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Name of Symptom/Sign:
Tetany

[[Image:|190px|center|]]
ICD-10	R290
ICD-O:
ICD-9	781.7
OMIM	[1]
MedlinePlus	[2]
eMedicine	/
DiseasesDB	29143

Tetany is a medical sign, the involuntary contraction of muscles, caused by diseases and other conditions that increase the action potential frequency. The muscle cramps caused by the disease tetanus are due to a blocking of the inhibition to the neurons that supply muscles and are not classified as tetany.

Contents 1 Mechanism 2 Causes 3 Diagnosis 4 External links

[edit] Mechanism

When the membrane potential is upset, for instance by low levels of ions (such as calcium) in the blood (hypocalcaemia), neurons will depolarize too easily. In the case of hypocalcaemia, calcium ions are drawn away from their association with the voltage-gated sodium channels thus sensitising them. The upset to membrane potential is therefore caused by an influx of sodium to the cell, not directly by the hypocalcaemia. As a result, too many action potentials are sent to muscles causing spasm.

[edit] Causes

The usual cause of tetany is lack of calcium, but excess of phosphate (high phosphate-to-calcium ratio) can also trigger the spasms. Milk-and-alkali tetany is an example of this imbalance.

Underfunction of the parathyroid gland can lead to tetany.

Low levels of carbon dioxide causes tetany by altering the albumin binding of calcium such that the ionised (physiologically influencing) fraction of calcium is reduced; the most common reason for low carbon dioxide levels is hyperventilation.

[edit] Diagnosis

The nineteenth-century clinician Professor Armand Trousseau devised the trick of occluding the brachial artery by squeezing to trigger the cramps in the fingers (Trousseau sign).

[edit] External links

• Bartleby

This box: view • talk • edit Symptoms and signs (R)
Circulatory and respiratory systems	Tachycardia - Bradycardia - Palpitation - Nosebleed - Hemoptysis - Cough - Dyspnea - Orthopnoea - Stridor - Wheeze - Cheyne-Stokes respiration - Hyperventilation - Mouth breathing - Hiccup - Chest pain - Asphyxia - Pleurisy - Respiratory arrest - Sputum - Bruit
Digestive system and abdomen	Abdominal pain - Acute abdomen - Nausea - Vomiting - Heartburn - Dysphagia - Flatulence - Burping - Fecal incontinence - Encopresis - Hepatomegaly - Splenomegaly - Hepatosplenomegaly - Jaundice - Ascites - Halitosis
Skin and subcutaneous tissue	Hypoesthesia - Paresthesia - Hyperesthesia - Rash - Cyanosis - Pallor - Flushing - Petechia - Desquamation - Induration
Nervous and musculoskeletal systems	Tremor - Spasm - Fasciculation - Gait abnormality - Ataxia - Tetany - Meningism - Hyperreflexia
Urinary system	Dysuria - Vesical tenesmus - Urinary incontinence - Urinary retention - Oliguria - Polyuria - Nocturia
Cognition, perception, emotional state and behaviour	Anxiety - Somnolence - Coma - Anterograde amnesia - Retrograde amnesia - Dizziness - Anosmia - Parosmia - Parageusia
Speech and voice	Dysarthria - Alexia - Agnosia - Apraxia - Dysphonia

pt:Tetania (sinal médico)

This page uses content from the English-language version of Wikipedia. The original article was at Tetany (medical sign). The list of authors can be seen in the page history. As with Psychology Wiki, the text of Wikipedia is available under the GNU Free Documentation License.