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Show f. CIin. Neuro-ophthalrnol. 3: 31-35, 1983. Acute Painful Cavernous Sinus Syndrome in Unruptured Intracavernous Aneurysms of the Internal Carotid Artery Possible Pathogenetic Mechanisms THOMAS-MARC MARKWALDER, M.D. OTMAR MEIENBERG, M.D. Abstract Three cases of painful ophthalmoplegia with acute onset due to an unruptured aneurysm of the intracavernous portion of the internal carotid artery are reported. The possible pathogenetic mechanisms responsible for this unusual mode of clinical manifestation are discussed and the neurovascular relationships of the cavernous sinus are analyzed in respect of ischemic versus compressive damage to the intracavernous neural structures. Most intracranial saccular aneurysms manifest themselves clinically with an acute subarachnoid hemorrhage from rupture. In contrast, aneurysms of the intracavernous portion of the internal carotid artery, which constitute about 2-3% of all intracranial aneurysms, I.:.! rupture only rarely. If they do so, they do not bleed into the subarachnoid space, but produce a carotid-cavernous fistula with exophthalmos, congestion of conjunctival and fundus veins, and often a bruit audible over the ipsilateral eye and the skull.:l-h The vast majority of intracavernous saccular aneurysms of the internal carotid artery, however, becomes manifest in either of two characteristic ways:l. ,-._111: 1) A slowly progressive and usually painless loss of function of the third, fourth, fifth, and sixth cranial nerves; or 2) An acute cavernous sinus syndrome with almost simultaneous paroxysmal functional loss of these nerves, accompanied by severe pain. While a progressive compression of the cranial nerves by the aneurysm appears to be an adequate pathogenetic explanation in the first type, II the rapid and painful onset of symptoms is not completely understood in the second type. In addition, the clinical picture From the Departments of Neurosurgery and Neurology, University of Bern, Switzerland. March 1983 of the second type requires differential diagnostic delimitation against other painful ophthalmoplegias such as the Tolosa-Hunt syndrome, diabetic cranial neuropathy, tumor infiltration of the cavernous sinus, and the paratrigeminal syndrome of Raeder. Three cases presenting with an acute painful cavernous sinus syndrome due to an intracavernous carotid aneurysm constitute the bJsis for discussion of possible pathogenetic mechanisms responsible for this unusual mode of manifestation of unruptured aneurysms which previously had remained asymptomatic. Case Reports Case 1 A 21-year-old male was admitted on February 6, 1978, because of a sudden onset of severe left frontal headache and double vision. Six weeks ago, he had already suffered from moderate similarily localized headache lasting several days. Neurological examination revealed a complete sixth nerve palsy on the left side, a slight palsy of the left internal rectus muscle, and a minimal ipsilateral mydriasis with preserved light and convergence reactions. In addition, there was a slight to moderate loss of tactile sensation in the left VI and V2 dermatomes. No proptosis nor any conjunctival or fundal venous congestion were detected. Furthermore, a slight right motor hemiparesis which was only present for some hours was noted. Correspondingly, an intermittent left frontotemporal delta focus was found in the EEG. Plain skull x-rays and a CT scan were normal. Within the following 6 days, a complete left external ophthalmoplegia developed. The left pupil, however, became only moderately dilated (5 mm in diameter as compared with 3 mm on the right eye) and still contracted promptly to light and 31 Acute Cavernous Sinus Syndrome dilated normally in the dark. Carotid angiography demonstrated a saccular aneurysm of the intracavernous portion of the left internal carotid artery which measured about 1.5 cm in diameter and was partially thrombosed. The latter originated from the lateral wall of the juxtasellar segment of the carotid syphon and moderately compressed the presellar segment. Ligation of the internal carotid artery in the neck was performed on February 24, 