Paraneoplastic neuromuscular syndromes

Small cell lung carcinoma: staging, imaging, and treatment considerations

Small cell lung carcinoma (SCLC) is the most common primary pulmonary neuroendocrine malignancy and is characterized by a rapid doubling time and high growth fraction. Approximately 60%-70% of patients present with metastatic disease at the time of diagnosis, and their prognosis is poor. However, improved survival has been demonstrated when SCLC is diagnosed early and specific treatment strategies are used. A modified version of the Veterans Administration Lung Cancer Study Group (VALSG) staging system has traditionally been used to categorize SCLC as limited-stage or extensive-stage disease to guide therapy. However, the International Association for the Study of Lung Cancer has recommended that the current seventh edition of the American Joint Committee on Cancer tumor-node-metastasis staging system for lung cancer replace the VALSG system for staging of SCLC. Appropriate staging and patient management require knowledge of imaging manifestations of SCLC across multiple imaging modalities, the strengths and weaknesses of specific examinations, the correlation of these findings with the staging criteria used in clinical practice, and the impact of appropriate staging on patient treatment and survival. Computed tomography (CT) is primarily used to evaluate the primary tumor and the extent of intrathoracic disease. In recent years, however, 2-[fluorine-18]fluoro-2-deoxy-d-glucose positron emission tomography/CT has proved to be more accurate than conventional imaging in the staging of SCLC and can be used to guide therapy and assess treatment response.

Lambert-Eaton myasthenic syndrome and solitary cerebellar metastasis in a patient with occult small-cell lung cancer: a rare experience

The authors describe a case of 60-year-old male patient presented with a 6 month history of progressive weakness of all the four limbs, ataxia, droopy eyelids and bulbar features. Further laboratory and electrodiagnostic studies confirmed the diagnosis of Lambert-Eaton myasthenic syndrome (LEMS). MRI of the brain showed a cerebellar tumour which, following surgery was revealed to be a metastatic small-cell lung carcinoma. Paraneoplastic LEMS together with solitary cerebellar metastasis was diagnosed but no evidence of primary malignancy was detected. An extensive search for related malignancies failed to get any clue. The patient underwent a total surgical excision of tumour and the histopathology revealed a metastatic small cell carcinoma. This case highlights that rarely both paraneoplastic LEMS and cerebellar mass can precede the primary malignancy causing them.

Non-paraneoplastic Lambert-Eaton myasthenic syndrome: a brief review of 10 cases

Lambert-Eaton myasthenic syndrome (LEMS) is an immune-mediated disorder of the presynaptic neuromuscular transmission, which more frequently occurs as the remote effect of a neoplasm, in the paraneoplastic form (P-LEMS), or in a non-paraneoplastic form (NP-LEMS); but few studies describe the clinical features of NP-LEMS. We analyzed the clinical manifestations, laboratory findings, electrophysiological studies, and treatment responses in ten Brazilian patients suffering from NP-LEMS. The mean age was 41.5 years. More often neurological findings were hyporeflexia or areflexia with a post-exercise improvement. Treatment response occurred with pyridostigmine, guanidine, prednisone, azathioprine, and cyclosporine; but not response was observed after intravenous immunoglobulin and plasma exchange. Age at onset, clinical manifestations, and electrophysiological abnormalities can help more in the diagnosis than serum antibodies; the symptomatic treatment with pyridostigmine was effective; and the immunosuppressive treatment with prednisone, azathioprine, or cyclosporine was more beneficial than plasma exchange or intravenous immunoglobulin treatment.

Paraneoplastic motor neuron disease associated with Purkinje cell autoantibody type 1

Motor neuron disease has been reported as a rare result of systemic cancers, likely related to an autoimmune effecter mechanism. These patients have been described as having a more rapid onset of symptoms than typical motor neuron disease. Few of these reports demonstrate an association of a cancer-related autoantibody and with motor neuron disease. We present a 54-year-old woman with infiltrating ductal carcinoma of the breast who later developed lower motor neuron disease and was found to have Purkinje cell autoantibodies type 1. The association of lower motor neuron disease as a consequence of breast cancer with this autoantibody profile has not been described previously. This report emphasizes the importance of considering a paraneoplastic syndrome in a patient with an uncommon presentation of motor neuron disease.

Diagnosis and management of adult patients with chronic intestinal pseudoobstruction

Chronic intestinal pseudoobstruction (CIP) is a motility syndrome that presents with symptoms and signs of intestinal obstruction and radiographic evidence of dilated bowels, but no anatomic obstruction can be found. It primarily is a disorder of small bowel motility, but it can occur anywhere in the gastrointestinal tract. This review will focus on the diagnosis and treatment of adult patients with CIP. The clinical presentation of CIP is variable, and its incidence is rare. It is a disorder with a multitude of etiologies, many of which are poorly understood. To properly manage the patient, clinicians should be aware of the various symptoms, signs, and systemic diseases that are associated with CIP. Diagnostic studies are needed to confirm the diagnosis, identify the etiology, and search for coexisting motility dysfunction. The management goals of CIP are to restore proper nutrition and fluid balance, relieve symptoms, improve intestinal motility, and treat complications.

Neuromuscular complications of cancer

Neuromuscular complications of cancer are common and can affect any component of the peripheral nervous system from peripheral nerve cell body to muscle. Perhaps the most common complication is a length-dependent symmetric axonal polyneuropathy that is often multifactorial in etiology, resulting from metabolic and treatment effects of the primary malignancy. However, neuromuscular disorders may also be the presenting complaint in many conditions, including disorders caused by malignant infiltration of nerve and disorders cause by paraneoplastic syndromes. Although many of the paraneoplastic conditions are poorly responsive to treatment, not all are, and one hopes that prompt diagnosis of the underlying malignancy will lead to improved patient outcome. Recognition of iatrogenic neuromuscular complications is also important to modify treatment protocols when possible and thus decrease the risk of long-term neurologic disability.

Successful immunosuppressant therapy of severe progressive cerebellar degeneration and sensory neuropathy: a case report

A 56 year old woman had a 19 month history of a severe subacute progressive cerebellar degeneration, peripheral sensory neuropathy, and urinary incontinence. She was confined to a wheelchair, needed assistance with eating, and her speech was almost unintelligible. No underlying cancer was found despite repeated investigations, and no autoantibodies were demonstrated. She received a 3-month course of intensive immunosuppressant therapy with intravenous immunoglobulin 400 mg/kg per day for 5 days every month, oral cyclophosphamide 50 mg twice or three times a day to maintain the total lymphocyte count between 500 and 750/mm(3), and prednisone 60 mg per day. She experienced dramatic subjective and objective improvement. The dysarthria and the upper extremity dysmetria disappeared, and she regained the ability to write and cook. The lower extremity ataxia improved and she became able to walk with a cane. Urinary incontinence disappeared. A trial of intensive immunosuppressant treatment is worth considering in a patient with a clinical syndrome resembling paraneoplastic disorders, even if an underlying neoplasm and autoantibodies are not demonstrated.

Bilateral phrenic neuropathy as a presenting feature of multifocal motor neuropathy with conduction block

Diaphragmatic paralysis has previously been reported as a result of diverse pathologic processes involving the peripheral nervous system. We report the clinical history, physical findings, and antibody profile of an atypical case of multifocal motor neuropathy with conduction block initially presenting with respiratory failure secondary to bilateral phrenic neuropathy.