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An Urban Experience
WSVA7-0343
EMERGENCY/CRITICAL CARE (VECCS)
LIFE THREATENING HYPER- AND HYPOKALEMIA
D. McBride1
1Royal Veterinary College, Queen Mother Hospital for Animals, London, United Kingdom
LIFE THREATENING HYPER- AND HYPOKALAEMIA
Duana McBride BVSc DACVECC MVMedSc MRCVS
Royal Veterinary College, Hawkshead Lane, North Mymms, United Kingdom
  dmcbride@rvc.ac.uk
Hyperkalaemia
Hyperkalaemia can occur due to the following causes listed in table 1.
Table 1. Causes of hyperkalaemia
   Causes of Hyperkalaemia
 Pseudohyperkalaemia
  Thrombocytosis
   Haemolysis
   Akita and other Japanese breed dogs
 Increased intake
  Iatrogenic administration of potassium containing fluids
 Extracellular translocation
  Acidaemia
    Insulin deficiency
    Reperfusion injury
   Tumour lysis syndrome
 Decreased excretion
  Urethral obstruction
   Bilateral ureteric obstruction
   Uroperitoneum
   Anuric or oliguric renal failure
    Hypoadrenocorticism; hypoaldosteronism
    Gastrointestinal disease (trichuris, salmonella, perforated duodenum)
   Potassium sparing diuretics (e.g. spironolactone)
    Chylothorax with repeat drainage
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Hyperkalaemia makes the resting membrane potential less negative, reducing the threshold potential. This initially results in a more excitable cell, however if the resting membrane potential is greater than threshold potential, depolarisation results but repolarisation cannot occur, and the cell become less excitable. This results in a bradyarrhythmia with ECG changes of tented T waves, short QT interval, prolonged PR interval, widening of QRS complex, decreased amplitude and widening of P waves.
Muscle weakness can also occur due to hyperkalaemia due the same mechanisms of cardiac arrhythmias, resulting in reduced cellular excitability.
Another complication of hyperkalaemia is acidaemia. As the serum potassium concentration increases, it causes intracellular movement of potassium in exchange for
an extracellular movement of hydrogen ions. Therefore, part of the life-threatening condition associated with hyperkalaemia is also the acidaemia.
Treatment for hyperkalaemia should be considered with a potassium of > 6.0 mmol/L. The severity of the ECG changes will depend on the chronicity of the disease, therefore some animals may display clinical signs, while some may not. Treatment options for hyperkalaemia is described in table 2.
 42ND WORLD SMALL ANIMAL VETERINARY ASSOCIATION CONGRESS AND FECAVA 23RD EUROCONGRESS
  

























































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