| OCR Text |
Show f. Clin. Neuro-ophthalrnol 2: 61-63, I Q82. The "Nuclear Third" Question Controversy and provocJtion rJise their heads again-even in this issue of the Journ.ll! Dr. Warren and associates suggest that lurking out there in the clinics is a relatively unappreciated clinical pattern, which they believe points to a central lesion within or contiguous to the oculomotor nerve nucleus in the midbrain. Although the pattern may be clinically subtle or only modest in degree, the picture they are painting is the combination of an isolated weakness of the inferior rectus muscle on one side, accompanied by a resting and intention tremor on the other side. Now, at first blush, my personal reaction would be to disagree with their suggestion and to tum the paper down for the Journal. On second thought, however, one must recall that Dr. BurdI' is not only a brilliant neuro-ophthalmologist, but is also on the editorial board of this quarterly publication. Next, we must consider the fact that we are continuously looking for good clinical papers, and a clinical proposal from a section of Neuro-ophthalmology of stature must not be lightly dismissed. I have therefore concluded that the best way to present the subject is to publish their paper, and to give some background editorial comments which may be pertinent to the general ophthalmologist reading about the subject. A classic breakdown of the types of III nerve palsy was given by Dr. Alfred Kestenbaum, and was given on pp. 274-283 of the second edition of his text Clinical Methods of Neuro-ophthalmologic Examination. This may be modified for practical topical differential diagnosis into eight types: 1) the nuclear type, 2) the dorsal fascicular type, 3) the ventral fascicular type, 4) the root or neuritic type, 5) the basal type, 6) the cavernous sinus type, 7) the superior orbital fissure type, and 8) the orbital apex type. Nuclear third nerve paresis has been considered as having the following attributes: 1) the lesions are rare; 2) diagnosis is facilitated by the neurologic company the lesion keeps; 3) a hall mark of nuclear third nerve disease is isolated involvement of muscles innervated by the oculomotor nerve; 4) Kestenbaum's modification of Mauthner's rule" Involvement of all oculomotor supplied muscles of one eye, while the other eye is intact, excludes a nuclear seat of the lesion;" and 5) since the March 1982 - Editorial Comments superior rectus muscle is the only contralaterally innervated muscle from the third nerve nucleus, the prototype nuclear lesion would be an ipsilateral third nerve paresis associated with a contralateral superior rectus weakness-according to the Warwick schema. Of course, on clinical grounds, the point has been repeatedly emphasized-isolated involvement of an extraocular muscle innerved by the third nerve must be due to a lesion either in the orbit or in the nucleus, and statistically the orbit wins in this differential about as often as Ivory Soap purity prevails (99 and 44/100ths). We can dismiss with the dorsal fasicular lesion producing Benedikt's syndrome; the ventral fascicular and root lesions producing Weber's syndrome; the isolated involvement of the basal and neuritic types; the associated involvements of cranial nerves 4,5, and 6 in the cavernous and fissure types; and the encroachment upon optic nerve and later proptosis in the orbital apex types-at this time. I think a big point in discussion of Dr. Warren's paper is a semantic difference with the classification of "skew deviation." One of the major salutary effects of the discussion now being engendered is that it hopefully will lead to a more definitive clinical workup of neurological patients who have vertical double vision, or who show a vertical deviation of the eyes in combination with other presenting signs. In my experience, many patients who present with a stroke, head injury, or other intracranial mishap, and who concomitantly note vertical diplopia are promptly labeled by many neurologists as having "skew deviation." They simply use this term "skew deviation" as a synonym for a vertical misalignment of the eyes that they do not otherwise appreciate or evaluate. They overlook thereby superior oblique palsies, orbital floor fractures, restricted inferior rectus muscles, Brown's superior oblique tendon sheath syndromes, old strabismus, and many other problems thereby. To help in this dilemma, we reported a classification of "skew deviation" in 1964, (Smith, J.L., David, N.j., and Klintworth, G.: Skew Deviation. Neurology. 14: 96, 1964) into three types of vertical ocular deviation: 1) comitant; 2) laterally comitant; and 3) noncomitant groups. The following diagnostic criteria were proposed to summarize the situation: 1) sudden onset of vertical diplopia 61 Editorial Comment: The "Nuclear Third" Question (usually in adults); 2) screen and cover test reveals a significant vertical deviation (comitant or noncomitant); 3) old photographs and careful history substantiate no preexisting strabismus; 4) a laterally comitant deviation (no deviation in left gaze, for example, but vertical deviation in right gaze, which is essentially equal both up and right and down and right, and is essentially the same in amount with either eye fixing in these positions); 5) associated signs and symptoms on the neurologic side; 6) clinical evidence of a brachium pontis level lesion (less commonly, mesencephalic level); 7) third and fourth nerve disease and orbital fractures, and the like, excluded by careful eye examination; and 8) noncomitant skew deviation-mimics either inferior rectus, superior rectus, or inferior oblique paresis, or primary overaction of an oblique-but with no other evidence of