Event-related evoked potentials in chronic respiratory encephalopathy.

BACKGROUND: Cognitive event-related potential (P(300)) is an index of cognitive processing time. It was found to be prolonged in dementia, renal, and hepatic encephalopathies, but was not extensively assessed in respiratory failure. OBJECTIVE: To evaluate P(300) changes in patients with respiratory failure, and especially those with mild or subclinical hypoxic-hypercapnic encephalopathy. METHODS: Auditory event-related evoked potential P(300) latency was measured using an oddball paradigm in patients with respiratory failure due to any cause (partial pressure of oxygen in arterial blood (PO(2)) should be 75 mm/Hg or less). Apart from blood gases measurement, patients underwent the Mini-Mental State Examination (MMSE). Patient performances were compared with that of matched normal control. Patients were admitted into the study from outpatient clinics and wards at King Khalid University Hospital and Sahara Hospital. RESULTS: Thirty-four patients (12 women, 22 men) were admitted to the study. Ages ranged from 19-67 years with a mean of 46.1 years. Respiratory failure was severe or very severe in 11 patients (33%), and mild or moderate in the rest (66%). Mean value for PO(2) and partial pressure of carbon dioxide in arterial blood (PCO(2)) were 63.7 and 45.2 mm/Hg, respectively. pH mean was 7.4 and O(2) saturation was 90.7%. P(300) latency ranged from 218 to 393 milliseconds, with a mean of 338.4 milliseconds. In comparison with control (309.9 milliseconds), there was a significant difference (P = 0.007). P(300) amplitude differences were not significant. No significant difference in MMSE was noted between mild and severe respiratory failure. Results of detailed neuropsychological assessment were clearly abnormal but were limited by the small number of tested patients. P(300) latency changes correlated significantly with age as well as severity of respiratory failure. P(300) was also significantly delayed whether hypoxia occurred with or without hypercapnia. CONCLUSION: Results show a significant delay of P(300) latency in patients with severe and mild respiratory failure. This was associated with subclinical encephalopathy in most patients, evidenced by a near-normal MMSE score. Apart from confirming the importance of P(300) latency measurement as a marker of respiratory encephalopathy, this study asserts the causal relationship between hypoxemia and cognitive derangement. Furthermore, it promotes the early use of oxygen therapy in a selected group of patients with mild or moderate respiratory failure, who have responsibilities which involve taking rapid critical decisions.

Behaviour and time-course of sleep disordered breathing in patients with acute coronary syndromes.

To our knowledge, no study has examined the persistence of sleep disordered breathing in acute coronary syndrome (ACS) patients. We examined the time course of SDB in ACS patients by assessing them within days of the acute event and again after 6 months. Consecutive patients with ACS were asked to voluntarily participate in the study. Patients underwent an overnight polysomnography (PSG) approximately 3 days after the acute event. Patients with an apnea hypopnea index (AHI) > 10/h then underwent another PSG after they were stable (approximately 6 months). Fifty patients were studied. First PSG showed an AHI was 23.1 +/- 3.6/h. A second PSG was performed 6.1 +/- 0.3 months later on 21 patients and showed an AHI > 10/h in the first assessment. The AHI and the obstructive apnea index did not change over the 6 months. However, the central apnea index all was lower at the second assessment.

Thrombosis complicating high dose intravenous immunoglobulin: report of three cases and review of the literature.

High dose intravenous immunoglobulin (IVG) is increasingly used in a broad range of immune mediated diseases. Thrombosis was exceptionally reported as a complication of this therapy. We describe three cases of thrombotic complications during or soon after IVIG treatment: myocardial infarction in a man and cerebral infarctions in an elderly man, associated with peripheral ischemia in a woman. In addition we review the published cases in the literature and discuss the possible etiologic factors.

Paradoxic response to diazepam in complex partial status epilepticus.

BACKGROUND: Antiepileptics including benzodiazepines have long been recognized to provoke seizures and precipitate status epilepticus occasionally. This has a special clinical importance in the case of diazepam because of its use as first choice medication in its management. This report is intended to highlight the clinical importance of such a situation. METHODS: The clinical course of a 28-year old man with complex partial status, which lasted for two months, is described in detail. RESULTS: Paradoxic response to diazepam was documented under EEG monitoring. A similar response was also noted for midazolam, and had probably contributed in exacerbating and prolonging the duration of status. CONCLUSION: Paradoxic response to diazepam and midazolam is rare, but may be under-recognized. It should be considered in the setting of refractory status epilepticus.

Localization of the gene for a novel autosomal recessive neurodegenerative Huntington-like disorder to 4p15.3.

A consanguineous family affected by an autosomal recessive, progressive neurodegenerative Huntington-like disorder, was tested to rule out juvenile-onset Huntington disease (JHD). The disease manifests at approximately 3-4 years and is characterized by both pyramidal and extrapyramidal abnormalities, including chorea, dystonia, ataxia, gait instability, spasticity, seizures, mutism, and intellectual impairment. Brain magnetic resonance imaging (MRI) findings include progressive frontal cortical atrophy and bilateral caudate atrophy. Huntington CAG trinucleotide-repeat analyses ruled out JHD, since all affected individuals had repeat numbers within the normal range. The presence of only four recombinant events (straight theta=.2) between the disease and the Huntington locus in 20 informative meioses suggested that the disease localized to chromosome 4. Linkage was initially achieved with marker D4S2366 at 4p15.3 (LOD 3.03). High-density mapping at the linked locus resulted in homozygosity for markers D4S431 and D4S394, which span a 3-cM region. A maximum LOD score of 4.71 in the homozygous interval was obtained. Heterozygosity at the distal D4S2366 and proximal D4S2983 markers defines the maximum localization interval (7 cM). Multiple brain-related expressed sequence tags (ESTs) with no known disease association exist in the linkage interval. Among the three known genes residing in the linked interval (ACOX3, DRD5, QDPR), the most likely candidate, DRD5, encoding the dopamine receptor D5, was excluded, since all five affected family members were heterozygous for an intragenic dinucleotide repeat. The inheritance pattern and unique localization to 4p15.3 are consistent with the identification of a novel, autosomal recessive, neurodegenerative Huntington-like disorder.

Motor terminal latency index in carpal tunnel syndrome.

We determined the motor terminal latency index (MTLI) of the median nerve across the carpal tunnel in 41 upper extremities of 31 patients with carpal tunnel syndrome. Changes in motor nerve conduction velocity (MNCV), motor terminal latency (MTL), sensory action potential and the amplitude of the compound muscle action potential recorded from the abductor pollicis brevis muscle were all suggestive of proximal and distal segment involvement of the nerve across the carpal tunnel. There was no correlation between forearm MNCV and MTL (r = 0.40), although MTLI was correlated with MTL (r = 0.67) but not with MNCV, indicating a disproportionate conduction across the carpal tunnel.

A novel autosomal recessive "Huntington's disease-like" neurodegenerative disorder in a Saudi family.

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Terminal Latency Index: A distinctive diagnostic criterion for carpal tunnel syndrome.

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