Differential Diagnosis for Inability to Abduct Eyes Bilaterally
Single Most Likely Diagnosis
- Thyroid Ophthalmopathy: This condition is a common cause of bilateral abduction deficits due to inflammation and swelling of the extraocular muscles, particularly the lateral rectus muscle, which is responsible for eye abduction.
Other Likely Diagnoses
- Myasthenia Gravis: An autoimmune disorder that affects the neuromuscular junction, leading to fluctuating muscle weakness, including the extraocular muscles, which can cause bilateral abduction deficits.
- Chronic Progressive External Ophthalmoplegia (CPEO): A mitochondrial disorder characterized by progressive weakness of the external eye muscles, including those responsible for eye abduction.
- Third Cranial Nerve (Oculomotor Nerve) Palsy: Although typically unilateral, bilateral involvement can occur, especially in cases of traumatic brain injury, aneurysms, or increased intracranial pressure, affecting the oculomotor nerves which control several eye movements including abduction (through its supply to the lateral rectus muscle via the abducens nerve in the case of the oculomotor nerve's indirect role).
Do Not Miss Diagnoses
- Wernicke's Encephalopathy: A neurological disorder caused by thiamine deficiency, which can lead to ophthalmoplegia, including bilateral abduction deficits. It's crucial to identify and treat promptly to prevent irreversible brain damage.
- Miller Fisher Syndrome: A rare variant of Guillain-Barré Syndrome, characterized by ophthalmoplegia, ataxia, and areflexia. Early recognition is vital for appropriate treatment and to prevent potential respiratory failure.
- Botulism: A rare but potentially life-threatening illness caused by a toxin that affects the nervous system, leading to muscle weakness, including the extraocular muscles, and can cause bilateral abduction deficits.
Rare Diagnoses
- Moebius Syndrome: A rare congenital disorder characterized by facial paralysis and impaired eye movements, including abduction, due to underdevelopment of the cranial nerves.
- Congenital Fibrosis of the Extraocular Muscles: A group of rare disorders characterized by restrictive eye movements due to fibrosis of the extraocular muscles, which can affect eye abduction.
- Graves' Ophthalmopathy with restrictive myopathy: While more commonly associated with proptosis and eyelid retraction, in rare cases, it can cause restrictive myopathy leading to limitation of eye movements including abduction.