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Biomedical subjects

P B Pritchard

Publications and source records attributed to P B Pritchard.

13 recordsLinked to original sources

Intensive neurodiagnostic monitoring.

Intensive neurodiagnostic monitoring is useful in the diagnosis and classification of epileptic seizures and other paroxysmal disorders. The correlation of clinical/behavioral data, EEG events, and serum prolactin levels may clarify the type(s) of epileptic seizures and may distinguish epileptic seizures from non-epileptic events. Serial determinations of AED's may assist in the detection of problems with AED compliance and with drug interactions which complicate the patient's management.

Anticonvulsants

The effect of seizures on hormones.

Serum prolactin (HPR) levels are influenced by waking and sleep states, as reflected by surges in serum concentrations during daytime naps and nocturnal sleep. Other physiological causes of hyperprolactinemia include sexual activity, pregnancy, and lactation. Drugs may stimulate or inhibit HPR secretion. Pathological causes for HPR secretion include destructive lesions of the hypothalamus, prolactin-secreting neoplasms of the pituitary gland, lesions of the spinal cord, and occasionally Parkinson's disease. The most predictable postictal changes are increased serum cortisol levels and hyperprolactinemia. Serum HPR rises after virtually all generalized tonic-clonic seizures, most complex partial seizures, and some simple partial seizures. Absence and myoclonic seizures do not affect serum HPR levels. Repeated epileptic seizures and electroconvulsive therapy treatments produce successively less marked rises in serum HPR. The postictal elevation of serum cortisol has a longer latency than for HPR and follows an earlier rise in serum ACTH. Other postictal hormonal changes are much more variable. Because of the normal diurnal variation in serum cortisol levels and the relative delay in the postictal elevation of serum cortisol, HPR is more useful as a diagnostic measure of epileptic seizures. This application of HPR requires an understanding of other factors that influence serum HPR and the use of baseline serum HPR levels for comparison. HPR data must be correlated with behavioral and electroencephalographic events.

Adrenocorticotropic Hormone

Prolactin in partial epilepsy: an indicator of limbic seizures.

A study was performed to evaluate changes in serum prolactin levels after simple and complex partial seizures, and to identify which specific anatomical structures must be involved in seizures for postictal elevation of prolactin levels to occur. Seventy-eight seizures were studied in patients with electrodes implanted bilaterally into amygdala, hippocampus, hippocampal gyrus, and frontal sites. All 38 complex partial seizures had bilateral limbic ictal discharges, and each was followed by a significant increase in prolactin concentration (mean peak, 50.8 ng/ml; range, 16.0 to 150.0 ng/ml). Eight of 10 simple partial seizures with unilateral high-frequency regional limbic discharges were followed by prolactin elevation (mean peak, 28.2 ng/ml; range, 13.4 to 44 ng/ml). Thirty simple partial seizures with other ictal limbic discharges or without limbic discharges were not followed by an elevated prolactin level. The data indicate that serum prolactin levels always rise after complex partial seizures involving the temporal lobes, and rise after certain simple partial seizures involving limbic structures. Thus, measurement of the prolactin level can help identify which simple partial seizures involve mesial temporal lobe structures. Limbic structures serve to trigger prolactin release, which may depend upon spread of the seizure to subcortical structures.

Electroencephalography

Serum prolactin and cortisol levels in evaluation of pseudoepileptic seizures.

In 6 patients with epilepsy, a twofold increase in serum prolactin levels followed true epileptic seizures, but no significant change followed pseudoepileptic attacks in 6 other patients. Serum prolactin concentration is a useful biochemical marker to distinguish between epileptic and pseudoepileptic seizures. Serum cortisol levels also increased after epileptic seizures, but diurnal and individual variations render the cortisol level a less reliable indicator of such attacks.

Diagnosis, Differential

Self-abatement of complex partial seizures.

Seven of 71 patients with complex partial seizures claimed they were able to abate their seizures, while none of 18 with simple partial seizures were able to do so. Self-abatement exercises included highly stereotyped cognitive and physical components unique to the individual. Those who could abate their seizures had attained higher educational status, better social and vocational adjustment, and better psychological adjustment than did the control group of patients with epilepsy. The self-abatement group was also more likely to have right hemispheric electroencephalographic abnormalities. Characterization of the self-abatement group may be relevant to the selection of candidates for behavioral therapy for epilepsy.

Adult

Epileptic amnesic attacks: benefit from antiepileptic drugs.

