Differential Diagnosis for Sudden Onset of Vertigo

Single Most Likely Diagnosis

• Benign Paroxysmal Positional Vertigo (BPPV): This condition is characterized by brief, intense episodes of vertigo triggered by specific head movements. Given the patient's history of ear infection and the description of feeling like she is constantly on a boat, BPPV is a plausible diagnosis. The fact that ENT findings and scans were normal also supports this, as BPPV often does not show abnormalities on these tests.

Other Likely Diagnoses

• Labyrinthitis: An inner ear disorder that can cause vertigo, often following an ear infection. The patient's history of ear infection makes this a likely consideration, although the duration of symptoms (six months) is somewhat prolonged for typical labyrinthitis.
• Vestibular Migraine: A condition that can cause vertigo without the headache phase of a migraine. The description of constant vertigo could fit with vestibular migraine, especially if the patient has a history of migraines.
• Meniere's Disease: A disorder of the inner ear that affects balance and hearing. While the patient's symptoms could fit, the lack of reported hearing loss or tinnitus (ringing in the ears) makes this less likely.

Do Not Miss Diagnoses

• Posterior Circulation Stroke or Transient Ischemic Attack (TIA): Although less likely given the duration of symptoms and normal scans, it's crucial to consider stroke or TIA, especially if there are other risk factors present. Vertebrobasilar insufficiency can cause vertigo and is a medical emergency.
• Multiple Sclerosis: An autoimmune disease that can affect the brain and spinal cord, leading to a wide range of symptoms, including vertigo. Given the duration and nature of the patient's symptoms, along with the absence of other clear explanations, multiple sclerosis should be considered.

Rare Diagnoses

• Superior Canal Dehiscence: A rare condition where there is an abnormal opening in the bone overlying the superior canal of the inner ear. This can cause vertigo and imbalance, especially with sound or pressure changes.
• Perilymphatic Fistula: A rare condition where there is an abnormal connection (fistula) between the inner and middle ear, leading to vertigo and hearing loss. This could be considered if the patient has experienced recent head trauma, barotrauma, or rapid changes in altitude.