Dizziness

 

Dizziness is an impairment in spatial perception and stability. The term dizziness is imprecise: it can refer to vertigo, presyncope, disequilibrium, or a non-specific feeling such as giddiness or foolishness.

One can induce dizziness by engaging in disorientating activities such as spinning.

Vertigo is the sensation of spinning or having one’s surroundings spin about them. Many people find vertigo very disturbing and often report associated nausea and vomiting. It represents about 25% of cases of occurrences of dizziness.
Disequilibrium is the sensation of being off balance and is most often characterized by frequent falls in a specific direction. This condition is not often associated with nausea or vomiting.
Presyncope is lightheadedness, muscular weakness, and feeling faint as opposed to a syncope, which is actually fainting.
Non-specific dizziness is often psychiatric in origin. It is a diagnosis of exclusion and can sometimes be brought about by hyperventilation.
A stroke is the cause of isolated dizziness in 0.7% of people who present to the emergency department.

Classification
Dizziness is broken down into 4 main subtypes: vertigo (~50%), disequilibrium (less than ~15%), presyncope (less than ~15%) and lightheadedness (~10%).

Mechanism
Many conditions cause dizziness because multiple parts of the body are required for maintaining balance including the inner ear, eyes, muscles, skeleton, and the nervous system.

Common physiological causes of dizziness include:

inadequate blood supply to the brain due to:
a sudden fall in blood pressure
heart problems or artery blockages
loss or distortion of vision or visual cues
disorders of the inner ear
distortion of brain/nervous function by medications such as anticonvulsants and sedatives
result of side effect from prescription drugs, including proton-pump inhibitor drugs (PPIs) and Coumadin (warfarin) causing dizziness/fainting

Diagnosis
Differential diagnosis
Many conditions are associated with dizziness. Dizziness can accompany certain serious events, such as a concussion or brain bleed, epilepsy and seizures (convulsions), strokes, and cases of meningitis and encephalitis. However, the most common subcategories can be broken down as follows: 40% peripheral vestibular dysfunction, 10% central nervous system lesion, 15% psychiatric disorder, 25% presyncope/disequilibrium, and 10% nonspecific dizziness. Some vestibular pathologies have symptoms that are comorbid with mental disorders. The medical conditions that often have dizziness as a symptom include:

Benign paroxysmal positional vertigo
Meniere’s disease
Labyrinthitis
Otitis media
Brain tumor
Acoustic neuroma
Motion sickness
Ramsay Hunt syndrome
Migraine
Multiple sclerosis
Pregnancy
low blood pressure (hypotension)
low blood oxygen content (hypoxemia)
heart attack
iron deficiency (anemia)
low blood sugar (hypoglycemia)
hormonal changes (e.g. thyroid disease, menstruation, pregnancy)
panic disorder
hyperventilation
anxiety
depression
age-diminished visual, balance, and perception of spatial orientation abilities

Epidemiology
About 20–30% of the population report to have experienced dizziness at some point in the previous year.

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