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Show ORIGINAL CONTRIBUTION Spontaneous Resolution of Aneurysmal Third Nerve Palsy Rod Foroozan, MD, Thomas L. Slamovits, MD, Susan M. Ksiazek, MD, and Rochelle Zak, MD Palsy of the third cranial nerve developed in a 33- year- old woman in her third trimester of pregnancy as a result of compression by a posterior communicating artery aneurysm. Prepartum complications forced postponement of surgical treatment. The palsy spontaneously resolved over 3 weeks after delivery by cesarean section. Repeat angiography suggested that the aneurysmal sac had shrunk. Spontaneous complete resolution of a third nerve palsy does not exclude an aneurysmal cause. ( JNeuro- Ophthalmol 2002; 22: 211- 214) Palsy of the third cranial nerve occurs in 30% to 40% of patients with internal carotid- posterior communicating artery ( ICA- PCoA) aneurysms ( 1). Studies on the prognosis of third cranial nerve palsy in patients with aneurysms of the ICA- PCoA have reported spontaneous recovery as a rare occurrence, without an easily identifiable mechanism for resolution ( 2,3). Pregnancy- induced hypertension has been identified as a risk factor for intracranial aneurysm development and rupture ( 4). Pregnancy is a state with an apparent stimulatory effect upon aneurysm growth ( 5), and hormonal, hemodynamic, and metabolic factors have been implicated in documented cases of rapid aneurysmal growth ( 6,7). We report spontaneous resolution of a third nerve palsy resulting from an ICA- PCoA aneurysm. CASE REPORT A 3 3- year- old nulliparous woman experienced painless diplopia and partial left- sided ptosis at 32 weeks Neuro- Ophthalmology Service, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania ( RF), Department of Ophthalmology, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York ( TLS), Department of Ophthalmology, Indiana University ( SMK), Indianapolis, Indiana, and Department of Neurology, Sleep- Wake Disorders Center, New York- Presbyterian Hospital, New York, New York ( RZ). Address correspondence to Rod Foroozan, MD, Neuro- Ophthalmology Service, Wills Eye Hospital, Thomas Jefferson University, 900 Walnut Street, Philadelphia, PA 19107, USA; E- mail: rforoozan@ hotmail. com Dr. Foroozan is supported by the Heed Ophthalmic Foundation, Cleveland, Ohio. gestation. She did not describe neck stiffness, nausea, or vomiting. The results of previous evaluations by her obstetrician were reportedly unremarkable and revealed normal blood pressures. At the time of neuro- ophthalmic presentation, her blood pressure was 140/ 100 mm Hg, and there was 2+ pedal edema bilaterally. Examination revealed a best- corrected visual acuity of 20/ 25 OD and 20/ 30 OS. The right pupil measured 4 mm in dim illumination and reacted briskly to light; the left pupil measured 6.5 mm and reacted sluggishly to light. There was no relative afferent pupillary defect. In the OD, ductions were full. In the OS, there was a mild supraduction, adduction, and infraduction deficit. The left upper eyelid was ptotic, with palpebral fissures measuring 10 mm on the right and 6.5 mm on the left. The results of slit lamp examination and applanation tonometry were normal bilaterally. There was no evidence of papilledema or retinal hemorrhages, and visual fields to confrontation were normal bilaterally. Magnetic resonance imaging ( MRI) was normal; magnetic resonance angiography ( MRA) showed an area of high signal intensity posterior to the carotid artery, below the level of the left PCoA, consistent with an aneurysm of the PCoA. A cerebral angiogram revealed an aneurysm 10 mm in diameter, arising from the left supraclinoid carotid artery just below the origin of the PCoA and oriented infe-riorly and posteriorly to it ( Fig. 1). Admission laboratory studies included an elevated partial thromboplastin time ( PTT): 65 seconds ( normal 26- 36 seconds) and serum glutamic- oxaloacetic transaminase ( SCOT): 65 U/ L ( normal 5- 40 U/ L). A lumbar puncture revealed no evidence of xanthochromia. Although a simultaneous craniotomy and delivery were planned, the patient's medical condition rapidly deteriorated, with signs of pre- eclampsia, fetal distress, hemolytic anemia, elevated liver enzymes, and thrombocytopenia ( HELLP syndrome). An emergent cesarean section was performed. Craniotomy was further precluded by a complicated postpartum course, including postpartum cardiomyopathy and gram- negative sepsis, which were reversed by medical treatment. Three days after admission, the patient was noted to have progression of her third nerve palsy to complete left- sided ptosis and a complete left adduction deficit. However, over