Tetany

Tetania is a syndrome of increased irritability CNS and PNS caused by changes in ion concentrations in ECT.

• Tetany can be manifest or latent, hypocalcemia or normocalcemic.
• Main changes of ions leading to tetany:
  • decrease: Ca ²⁺ (hypocalcemia), H ⁺ (alkalosis), Mg ^{2 +} (hypomagnesemia);
  • rise: K ⁺ (hyperkalemia), Na ⁺ (hypernatremia) ( and indirectly P - this reduces Ca…).

• Neuromuscular excitability = (Ca ²⁺ × H ⁺ × Mg ²⁺ ) / (K ⁺ × PO ₄ ^2- × OH ^- ).

Causes

Hypocalcemic tetany

• Early and late neonatal tetany;
• deficiency vitamin D;
• congenital parathyroid defects (isolated or DiGeorg's syndrome);
• losses calcium;
• alkalosis (hyperventilation, hysterical seizures…);
• renal insufficiency.

Normocalcemic tetany

• Hypomagnesaemia;
• neurogenic (organic CNS disorders - inflammation, tumor, injuries, CNS functional disorders - neurosis, psychosis);
• spasmophilia syndrome.

Manifest tetany

• Classically, it manifests itself in three forms:
  1. recurring generalized tonic cramps in patient s full consciousness - starting at the fingertips and spreading cranially;
  2. carpopedal spasm (tonic wrist flexion, finger extension, thumb adduction into the palm), spasms are very painful, paraesthesia persists between seizures - increased irritability of peripheral nerves of the limbs;
  3. laryngospasm - laryngeal muscle spasm, loud strenuous inspiration, dyspnoea, cyanosis.

Latent tetany

• It manifests itself as a so-called spasmophilia - a tendency to convulsions;
• manifests as convulsions after ischemia or after electrical or mechanical irritation.
• It shows various symptoms:
  • Chvostek sign - tap in front of the ear on n. & Nbsp; VII → the corner twitches;
  • Lust's symptom - phenomenon of nerve peronei - tapping over the proximal head of the fibula → lifting of the lateral edge of the foot;
  • Trousseau's symptom - inflate the cuff of the tonometer on the arm, it ischemic to the nerves of the arm - spasm.

Differential diagnostics

• Eg. aminoaciduria and other inherited metabolic disorders, epilepsy, CNS inflammation.

Links

References

• Disorders of calcium-phosphate metabolism

External links

• Tetanie (česká wikipedie)
• Tetany (medical sign) (anglická wikipedie)