Benign Paroxysmal Positional Vertigo (BPPV): This condition is characterized by brief, intense episodes of vertigo triggered by specific head movements, such as laying down or turning the head. The symptoms described match closely with BPPV, especially given the positional nature of the vertigo.

Vestibular Migraine: This condition can cause vertigo and is often triggered by specific movements or positions. While it's less directly linked to positional changes than BPPV, it's a common cause of vertigo and could be considered, especially if the patient has a history of migraines.
Labyrinthitis: An inner ear disorder that can cause vertigo, often accompanied by hearing loss or tinnitus. The vertigo can be severe and is sometimes triggered by movement, although it's not as specifically positional as in BPPV.

Posterior Circulation Stroke: Although less common, a stroke in the posterior circulation can cause sudden onset vertigo, among other symptoms. It's crucial to rule out a stroke, as timely intervention is critical for outcomes.
Multiple Sclerosis: In rare cases, multiple sclerosis can present with vertigo as an initial symptom, especially if there's involvement of the brainstem or cerebellum. Given the potential for serious consequences if missed, it's essential to consider, especially in younger patients.
Vestibular Neuronitis: An inflammation of the vestibular nerve, which can cause severe vertigo. While not typically life-threatening, missing this diagnosis could lead to prolonged discomfort and disability.

Meniere's Disease: A disorder of the inner ear that affects balance and hearing. While it can cause vertigo, the episodes are typically longer-lasting than those described, and it's accompanied by hearing loss, tinnitus, and ear fullness.
Chiari Malformation: A structural defect in the cerebellum that can cause vertigo, among other symptoms, especially with certain head movements. However, it's much rarer and usually accompanied by other neurological symptoms.
Superior Canal Dehiscence: A rare condition where there's an abnormal opening in the bone overlying the superior canal of the inner ear, leading to vertigo and hearing symptoms triggered by sound or pressure changes.