Differential Diagnosis for the Patient

The patient presents with eye deviation, worsening symptoms over 3 days, a history of obesity, epilepsy, and a possibility of Cushing's syndrome under investigation. Here's a structured approach to the differential diagnosis:

• Single Most Likely Diagnosis

  • Stroke or Transient Ischemic Attack (TIA): Given the acute onset of eye deviation, which could be indicative of a cranial nerve palsy (e.g., third nerve palsy), and considering the patient's history of obesity (a risk factor for vascular diseases), a stroke or TIA is a plausible diagnosis. The worsening symptoms suggest a need for urgent evaluation.

• Other Likely Diagnoses

  • Multiple Sclerosis: This condition can cause a variety of neurological symptoms, including eye movement abnormalities due to its demyelinating effects on the central nervous system. The history of epilepsy might be unrelated but could also be part of the clinical picture in some cases of MS.
  • Diabetic Ophthalmoplegia: If the patient has undiagnosed diabetes (which could be related to his obesity), diabetic ophthalmoplegia (third nerve palsy) is a possibility, although it typically spares the pupil.
  • Thyroid Ophthalmopathy: Although less directly linked to the acute onset, thyroid issues can cause eye movement abnormalities and are worth considering, especially if there's an underlying metabolic or endocrine disorder like Cushing's syndrome.

• Do Not Miss Diagnoses

  • Pituitary Apoplexy: Given the investigation into Cushing's syndrome, which involves the pituitary gland, pituitary apoplexy (a sudden hemorrhage or infarction of the pituitary gland) is a critical diagnosis not to miss. It can cause acute neurological symptoms, including eye movement abnormalities, and is a medical emergency.
  • Cavernous Sinus Thrombosis: This is a rare but potentially life-threatening condition that can cause cranial nerve palsies, including those affecting eye movement. It's more likely in the context of an underlying infection or inflammatory condition.
  • Giant Cell Arteritis: Although more common in older adults, giant cell arteritis can cause sudden onset of eye symptoms, including diplopia, and is a diagnosis that should not be missed due to its potential for causing permanent vision loss if not promptly treated.

• Rare Diagnoses

  • Tolosa-Hunt Syndrome: A rare condition characterized by painful ophthalmoplegia due to nonspecific inflammation of the cavernous sinus or superior orbital fissure. It's a diagnosis of exclusion but should be considered if other causes are ruled out.
  • Wernicke's Encephalopathy: Typically associated with alcohol misuse and thiamine deficiency, this condition can cause ophthalmoplegia among other symptoms. It's less likely given the information provided but could be considered in a broader differential, especially if there are other suggestive features in the history or examination.