the next 3 weeks, the third nerve palsy „ JNeuro- QpMhalxnol,. Vol. 22,, Np„ J, 2002 „ , „ , . , . , . . DOI: 10.1097/ 01. WNO.. 0Q00028870.92670.41 , 211 , Copyright © Lip pincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. JNeuro- Ophthalmol, Vol. 22, No. 3, 2002 Foroozan et al. FIG. 1. Cerebral angiogram of left internal carotid artery injection, lateral view, obtained shortly after onset of left third cranial nerve palsy, showing a left posterior communicating artery aneurysm { arrow) oriented posteriorly and interiorly to the left supraclinoid carotid artery. gradually improved, and 4 weeks after initial presentation, her deficit was limited to a mildly hyporeactive left pupil 4.5 mm in diameter in dim illumination, compared with a briskly reactive right pupil measuring 4.0 mm. Extraocular movements were normal, without evidence of aberrant regeneration. Evaluation for recurrent thrombocytopenia revealed positive antinuclear antibodies and the lupus- anticoagulant, consistent with a diagnosis of systemic lupus erythematosus. Six weeks after admission, the patient was discharged receiving oral corticosteroid treatment. A repeat cerebral angiogram, performed 2 months after hospital discharge, revealed that the aneurysm diameter had shrunk from 10 mm to 4.5 mm ( Fig. 2). Two weeks later, elective craniotomy and clipping of the aneurysm were performed withut complication. On postoperative follow- up examinations, extraocular movements were full, without evidence of aberrant regeneration, and there was no evidence of anisocoria. DISCUSSION Our patient's aneurysm spontaneously shrank from 10 mm to 4.5 mm in diameter after cesarean delivery, and the third nerve palsy completely resolved. In their review of 161 unruptured intracranial aneurysms, Wiebers et al. ( 8) noted that with two exceptions, all symptomatic aneurysms were 10 mm in diameter or greater. Although a true measure of aneurysm size cannot be determined solely by angiography ( 9), this finding suggests that a reduction in the size of the aneurysm sac, and hence a relief of compression on the third nerve, was responsible for the spontaneous clinical resolution. However, we cannot exclude the possibility that the aneurysm sac, while initially patent, became partially thrombosed after the first angiogram, and that this accounted for an apparent reduction in intraluminal diameter. Spontaneous resolution of third cranial palsy resulting from intracranial aneurysm formation has been reported ( 3,10). In a review of isolated third cranial nerve palsy caused by intracranial aneurysms, Jefferson ( 11) noted that partial recovery occurs in several cases and speculated that " the cause of recovery is partly shrinkage by thrombosis sufficient to free the nerve..." Giombini et al. ( 3) reported five patients with third cranial nerve palsy caused by ICA-PCoA aneurysms who recovered within 3 months after the onset of the motility deficit and before surgery, although the mechanisms for recovery could not be identified. Greenspan and Reeves ( 10) reported a case of transient oculomotor nerve paresis that resolved before cerebral FIG. 2. Cerebral angiogram obtained 2 months after onset of third cranial nerve palsy and before surgical intervention, showing an attenuated left posterior communicating artery aneurysm { arrow) in the same position as seen in Figure 1. ^ 212 . _ „ , . © 2002 Lippincott Williams & WUkins , Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. ANEURYSMAL THIRD NERVE PALSY JNeuro- Ophthalmol, Vol. 22, No. 3, 2002 angiography documented the presence of a PCoA aneurysm. They postulated that a temporary conduction block or a shift in aneurysm position may have been responsible for the transient third nerve palsy, although sequential angiograms were not available for comparison. Similarly, our patient's deficit may have resolved because of a shift in aneurysm position, relieving compression on the third nerve. Although initial evaluation of the cerebrospinal fluid revealed no evidence of xanthochromia, a reduction in aneurysm size may have subsequently occurred by leakage of small amounts of blood. Wiebers et al. ( 8) have postulated that bleeding into the cerebrospinal fluid may be responsible for a reduction in the diameter of some intracranial aneurysms, suggesting that a newly formed clot may seal the point of rupture. In addition, Hamer ( 2) has suggested that bleeding of some intracranial aneurysms may occur without producing the typical symptoms of subarachnoid hemorrhage. The occurrence of our patient's deficit in the third trimester of pregnancy and in the setting of pre- eclampsia offers another explanation for