Differential Diagnosis for Left Eye Not Able to Open with Angle of Mouth Deviation

Single Most Likely Diagnosis

• Stroke: The combination of an inability to open one eye (suggesting a problem with the cranial nerves controlling eye movement, such as the third cranial nerve) and deviation of the angle of the mouth (indicating facial weakness) is highly suggestive of a stroke, particularly one affecting the brainstem or the cerebral cortex areas responsible for motor control.

Other Likely Diagnoses

• Bell's Palsy: While primarily causing facial weakness, in severe cases, it could potentially affect the eye's ability to open due to orbicularis oculi weakness, though the primary issue would be facial asymmetry and difficulty closing the eye.
• Myasthenia Gravis: An autoimmune disease that can cause weakness in various muscle groups, including those controlling eye and facial movements, leading to symptoms like ptosis (drooping eyelid) and facial weakness.
• Guillain-Barré Syndrome: A rare neurological disorder in which the body's immune system mistakenly attacks part of its peripheral nervous system, potentially leading to muscle weakness and, in some cases, facial and eye movement abnormalities.

Do Not Miss Diagnoses

• Cavernous Sinus Thrombosis: A rare but potentially life-threatening condition that can cause cranial nerve palsies, including those affecting eye movement and facial expression. It requires immediate medical attention.
• Brain Tumor: Though less common, a tumor in the brain could compress or invade areas responsible for controlling facial and eye movements, leading to the described symptoms.
• Multiple Sclerosis: An autoimmune disease that affects the central nervous system, potentially causing a wide range of neurological symptoms, including vision problems and facial weakness.

Rare Diagnoses

• Lyme Disease: In rare cases, Lyme disease can cause neurological symptoms, including facial palsy and, less commonly, issues with eye movement.
• Tolosa-Hunt Syndrome: A rare disorder characterized by headache, pain around the eye, and weakness of the muscles around the eye, including those that control eye movement.
• Mitochondrial Myopathies: A group of disorders caused by mitochondrial dysfunction that can lead to muscle weakness, including the muscles controlling eye and facial movements.