Dizziness

Dizziness

ICD-10	R42
ICD-9	780.4
DiseasesDB	17771
eMedicine	neuro/693
MeSH	D004244

Dizziness refers to an impairment in spatial perception and stability.^[1] The term is somewhat imprecise.^[2] It can be used to mean vertigo, presyncope, disequilibrium,^[3] or a non-specific feeling such as giddiness or foolishness.^[4]

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

• Vertigo is a specific medical term used to describe 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.^[5]
• 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.^[4]

A stroke is the cause of isolated dizziness in 0.7% of people who present to the emergency room.^[5]

Classification

Dizziness is broken down into 4 main subtypes: vertigo (~50%), disequilibrium (less than ~15%), presyncope (less than ~15%) and lightheadedness (~10%).^[6]

Differential diagnosis

Many conditions are associated with dizziness. 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/dysequilibrium, and 10% nonspecific dizziness.^[7] The medical conditions that often have dizziness as a symptom include:^{[7][8][9][10]}

• Benign paroxysmal positional vertigo
• Meniere's disease
• Vestibular neuronitis
• Labyrinthitis
• Otitis media
• Acoustic neuroma
• Chronic motion sickness
• Ramsay Hunt syndrome
• Migraine
• Multiple sclerosis
• pregnancy
• low blood pressure (hypotension)
• low blood oxygen content (hypoxemia)
• 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

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.^[9]

Common physiological causes of dizziness include:

• inadequate blood supply to the brain due to:
  • a sudden fall in blood pressure^[9]
  • heart problems or artery blockages^[9]
• loss or distortion of vision or visual cues^[9]
• disorders of the inner ear^[9]
• distortion of brain/nervous function by medications such as anticonvulsants and sedatives^[9]

Epidemiology

About 20–30% of the population report to have experienced dizziness at some point in the previous year.^[5]

See also

• Motion sickness
• Balance disorder
• Postural orthostatic tachycardia syndrome
• Equilibrioception
• The spins, a state of dizziness and disorientation due to intoxication
• Coriolis effect (perception)

References

1. ^ "dizziness" at Dorland's Medical Dictionary
2. ^ MeSH Dizziness
3. ^ Reeves, Alexander G., Swenson, Rand S. (2008). "Chapter 14: Evaluation of the Dizzy Patient". Disorders of the Nervous System: A Primer. Dartmouth Medical School. http://www.dartmouth.edu/~dons/part_2/chapter_14.html#chpt_14_presyncope. 
4. ^ ^{a b} Branch, Jr, William T., Barton, Jason (February 10, 2011). "Approach to the patient with dizziness". UpToDate. http://www.uptodate.com/contents/approach-to-the-patient-with-dizziness. 
5. ^ ^{a b c} Neuhauser HK, Lempert T (November 2009). "Vertigo: epidemiologic aspects". Semin Neurol 29 (5): 473–81. doi:10.1055/s-0029-1241043. PMID 19834858. 
6. ^ Post RE, Dickerson LM (August 2010). "Dizziness: a diagnostic approach". Am Fam Physician 82 (4): 361–8, 369. PMID 20704166. 
7. ^ ^{a b} Chan Y (June 2009). "Differential diagnosis of dizziness". Curr Opin Otolaryngol Head Neck Surg 17 (3): 200–3. doi:10.1097/MOO.0b013e32832b2594. PMID 19365263. 
8. ^ Tusa RJ (March 2009). "Dizziness". Med. Clin. North Am. 93 (2): 263–71, vii. doi:10.1016/j.mcna.2008.09.005. PMID 19272508. 
9. ^ ^{a b c d e f g} "Dizziness and Vertigo". Merck Manual. 2009. http://www.merck.com/mmpe/sec08/ch084/ch084e.html?qt=dizziness&alt=sh. 
10. ^ Bronstein AM, Lempert T (2010). "Management of the patient with chronic dizziness". Restor. Neurol. Neurosci. 28 (1): 83–90. doi:10.3233/RNN-2010-0530. PMID 20086285. 

External links

• Dizzytimes.com Online Community for Sufferers of Vertigo and Dizziness
• Dysautonomia Youth Network of America, Inc.

[[Category:Otolo