Hemiplegic migraine associated with interscalene block and general anaesthesia

Abstract

We report a case of new onset hemiplegic migraine following general anaesthesia and an interscalene block, the first reported case in the literature. A middle-aged man underwent manipulation of the left shoulder under anaesthesia. An awake left interscalene block under sedation was performed. The plexus was located easily with a 25 Stimiplex needle and 30 ml 0.5% levobupivicaine injected at an end point of 0.4 mA (biceps twitch) uneventfully. General anaesthesia was then induced with 50 μg fentanyl and 200 mg propofol. A laryngeal mask airway was placed and the patient ventilated spontaneously with oxygen, air and sevoflurane. The patient was positioned in the right decubitus position. There were no adverse events during the 40 min procedure. In recovery he was unable to move or feel the left side of his body and had difficulty responding to questions with slurred speech. Cranial nerve examination revealed reduced sensation of the left cheek, flaccid paresis of the left cheek, and left hypoglossal nerve impairment. A dense left-sided hemiplegia and hemisensory loss was found on peripheral nervous system examination. Symptoms resolved gradually. Within 4 h he was able to move his foot but sensation was still impaired on the left side of his body. Cranial nerve assessment at this time showed tongue movement and speech back to normal. At 15 h upper limb movement had partially recovered, he was able to lift the arm, but still unable to move the fingertips. By 24 h the upper limb signs had almost completely resolved, and the leg weakness appeared to be resolving. Cranial nerve examination demonstrated ongoing numbness of the left side of the tongue. He notes having very slight generalised weakness thereafter which lasted for a further 3 days. Immediate MRI of the cervical spinal cord was normal. Carotid duplex scans and cranial MRI performed later revealed no abnormality. Since the initial episode he had six further attacks of left-sided weakness. Severe stabbing pains in the head followed by mild to moderate headache have preceded each episode. Both his left arm and leg are affected. Symptoms resolve after 3 days. A diagnosis of hemiplegic migraine was made following neurological consultation. Propranolol was commenced and he was reviewed after 3 months. At this stage he reports suffering headaches every 2 weeks which were more tolerable. He had no further attacks of associated left-sided weakness or numbness. EEG undertaken was normal. Our case highlights the diagnostic dilemma posed by a neurological deficit following anaesthesia with interscalene block. A number of central and peripheral diagnoses should be considered. A left interscalene block could lead to left-sided neurology if injected directly into the substance of the spinal cord. A total spinal is likely to have occurred simultaneously. Literature describing this complication describes predominantly upper limb neurological loss, all being in individuals where interscalene block was performed under general anaesthesia [1]. Spontaneous right-sided stroke under anaesthesia is a possible differential diagnosis, but no radiology supported this, and the recurrent nature of the symptoms confirmed this. General anaesthesia is known to precipitate migraine in sufferers. Ten per cent of migraine sufferers have neurological deficits and in 4% this persists beyond the duration of the headache. Hemiplegia associated with migraine post general anaesthesia has to date only been reported in individuals with a prior history of the condition or a known strong family history of hemiplegic migraine [2]. Hemiplegic migraine is a rare disorder characterised by attacks of transient hemiparesis followed by migraine headache. Classically there is an aura, followed by development of neurological signs lasting a mean of 60 min followed by headache lasting 30 min to 5 days. Motor signs occur unilaterally in approximately 60% of cases and are never isolated – most commonly associated with sensory signs and language disturbance, and least commonly with visual disturbances – in contrast to classic migraine. Triggers for the development of migraine in these individuals are commonly minor stressful events, which is the postulated mechanism in this gentleman [3]. This case highlights that hemiplegic migraine should be considered as a possible differential when faced with neurological deficit postoperatively.