Benign Paroxysmal Positional Vertigo (BPPV): This condition is often the most common cause of acute dizziness and lightheadedness, especially in older adults. It is characterized by brief, intense episodes of vertigo triggered by specific head movements.

Vestibular Neuritis: An inner ear disorder that causes inflammation of the vestibular nerve, leading to severe vertigo, often accompanied by nausea and vomiting.
Orthostatic Hypotension: A sudden drop in blood pressure when standing up, causing dizziness or lightheadedness due to inadequate blood flow to the brain.
Labyrinthitis: An inner ear infection that causes dizziness, hearing loss, and sometimes tinnitus.
Migraine-associated Vertigo: Some people experience vertigo as part of their migraine symptoms, which can be debilitating.

Stroke or Transient Ischemic Attack (TIA): Although less common, a stroke or TIA can present with sudden onset of dizziness or vertigo and is a medical emergency.
Cardiac Arrhythmias: Abnormal heart rhythms can lead to reduced blood flow to the brain, causing dizziness or lightheadedness.
Hypoglycemia: Low blood sugar can cause dizziness, confusion, and loss of consciousness if not promptly treated.
Carbon Monoxide Poisoning: A silent killer that can cause dizziness, headache, and nausea due to reduced oxygen delivery to tissues.

Meniere's Disease: A disorder of the inner ear that affects balance and hearing, causing episodes of vertigo, tinnitus, and hearing loss.
Acoustic Neuroma: A rare, non-cancerous tumor on the nerve connecting the inner ear to the brain, which can cause vertigo, hearing loss, and tinnitus.
Multiple Sclerosis: A chronic autoimmune disease that can affect the brain and spinal cord, sometimes presenting with vertigo or dizziness as an initial symptom.
Vasovagal Syncope: A condition that causes fainting spells due to a sudden drop in heart rate and blood pressure, often triggered by stress or pain.