Anesth Analg 2000;91:691-692
© 2000 International Anesthesia Research Society
REGIONAL ANESTHESIA AND PAIN MEDICINE
Downbeat Nystagmus Associated with Intravenous Patient-Controlled Administration of Morphine
Robert D. Henderson, FRACP, and
Eelco F. M. Wijdicks, MD
Department of Neurology, Mayo Clinic, Rochester, Minnesota
Address correspondence and reprint requests to E. F. M. Wijdicks, MD, Mayo Clinic, Department of Neurology, 200 First St. SW, Rochester, MN 55905. Address e-mail to wijde{at}mayo.edu
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Abstract
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Implications: This case documents a patient who developed dizziness with downbeating nystagmus while receiving a relatively large dose of IV patient-controlled analgesia morphine. Although there have been case reports of epidural morphine with these symptoms and signs, this has not been previously documented with IV or patient-controlled analgesia morphine.
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Introduction
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We report a case of downbeat nystagmus associated with IV patient-controlled administration of morphine. The known association of vertigo with morphine given by the epidural route is reviewed.
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Case Report
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A 61-yr-old man of average height and weight was admitted to our hospital, the Mayo Clinic, with a Grade 3 adenocarcinoma of the gastroesophageal junction. He had a medical history of paroxysmal atrial fibrillation and had suffered a small left cerebellar infarct, without residual clinically detectable deficit, 6 mo before this presentation. Magnetic resonance imaging at that time had shown a small infarct in the left cerebellar hemisphere but revealed no abnormality in the medulla or floor of the fourth ventricle. The second day after a gastroesophagectomy, he noted profound dizziness that he described as the sensation of the "world moving around" with blurring of vision but no nausea. Looking around the room exacerbated the sensation of dizziness.
On examination, he was alert with a normal respiratory rate. A downbeat nystagmus in the primary position with the fast-phase beating downward was noted. The downbeat nystagmus became marked on downward gaze (Alexander’s Law) but was also present in the other directions of gaze. There were no other clinically abnormal features on his neurologic examination; in particular, his pupils were not noticeably miotic. He had received 56 mg of morphine sulphate via an IV patient-controlled analgesia (PCA) pump in the preceding 9 h. Before this, he had not received opioids. Other medications included ketorolac, atenolol, subcutaneous heparin, famotidine, tamsulosin, and cefazolin. Tamsulosin, for benign prostatic hypertrophy, predated his hospital admission. His electrolytes and renal and hepatic function were normal. Cessation of the PCA morphine led to the complete resolution of all signs and symptoms within 12 h.
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Discussion
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The temporal association of the downbeat nystagmus with the administration of a relatively large amount of parenterally administered morphine, the rapid resolution with its discontinuation, and the absence of other cerebellar or brainstem features implicates morphine and makes other causes, such as a stroke on the pons or cerebellum much less likely. The presentation with symptoms and signs of vertigo without drowsiness, nausea, dysarthria, or respiratory depression is notable.
The association of epidural morphine with nystagmus (1–3), predominantly reported as vertical, and with vertigo (4,5), has been previously reported. Naloxone may reverse this nystagmus associated with epidural morphine (3). Schmidt (6) noted previous reports of downbeating nystagmus with morphine derivatives used in general anesthesia. However, its association has not previously been reported with the IV administration of morphine and has not been reported with PCA morphine. Presumably, the association of downbeat nystagmus with morphine is caused by morphine in the region of the medullocervical junction or midline cerebellum, and it is quite possible our patient was predisposed by previous ischemic damage to the cerebellum. A lesion in these regions was not present on the magnetic resonance imaging performed five months before the present admission. Repeat cerebral imaging was not clinically indicated at the time of his current review as his symptoms and signs were restricted and resolved with cessation of the PCA morphine.
Other medications that have been associated with downbeat nystagmus include lithium carbonate, phenytoin, carbamazepine, and amiodarone (6,7). Morphine, IV or epidural, should be added as a possible cause of drug-induced downbeat nystagmus and, in patients given morphine, considered in the differential diagnosis of vertigo.
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References
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Fish DJ, Rosen SM. Epidural opioids as a cause of vertical nystagmus. Anesthesiology 1990; 73: 785–6.[ISI][Medline]
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Stevens RA, Sharrock NE. Nystagmus following epidural morphine. Anesthesiology 1991; 74: 390–1.[ISI][Medline]
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Ueyama H, Nishimura M, Tashiro C. Naloxone reversal of nystagmus associated with intrathecal morphine [letter]. Anesthesiology 1992; 76: 153.[ISI][Medline]
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Goundrey J. Vertigo after epidural morphine. Can J Anaesth 1990; 37: 804–5.[Abstract/Free Full Text]
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Linder S, Borgeat A, Biollaz J. Meniere-like syndrome following epidural morphine analgesia. Anesthesiology 1989; 71: 782–3.[ISI][Medline]
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Schmidt D. Downbeat nystagmus: a clinical review. Neuro Ophthalmol 1991; 11: 247–62.
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Leigh RJ, Zee DS, eds. The neurology of eye movements. 3rd ed. New York: Oxford University Press, 1999:415–6.
Accepted for publication May 4, 2000.
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Abstract
Introduction
