Spotlight on Drug-induced parkinsonism

Despite the development of atypical antipsychotic drugs, parkinsonism is still a common problem among patients treated with these drugs as well as with antiemetics. Because drug-induced parkinsonism frequently produces disability in the elderly, it has replaced tardive dyskinesia as the most significant neurologic complication of antipsychotic drugs in the elderly, increasing the risk of falls and institutionalization. Despite the FDA’s concern about increased mortality with these drugs, carried in a “black box warning,” these drugs are widely used in the elderly, particularly in nursing homes. Aripiprazole is one of the most commonly prescribed drug in the United States, and other neuroleptics are also used in treating major depression and depression in bipolar disorder. Distinguishing purely drug-induced parkinsonism from idiopathic Parkinson disease is often clinically impossible.

In this article, Dr. Joseph Friedman of the Alpert Medical School of Brown University and University of Rhode Island discusses phenomenology, pathophysiology, diagnosis, and treatment.

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Spotlight on Sarcoid neuropathy

Sarcoidosis can involve the peripheral nervous system in a variety of ways. Patients can have a motor, sensory, sensorimotor, or autonomic neuropathy; the neuropathy may be primarily axonal or demyelinating. Patients can have involvement of isolated peripheral nerves, such as an ulnar neuropathy, or generalized involvement. Sarcoidosis is associated with virtually all peripheral neuropathy subtypes, eg, large fiber sensorimotor, pure motor, etc.

In this article, Dr. Jinny Tavee of Northwestern University Feinberg School of Medicine reviews current concepts of sarcoidosis-associated neuropathies. Clinical features, diagnostic considerations, and management strategies are discussed. In particular, the recent literature on sarcoidosis-associated small fiber neuropathy and possible new target-directed treatment options are highlighted. Concepts regarding the use of immunomodulatory agents are also highlighted.

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Spotlight on Schizophrenia

In this article, Dr. Rebekah Jakel of Duke University discusses schizophrenia, a serious and persistent mental illness that has instilled fear, curiosity, and reverence through the ages. This complex condition affects an individual’s grasp on reality, severely limiting the ability to live and work independently. The impact of the schizophrenia extends beyond the individual to families and communities. Schizophrenia is associated with increased morbidity and mortality as well as significant health care costs and resource utilization. The term “schizophrenia” likely encompasses a syndrome with various symptoms and signs that share a common feature of impairment in reality testing.

Current research aims to identify mechanisms to explain the diverse phenotypes observed and to identify and understand possible subtypes. Alterations in the mesolimbic dopaminergic pathways as well as changes in the prefrontal cortex are thought to play a role in pathology. Pharmacological treatments targeting these pathways are the primary intervention; however, research demonstrates the importance of psychosocial treatments in improving function and quality of life. Advances in neurobiology, brain imaging, and genetics have given us a window of understanding into the complexity of schizophrenia. This article aims to provide an understanding of current research into this complex condition.

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Spotlight on Holoprosencephaly

In this updated review of holoprosencephaly, Dr. Joseph Siebert of the University of Washington discusses basic diagnostic anatomical features, pathogenetic and etiologic factors, and genetic, epidemiologic, and other data essential to understanding this complex disorder. Research indicates that the diverse phenotypic variations may stem from a host of genetic mutations and is further suggestive of gene-environment interactions. In severe forms, the disease is lethal. The treatment of patients with less severe forms continues to be refined, but can be substantial.

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Spotlight on Amebic meningoencephalitis

This infection of the central nervous system caused by free-living amoebae is rare but usually lethal. Granulomatous amebic encephalitis is a subacute infection caused by Acanthamoeba species or Balamuthia mandrillaris, with the former occurring almost exclusively immunocompromised patients. In contrast, primary amebic meningoencephalitis is a fulminant infection caused by Naegleria fowleri that most commonly effects healthy children and teenagers. Early diagnosis and prompt treatment with combination antimicrobials has proven lifesaving for what had previously been an almost uniformly fatal disease. In this article, Dr. Karen Bloch of Vanderbilt University Medical Center reviews the clinical presentation and diagnostic evaluation for amebic meningoencephalitis, with an update on new treatment options.

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Spotlight on Alcohol abuse and its neurologic complications

The topic of alcohol abuse related to acute and chronic exposure covers a wide spectrum of neurologic syndromes involving the central and peripheral nervous system. In this article, Dr. Kelly Devers of the University of South Florida and Deputy Chief Medical Examiner for Hillsborough County discusses historical perspectives, clinical manifestations, clinical vignettes, etiology, pathogenesis, pathophysiology, epidemiology, prognosis, complications, and management of this complex disorder of the brain. In addition, Dr. Devers discusses select mechanisms of cellular injury by alcohol.

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Spotlight on Craniopharyngioma

Craniopharyngioma is a rare histologically low-grade (WHO grade 1) suprasellar tumor believed to originate from Rathke s pouch. It occurs in adamantinomatous and papillary subtypes. Consistent with its location, patients experience visual abnormalities, symptoms of increased intracranial pressure, and endocrine dysfunction. If the tumor is favorably located, the most effective treatment is adequate resection.

In this article, the authors present the protean clinical manifestations, suspected pathogenesis, and currently available treatment options for craniopharyngioma, with emphasis on the importance of a multidisciplinary approach. Genetic analysis has shown that adamantinomatous and papillary craniopharyngiomas have distinct tumor biology. Adamantinomatous craniopharyngiomas demonstrate activating mutations in the gene encoding beta-catenin. On the other hand, the majority of papillary craniopharyngiomas harbor the oncogenic BRAF V600E substitution, which can be used as a confirmatory test using immunochemistry and shows promise as targeted therapy in selected patients.

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Spotlight on Myoclonus

In this article, Dr. John Caviness of the Mayo Clinic College of Medicine presents an overview of myoclonus with an emphasis on differential diagnosis, etiology, and treatment.

Myoclonus occurs as a symptom or sign in numerous diseases and conditions, necessitating an organized approach to diagnostic evaluation. Noting the clinical circumstances that surround the myoclonus is key. The first step in focusing on the myoclonus is to determine its category of clinical classification. Subsequent phases of testing can then be added as necessary. The physiological classification of myoclonus compliments the other information for diagnostic purposes. Once the diagnosis is determined, treatment of the underlying cause or symptomatic treatment of the myoclonus can be undertaken. For this update, the author has organized the treatment of myoclonus according to its pathophysiology with new treatment information added. This includes instances where deep brain stimulation or botulinum toxin injection may treat myoclonus.

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Spotlight on Peripheral neuropathies: supportive measures and rehabilitation

Physical and occupational therapies can improve functional capacity in patients with peripheral nerve disorder. In this article, Dr. Yi Pan of St. Louis University Therapeutic and Dr. Florian Thomas of Hackensack University Medical Center discuss exercises, orthoses, devices, and other therapies as the basis for rehabilitation in peripheral neuropathy. Patients should refer to physical and occupational therapists for evaluation and treatment. New orthoses and devices may be available with time to provide more comfort and mobility for patients with peripheral nerve disease.

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Spotlight on Spasmodic dysphonia

Spasmodic dysphonia is a focal laryngeal dystonia. The more common adductor type typically results in strained effortful speech with breaks in phonation. Abductor spasmodic dysphonia generally causes breathy speech with voiceless pauses. The task-specific nature of this condition means that it may normalize with changes in pitch or volume or with other activities, such as laughing or yawning. Several causative genes have been identified in spasmodic dysphonia.

In this article, Dr. Steven Bellows of Baylor College of Medicine discusses risk factors, clinical features, pathophysiology, treatment, and updates on genetic causes.

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