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What are the causes of Hyponatraemia?
Hyponatraemia is seen when there is loss of sodium or excess water in the body which dilutes the sodium.
- Loss of sodium as in diarrhea
- Loss of sodium from the kidney as with diuretics
- Excess water retention as seen in heart or kidney failure.
- SIADH (Syndrome of Inappropriate ADH production)
Is Hyponatraemia dangerous?
Symptoms of hyponatraemia depends on the rapidity with which sodium level drops. Usually patients present with confusion, and sometimes even seizures, coma and death, if levels are too low.
What is Hypernatremia?
Hypernatraemia is characterized by increased sodium level in the blood. It is more a disorder of water metabolism and is seen when the ratio of solutes to water in the body is increased.
What are the causes of Hypernatremia?
- Impaired thirst e.g.: coma
- Presence of osmotic substances in the urine which cause excessive water loss. e.g. glucose, mannitol administration, diabetic ketoacidosis.
- Excess loss of water from the kidney as in diabetes insipidus.
- Excess loss of water from the skin: e.g. sweating, burns.
How much potassium is present in the body?
The human body contains 3500 meq of potassium majority of which is in the cells.
What is Hyperkalemia?
Abnormal elevation of potassium in the blood is called hyperkalemia. Normal potassium level is between 3.5 to 4.5 meq per liter. A level greater than 4.5meq/L is called Hyperkalemia.
What are the major causes of Hyperkalemia?
- It can result from decreased excretion from the kidneys as in renal failure
- Drugs such as potassium sparing diuretics (e.g. spironolactone)
- Trans cellular shifts i.e. the potassium tends to move out of the cells. Seen in a condition called acidosis (low pH of blood).
How do patients present if they have Hyperkalemia?
- Limb weakness.
- Abnormal heart rhythms which can be fatal if the level is very high. The ECG usually shows tall T waves.
What is the treatment for Hyperkalemia?
- In emergent condition calcium is given intravenously to protect the heart from high potassium.
- Insulin and glucose is given intravenously. The insulin drives the potassium into the cell.
- Cationic exchange resins such as polysterene sulfonate( Kayexalate) can be given orally or rectally.
- Hemodialysis is used in renal failure patients.
The appropriate cause of Hyperkalemia should be sought.
What is hypokalemia?
When the serum potassium level goes below 3.5 meq/L it is called hypokalemia.
What are the causes of hypokalemia?
- Inadequate intake.
- Excessive loss of potassium from the kidney can occur with diuretics, antibiotics harmful to the kidney such as amphotericin and gentamicin.
- Gastrointestinal loss from vomiting, diarrhea.
- Excess loss from skin as in burns.