The Remote Effects of Cancer on the Nervous System

Autoimmune encephalitis: a potentially treatable cause of mental disorder

Autoimmune encephalitides can present with altered mental states, particularly psychosis and delirium. Psychiatrists need to be particularly vigilant in cases of first-episode psychosis and to look out for other, sometimes subtle, features of encephalitis. Encephalitis related to N-methyl-d-aspartate (NMDA) receptor autoantibodies is the most common autoimmune cause of isolated psychosis, the second being related to voltage-gated potassium channel (VGKC)-complex antibodies. Psychiatrists should note ‘red flag’ signs of seizures, autonomic instability, movement disorders and sensitivity to antipsychotic medication (including neuroleptic malignant syndrome). They should also be aware that, in some cases, encephalitis is a non-metastatic manifestation of malignancy. Treatment primarily involves suppression of immunity and is often successful if delivered early. There is accumulating evidence that isolated psychiatric syndromes can be caused by autoimmunity and this could potentially signal a significant change in the approach to disorders such as schizophrenia. Psychiatrists and neurologists need to work together to diagnose, manage and understand this group of conditions.

LEARNING OBJECTIVES

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Myasthenia Gravis in a Child with Sequelae of Opsoclonus-Myoclonus Syndrome

Immune-mediated myasthenia gravis occurred in a 13-month-old girl who had sequelae of an opsoclonus-myoclonus syndrome. She had an abnormal Raji cell assay along with elevated antiacetylcholine receptor and antithyroglobulin antibodies. No evidence of an associated malignancy was found with either condition. Clearly, the co-occurrence of two diseases within a single patient does not establish a common pathogenesis. Nevertheless, this is a provocative association and may point to an immunologically mediated process in the opsoclonus-myoclonus syndrome.

Progressive ataxic gait disorder

Paraneoplastic cerebellar degeneration (PCD) is a well-described paraneoplastic syndrome. In patients with anti-Yo associated PCD, neurological symptoms precede the diagnosis of the underlying cancer in approximately 60% of cases. Ovarian, breast and other gynaecological malignancies are most frequently found as causative malignancies. Antitumour treatment should be commenced at an early stage of the disease. Identification of the tumour is a diagnostic challenge in many of these patients. In the case reported herein, a secondary tumour with unknown primary was suggested after detection of a pathological lymph node in the right axilla by a positron emission tomography scan. Microscopic examination of the ultrasound-guided resected tissue was a poorly differentiated adenocarcinoma strongly positive for the C-ERB 2 oncoprotein. A micro-invasive mammary carcinoma was unable to be localized, even with the aid of magnetic resonance mammography and axillary clearance. Intravenous gamma-globulin and steroid treatment and rehabilitation failed to influence the neurological symptoms. The present patient also demonstrated diffuse increase on the T2 signal in the cerebellum, which may provide a useful diagnostic clue in the assessment of PCD.

Delirium

BACKGROUND

Delirium is a serious and often undetected neuropsychiatric syndrome. Failure to recognize and manage delirium can lead to longer hospital stays and increased morbidity and mortality, especially among the elderly.

REVIEW SUMMARY

This article reviews definitions and diagnosis. The Diagnostic and Statistical Manual of Mental Disorders, 4th edition, and the International Statistical Classification of Diseases and Related Health Problems, 10th edition, criteria are quite similar in their diagnostic criteria. Risk factors include advanced age, preexisting brain disease or cognitive impairment, multiple medications, and severe medical problems. Delirium in the elderly can be more subtle and recovery more prolonged. Diagnosis is more complex if there is already an underlying dementia. An organized approach should be used to discover etiology and in ordering appropriate laboratory studies. At the cellular level, delirium is considered to be a reversible disregulation of neuronal membrane function. This involves a selective vulnerability of certain populations of neurons and neurotransmitter dysfunction. Practical treatment issues are reviewed.

CONCLUSIONS

Despite advances, delirium is usually still diagnosed at the bedside. Having an organized approach to diagnosis and understanding the underlying pathophysiology should help with overall evaluation and treatment.

Anti-Ri-associated paraneoplastic opsoclonus-ataxia syndrome in a man with transitional cell carcinoma

BACKGROUND

There are several case reports describing paraneoplastic syndromes in patients with various forms of bladder carcinoma. Current immunologic analyses have enabled the identification of the antineuronal autoantibodies associated with specific syndromes.

METHODS

A patient with a history of bladder carcinoma presented with opsoclonus and myoclonus.

RESULTS

Workup confirmed the presence of anti-Ri antibodies in the patient's serum and cerebrospinal fluid. The target Ri antigen was found to be expressed by the tumor.

CONCLUSIONS

To the authors' knowledge, there are few reports in the literature describing the long-term clinical follow-up and postmortem evaluation in a patient with this form of paraneoplastic syndrome. More important, the authors believe the current study represents the first time that the presence of anti-Ri antibodies has been noted in a paraneoplastic syndrome associated with transitional cell carcinoma of the bladder.

