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Show J. Gill. No'lIro-(ll'l1Ilta/l/wl. 5: 73-75, 1985 "J 1985 Raven Press, New York Editorial Myasthenia Gravis and Charcot-MarieTooth Disease In this iSSUt' t)t tht' Journal. Dr. J. R. lkrger and ,lssoci,lh,'s rt'port till' C,lSt' lli ,1 68-~'t'ar-(lld mdn with d typiC'll historv l)f Charcot·Maril'Tooth dise.lSl' tpt'rl)nt',l1 musndar .ltwphy) th,lt beg,:lO with slowl~' prl1gressivl' wt'tlknt'ss in thl' legs as a ylluth, pwgrt'ssed to the degret' that he was undble to wurk as d barber by age 36, dnd iin.,ll~· the diagnt1sis oi Chdro.:ot·MarieTOllth diseasl' W.1S made .1t age 42. In 1975, he del'eloped impaired ocular gaze to the left, which responded to Tensikm, and a nota bIt' imprCl\ ·t'ment in ocular motility WdS demonstrated on Mestinon therap~' thereafter. Two years later, ptosis, hoarseness, dysphagia, and external ophthalmoplegia developed, and again there was a pOSitive Tensilon test. Convincing clinical data contirmed the fact that this patient did indeed han.' both diseases, i.e., CharcotMarie- Tooth disease and myasthenia gravis. The reason that this report is of particular interest is that reports of ocular findings mimicking mvasthenia gravis have been made previously (Spector et al. l and Brust et a1. 2) and Brust and associates) also reported the case of a patient with Charcot-Marie-Tooth disease and ocular myasthenia gravis. What arc these data saying? A fairly rare disease-Charcot-MarieTooth syndrome-has now been reported in three interesting relationships with my.lsthenia gravis. Peroneal muscular atrophy can at times look like myasthenia gravis, it can at times llCCur with ocular myasthenia gravis, and it can at times occur with generalized myasthenia gr.1Vis. Charcot-Marie-Tooth disease is of sufficient rarity, as is myasthenia gravis, that one bq~ins to wonder if a possible relationship bl,twt'l'n these two disorders may not be wurth investigating. At the least, this report should spur clinicians to make sure they dll il particul<lTly careful examination of the eyes of patients ~uspected of having Charcot-Marie-Tooth diSl'ase. For the ophthalmologists reading this issllt', a few words about Charcot-Maric-Tooth disease: Harrison's Principles vf hltt'rl/al MI'dif;lI(' (10th edition) lists eight genetically determined neuropathies, as follows. I. Chrllnic f,)mili,lI pplynl'uropathie~ without a known 'lssociatl'd mdab'llic disturbancl' I. Pl'Tllnl',ll muS(uliH 'ltrophy :!. Hl'Tl'ditMy Sl'nSory neuropathy 3. Prvgn'ssivt' hypertrophic polynt'uropathy II. Ct'ndic polyn~uropathies.lssociated with a known metabolic disordl'r I. r~efsum's disl'aSl' 2. Abl'talipoproteinemia 3, Ml't,lChromalic leukodystrophy 4. Tangil'r disease 5. F.lmilial amyloidosis with n~uropalh.v Prillcipft's of Illtenwl Medici,,!, describes Charcot-Marie-Tooth disease as a dominant hereditary disease with ons",t during adolescence or adulthood. Distal muscle atrophy, secondary to chronic degeneration of peripheral nerves and roots, begins in the feet and legs and later involves the hands. Early symptoms are muscular wasting and weakness, involving extensor and everter muscles of the feet and producing an cquinovarus deformity. Later, all muscles below the middle third of the thigh may atrophy, resulting in the classic "stork leg" or "Champagne bottle" appearance. After a period of years, atrophy of hand and torearm muscles devl'lops. A~ain, the wastin~ seldom extends "bow the elbllws, just as it seldom gtleS aoov(' tlw middll' third l)f tht' thi~hs. The feet ,ue short .md archt'J, Sllmdinws with perfl1r"ting ulcers. Pain, pMt.'sthl'sias, and cramps Me Cllmnum. Thl' llbj,xtiVt' scnSllT\' disorder is usu"lJV r"ther sli~ht, but is conspicuous enllu~h to en'lble one to distin~uish this syndTt)me from progressive musculclT atrophy. lmp"ired positil1ll and vibrali1ry sl'nsati~lIl, and "PSt'llt touch .llld p"in senSiltiOIl llo.:cur in tilt' ft.'el. Refkxt.'s arc absent in tilt' inv\llvl'J limbs. Thl' pro~ression is very SlllW .1I1J it mOlY Pt' .lrrestt'd ilt allY stage. In families with onset dllrin~ achllescenCl" nerve (tmdUl-tioll vl'locities arl' very slow, and, pathologically, llnt.' Sl'l'S hypl'rtrophic neuropathy with '\mion bulp" fllrm.ltion. In families with adult onset in the h)llTth ~lr fifth decade, nerve wnductill!l velocities are normal llr minimally reduced and tht' p<lthology is that (lfaxonalloss. 73 rn' ~ihl1~ ,Ire ~,Iid to l1l' infrl'qul'nl with Ch,lrcI't-t\l,lril,-Tuoth di~l',lSI" but ,I surprising lllllllb'T 1I,In' b"I'1l n'l'ortl'd'l: I{dIlHII" I'lh"wnlu"" l'up.Il,"'\" ,1l1"IIl.lli,'" 1 t'\t,'rn"t"l'hth"lrn"I']I'hi,l ·1 ~\'''1.,pnll'' .; l)l'lil' ,IITI'I'hv 4' l '!,li,' lW(lTili .. I d','r· .. ,'pli,' llt'llrt'p"lhv S, I't".. i.. ,Hld "I'hlh"lrm'I']"hi" "illllll,'linh Illy,,..11wlll, l hr,l\'is '1 t\ ..",,(j,lh,d ,'nd,lf ll1\"'"l11l'ni" !-:r"vi" Ill, t\ ....."·i,llt'd !-:"lwr,lli",'d my,l.. tl11'ni,l !-:T,wis \V,llsh ,md flll,,!"1 pllintllut thai onst't occurs llsllall~' bl'hwl'n ',lgl'S ='- and 15, bul may be dl'll'rrl'd unlil Ihl' third d",'adl'. W,1Stinh st.lfts in the Slll,lll mllsdl's llf thl' fl't'L thl'n in pl'ron(.'al musdl'S, tlwn in tht' .-ali, fllrl'arm, ilnd hand. The musd,' atrophy pfllgrt'sscs, foot drop de\" l'II)PS, <lnd, in r,lrl' instan.-es, fibrillations are l,bsern'd. The musclc atrophy tends to spar(' th,' thighs, hips, upper <lrms, and shoulders. The tl'ndlln rl'lll'xl'S are ultimately lost. SensdhIm often is not affected, ataxia is not obSl'rved, and thl' weakness and atwphy are usually symmetrical. However, Ford' noted one leg ilnd arm dS being extensively involved several years before the opposite side was aHected. Mentality is normal, and sphincter control is preserved. Lemieux and Neeneht< described an association between Charcot-Marie-Tooth disease and hereditary nephritis. A relationship between Charcot-Marie-Tooth disease and Friedreich's ataxia has been noted repeatedly. Stephens? reported a family of four generations with 63 members, and four in one generation had features of Friedreich's ataxia, CharcotMarie- Tooth disease, and external ophthalmoplegia. Pleasure and Schotland~ in Merritt's Tt'xtl1l.10k of Neurology (7th edition) describ(' peroneal muscular atrophy as including several genetic disorders of the peripheral nervous system that most severely involve the distal leg muscles. Inheritance is usually autosomal dominant but is less frequently autosomal recessive. Foot deformities are frequent and mav be the only .1pparent feature of the disease in mildlv affected family mt.'mbers, One may need to Ill,'k at thl' feet of family memb('rs even if they .In.' asymptomatic. Stocking-glove sensation impairment is usually present, but sensation is preservl'd in some families. Achilles reflexes are absent and other tendon refll'xes may be diminished. Ple.lsure and S.