Diagnosis of delirium: a practical approach.

Delirium is an acute disorder of fluctuating attention and awareness with cardinal features that allow it to be positively distinguished from other causes of an acute confusional state. These features include fluctuations, prominent inattentiveness with other cognitive deficits, a change in awareness and visual hallucinations. We describe a framework for diagnosing delirium, noting the need to consider certain caveats and differential diagnoses. Delirium is a clinical diagnosis where a thorough history and clinical examination are much more helpful diagnostically than any single test or combination of tests.

Training in neurology: lessons learnt.

There is no consensus on how to structure and deliver neurology training. The General Medical Council's annual National Training Survey indicates that the quality of UK neurology training is very variable, but does not explain this variation. We used the survey data to identify the four highest and lowest performing sites for neurology training across the UK. We conducted semistructured interviews with groups of local trainees and, separately, local trainers in an exploratory qualitative study, and identified common themes across a range of aspects of neurology training. Here we present our findings, share case studies from top-performing sites and make recommendations on how best to train a neurologist.

Guillain-Barré syndrome with exaggerated pleocytosis and anti-GM1 ganglioside antibodies.

An 81-year-old man presented with fever, confusion and rapidly-progressive flaccid tetraparesis. Clinical presentation and neurophysiology were consistent with a severe axonal polyneuropathy. Anti-GM1 and Campylobacter serology were both positive, consistent with postinfectious axonal-variant Guillain-Barré syndrome (GBS). GBS is characterised by albuminocytological dissociation, where an elevated protein and acellular cerebrospinal fluid are typical. However, in this case, CSF analysis revealed an exaggerated pleocytosis (72 white blood cells (WBC)/mm3). No source of central nervous system infection or inflammation was identified despite thorough investigation. The patient was treated with intravenous immunoglobulin and intensive rehabilitation.Albuminocytological dissociation classically distinguishes GBS from infective causes of flaccid weakness (eg, enteroviruses, flaviviruses and HIV). Diagnostic criteria frequently cite a pleocytosis of <50 WBC/mm3 as required in the diagnosis of GBS. However, this case demonstrates that pleocytosis exceeding this level can occur in the presence of convincing evidence of GBS and without demonstrable neurotropic infection.

Rheumatoid disease: an unusual cause of relapsing meningoencephalitis.

A 73-year-old man presented with three episodes of dysphasia and disinhibited behaviour, a single seizure and transient ischaemic attack-like events characterised by right arm and/or leg weakness. These episodes were separated by month-long asymptomatic intervals. Medical history included rheumatoid arthritis, which was clinically quiescent on leflunomide.Repeated cerebrospinal fluid examination showed a persistent lymphocytosis with mildly reduced glucose and elevated protein; oligoclonal bands and viral PCR were negative. MRI of the brain was initially normal, but 7 months after initial presentation revealed meningeal enhancement with bifrontal cortical hyperintensities on T2/fluid-attenuated inversion recovery. Brain biopsy demonstrated necrotising granulomatous meningitis with mixed T cell and B cell infiltrates and without evidence of vasculitis or infection. Serum anticyclic citrullinated peptide antibodies were strongly positive.The diagnosis of rheumatoid meningoencephalitis was made on the basis of brain biopsy findings and serological evidence of active rheumatoid disease. Steroids and rituximab therapy were started leading to clinical stabilisation.

Neuronal surface and glutamic acid decarboxylase autoantibodies in Nonparaneoplastic stiff person syndrome.

