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Clinical Reasoning: a Case of Acute Onset Bilateral Ptosis in a Young Child

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Clinical Reasoning: a Case of Acute Onset Bilateral Ptosis in a Young Child RESIDENT & FELLOW SECTION Clinical Reasoning: Section Editor A case of acute onset bilateral ptosis in a Mitchell S.V. Elkind, MD, MS young child Darshan Das, MRCPCH SECTION 1 sizes were 4 mm, equal, and reacted briskly to light Stefan Spinty, A 5-year-old boy presented with acute onset bilateral and accommodation without relative afferent pupil- MRCPCH ptosis. An initial unilateral ptosis had evolved over lary defect. Fundus examination was normal. There Ram Kumar, MRCP the preceding 3 days, following a resolved pyrexial was full range and no fatigability of extraocular upper respiratory tract illness (URI) treated with oral movements. Cover test findings were equivocal: a penicillin. His mother reported that recently he was subtle left esophoria at near, and small (8 D) esotro- Correspondence & reprint unable to walk half a mile to school, but had no pia with horizontal diplopia at distance. Forced eye requests to Dr. Kumar: [email protected] difficulty with stairs. There was no history of ocular closure was normal without eyelid myotonia. Other pain, vomiting, headaches, weight loss, dysphagia, cranial nerve examination was normal including fa- constipation, or urinary disturbance. The ptosis was cial sensation, bulbar strength, and gag reflex. He reported not to fluctuate, with no reported tearing, had normal muscle bulk, tone, and active muscle photophobia, or visual disturbance. His prior devel- strength in all limbs. Gower sign was negative and opment was normal, and there was no family history limb girdle fatigability could not be elicited. His deep of relevant neuromuscular or autoimmune disorders. tendon reflexes (DTR) were normal, and symmetric with plantars downgoing. Gait was normal without On examination he was alert and apyrexial, with- cerebellar signs. out rash or lymphadenopathy. His systemic exam- ination was unremarkable aside from enlarged Questions for consideration: noninflamed tonsils. He had bilateral ptosis obscur- 1. What are the differential diagnoses for an acute ing the visual axis: marginal reflex distances were Ϫ3 onset ptosis? mm and Ϫ2 mm on the left and right, respectively. 2. Which diagnoses are most likely in light of the There was no conjunctival injection or tearing. Pupil above clinical findings? GO TO SECTION 2 Supplemental data at www.neurology.org From the Department of Neurology, Alder Hey Children’s Hospital, Liverpool, UK. Study funding: The case study was sponsored by the author’s institution, Alder Hey Children’s NHS Foundation Trust. Go to Neurology.org for full disclosures. Disclosures deemed relevant by the authors, if any, are provided at the end of this article. © 2012 American Academy of Neurology e155 SECTION 2 toms to suggest an ongoing systemic inflammatory The differential diagnosis for ptosis should include pathology. both acute onset and chronic conditions (table 1). The bilateral involvement suggested a systemic or Ptosis may present acutely irrespective of the under- diffuse CNS pathology. The normal pupillary re- lying cause being acute or chronic. Parents may not flexes, visual acuity, and lack of involvement of para- have recognized a longstanding mild ptosis that does sellar cranial nerves did not support a focal pathology not fluctuate. Examining photographs from infancy along the course of the third nerve. can help to distinguish a recent onset from chronic The ptosis was painless, also against an anatomic ptosis. third nerve lesion or migraine variant. Cavernous si- The pertinent positive features were the acute nus thrombosis, orbital pathology, infection, and in- onset following URI, bilateral involvement, and flammatory disorders including the heterogeneous report of walking distance limitation pointing to- Tolosa-Hunt syndrome typically involve ocular pain, ward a form of myasthenia. Formal examination tearing, and conjunctival injection. A persistent could not demonstrate limb-girdle fatigability which, as with manual muscle strength testing, is mild, unilateral ptosis with other features of Horner often difficult to demonstrate formally at this age. syndrome may evolve over time in migraine. Fatigue is a nonspecific feature of many peripheral The absence of ataxia and normal DTR were not and CNS disorders. in favor of Miller Fisher syndrome (MFS) (an Given the acute onset following URI, causes ophthalmoplegia-predominant variant of Guillain- to consider include immune-related illnesses such Barre´syndrome [GBS]). The normal DTR were also as myasthenia gravis, postinfectious demyelina- against a widespread neuropathy, myopathy, or botu- tion, diphtheria toxin-related neuropathy, and lism. Botulism was unlikely since there was no cranial