John F. Brick

Reflex epilepsy and nonketotic hyperglycemia in the elderly A specific neuroendocrine syndrome

We present five elderly patients with focal reflex or posture-induced seizures and nonketotic hyperglycemia (NKH). Each patient exhibited interictal focal findings, such as hemiparesis or hemisensory or aphasic deficits. With control of the hyperglycemia, the seizures stopped, and the neurologic deficits resolved. The syndrome of focal reflex epilepsy and neurologic deficits in the elderly is transient and almost invariably related to NKH, thus representing a specific neuroendocrine syndrome.

Timber rattlesnake venom‐induced myokymia Evidence for peripheral nerve origin

Facial and limb myokymia occurred in four consecutive cases of timber rattlesnake envenomation and represents the “fasciculations” frequently reported in this entity. The facial myokymia disappears within hours of antivenin therapy and the limb myokymia by increasing serum ionized calcium. These observations suggest that the action of the venom is a biochemical one, increasing peripheral nerve excitability.

Ultrastructural pathology in emetine-induced myopathy*

SummaryProgressive myopathy developed in two women who consumed ipecac syrup containing emetine hydrochloride to induce vomiting as part of their anorexia nervosa. Muscle biopsy specimens were characterized by severe disruption of the sarcomeres. The ultrastructural spectrum extended from “Z-band streaming” to the formation of cytoplasmic bodies and also comprised abnormalities of the sarcotubular system, thus suggesting that muscle weakness may be related to both sarcomeric and sarcotubular lesions in this self-inflicted myopathy. It is tempting to suggest that muscle weakness may be correlated with or based on the pathology in sarcomeres and the sarcotubular system. As the myopathy is clinically reversible upon discontinuation of ipecac consumption the morphological findings should also be potentially reversible. Experimentally induced emetine myopathy may, thus, serve as a useful model to study morphological dynamics of sarcomeric lesions, which may be observed separately or simultaneously in a variety of spontaneously occurring human neuromuscular disorders.

Dipole Reversal: An Ictal Feature of Benign Partial Epilepsy with Centrotemporal Spikes

Summary: Benign epilepsy with centrotemporal spikes (BECTS) is characterized by brief stereotypical partial seizures with motor and/or sensory symptoms with frequent secondarily generalized seizures. The interictal EEG shows slow, disphasic, high‐voltage spikes in the centrotemporal areas. The few published examples of ictal tracings depict focal rhythmic sharp waves and spikes without significant postictal slowing. We report an ictal event in BECTS that is unusual in the evolution and polarity of the ictal discharges. In this subclinical seizure, ictal multiple spike and wave discharges appear as a dipole: they are electropositive in T3‐C3 and negative in F3. These surface positive epileptic discharges are unique and require explanation. We postulate that the seizure discharge arises in the depths of the sylvian fissure involving folded cortical areas. This occurs in such a way that the negative component of the discharges is concealed from the scalp electrodes. Thus, a relative positivity is recorded on the surface. This represents a dipole reversal relative to the interictal discharges (characteristic of BECTS). This geometrical explanation allows us to avoid postulating an unusual mechanism of generation of this seizure.

Calcium effect on generation and amplification of myokymic discharges

Maneuvers designed to manipulate ionized calcium (Ca++) were carried out in two patients with inflammatory polyradiculoneuropathy and myokymia. Increased clinical myokymia and myokymic burst amplification occurred when ionized Ca ++ was lowered by plasma exchange or hyperventilation. Increasing ionized Ca++ (by intravenous infusion of CaCl2) decreased the myokymia. These findings indicate that myokymic discharges are altered by changes in serum ionized Ca++ and effects on axonal excitability.

EEG and pathologic findings in patients undergoing brain biopsy for suspected encephalitis

Previous studies have suggested that EEG may be helpful in the diagnosis of herpes encephalitis (HE). To further define the value of EEG in an acutely ill, febrile, encephalopathic patient suspected as having encephalitis, we reviewed initial preoperative EEGs with the results of cerebral biopsies in 24 consecutive patients suspected of having encephalitis. Statistical analysis demonstrated that EEG patterns have only limited association with biopsy results. Since diseases which mimic encephalitis may also generate identical EEG changes, this is not an unexpected finding. EEG is useful in the evaluation and management of patients with encephalitis. However, the absence of specific wave forms or focal EEG abnormalities in the proper clinical setting should not deter consideration of HE or delay treatment.

Vanishing cerebrovascular disease of pregnancy

A woman developed TIAs in the last days of her pregnancy. Angiography revealed partial obstruction of the left middle cerebral artery. Following delivery and anticoagulation her symptoms abated. Angiography 11 weeks later revealed resolution of the obstruction. We propose that this intrinsic vascular lesion was secondary to reversible intimal hyperplasia brought on by reproductive steroids.

Calcium and myokymia of brainstem origin.

In five patients with Guillain-Barré syndrome, clinical myokymia increased and myokymic burst amplification occurred when ionized Ca++ was lowered by hyperventilation. Myokymia decreased when ionized Ca++ was increased after IV infusion of CaCl2. These responses were absent or diminished in the four patients with myokymia due to brainstem lesions, suggesting that the blood-brain barrier impedes the effects of altered serum ionized Ca++ on axonal excitability. Altering serum Ca++ can distinguish peripheral and central myokymia.

Reversible coma with prolonged absence of pupillary and brainstem reflexes An unusual response to a hypoxic‐ischemic event in MS

A quadriparetic man with multiple sclerosis became comatose with absent pupillary and brainstem reflexes for 48 hours following a respiratory arrest. A periodic electroencephalographic pattern was recorded 12 hours after arrest suggesting a poor prognosis. Despite the poor prognostic signs, clinical recovery to baseline occurred within 2 weeks. Reversible coma with absent pupillary and brainstem reflexes may occur in MS patients for prolonged periods and lead to potential errors in prognosis if not recognized.

Perspective on carbamazepine‐induced water intoxication Reversal by demeclocycline

Carbamazepine (CBZ)-induced water intoxication occasionally limits its usefulness in refractory seizures and trigeminal neuralgia. Fluid restriction, CBZ dose reduction, or concomitant phenytoin therapy may be impractical or ineffective. Demeclocycline (7-chloro-6 demethyl tetracycline) (DMC) corrected the CBZ-induced water intoxication in a 51-year-old man with refractory complex partial seizures and a normal antidiuretic hormone (ADH) level. DMC inhibits ADH-sensitive adenylate cyclase activity in the renal collecting duct and may be useful in correcting the ADH-like or renal antidiuretic effect of CBZ.