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Ischemic cranial nerve 6 palsy and lipemia retinalis in a patient with hypertriglyceridemia

Published:February 03, 2022DOI:https://doi.org/10.1016/j.jcjo.2022.01.011
      Severe hypertriglyceridemia can occur as a primary (genetic) disorder or secondary to diabetes mellitus, hypothyroidism, alcohol use, or medications. Ophthalmic signs of hypertriglyceridemia include xanthomas, xanthelasmas, and corneal arcus.
      • Zahavi A
      • Snir M
      • Kella YR.
      Lipemia retinalis: case report and review of the literature.
      However, atypical presentations also can occur. Prior case reports describe presenting symptoms of intermittent vision loss due to associated hypertensive retinopathy or blurry vision from secondary central serous chorioretinopathy or branch retinal vein occlusion.
      • Nagra PK
      • Ho AC
      • Dugan Jr., JD
      Lipemia retinalis associated with branch retinal vein occlusion.
      • Wong S
      • Shields R
      • Silva RA.
      Lipemia retinalis in a woman with hypertriglyceridemia.
      • Mishra C
      • Tripathy K
      Lipemia retinalis. [Updated 2021 Dec 12]. In: StatPearls [Internet].
      In this report we describe a unique presentation of an isolated cranial nerve 6 palsy and lipemia retinalis in a young patient with severe hypertriglyceridemia. The case aims to inform clinicians to consider an urgent systemic evaluation for life-threatening hypertriglyceridemia when faced with this presentation.
      A 43-year-old male with no known medical history presented to our clinic with 4 days of binocular horizontal double vision. He denied any other vision changes, recent trauma, headache, neck pain, tinnitus, fatigue, fevers, chills, weight changes, joint pain, or discomfort with chewing. His uncorrected visual acuity was 20/40 OU, and intraocular pressures were 10 mm Hg OU. He had no relative afferent pupillary defect, and his confrontation visual fields were full OU. Ocular motility testing revealed a –2 abduction deficit OD and full ductions in the other 8 cardinal directions. He had full extraocular movements OS. On strabismus examination, the patient had no manifest deviation in primary gaze, and the deviation was incomitant. He exhibited approximately 30 PD of esotropia in left gaze, left and upgaze, and left and downgaze. Slit-lamp examination was unremarkable OU. A dilated fundus examination revealed white and milky retinal vessels in both eyes (Fig. 1). He had no disc edema. He was afebrile and had no other cranial nerve or focal neurologic deficits on physical examination. A diagnosis of a right-sided cranial nerve 6 palsy and lipemia retinalis OU was made.
      Fig 1
      Fig. 1Ultra-wide-field fundus photography of the right (A) and left (B) eyes at presentation.
      This patient was referred to the emergency department, where magnetic resonance imaging and angiography of the brain and orbits were emergently obtained and showed no acute infarct, no vascular stenotic disease, no masses, and an incidental aneurysm of the right anterior cerebral artery. Blood work revealed a total cholesterol level of 22.68 mmol/L (normal, <5.2 mmol/L), a triglyceride level of 61.73 mmol/L (normal, <1.69 mmol/L), and an HbA1C of 12.5% (normal, <6.5%). The patient was ultimately started on gemfibrozil and metformin and was counselled regarding dietary and lifestyle modifications. At his follow-up visit 1 week later, his serum cholesterol and triglyceride levels had normalized, and a repeat dilated fundus examination demonstrated resolution of his lipemia retinalis findings (Fig. 2). His abduction deficit OD was stable at short-term follow-up with ophthalmology, but he was noted to have resolution of diplopia and full extraocular motility several months later with his primary care physician.
      Fig 2
      Fig. 2Ultra-wide-field fundus photography of the right eye after treatment.
      Lipemia retinalis is a rare manifestation of severe hypertriglyceridemia that develops due to light scatter by triglyceride-laden chylomicrons in the plasma when serum triglyceride levels exceed 16.94 mmol/L.
      • Nagra PK
      • Ho AC
      • Dugan Jr., JD
      Lipemia retinalis associated with branch retinal vein occlusion.
      A staging system for lipemia retinalis was proposed by Vinger and Sachs: stage I (mild) is characterized by creamy vessels isolated to the periphery; stage II (moderate) is characterized by creamy vessels extending toward the optic disc; and stage III (marked) is characterized by all retinal vessels becoming cream coloured and the posterior pole becoming salmon coloured.
      • Vinger PF
      • Sachs BA.
      Ocular manifestations of hyperlipoproteinemia.
      In most cases, lipemia retinalis is asymptomatic and is found incidentally on dilated fundus examination.
      Lipemia retinalis itself is not visually significant. However, it is a critical ocular manifestation of a readily treatable life-threatening metabolic disorder associated with significant morbidity and mortality due to coronary artery disease, myocardial infarction, and stroke..
      • Mishra C
      • Tripathy K
      Lipemia retinalis. [Updated 2021 Dec 12]. In: StatPearls [Internet].
      Patients should be referred for systemic management on an urgent basis, including a lipid panel. Treatment is aimed at reducing serum triglyceride levels to <5.65 mmol/L with pharmacotherapy.
      • Mishra C
      • Tripathy K
      Lipemia retinalis. [Updated 2021 Dec 12]. In: StatPearls [Internet].
      Dietary and lifestyle modifications are also important for optimal control. The posterior-segment changes seen in lipemia retinalis typically improve once serum triglyceride levels have normalized.
      In conclusion, this case describes an unusual presentation of hypertriglyceridemia and highlights the importance of a full dilated fundus examination when evaluating a patient with a cranial nerve palsy. A lipid panel is not part of the routine work-up of an abducens nerve palsy, so recognizing lipemia retinalis on fundus examination was critical in guiding management. Had the fundus findings not been recognized, a reasonable next step—after negative magnetic resonance imaging and considering his younger age—may have been a lumbar puncture, which would have subjected the patient to unnecessary procedures.

      Footnotes and Disclosure

      The authors have no proprietary or commercial interest in any materials discussed in this article.
      The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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