David H. Sprague

Enflurane seizures in patients taking amitriptyline.

Even in patients without preexisting central nervous system disorders, enflurane has been reported to induce cerebral irritability and involuntary motor activity during its clinical use (1, 2). Similarly, tricyclic antidepressants in therapeutic doses and in overdoses are capable of producing both clinical and electroencephalographic evidence of seizure activity (3-5). As a result of this latter observation, it has been suggested that tricyclic antidepressants be used with caution in patients with lowered convulsive thresholds (6, 7). Therefore, although little is known about the effect of concomitantly administered medications on the seizure threshold of enflurane, the available data appear to indicate that the administration of enflurane to a patient taking tricyclic antidepressants might facilitate seizure activity. The following case reports suggest that such an interaction between enflurane and tricyclic antidepressants does exist.

Retrolental fibroplasia: a multifactorial disease.

Among the factors that are often thought responsible for the resurgence of cicatricial retrolental fibroplasia (RLF) in premature, low birth weight neonates, a history of oxygen therapy is often held to be of greatest importance (1-3). Indeed, a history of oxygen therapy is found in most low birth weight infants who develop the acute retinovascular changes; however, a history of oxygen therapy alone has little reliability in predicting those infants who develop the blinding cicatricial changes (4). These facts suggest that the development of RLF may be influenced by many factors that, although not always identified, may exert a summating effect on the premature retina. The following case report of a premature infant who developed blinding cicatricial RLF following an operation emphasized the importance of the multifactorial origin of this disease.

Lensectomy-vitrectomy for stage V cicatricial retrolental fibroplasia.

Ten infants (18 eyes) blind from stage V cicatricial retrolental fibroplasia were examined from January 1978 to January 1981 at North Carolina Memorial Hospital. The early perinatal factors which may have predisposed to the binding end-stage cicatrix are identified. To increase their visual potential and to prevent secondary angle closure glaucoma, 12 lensectomy-vitrectomies were performed on 12 eyes (eight infants). One eye (one infant) had a pars plana vitrectomy without lensectomy. Seven eyes (seven infants) were not operated. Five of these eyes (five infants) had stage VRLF while two eyes (two infants) remained stable at stage II RLF. All retinas remained detached immediately after surgery. Secondary vitrectomies with air injections (three eyes, two infants) similarly failed to attach any retinas. Adherence of ciliary epithelium to clear lens and retrolental membrane as visualized within the dilated pupil (Eifrig-Merritt sign) was an intra-operative indicator of imminent surgical failure. Two eyes (two infants) developed early vitreous hemorrhages, hyphemas, secondary glaucoma, and phthisis bulbi within 12 months. Follow-up data were unavailable on two infants. Blindness secondary to cicatricial retrolental fibroplasia is increasing due to increased survival of low birthweight premature infants. Since surgical visual rehabilitation is not possible after the retrolental cicatrix has formed, the risk factors common to this high risk population should prompt preventive therapies.

Hypocalcemia following brachial plexus block.

References 1. McLean BY, Rottman RL, Kotelko DM. Failure of multiple test doses and techniques to detect intravascular migration of an epidural catheter. Anesth Analg 1992;74454-6. 2. Landry DP, Oriol NE. Comments on the problems associated with epidural test dosing. Reg Anesth 1990;15154. 3. Bromage, PR. Choice of local anesthetics in obstetrics. In: Shnider SM, Levinson G, eds. Anesthesia for obstetrics. 2nd ed. Baltimore: Williams & Wilkins, 198760. 4. Man, GF. Comment: Comments on the problems associated with epidural test dosing. Obstet Anesth Digest 1990;10146.