Case Presentation: A man in his 30s with essential thrombocythemia (ET; JAK2-negative) presented with one week of blurry vision, gait disturbance, and paresthesias following a viral upper respiratory tract infection. His symptoms began with retro-orbital pressure and diplopia with eye movement, progressing to paresthesias in his fingers and toes, and subjective hand weakness. By the time of presentation, paresthesias involved his hands and feet with symptoms of intermittent dysphagia. He denied recent vaccinations or medication changes. Vital signs were normal. Neurological exam showed a positive Romberg sign, unsteady gait, diminished light-touch sensation, and areflexia, but no ophthalmoplegia. Laboratory studies revealed a platelet count of 1,125 × 10⁹/L (normal 168–382). Toxicology screen, HIV Ag/Ab, hepatitis B and C serologies, and myasthenia gravis work-up was negative. Respiratory pathogen testing was positive for human rhinovirus. CT and MRI of the brain and spine were negative for demyelinating disease. CSF showed normal protein and cell count without albuminocytologic dissociation (ACD; normal CSF cell count and elevated CSF protein level).On hospital day 2, he developed hypernasal speech (rhinolalia aperta). He was diagnosed with Miller Fisher syndrome (MFS) and treated with IVIG for 5 days. Given his elevated thrombotic and potential bleeding risk from ET, Ristocetin cofactor activity and factor VIII activity were not consistent with acquired von Willebrand syndrome. He received aspirin during treatment without complications of thrombosis or bleeding. His symptoms improved, with persistent stocking-glove sensation changes and mild hypernasality at discharge. After discharge, anti-GQ1b antibody titer returned elevated at 1:3,200 (normal < 1:100).
Discussion: MFS is a rare Guillain–Barré syndrome variant often characterized by ophthalmoplegia, ataxia, and areflexia in 80% of cases. Other cranial nerves may be affected, leading to bulbar symptoms such as palatal paralysis and dysphonia. Diagnosis is supported by IgG anti-GQ1b antibodies, present in 89–95% of patients, as well as ACD, though this is only present in 47% of cases in the first week of illness and increases to 80% by week 3. His early lumbar puncture likely explains his normal CSF. Despite this, his paresthesias, areflexia, and rhinolalia aperta one week after a viral illness supported a clinical diagnosis of MFS.Hypernasality in MFS reflects bulbar neuropathy, likely due to anti-ganglioside antibodies affecting palatal innervation and causing velopharyngeal insufficiency. Rhinolalia aperta is an unusual feature that may precede the classic triad. His ET raised concern for thrombosis with IVIG; however, given his JAK2-negative status and lack of prior thrombosis, his risk was considered low. This case highlights rhinolalia aperta as a unique, early clue to MFS. Clinicians should “have a nose” for these nuances, as albuminocytologic dissociation may be absent early and ophthalmoplegia may not be present at onset. Coordination with hematology was essential to evaluate IVIG-related thrombosis risk in ET.
Conclusions: This case highlights rhinolalia aperta as a rare clinical finding in MFS that can precede the onset of the classic symptom triad. Diagnosis was supported by elevated anti-GQ1b titers. Clinicians should “have a nose” for these nuances and be wary that the lack of ACD does not rule out MFS. ACD is present in only 47% of cases in the first week, but the incidence rises to 80% by the third week.