aneurysmal growth followed by diminution before craniotomy. Pregnancy has been identified as a state that has stimulatory effects on aneurysmal growth, with the majority of aneurysms occurring during the third trimester ( 12). Hemodynamic changes during pregnancy include an increase in cardiac output, total blood volume, and stroke volume, with an associated decrease in arterial blood pressure ( 13). Histologic studies of arterial walls have shown alterations in elastic fibers, smooth muscle cells, and intimal thickening during pregnancy ( 14- 16). In their review of the risk factors for the development and rupture of intracranial aneurysms, de la Monte et al. ( 4) noted that many of the predisposing factors led to a reduction in prostaglandin levels. They suggested that a reduction in prostaglandins, which is believed to occur in preeclampsia ( 17,18), may be responsible for an increase in local cerebral blood flow, which could cause stretching of the arterial walls. Other investigators have stressed the importance of nitric oxide ( NO) in maintaining vascular tone during pregnancy, and patients with preeclampsia are thought to have abnormalities in NO metabolism ( 13). Several cases support the belief that alteration of the aneurysmal sac may occur during pregnancy. Pool ( 6) reported the case of a 21- year- old woman who, in her third trimester of pregnancy, experienced a subarachnoid hemorrhage and, by angiography 5 weeks later, had documented growth of the aneurysm sac. Weir and Drake ( 7) reported a 34- year- old woman in the 20th week of pregnancy who underwent surgical clipping of an aneurysm of the superior cerebellar artery. Postoperatively, the aneurysm neck underwent rapid growth over the ensuing 4 months, documented by angiography. Ortiz et al. ( 19) reported enlargement of a cavernous carotid aneurysm during pregnancy, which produced an ipsilateral Horner's syndrome and abduction deficit that partially resolved in the postpartum period. A reduction in the size of the aneurysmal sac was noted with MRI; repeat angiography was not performed in the postpartum period. The third cranial palsy in our patient could have been caused by lupus erythematosus, and the aneurysm could have been merely an incidental finding. Corticosteroid treatment could have been responsible for its resolution. The elevation in the PTT noted on admission, while thought to be an early marker of the ensuing HELLP syndrome, may have been caused by the lupus anticoagulant. Rosen-stein et al. ( 20) reported a 29- year- old woman who had an isolated, pupil- sparing third nerve palsy as an initial manifestation of lupus erythematosus. The third nerve palsy resolved after 4 weeks, during which time the patient received corticosteroids. They noted that the deficit spared the pupil and hence was most likely vasculopathic. Our patient's pupil was not spared, and the presence of an ipsilateral aneurysm in close proximity to the course of the third cranial nerve suggests that the neuropathy was caused by aneurysmal compression rather than by lupus-related vasculopathy. Furthermore, resolution of our patient's third nerve palsy was nearly complete before the introduction of corticosteroid therapy, which began 3 weeks after initial presentation. REFERENCES 1. Newman SA. Aneurysms. In: Miller NR, Newman NJ, eds. Walsh andHoyt's Clinical Neuro- Ophthalmology, 5th ed, Vol 3, Chapter 53. Baltimore: Williams & Wilkins, 1998; 2975- 3262. 2. Hamer J. Prognosis of oculomotor palsy in patients with aneurysms of the posterior communicating artery. Acta Neurochir 1982; 66: 173- 85. 3. Giombini S, Ferraresi S, Pluchino F. Reversal of oculomotor disorders after intracranial aneurysm surgery. Acta Neurochir 1991 ; 112: 19- 24. 4. de la Monte SM, Moore GW, Monk MA, et al. Risk factors for the development and rupture of intracranial berry aneurysms. Am J Med 1985; 78: 957- 64. 5. Reichman OH, Karlman RL. Berry aneurysm. Surg Clin North Am 1995; 75: 115- 21. 6. Pool JL. Treatment of intracranial aneurysms during pregnancy. JAMA 1965; 192; 109- 14. 7. Weir BK, Drake CG. Rapid growth of residual aneurysmal neck during pregnancy. JNeurosurg 1991; 75: 780- 2. 8. Wiebers DO, Whisnant JP, Sundt TM, et al. The significance of unruptured intracranial saccular aneurysms. J Neurosurg 1987; 66: 23- 9. 9. Atlas SW. Intracranial vascular malformations and aneurysms: current imagining applications. Radiol Clin North Am 1988; 26: 821- 37. 10. Greenspan BN, Reeves AG. Transient partial oculomotor nerve paresis with posterior communicating artery aneurysm. J Clin Neuro- Ophthalmol 1990; 10: 56- 8. 11. Jefferson G. 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