1978. Postoperatively, the patient was immediately relieved from his pain and the oculomotor deficits improved quickly. By the fifth postoperative day, the fifth and sixth cranial nerves had already fully recovered. Only a slight adduction and elevation deficit remained from the third nerve palsy while the pupils were equal and normally reacting. The fourth nerve had remained completely paralyzed at that date. The further postoperative course was uneventful except for the transient ischemic attacks which presented as motor hemisyndromes. Within the following weeks all neurological deficits returned to normal. Case 2 A 70-year-old female was admitted on September 9, 1981, after onset of a paroxysmal right frontal headache and vomiting accompanied by double vision on right lateral gaze. The neurological examination revealed a sensory loss in the right VI and V2 divisions with a reduced corneal reflex and a complete sixth and partial third nerve palsy with moderate ptosis and an elevation deficit. Additionally, there was a Homer's syndrome on the right with the pupil only slightly dilating in dim light, while the light and convergence reactions were full and prompt. There was neither proptosis nor venous congestion of the conjunctiva or in the fundus. A CT scan revealed a large, slightly hyperdense space occupying lesion in the right parasellar region with marked enhancement after intravenous contrast infusion. Carotid angiography demonstrated a large, partially thrombosed intracavernous saccular aneurysm whose exact origin could not be determined. It was located laterally to the carotid syphon and was partially compressing the internal carotid artery in its intracavernous course leading to a distinct delay of circulation. Because of the age of the patient no operative intervention was undertaken. Under analgetic drugs the headache subsided during the following weeks, and the neurological deficits remained unchanged. Case 3 A 58-year-old woman was admitted on July 22, 1981,3 days after a sudden onset of left retrobulbar pain, double vision, and sensory loss on the left forehead and cheek accompanied by vomiting. 32 Neurological examination disclosed a complete sixth nerve palsy on the left. Oculomotor and trochlear nerve functions were normal. The pupils were equal and reacted fully and promptly to light, convergence, and dark. A sensory loss was present in all divisions of the left trigeminal nerve with absence of the corneal reflex. In addition, the left masseter and pterygoid muscles were partially paretic. There was no venous congestion. Plain x-rays of the skull were normal. A CT scan demonstrated a left parasellar mass with shell-like calcifications in its lateral aspect and marked enhancement on intravenous contrast infusion (Fig. 1, left). The left carotid angiogram showed a large, partially thrombosed intracavernous saccular aneurysm of the preophthalmic portion of the internal carotid artery. First an expectative attitude was taken but because of persisting heavy facial pain requiring high doses of analgesics, a four-vessel angiography was undertaken to investigate the flow efficiency in the circle of Willis. The latter again demonstrated the aneurysm (Fig. 1, right) and normal patency of the circle of Willis. This angiographic study was complicated by a right-sided hemiparesis and aphasia which both resolved within 2 days. In view of the high risk of an operative intervention, the patient was thereafter dismissed and drug therapy of the heavy facial pain was continued. The patient was last seen in August 1982. There was still some neuralgic pain in the right VI and V2 divisions which is now controlled by common analgesics. The right corneal reflex was absent, and third nerve function had returned to normal but there was still a complete sixth nerve palsy. Discussion The most conspicuous clinical features in our three patients with an intracavernous aneurysm of the internal carotid artery were the acute appearance of a cavernous sinus syndrome accompanied by severe pain. Although about half of the aneurysms of the intracavernous portion of the internal carotid manifest themselves in this way,a· 5. 