What is the cause of horizontal diplopia (double vision)?

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Differential Diagnosis for Horizontal Double Vision

  • Single most likely diagnosis
    • Fourth Cranial Nerve (Trochlear Nerve) Palsy: This condition often presents with horizontal double vision due to the inability to properly rotate the eye. The trochlear nerve controls the superior oblique muscle, which is responsible for rotating the eye downward and inward. Damage to this nerve can lead to difficulty moving the eye in these directions, resulting in double vision.
  • Other Likely diagnoses
    • Sixth Cranial Nerve (Abducens Nerve) Palsy: The abducens nerve controls the lateral rectus muscle, which is responsible for outward eye movement. Damage to this nerve can cause horizontal double vision due to the inability to properly move the eye outward.
    • Third Cranial Nerve (Oculomotor Nerve) Palsy: While the oculomotor nerve controls several eye muscles, damage to it can also lead to double vision, including horizontal diplopia, due to impaired eye movement.
    • Strabismus (Misalignment of the Eyes): This condition can cause double vision due to the misalignment of the eyes, which can be horizontal in nature.
  • Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
    • Myasthenia Gravis: An autoimmune disorder that can cause fluctuating muscle weakness, including the muscles controlling eye movement, leading to double vision. It's crucial to diagnose and treat this condition promptly to avoid serious complications.
    • Stroke or Cerebral Vasculitis: These conditions can cause damage to the brain areas responsible for controlling eye movement, leading to double vision. Early diagnosis and treatment are critical to prevent further brain damage and other complications.
    • Multiple Sclerosis: An autoimmune disease that can affect the brain and spinal cord, leading to a wide range of symptoms, including double vision. Early diagnosis and treatment can help manage the disease and prevent further damage.
  • Rare diagnoses
    • Thyroid Ophthalmopathy: A condition associated with Graves' disease that can cause the muscles around the eye to become inflamed, leading to double vision.
    • Orbital Tumors or Cysts: Rarely, tumors or cysts in the orbit can cause double vision by pressing on the eye or the nerves controlling eye movement.
    • Congenital or Acquired Nystagmus: Abnormal eye movements that can cause double vision, although this is less common and often associated with other symptoms.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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