The signs and symptoms of hypokalemia (decreased potassium levels in the blood) start to appear when potassium levels drop to less than 2.5 mEq/L. They include :

• Muscles weakness.
• Muscle cramps and pains.
  
• Diminshed dep reflexes (knee reflex, biceps reflex, etc)
• Reduction of intestinal movements (paralytic ileus).
• Renal affection (hypokalemic nephropathy).
• The electrocardiogram shows depressed T-wave and U-wave appears.
• Palpitations and arrhythmias (a dangerous complication).

Potassium is important for the muscle functions and it's reduced levels will alter the muscle activity producing the above manifestations. These also affect the heart (which is a muscle too), also the heart is affected by the levels of electrolytes in blood such as potassium, calcium and sodium affecting it's conducting system and may lead to arrhythmias in abnormal levels of these substances.

Causes of hypokalemia:

Hypokalemia can have different causes among these are:

-Low intake as in starvation.

-Persons suffering from malabsorbtion syndrome.

-Loss of potassium in cases of vomiting and diarrhea as in Conn's and cushing's syndrome.

-Diuretics causing potassium loss.

-Alkalosis.

-Insulin may also cause intracellular shift of potassium so it's plasma levels decrease.

The signs and symptoms of hypokalemia suggest an underlying condition (primary cause) that need to be treated, if a patient shows these signs, an ECG should be done and a correct diagnosis is done to make sure he gets the right treatment when he reaches a hospital to receive potassium (KCl).