acute deterioration in mitochondrial and congeni- and peripheral muscle weakness, nor any autonomic tal myopathies. There was no persistent local pain, disturbance, e.g., abnormal pupillary reflexes, constipa- facial edema, rash, fever, or constitutional symp- tion, and urine retention. Importantly, DTR are typi- Table 1 Causes of ptosis Causes Neurologic Muscle and neuromuscular junction causes Myasthenic syndromes Myasthenia gravis, congenital myasthenic syndromes Botulism Including iatrogenic botulinum toxin Congenital myopathies Myotonic dystrophy, RYR1, and X-linked myotubular Mitochondrial myopathies POLG, Leigh syndrome Acquired focal and generalized Orbital myositis myopathies 3rd nerve lesions Compression Raised intracranial pressure, tumors, aneurysm, hemorrhage, cavernous sinus thrombosis, skull base and orbital pathology Demyelination Guillain-Barré syndrome and variants (Miller Fisher syndrome) Infection/inflammation Basal meningitis, sarcoidosis, Tolosa-Hunt syndrome Vascular Basilar territory infarct, vasculitis, venous sinus thrombosis Toxic Diphtheria, drugs (highly active antiretroviral therapy) Ophthalmologic/ocular Congenital Myogenic dysgenesis, syndromes (e.g., Noonan, Smith-Lemli-Opitz) Acquired Aponeurotic disinsertion, lid tumors, and other lid lesions Pseudo-ptosis Microphthalmia, hypotropia, contralateral lid retraction Others Psychogenic “Functional pseudoptosis” Endocrine/metabolic Diabetes mellitus, thiamine deficiency, thyroid disorders Migraine Ophthalmoplegic migraine, trigeminal autonomic cephalalgias Autonomic Acquired Horner syndrome, genetic disorders including neurotransmitter synthesis e156 Neurology 79 October 30, 2012 cally normal in myasthenia gravis. Ocular myasthenia ent acute onset ptosis in the absence of other cranial was a possibility since limb girdle weakness and fatiga- or peripheral neurologic signs. bility may be minimal. It would be extremely unusual to consider psy- Question for consideration: chogenic causes at this age. Psychogenic causes 1. Which investigations would you consider to dis- should be considered in an adolescent with an appar- tinguish among the differential diagnoses? GO TO SECTION 3 Neurology 79 October 30, 2012 e157 SECTION 3 18 mm tonsillar herniation, without other abnor- The investigations were targeted toward identifying malities. A lumbar puncture was deferred on neu- ® myasthenia gravis (table e-1 on the Neurology Web rosurgical advice due to concern of inducing site at www.neurology.org). Normal investigations decompensation of the Chiari malformation. included complete blood count, urea and electro- The child had stimulated SFEMG (SSFEMG) of lytes, aspartate aminotransferase, alanine amino- orbicularis oculi, repetitive nerve stimulation test transferase, C-reactive protein, and thyroid function (RNS) of abductor pollicis brevis, and nerve conduc- tests. Anti-streptolysin O titer was raised at 300 IU/ tion studies (NCS) under propofol sedation. The mL. The ice-pack test was attempted but the child RNS and SSFEMG were normal. NCS revealed ab- could not cooperate. The ice-pack test is a safe and sent F waves but was otherwise normal. Propofol can 1 sensitive alternative to the Tensilon test. The Tensi- transiently abolish F waves, but is not typical in chil- lon test was deferred because of its side effect profile dren having NCS performed with sedation in our and the ready availability of single fiber EMG department. (SFEMG) in the department. An MRI of the brain without contrast enhance- Question for consideration: ment showed a type 1 Chiari malformation with 1. What diagnoses would you consider at this stage? GO TO SECTION 4 e158 Neurology 79 October 30, 2012 SECTION 4 DISCUSSION The clinical diagnosis was MFS. A neuromuscular junction disorder was unlikely in Clarifying the diagnosis took 3 weeks, requiring the light of the neurophysiologic studies. Neurophysio- evolution of neurologic deficits from the initial iso- logic studies including RNS and SSFEMG can be lated ptosis, and exclusion of alternative diagnoses. used to diagnose myasthenic syndromes in young The absent F waves and the response to the IVIg children. These investigations are highly operator de- supported the diagnosis. pendent, relying on expertise of the neurophysiolo- MFS is a GBS variant characterized by partial or gist with children, compliance of the child, and complete ophthalmoplegia, ataxia, and areflexia. specific muscles chosen for study. The sensitivity of These deficits may evolve after initial presentation.4 RNS for ocular myasthenia is low, whether facial, MFS is an immune-related disorder, associated with axial, or limb nerve-muscle pairs are tested.2 a specific antibody to a peripheral nerve antigen, the 5 SSFEMG involves stimulation of the nerve to the glycolipid GQ1b. The antibody appears to be di- muscle undergoing single fiber recording.
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