8.10 the underlying pathogenetic mechanisms have not been a point of discussion. Why do such aneurysms, which probably have existed for many years without making any symptom or sign, present themselves one day so dramatically without having ruptured? A sudden simultaneous compression of several cranial nerves from acute dilatation of the aneurysm is hard to imagine. In addition, at the moment such aneurysms become manifest, most of them are partially thrombosed or calcified.3.4.5. 10 In addition, the lateral wall of the cavernous sinus prevents further aneurysmal expansion and acts as a rather firm encoating membrane.5 . I) In our opinion, it is conceivable that acute ischemia of the cranial nerves associated with the Journal of Clinical Neuro-ophthalmology Markwalder, Meienberg Figure 1. CT scan (upper part without and lower part with intravenous contrast infusion) and angiogram of case 3. Note the calcification of the aneurysmal wall (upper left) and partial thrombosis of the intracavernous aneurysm (lower left, right). (Reprinted with permission from the Department of Neuroradiology, University of Bern, SWitzerland, attention of Director Prof. P. Huber.) cavernous sinus could produce this symptomatology. This assumption is also consistent with the fact that almost all patients whose intracavernous aneurysm became manifest as described above were more than 50 years old.:J • 4. 5. 10 In our first case (a 21-year-old patient), a transient right-sided hemiparesis with a left frontotemporal EEG-focus, which appeared together with the acute painful cavernous sinus syndrome, indicated an acute thrombotic or embolic event. The carotid angiogram revealed a partially thrombosed aneurysm which moderately compressed the presellar segment of the carotid syphon. Even those patients in whom the intracavernous aneurysm directly compresses the nerves and leads to a slowly progressive and painless loss of function have occasional episodes (of some days or weeks) with severe pain and sometimes worsening of the clinical signs.:J• 5. Ii, 9 These patients can possibly develop a sufficient collateral circulation to compensate for the additional ischemic nerve lesion. An acute onset of eye muscle palsies accompanied by pain closely resembles the clinical picture of diabetic cranial neuropathy. Ischemic lesions of the oculomotor nerve have been demonstrated in March 1983 the latter disease.I~-14 An essential feature of ischemic third nerve palsies is sparing of the parasympathetic fibers. Therefore, the light reaction of the pupil remains intact or is only minimally affected in spite of a marked palsy of the external ocular muscles. Meadows,5 in his analysis of 15 cases of intracavernous carotid artery aneurysms, mentioned that the pupil was usually small. He did not attribute this observation to sparing of the parasympathetic fibers but to additional damage of the sympathetic innervation of the pupil. Unfortunately, he did not examine the reactions of the pupils to light and dark. While his interpretation may be correct in some cases, there are also cases of intracavernous aneurysms with sudden onset of symptoms and fully or relatively preserved pupillary light reactions with respect to the severity of the palsies of the extraocular muscles innervated by the third nerve. III. 15 Cogan'slli experience that "The surprising lack of mydriasis despite total paralysis of other functions of the lllrd nerve in lesions about the superior orbital fissure and cavernous sinus ... is not always explicable on the basis of coexistent involvement of the sympathetic fibers since the pupillary size and reactions are 33 Acute C,)\'ernous Sinus Svndn1me I lemal calOll a I J:all roouS $11111$ J en ngoh Jlophsra 1I lloIsal mrntngnl a TI!/ltBlJal Figure :!. :'\:('Ufl)\'.-l5(ul.H r('1.ltil)n~hlr~ l,f the (.l\'C'flll)U5 5111U5, .)(l-ordin~ h.l r.nklns()n 1" oJ HubN:' often norma!," might be explained by the predominance of ischemic over mechanical nerve lesions in this area, in dependence L~f the particular ,\11.1tomical conditions in the region of the cavernous sinus. Most anatomy books omit the intrac.wen1l1US branches of the carotid arterv, although thev have been described in large .IUtopSV studiesl~ ..]