third or fourth nerve disease. Now, we are getting down to the "moment of truth!" Is there such an animal as a "noncomitant skew deviation"? If we look at case 1 in the paper of Warren et aI., they present a patient with a right inferior rectus palsy and state-"This was differentiated from a skew deviation by the marked secondary deviation demonstrable on the Hess chart." If one takes that statement at face value, this would mean that the authors demand that skew deviation must always be comitant. Against this is the observation that Dr. Hoyt told me about in a discussion when we were at the Wilmer Institute, about 1956. He pointed out that if you take patients with fresh and classic instances of Wallenberg's syndrome (lateral medullary plate infarction or the so-called posterior-inferior cerebellar artery syndrome)-and study them carefully with the red glass test, it is found that a majority of these patients will note a component of vertical diplopia during the early phases of this disease. Furthermore, if one analyzes these cases very carefully, it is not uncommon at all to see that the patient is calling an isolated weakness of an inferior rectus, or isolated weakness of a superior rectus, or even a primary overaction of an oblique muscle- as the motility pattern that is accompanying the Wallenberg's syndrome. When one first encounters this, the possibility enters the mind that although we have a classically localizing and restricted lateral medullary softening, that maybe there is also a concomitant minute lesion in the third nerve nucleus up in the midbrain in that patient, too. However, after finding this over and over again, that possibility begins to fade from reasonableness, and one then begins to ponder the possibility that perhaps a vertically noncomitant deviation can be produced by a lesion much, much lower in the brain stem, and that this may be a noncomitant skew deviation associated with the primary softening. Carpenter and others demon-strated some years ago the existence in primates of a vertically connecting pathway coming down from III nerve nuclear level in the midbrain ipsilaterally, down the stem via medial longitudinal fasciculus, passing thence back through brachium pontis to cerebellum, and returning via cerebellar outflow tracts through brachium conjunctivum, again back to about red nucleus level. This seemed to be an appropriate explanation for the syndrome of "lateral comitance," which can certainly be seen in the human as a form of skew deviation, and might even be a related explanation for noncomitant patterns. As I look at the other cases presented by Dr. Warren and associates, I personally do not find that their thesis has been anatomically or neuroradiologically verified as yet. Basically, case 1 is the combination of right inferior rectus weakness and a left tremor; case 2 is a left inferior rectus weakness and a left tremor; case 2 is a left inferior rectus weakness and a right sided tremor; case 3 has extensive multiple sclerosis with quadriparesis, dysarthria, clonus, bilateral Babinski signs, and a left inferior rectus paresis, and the locus of lesion or lesions in that case could certainly not be established. Case 4 has bilateral inferior rectus weakness- greater on the left, plus a left superior rectus weakness. I could not agree that the lesion was greater on the right (to account for left superior rectus weakness) when inferior rectus involvement was greater on the left. Again, the need for neuropathologic documentation is great. To me, case 5 is really skew deviation. The combination of right inferior rectus weakness (giving a right hyper deviation down and right) and a left superior rectus weakness (giving a right hyper deviation up and left) certainly sounds like a skew pattern, particularly when we add left beating nystagmus and 50 monocytes in the spinal fluid. Therefore, I think the point proposed by Warren et al. has yet to be substantiated. Out of their presentation, however, should definitely come the following points, which are all positive and edifying to my mind: 1) neurologic patients with vertical eye deviations should have the patterns specified by appropriate measurements of quantitative phorias, red glass tests, lancaster tests, Hess screen, or other methods; and 2) ophthalmological patients with isolated inferior rectus weakness should have a careful neurological evaluation, particularly looking for a resting or intention tremor on the other side. Certainly, the ophthalmologist can have the patient walk down the hall, tum around, check the Romberg test, and see if the patient can walk tandem, and then do a finger-to-nose test and watch the stretched out hands for a tremor. Finally, we will leave it up to Dr. BurdI' and associates to continue to look for their syndrome and to give us a follow-up with high-resolution computed tomo- Journal of Clinical Neuro-ophthalmology graphic confirmation ,1Od in the fin.ll analysis, neuropathologic confirm.1tion. One thing we must .111 le.un ,1S we pass through life is how to disagree without being disagree.lble. I hold Dr. Burde in such high esteem th.lt I am simply making these points in overview, ,1nd will try my best to be on the lookout for simil,lf cases. I do not want .tll the practicing ophth.1lmologists who find inferior rectus muscle limitations, however, to forget the periphery .1Od conclude there March 1982 Smith must be midbrain mischief in their patients, however! J. lawton Smith, M.D. References I. Kestenbaum, A.: Clinical Methods of Neuro-ophthaJmo/ ogic [x.Jmin.ltion (2nd I'd.). Grune & Stratton, New York, 1961, p. 274-283. 2. Smith, '.L., D,lVid, N.j., and Klintworth, G.: Skew deviation. Neurology 14: 96, 1964. 63 |
