Differential Diagnosis for Dizziness

The patient presents with a one-week history of dizziness, blurred vision, and feelings of her eyes rolling back, without any loss of consciousness (LOC) or history of diabetes. Considering the symptoms and the absence of diabetes, the differential diagnoses can be categorized as follows:

• Single Most Likely Diagnosis
  • Dehydration: Despite the patient reporting increased water intake, dehydration could still be a factor, especially if the increase in water consumption is recent or insufficient to compensate for losses. Dehydration can cause dizziness, blurred vision, and a feeling of lightheadedness.
• Other Likely Diagnoses
  • Vasovagal Syncope: This condition is characterized by a sudden drop in heart rate and blood pressure, leading to reduced blood flow to the brain and causing dizziness or fainting. The symptoms of blurred vision and feeling as if about to pass out align with vasovagal syncope.
  • Orthostatic Hypotension: A drop in blood pressure upon standing can cause dizziness, lightheadedness, and blurred vision. Increased water intake might not directly address underlying issues leading to orthostatic hypotension.
  • Anxiety or Panic Disorder: These conditions can manifest with symptoms of dizziness, blurred vision, and a feeling of impending doom or passing out, which could be exacerbated by or contribute to the patient's experience of her eyes rolling back.
• Do Not Miss Diagnoses
  • Cardiac Arrhythmias: Although less likely, arrhythmias such as atrial fibrillation or other heart rhythm disorders can cause dizziness and near-syncope. Missing this diagnosis could be critical.
  • Seizure Disorder: The description of the eyes rolling back could be suggestive of a seizure, particularly if it's a focal seizure with impaired awareness. This would be a critical diagnosis not to miss.
  • Multiple Sclerosis or Other Demyelinating Diseases: These conditions can present with a wide range of neurological symptoms, including dizziness, blurred vision, and unusual sensations.
• Rare Diagnoses
  • Vertebrobasilar Insufficiency: A condition where the blood flow through the posterior circulation of the brain is compromised, leading to symptoms like dizziness, blurred vision, and ataxia.
  • Chiari Malformation: A structural defect in the cerebellum that can cause dizziness, blurred vision, and other neurological symptoms, especially with certain head movements or positions.

Each of these diagnoses requires careful consideration of the patient's history, physical examination, and potentially further diagnostic testing to determine the underlying cause of her symptoms.