., .md sometimes can even be seen on normal carotid angiograms. 111 The meningohypophyseal artery .1I1d the inferior cavernous sinus artery supply the third, fourth, and sixth crani.ll nerves as those vessels pass within the wall of L~r through the C.wernL'US sinus. In addition, the inferior cavernous sinus artery supplies the Gasseri.ln g.mglion (Fig. 2). Occlusion of these vessels, whose origin m.1\' be incorporated in the .1I1eurvsm.l1 wall. may occur .IS a result of either compression by the aneurysm L'r thrombosis and may cause an .\Cute simult.meL~us ischemic lesion of the cr.mial nerves. The prLlb.lbilitv that such a phenomenon L~CCurS in the C.lse of an aneurysm of the intr.lcavernous portion Llf the internal carotid .lrtery is reLltivelv high; these aneurysms typically origin.lte fwm the "br.mching off" of the feeding vessels Llf the C.wernl~US sinus structures. II The usually sudden relief fwm p.lin and the impwvement of the (.wernLlus sinus symptoms .lfter cMotid Iig,ltiLln 1.'. I" (,111 be well-e,\plained by decompressiL~n Llf the V.1S.l nerYLlrum .15 by .1 decompressiLln of the nerves themseh'es. Thomas and Yoss,~ in a studv of 102 parasellar syndromes of different etiology, have emphasized that neither the mode of onset of svmptoms nor the sequence of evolution or p.1ttern of the neurological deficit is characteristic for the etiology of the underlving lesions. More than two-thirds of their patients had .1 tumor; 10 patients had a intracavernous aneurysm; ,1I1d only three had a TolosaHunt syndrome. Neuwradiological examination of patients with .111 acute p.linful CaVern(lUS sinus svndrome, therefore, is n1.1nd.1tory. One might .1IsL~ .ugue that in p,ltients with other causes than aneurvsms, some phenL~mena could be explained by ischemic lesiL~ns of the intr.1CJ\'ernous structures. Recent observ.ltiLlns in p.ltients with Tolosa-Hunt syndwme seem to c,mfirm this in p.lrt.~" References 1. Locl-,sky, H.B.. :--':,ltur,ll history of sub,u.lchnoid hen1l1rrh,lge. intr,lCr,1l1i,11 .1l1euf\:sms ,md ,ulerilwt'11LlUS m.llfl1rm,ltill ns 1. ,\"eurl;sun; Z5: 21°-23°, IU~Q. ~ .., Kr..lyenbuehl. H.. KLls~ifil--. ..1tion und klinische Symptlln1.1tl1!Llgie der zerebr.lIen Aneurvsmen. l)ph th.l Jn1l1!L1gic,1 167: 122-1<:'-1, 1073. 3, Jefferson, C: Lln the s,1CcuIM .lneurvsms of the intern,ll CMlltid .lrtery in the c,1\'ernous' sinus. Br J. Surg. Z6: 2<:'7-302, 103S. -I, kffersLln, G. Cl1ncerning injuries, ,1lleUf\'sms ,ll1d tumors il1Vll l\'ing the C.l\'ernou~ sinus. Tr,;ns. Ophth. l/nlLlJ. Slll. 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Dreyfus, P.M., Hakim, S., and Adams, R.D.: Diabetic ophthalmoplegia: Report of a case with postmortem study and comments on vascular supply of human oculomotor nerve. Arch. Neurol. 77: 337-349, 1957. 13. Asbury, AX., Aldredge, H., Hersberg, R., and Miller-Fisher, C: Oculomotor palsy in diabetes mellitus: A clinico-pathological study. Brain 93: 555-566, 1970. March 1983 Markwalder, Meienberg 14. Weber, R.B., Daroff, R.B., and Mackey, E.A.: Pathology of oculomotor nerve palsy in diabetes. Neurology 20: 835-838, 1970. 15. Boghen, D.: The pupil in cavernous sinus aneurysm. Ann. Neurol. 8: 202, 1980. 16. Cogan, D.G.: Neurology of the Ocular Muscles (2nd ed.). C Thomas, Springtield, Illinois, 1956, pp. 174-177. 17. Parkinson, D.: Collateral circulation of cavernous carotid artery: Anatomy. Can. ]. Surg. 7: 251-268, 1964. 18. Harris, E.S., and Rhoton, A.L., jr.: Anatomy of the cavernous sinus: A microsurgical study. ]. Neurosurg. 45: 169-180, 1976. 19. Wallace, S., Goldberg, H.j., leeds, N.E., and Mishkin, M.M.: The cavernous branches of the internal carotid artery. Am.]. Roentgenol. 101: 34-46,1967. 20. Takeoka, j.E., Gotoh, F., Fukuuchi, Y, and Inagaki, Y: Tolosa-Hunt syndrome: Arterio-graphic evidence of improvement of carotid narrowing. Arch. Neurol. 35: 219-223, 1978. 21. Huber, P.: Zerebrale Angiographie fuer Klinik und Praxis, von Peter Huber, Geleitwort von Hugo Krayenbuehl, und M Gazi Yasargil, Eds. Stuttgart, Thieme, 1979, p. 63. Write for reprints to: Thomas-Marc Markwalder, M.D., Neurochirurgische Universitatsklinik, Inselspital, CH-3010 Bern, Switzerland. 35 |
