoclonus syndrome with abnormal single photon emission computed tomography imaging

The single photon emission computed tomography (SPECT) findings in 2 patients with opsoclonus-myoclonus syndrome (OMS) who had similar symptoms in the acute stage of the disease are described. In 1 patient with encephalitis, SPECT showed increased blood flow in most of the cerebellum; the highest accumulation of the radiotracer was found in the cerebellar vermis and neighboring structures. These changes disappeared with clinical improvement. In the other patient with chronic OMS, SPECT demonstrated hypoperfusion in most of the cerebellum. Our results suggest that the cerebellum, particularly its middle portion, is involved in the generation of OMS. SPECt is a useful method that enables us to detect in vivo functional impairment in patients with OMS.

The movement disorder of adult opsoclonus

We present three cases of the adult opsoclonus-myoclonus syndrome in patients with systemic carcinoma. In addition to opsoclonus and myoclonus, other clinical components of the syndrome can include ataxia, tremor, gait and stance dysfunction, altered mental status, and head and face dyskinesias. The most common etiologies are idiopathic, paraneoplastic, and infectious encephalitis. Radiographic and pathological studies suggest brain-stem dysfunction with associated cerebellar and/or cerebellar pathway dysfunction. In many cases, there is evidence for the involvement of immunologic and/or inflammatory processes in the pathogenesis of this syndrome. The timely recognition of this syndrome is important because of its implications for the underlying etiology and prognosis. The appearance of this syndrome should prompt the search for an occult malignancy.

Myoclonic encephalopathy of infancy: a 10 year review

Myoclonic encephalopathy of infancy (MEI) is a unique cause of acute ataxia in infants and is a rare presentation of neuroblastoma. Five cases presenting to a tertiary referral children's hospital during a 10 year period are reviewed. Two cases were associated with a neuroblastoma. All children were treated with intramuscular injections of adrenocorticotropic hormone, with symptomatic improvement. One child died from an opportunistic infection following chemotherapy for neuroblastoma. The four survivors have mild to moderate clinical and intellectual deficits. Investigation and continuing observation for occult neural crest tumours is emphasized for all cases of MEI, though no underlying cause was found in 60% of children in this study.

Transient opsoclonus in organophosphate poisoning

Opsoclonus transiently occurred in the acute stage of combined parathion and methyl-parathion poisoning. Despite persistent cholinesterase inhibition this symptom subsided spontaneously. This observation provides strong evidence for cholinergic pathways being reversibly involved in isolated opsoclonus.

Nervous system dysfunction in children with paraneoplastic syndromes

Paraneoplastic syndromes are complexes of symptoms and signs that occur in association with cancer and that are unexplained by the known anatomic and physiologic characteristics of the tumor. Many of these syndromes are neurologic in nature or have consequences for the central or peripheral nervous system. These syndromes have been well characterized in adults. With the exception of opsoclonus-myoclonus, little has been written about the occurrence of such syndromes in children. This review looks at published reports of paraneoplastic syndromes in children and concludes that paraneoplastic syndromes in childhood differ from those seen in adulthood because of differences in both the host and the kinds of neoplasms most prevalent in each age group. Paraneoplastic syndromes may be underreported in childhood because of the difficulty in eliciting specific neurologic complaints from children and because a thorough neurologic examination is often not undertaken as a matter of routine.

Opsoclonus-ataxia due to childhood neural crest tumors: a chronic neurologic syndrome

Five children with subacute or acute onset of cerebellar ataxia and opsoclonus are described. Two had cerebrospinal fluid pleocytosis at the onset of ataxia and were initially thought to have acute parainfectious cerebellar ataxia of childhood. All were found to have tumors of neural crest origin (two neuroblastomas, three ganglioneuroblastomas). Tumors were small and only found by computed tomographic techniques. Urinary catecholamine metabolites were elevated in only two of the patients. Four of the five failed to improve neurologically with resection of the tumor. All four have had a steroid-sensitive chronic ataxic syndrome that worsens with acute nonspecific illnesses and has resulted in long-term deficits, particularly in speech and gross motor function. This is a metabolic encephalopathy associated with permanent residual neurologic deficits but without visible lesions on neuroimaging studies. We stress the frequency of cerebrospinal fluid pleocytosis in patients with tumor-associated opsoclonus and the clinical difficulty in separating tumor-associated cases from those due to other causes [corrected].

Opsoclonus-myoclonus syndrome: correlation of radiographic and pathological observations

We report a case of a child with opsoclonus-myoclonus syndrome. Neuroradiological studies indicated a lesion in the cerebellar vermis. A cerebellar biopsy revealed changes consisting of Purkinje and granular cell loss with gliosis. This case report documents the correlation of radiologic and pathological findings in a patient with opsoclonus-myoclonus syndrome.

Movement disorders as a manifestation of nonketotic hyperglycemia

Movement disorders are well-known presenting signs of metabolic disorders. Focal motor abnormalities may be the chief initial presentation of diabetes mellitus in the nonketotic hyperglycemic state in 6% of patients. Nonketotic hyperglycemia (NKH), in particular, may manifest any of a wide variety of movement disorders. These have been described as focal seizures, epilepsia partialis continua, myoclonus, and opsoclonia. There are descriptions of movement disorders in hyperglycemia that are similar to the coarse flapping tremor of asterixis, the posturing of paroxysmal kinetogenic choreoathetosis, and of "fencing (stance) seizures." Disorders of facial motor function including aphasia, facial muscle twitching and jerking, and disorders of muscular tone have been described. These may include hemiparesis and hemiplegias as well as increased tone, in some cases mimicking the nuchal rigidity of meningitis. The movement disorders in NKH may mimic cerebral vascular accidents, meningitis, or psychiatric disorders, as well as various types of seizures. Clinicians may be able to avoid expensive and time-consuming diagnostic evaluations to rule out NKH in patients with movement disorders. We present two patients with focal motor abnormalities associated with nonketonic hyperglycemia and review the pertinent literature.