Neurological sequelae of the dancing eye syndrome

Fifty-four patients with dancing eye syndrome (DES), presenting over a 25-year period, were reviewed retrospectively. One third of them were on active follow up at the time of the study. Malignancy was uncommon, diagnosed in only 4 patients, neuroblastoma in 3 cases and acute lymphoblastic leukaemia (ALL) in 1. An intercurrent illness preceded onset of DES in 51% of the children and was of equivocal significance. There was no clear temporal relationship to immunization. The acute phase of the illness was severe and caused total immobilization in 88% of patients. A favourable initial response to treatment with prednisolone or corticotrophin gel was observed in all patients. Although corticotrophin seemed to produce a more rapid response, overall improvement was similar with both treatments. Long-term neurological morbidity was a major problem with 91% of children suffering either persisting symptoms or repeated relapses. A persisting disability was found in 88% and was considered severe in 61% of patients. No features prognostic of neurological severity or outcome were identified.

CONCLUSION

Demonstrable malignancy is uncommon in the dancing eye syndrome. The neurological legacy of DES is often evident well into adult life.

Opsoclonus myoclonus syndrome secondary to Epstein-Barr virus infection

We report the first two children to have the "opsoclonus myoclonus syndrome" after a serologically confirmed acute Epstein-Barr virus infection. Although opsoclonus was absent in one patient, both patients had all other features typical of this syndrome. Patients without opsoclonus have been described as having an isolated postinfectious myoclonus syndrome but probably lie within the spectrum of opsoclonus myoclonus syndrome. The prognosis for the opsoclonus myoclonus syndrome in children with Epstein-Barr virus infection and without evidence for a neuroblastoma appears to be better than in those patients where a cause cannot be identified.

Paraneoplastic manifestations in children

Paraneoplastic manifestations are signs and symptoms observed in patients with cancer, distant from the tumour or its metastases and not caused by invasion, obstruction or bulk mass. In children with cancer, paraneoplastic manifestations are rare and distinct from those observed in adults. Knowledge about paraneoplastic manifestations can be of great clinical importance because they may be the presenting sign of a tumour or its recurrence and hence facilitate early diagnosis. In contrast, they sometimes mask the symptoms of a tumour and cause diagnostic delay. In this review, paraneoplastic manifestations in children are described, including hypercalcaemia, Cushing syndrome, precocious puberty, opsoclonus/myoclonus, acquired von Willebrand disease, watery diarrhoea syndrome, and hypertension. The mechanisms causing these manifestations are also discussed.

Anti-Hu antibody in a neuroblastoma-associated paraneoplastic syndrome

A 20-month-old infant with Turner syndrome presented with opsoclonus-myoclonus and tonic pupils in association with an abdominal neuroblastoma. Despite complete removal of the tumor, the child developed progressive hearing loss, areflexia, and seizures. Immunohistochemical and Western blot studies of serum and cerebrospinal fluid revealed the presence of anti-Hu antineuronal antibody, which cross-reacted with areas of the patient's tumor. Treatment with intravenous immunoglobulin coincided with the resolution of opsoclonus-myoclonus and the cessation of new neurologic symptoms. This case provides direct support for the autoimmune basis of paraneoplastic symptoms associated with neuroblastoma and suggests that treatment with intravenous immunoglobulin may be of value.

[Acute idiopathic sensory neuropathy: a case report]

Pure sensory neuropathies are clinically characterized by paresthesias, sensory ataxia and areflexia without muscle weakness. We report the case of a 21 years-old female patient with acute onset of distal paresthesias, marked sensory ataxia and hyporeflexia. Motor strength was normal. Sensory nerve conduction was absent and motor nerve conduction slightly decreased. CSF showed 2 leucocytes/mm3 and 1.06 g/dL protein. Collagen disorder and neoplasia were not found. Type 2 fiber atrophy was observed on muscle biopsy, and axonal demyelination on sural nerve biopsy. The patient was treated with prednisone. After 1.5 years she was recovered, but a minor proprioceptive deficit persisted. A revision is made on the etiology, pathophysiology and clinical manifestations of the disease.

Case-of-the-month: perineuritis presenting as mononeuritis multiplex

Perineuritis unassociated with other significant pathological changes is a rare finding. A patient is described with mild, non-insulin dependent diabetes mellitus who presented with the clinical picture of mononeuritis multiplex, and in whom perineuritis but no occlusive vascular disease was found on sural nerve biopsy. Treatment with prednisone and plasma exchange resulted in some improvement. We conclude that the focal perineuritis, rather than the diabetes, was responsible for the clinical picture mimicking mononeuritis multiplex. In conjunction with previous reports, this suggests that perineuritis may be a treatable neuropathy.

Opsoclonus-myoclonus with Beckwith-Wiedemann syndrome and hepatoblastoma

The association between Beckwith-Wiedemann syndrome and hepatoblastoma is well established and relatively commonplace. The occurrence of opsoclonus-myoclonus syndrome in individuals with occult neoplasia is also well documented. However, the development of opsoclonus-myoclonus syndrome in an infant with Beckwith-Wiedemann syndrome and hepatoblastoma has not been reported previously. The list of underlying causes of opsoclonus-myoclonus syndrome should be expanded to include hepatoblastoma, particularly in any child with features suggestive of Beckwith-Wiedemann syndrome.