Delayed Convulsions and Brief Contralateral Hemiparesis After Retrobulbar Block

Abstract

Objective: This case report describes convulsions and hemiparesis after retrobulbar injection with good outcome in a patient undergoing outpatient cryocoagulation of his right eye.Case Report: We report a young man in which localized convulsions of the ipsilateral face occurred 9 minutes after retrobulbar injection followed shortly by convulsions of the contralateral arm and leg. After the convulsions, the patient experienced left-sided hemiparesis resolving approximately 1 hour after the injection. There was no hemodynamic instability during this period. It was difficult to determine the exact cause of convulsions and hemiparesis. Conclusions:We believe these complications occurred because of unintentional injection of local anesthetic agent into the subarachnoid space without affecting the brainstem. Possible mechanisms of spread of local anesthetic agent into the central nervous system after retrobulbar block are discussed. Reg L ocal anesthesia for major ophthalmic surgical procedures includes peribulbar, retrobulbar, and sub-Tenon's block, 1-3 but the exact frequency of their use is not known. Although the classical retrobulbar technique 4 is still in use, the technique has evolved over the years. In current or modern retrobulbar block, a needle Յ32 mm long is inserted through the extreme inferolateral quadrant just below the lateral rectus muscle. 5 Despite its careful use, sight and/or life-threatening complications have occurred. 6-8 Numerous case reports of apnea, respiratory difficulties, cardiovascular collapse, convulsions, and paralysis of 1 or more limbs have been reported after local anesthetic spread to unusual neurologic locations. 9 The exact mechanism of spread is not fully understood in most cases. A variety of signs and symptoms after injection of local anesthetic agent into the optic nerve sheath have been reported. 9 A case of contralateral hemiparesis was reported after retrobulbar block in addition to which the patient developed bilateral ophthalmoplegia and loss of consciousness for approximately 2 hours. 10 We present a case in which localized ipsilateral convulsions occurred 9 minutes after retrobulbar injection, and this was followed shortly by convulsions in the contralateral arm and leg. Contralateral hemiparesis occurred, but the patient recovered full muscle power within an hour. To our knowledge, delayed convulsions and contralateral hemiparesis after retrobulbar block have not been reported. Case ReportA 36-year-old man (height 1.73 m, weight 80 kg, and American Society of Anesthesiologists 2) was scheduled for outpatient cryocoagulation of his right eye. The medical history included congenital blindness in the right eye and non-Hodgkin's lymphoma with leptomeningeal metastasis. He received intrathecal chemotherapy and skull radiotherapy more than 5 years before. Although his medical conditions remained stable, he developed radiation retinitis in both eyes. He was addicted to nicotine and

Pulmonary oedema in a patient undergoing vitreo-retinal surgery under peribulbar block

“…The delayed manifestations of LA toxicity in our patient as well as other reported cases of delayed brainstem toxicity with eye blocks[89] could be explained by the slow diffusion constants of lignocaine and bupivacaine as demonstrated in the study by Thomas et al (the LAs diffuse through 1 mm 3 of brain tissue in 16 mins when small quantities are applied to the medulla). [10]…”

“…However, due to the anatomic proximity between the eye and the central nervous system, LAs may track along the optic nerve sheath or through a dural cuff breach and reach the brain stem directly after an eye block. [2389] The resulting presentation is variable depending on the amount of drug reaching the medulla and the exact areas affected. [810]…”

Brainstem Anesthesia after Retrobulbar Block: A Case Report and Review of Literature

“…Similar cases to ours of BSA causing loss of consciousness, apnea and bradycardia have been well documented (6, 8, 10–12). There are reported cases presenting with dysarthria (13), ocular motor nerve paresis (14–17), bilateral hearing loss (18) and localized convulsions of the ipsilateral face followed by hemiparesis (19). …”

It is Just an Eye Case! Delayed Awakening After Retro-Bulbar Block

“…Different CNS events have been reported in literature after Retrobulbar block like seizure, hemiparesis and coma [6][7][8] possible mechanism of CNS symptoms is unintentional intra-arterial injection. Retrograde flow of local anesthetic into the carotid circulation is another mechanism of spread that has been postulated by Aldrete et al [7] rarely the local anesthetic can be injected into CSF unintentionally and cause brainstem anesthesia [9][10][11][12].…”