We studied two sexagenarians who had recurrent circumscribed attacks of amnesia. Their EEGs showed frequent bilateral spikes that arose independently from the temporal lobes, primarily from mesiobasal structures. Amnesic attacks ceased after treatment with antiepileptic drugs. Neuropsychological tests demonstrated selective cognitive impairments, and short-term memory improved after treatment in one patient. Epileptic amnesic attacks should be distinguished from transient global amnesia, which is clinically similar.

Aged

Nonconvulsive status epilepticus following metrizamide myelography.

Epileptic seizures are a known complication of metrizamide myelography. To our knowledge, this is the first report of a case of nonconvulsive status epilepticus of the absence type following metrizamide myelography. There was symptomatic and electroencephalographic improvement after intravenous administration of antiepileptic drugs, and there was no neurological residual. Nonconvulsive status epilepticus should be considered when impairment of consciousness supervenes after radiographic procedures using metrizamide.

Electroencephalography

Endocrine function following complex partial seizures.

Previous studies have demonstrated hyperprolactinemia following generalized tonic-clonic seizures and after electroconvulsive therapy. We found transient hyperprolactinemia following complex partial seizures but little change in serum gonadotropins, thyroid-stimulating hormone, growth hormone, or cortisol. Serum prolactin was invariably normal interictally. Postictal elevation of serum prolactin may represent a biochemical marker of complex partial seizures, and it offers a potential pathogenic mechanism for the sexual dysfunction that often complicates temporal lobe epilepsy.

Adult

Dural plasmacytoma.

Dural plasmacytoma is an unusual form of myeloma. We describe a woman with plasmacytoma of the tentorium cerebelli that was managed successfully with surgical decompression and radiotherapy. Computed tomography, not previously reported in cases of dural plasmacytoma, was useful in her management. Another unique feature was the restoration of a normal immunoglobulin G content in the blood and cerebrospinal fluid after local treatment of the neoplasm. Two previously reported cases showed similar normalization of cerebrospinal fluid immunoglobulin G after local radiotherapy. Dural plasmacytoma presents a characteristic clinical syndrome. The typical patient is a woman (92% of the reported cases) in the 5th decade of life. Clinical findings reflect intracranial hypertension, often with focal neurological signs, consistent with the usual dural or tentorial origin of the tumor. Immunoglobulin abnormalities may be found in serum or cerebrospinal fluid. The prognosis is good after surgical decompression and local radiotherapy.

Adult

Psychological complications of temporal lobe epilepsy.

A series of young adults with temporal lobe epilepsy included 36% with psychological complications. The incidence of overt psychosis was 11%. Psychopathology was more common in subjects with left temporal lobe spike foci (43%) and in males (42%), but these trends did not attain statistical significance. Psychological complications became manifest in adolescence in 85% of the affected cases, and were more likely (p less than 0.01) to occur when seizures began in the second 5 years of life. Although seizures nearly always antedated psychological problems, the onsets of epilepsy and psychological complications did not directly correlated (p = 0.43).

Adolescent

Left and right temporal lobe epileptics: a controlled investigation of some psychological differences.

Twenty-two young adults with clinically and electroencephalographically diagnosed temporal lobe epilepsy were selected from an outpatient neurology source; 11 with focal epileptic activity in the right temporal lobe and 11 with left temporal lobe involvement were included. All patients had normal intelligence and comparable educational and socioeconomic backgrounds. Matched nonepileptic controls were also tested. Subjects were given psychological tests assessing differences in cognitive style and affect communication. Greater reliance on the ear ipsilateral to discharge focus in a dichotic listening paradigm was discovered, confirming appropriate lateralization assignment. Left lateralized patients exhibited a more reflective cognitive style than controls; right lateralized patients were more impulsive. Previously confirmed associations between impulsivity and externalized aggressive responses suggest the hypothesis that externalization of aggressive responses may occur more often among right lateralized patients. Left lateralized patients exhibited a more reflective cognitive style than controls; right lateralized patients were more impulsive. Previously confirmed associations between impulsivity and externalized aggressive responses suggest the hypothesis that externalization of aggressive responses may occur more often among right lateralized patients. Left lateralized patients made more atypical assignments of affect labels to emotionally evocative descriptions. Right laterlized patients tended to assign affect labels as controls. A greater potential for disturbance in the verbal communication of affect among left laterlized patients is suggested.

Adolescent