History and Physical

38F with no medical history, presenting with double vision. The patient reported six weeks of intermittent diplopia for which she had presented to this hospital previously. She was briefly admitted for evaluation of possible cranial nerve IV palsy. Extensive imaging was unremarkable, without mass lesion, infarction, vascular malformation, or meningeal enhancement. She was discharged with outpatient follow-up including ophthalmology clinic and further imaging.

The patient represented due to persistent diplopia that is worse with right gaze. The diplopia is predominantly vertical, alleviated by head tilt. Now associated with three days of right ptosis as well as two weeks of progressive weakness and fatigue – most notable when climbing stairs.

Examination notable for right hypertropia increased on right or downward gaze suggestive of isolated inferior rectus weakness. Pupils were equal and reactive. There was marked fatigable ptosis with 2mm right palpebral fissure compared to 10mm on contralateral side. Symmetrical muscle weakness was noted, 4/5 neck flexion, elbow extension, wrist flexion/extension, shoulder abduction, hip flexion. Gait was wide-based. Application of ice for 5 minutes improved right palpebral fissure opening to >7mm.

Further evaluation included CXR and CT chest with intravenous contrast which did not identify a mediastinal mass. The patient’s respiratory status remained stable throughout hospitalization as assessed by measurements of forced vital capacity. On hospital day one, an edrophonium test was performed which was positive. The patient was started on pyridostigmine, completed a course of IVIG and was discharged with outpatient neurology follow-up.

Evaluation of Diplopia ¹

History

1. Onset/cadence
2. Direction of gaze with worst diplopia
3. Orientation (vertical/horizontal)
4. Associated symptoms (headache, vertigo, dysarthria, eye pain)

Terms Describing Eye Position

Algorithm for the Evaluation of Diplopia ²

Causes of Diplopia ^3,4,5,6

Finding	EOM	Causes	Features
Mechanical orbitopathy	Variable. Abrupt restriction of movement	Orbital cellulitis	Pain, erythema
		Orbital pseudotumor	Autoimmune
		Trauma	History
		Thyroid eye disease	Bilateral
Isolated CN III	Limited adduction/upgaze/downgaze	Microvascular ischemia	Pain, risk factors, pupil-sparing
		Aneurysm	Pupil involvement
		Demyelination	MRI
Isolated CN IV	Limited downgaze (hypertropia)	Trauma	May be mild
		Microvascular ischemia	Less common than CN III
		ICP	Fundoscopy, imaging
		Demyelination	MRI
Isolated CN VI	Limited abduction (esotropia)	ICP	Fundoscopy, imaging
		Demyelination	MRI
		Microvascular ischemia	Less common than CN III
INO	Limited adduction (exotropia)	Demyelination	MRI
		Stroke	Dysarthria, ataxia, facial weakness
Multiple CN involvement (III, IV, VI)	Variable	Cavernous sinus process	Retroorbital pain, conjunctival injection or chemosis
Brainstem deficits	Variable	Brainstem stroke	Weakness, dysmetria, tremor
		Basilar artery occlusion	Vertigo, slurred speech
		Wernicke	AMS, ataxia, nystagmus
		Basilar meningitis	Fever, photophobia, meningismus
		Miller-Fisher	Ataxia, areflexia
Neuromuscular process	Variable	Myasthenia gravis	Fatigability, ice test

References

1. Alves, M., Miranda, A., Narciso, M. R., Mieiro, L., & Fonseca, T. (2015). Diplopia: a diagnostic challenge with common and rare etiologies. The American journal of case reports, 16, 220–223. doi:10.12659/AJCR.893134
2. Borooah, S., Wright, M., & Dhillon, B. (2011). Pocket Tutor Ophthalmology. JP Medical Limited. Retrieved from https://books.google.com/books?id=z\_CfWj8-ftoC
3. Dinkin, M. (2014). Diagnostic approach to diplopia. Continuum (Minneapolis, Minn.), 20(4 Neuro-ophthalmology), 942–965. doi:10.1212/01.CON.0000453310.52390.58
4. Rucker, J. C., & Tomsak, R. L. (2005). Binocular diplopia. A practical approach. The neurologist, 11(2), 98–110. doi:10.1097/01.nrl.0000156318.80903.b1
5. Friedman, D. I. (2010). Pearls: diplopia. Seminars in neurology, 30(1), 54–65. doi:10.1055/s-0029-1244995
6. Guluma, K. (2013). Diplopia. In Rosen’s Emergency Medicine – Concepts and Clinical Practice (8th ed., Vol. 1, pp. 176-183). Elsevier Health Sciences.
7. WikEM: Diplopia