Spotlight on Stroke in young adults

Current epidemiological data suggest that strokes are occurring at a younger age. As many as 1 out of every 6 strokes occurs in a young adult (18 to 50 years old). Heterogeneity in incidence rates, stroke subtypes, and etiology among younger stroke victims in both developed and developing countries is often noted. Certain historical features and clinical manifestations may occasionally serve as clues toward specific stroke etiologies; nevertheless, determination of etiology, particularly of ischemic strokein the young, poses many challenges due to a broad array of potential causes, both common and uncommon.

In this article, Dr. Jorge Moncayo-Gaete of the International University of Ecuador and Dr. Julien Bogousslavsky of the Swiss Medical Network emphasize areas in which the differential diagnosis of stroke and etiologies (including those in pregnancy and puerperium) differs from that in older adults. The authors also note relevant information concerning prognosis of young adults with stroke.

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Spotlight on Mercury neuropathy

Mercury neuropathy is a recognized sequela of occupational or environmental exposure to one of the various forms of the heavy metal. In this article, Dr. Jonathan Rutchik of the University of California at San Francisco discusses common exposure sources, biological exposure indices, and clinical manifestations of mercury toxicity while focusing on mercury neuropathy for elemental, inorganic, and organic mercury. The author has updated this article to reflect the current literature regarding peripheral nervous system disease and this commonly encountered metal.

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Spotlight on Ectopic neurohypophysis

Ectopic neurohypophysis refers to an interrupted or greatly thinned pituitary stalk with ventral displacement of the posterior pituitary. The diagnosis is based on MRI; neuropathological examination to confirm the status of the pituitary stalk is rare because treatment is nonsurgical and autopsy findings are not well documented in this regard and are prone to artifactual disruption even if considered before brain removal.

In this article, Dr. Harvey Sarnat, Dr. Xing-Chang Wei, and Dr. Laura Flores-Sarnat of the University of Calgary and Alberta Children’s Hospital review the neuroimaging features of ectopic neurohypophysis and make clinical, genetic, and pathological correlations. This “incidental finding” in MRI may be associated with cerebral defects, including periventricular nodular heterotopia, holoprosencephaly, septo-optic-pituitary dysplasia, infundibular aplasia, perisylvian syndrome, and other brain anomalies. Associated telencephalic malformations may be epileptogenic. Panhypopituitarism or isolated growth hormone deficiency are frequent; diabetes insipidus is rare. The etiology is genetic.

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Spotlight on Colloid cysts

Colloid cysts are benign intraventricular lesions that may present with a variety of neurologic symptoms, most commonly headache from obstructive hydrocephalus. Dr. Matthew Tate of Northwestern University discusses the clinical presentation, diagnosis, and management of colloid cysts. In particular, data regarding management of asymptomatic colloid cysts as well as comparison of risks/benefits of different surgical techniques are discussed.

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Spotlight on Atypical absence seizures

Atypical absences are epileptic seizures that occur in children with severe learning and neurologic disabilities of epileptic encephalopathies, mainly, Lennox-Gastaut syndrome. They are distinct from typical absences in that onset and termination is slow, impairment of consciousness is mild, and they are often associated with significant tone disturbances. The ictal EEG shows diffuse spike waves that are slower than the typical absence, usually between 1.5 and 2.5 Hz. Patients with atypical absences also suffer from concurrent tonic, atonic, and other types of epileptic seizures according to the primary epileptic syndrome. Management is usually difficult, and prognosis is that of the underlying disorder.

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Spotlight on Headache associated with intracranial infection

In this article, Dr. Jong-Ling Fuh of Taipei Veterans General Hospital and National Yang-Ming University School of Medicine discusses headache associated with intracranial infection. Headache is usually the first and most frequently encountered symptom in intracranial infection, but it only accounts for less than 1% of acute headache presentation to the emergency department.

Encephalitis is characterized by headache, fever, alteration of consciousness, focal neurologic deficit, and seizures (usually focal). Because the brain parenchyma has no sensory receptors, the headache of encephalitis and brain abscess may result from the meningeal inflammation that often accompanies these processes, including a nonspecific response to fever, increased intracranial pressure, or a mass-effect producing traction on pain-sensitive intracranial structures.

The most common predisposing conditions of brain abscesses are otitis or mastoiditis. Physical signs of meningeal inflammation do not help clinicians rule in or rule out meningitis accurately. Headache remits with resolution of the infection in most cases, and headache might persist for more than 3 months after resolution of the causative infection in only a few patients. However, one longitudinal study showed that the 1-year prevalence of headache suffering was not higher amongst patients with prior intracranial infection than in the general population.

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Spotlight on Tuberculosis of the CNS

The frightening appearance of multidrug-resistant tuberculosis has focused new attention on this ancient human scourge. Although tuberculosis remains a common infectious disorder in the underdeveloped and developing world, immigration has resulted in an increased frequency in developed countries.

In this article, Dr. Joseph Berger of the Perelman School of Medicine, University of Pennsylvania, describes the large number of neurologic complications, particularly tuberculous meningitis, that occur with this micro-organism. In developed countries, tuberculous infection is often unsuspected, and a high level of suspicion is required to establish the diagnosis. Cultures of CSF are time consuming and, therefore, of little diagnostic value at the time of presentation. However, polymerase chain reaction for M tuberculosis is now widely employed to assist in early diagnosis. Corticosteroid therapy, although controversial, is increasingly employed as an adjunctive therapy to decrease the complications that attend tuberculous meningitis.

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Spotlight on Multiple sclerosis: biological differences in children and adults

In this article, Dr. Susan Kim of the Sacramento VA Medical Center and Dr. Mark Agius of Barrow Neurological Institute discuss the particular concerns for children as compared to adults with multiple sclerosis.

The behavior of the immune system in children with multiple sclerosis appears to parallel that in children with other chronic inflammatory diseases. Children with multiple sclerosis represent a group in whom a strategy of induction of remission and maintenance of remission is likely to prevent long-term disability. The developing nervous system is a particularly susceptible target of the immune system. At the same time, the potential for enhanced neural plasticity in children provides a unique opportunity for functional recovery along with long-term disability prevention.

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Spotlight on Vitamin B12 deficiency

B12 deficiency may cause an extraordinary variety of progressive neurologic syndromes. In this article, Dr. Ryan Jacobson of Loyola University Chicago Stritch School of Medicine describes the well-established manifestations of B12 deficiency as well as more controversial associations with macular degeneration, cerebrovascular disease, and dementia. In addition, although severe B12 deficiency has long been known to cause severe developmental delay, this update includes emerging information suggesting that a relative B12 deficiency may cause a common metabolic syndrome in infancy that is potentially linked to subtle developmental problems.

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Spotlight on Cerebral venous thrombosis in infants and children

In this article, Dr. Mahendranath Moharir and Dr. Gabrielle deVeber of the University of Toronto discuss cerebral sinovenous thrombosis. The condition is often unrecognized in neonates and children due to nonspecific clinical features and challenges in radiographic diagnosis. Risk factors for cerebral sinovenous thrombosis in neonates are different from those in older children. Treatment with anticoagulants, a well-established practice in adults, is increasingly offered in children and, to a lesser extent, in neonates. The safety of anticoagulants and recanalization outcomes in cerebral sinovenous thrombosis has been established in children as well as in neonates based on consecutive cohort studies; however, its influence on neurologic outcome, particularly in neonates, has not been proven. The clinical outcome from cerebral sinovenous thrombosis remains worse in neonates than in children.

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