-hntland diffl'rentiate tWll types of Charnl1-M,lTi,'·'1 ""th di~l'asl' on thl' basis of n,'n'l' ",ndll,'II"I1' 'I",itil'~ and SUfdl nerve bi"~ I' I:,' '"".'/. ,:',." lorm (type I) shows motor and sensory nerve conduction velocities of less than 65% of normal and prolonged distal latencil's; nerve biopsy shows segmental demyl'lination. The axonal form (type II) shows motor and !;ensory nerve conduction velocities of Wl'ater than 65'X, of normal; biopsy shows Wallerian degeneration to be most severe in distal nerve segments. In type I Charcot-Marie-Tooth disease, symptoms begin in the first or second decade of life with foot drop and steppage gail. Distal atrophy produces the stork leg deformity and intrinsic hand muscle atrophy develops later. Distal reflexes are decreased or absent and stockingglove sensory deficit is found. Scoliosis and high arches or clubbed feet are common. Peripheral n('rves are often palpably enlarged. If an associated tremor is present, the constellation of Charcot-Marie-Tooth syndrome with tremor is called the Roussy-Levy syndrome. In type II Charcot-Marie-Tooth disease, the first symptoms often appear in adulthood, although foot deformities may be evident much earlier. Atrophy, sensory changes, and depressed feflexes usually show less severe deficits than in type L and nerves are not palpably enlarged. The spinal fluid protein level is frequently ele\'ated in type I but is normal in type II Charcot-Marie-Tooth disease. The spinal fluid is othem'ise normal. The differential diagnosis of peroneal muscular atrophy includes Fried· reich's ataxia, familial amvloidosis, DejerineSollas disease, Refsum's d-isease, lipomas and other masses in the lumbosacral canal, and myotonic muscular dystrophy. I have seen two brothers with Charcot-r.,'tarie-Tooth disease in whom there was an interesting association with Duane's retraction syndrome. The Duane's syndrome was unilateral in one brother and bilateral in the other. The point to be emphasized here is that every patient with suspected Charcot-rvlarie-Tooth s\'ndrome merits a careful neufll-ophthalmologic examination. The ductions Shlluld be quantitated. Photographs of the lids 'llld l'cular rotations are helpful in the recllrd. Finally, even' patient with ptosis and diplopia should ha\'e a Tensilon tesl. This continues to be an excellent clinical dictum. I believe I have seen a family with chronic progressive external ophthalmoplegia and ocular myasthenia gravis together, Dr. S. W. Clark of Waycross, Georgia, saw three brothers with a classic slow progression of ptosis and external ophthalmoplegia. A family photograph album documented the presence of the syndrome in several family members. When I saw one of them in consultation, the findings of chronic progressive external ophthalmoplegia or Kiloh-Nevin ocular muscle Journal of Clinical Neuro-ophthalmology Editorial: My.lstncnill CravisiCnarcol-Marie-Toolh Disease dystrophy were so impressive that it was thought unnecessary even III do a Tensilon h.'st. Dr. P. S. O'Connor reminded mt" of the dictum, however. and a Tensillln t","st Wd!i performt"d. To my amazement, there was .m unequivocal improvement in ptosis .tnd lll,:ul'lr motility in thl' patient after d dose l)f Tensilon. Careful dinical June 1985 obsl'rvations need to be continually made in neurologic diseases. We are grateful to Dr. Beq.;N and associatt"s for adding this additional intl'Tl'Sting case to the literature. J. l. Smith, M.D. 75 |