IMPORTANCE: High titers of autoantibodies to glutamic acid decarboxylase (GAD) are well documented in association with stiff person syndrome (SPS). Glutamic acid decarboxylase is the rate-limiting enzyme in the synthesis of γ-aminobutyric acid (GABA), and impaired function of GABAergic neurons has been implicated in the pathogenesis of SPS. Autoantibodies to GAD might be the causative agent or a disease marker. OBJECTIVE: To investigate the characteristics and potential pathogenicity of GAD autoantibodies in patients with SPS and related disorders. DESIGN: Retrospective cohort study and laboratory investigation. SETTING: Weatherall Institute of Molecular Medicine, University of Oxford. PARTICIPANTS: Twenty-five patients with SPS and related conditions identified from the Neuroimmunology Service. EXPOSURES: Neurological examination, serological characterization and experimental studies. MAIN OUTCOMES AND MEASURES: Characterization of serum GAD antibodies from patients with SPS and evidence for potential pathogenicity. RESULTS: We detected GAD autoantibodies at a very high titer (median, 7500 U/mL) in 19 patients (76%), including all 12 patients with classic SPS. The GAD autoantibodies were high affinity (antibody dissociation constant, 0.06-0.78 nmol) and predominantly IgG1 subclass. The patients' autoantibodies co-localized with GAD on immunohistochemistry and in permeabilized cultured cerebellar GABAergic neurons, as expected, but they also bound to the cell surface of unpermeabilized GABAergic neurons. Adsorption of the highest titer (700 000 U/mL) serum with recombinant GAD indicated that these neuronal surface antibodies were not directed against GAD itself. Although intraperitoneal injection of IgG purified from the 2 available GAD autoantibody­ositive purified IgG preparations did not produce clinical or pathological evidence of disease, SPS and control IgG were detected in specific regions of the mouse central nervous system, particularly around the lateral and fourth ventricles. CONCLUSIONS AND RELEVANCE: Autoantibodies to GAD are associated with antibodies that bind to the surface of GABAergic neurons and that could be pathogenic. Moreover, in mice, human IgG from the periphery gained access to relevant areas in the hippocampus and brainstem. Identification of the target of the non-GAD antibodies and peripheral and intrathecal transfer protocols, combined with adsorption studies, should be used to demonstrate the role of the non-GAD IgG in SPS.

Mirror-image temporal arteriovenous malformations presenting with left cervical internal carotid aneurysm.

We report an unusual case of bilateral mirror-image arteriovenous malformations (AVMs) in association with a large internal carotid aneurysm. The patient, a 45-year-old man, was asymptomatic apart from a lump in his neck. Both AVMs were successfully occluded with embolisation and the patient remains clinically well.

Antibodies to Kv1 potassium channel-complex proteins leucine-rich, glioma inactivated 1 protein and contactin-associated protein-2 in limbic encephalitis, Morvan's syndrome and acquired neuromyotonia.

Antibodies that immunoprecipitate (125)I-alpha-dendrotoxin-labelled voltage-gated potassium channels extracted from mammalian brain tissue have been identified in patients with neuromyotonia, Morvan's syndrome, limbic encephalitis and a few cases of adult-onset epilepsy. These conditions often improve following immunomodulatory therapies. However, the proportions of the different syndromes, the numbers with associated tumours and the relationships with potassium channel subunit antibody specificities have been unclear. We documented the clinical phenotype and tumour associations in 96 potassium channel antibody positive patients (titres >400 pM). Five had thymomas and one had an endometrial adenocarcinoma. To define the antibody specificities, we looked for binding of serum antibodies and their effects on potassium channel currents using human embryonic kidney cells expressing the potassium channel subunits. Surprisingly, only three of the patients had antibodies directed against the potassium channel subunits. By contrast, we found antibodies to three proteins that are complexed with (125)I-alpha-dendrotoxin-labelled potassium channels in brain extracts: (i) contactin-associated protein-2 that is localized at the juxtaparanodes in myelinated axons; (ii) leucine-rich, glioma inactivated 1 protein that is most strongly expressed in the hippocampus; and (iii) Tag-1/contactin-2 that associates with contactin-associated protein-2. Antibodies to Kv1 subunits were found in three sera, to contactin-associated protein-2 in 19 sera, to leucine-rich, glioma inactivated 1 protein in 55 sera and to contactin-2 in five sera, four of which were also positive for the other antibodies. The remaining 18 sera were negative for potassium channel subunits and associated proteins by the methods employed. Of the 19 patients with contactin-associated protein-antibody-2, 10 had neuromyotonia or Morvan's syndrome, compared with only 3 of the 55 leucine-rich, glioma inactivated 1 protein-antibody positive patients (P < 0.0001), who predominantly had limbic encephalitis. The responses to immunomodulatory therapies, defined by changes in modified Rankin scores, were good except in the patients with tumours, who all had contactin-associated-2 protein antibodies. This study confirms that the majority of patients with high potassium channel antibodies have limbic encephalitis without tumours. The identification of leucine-rich, glioma inactivated 1 protein and contactin-associated protein-2 as the major targets of potassium channel antibodies, and their associations with different clinical features, begins to explain the diversity of these syndromes; furthermore, detection of contactin-associated protein-2 antibodies should help identify the risk of an underlying tumour and a poor prognosis in future patients.