What is Hypokalemia?
It is a condition in which the levels of Potassium in the blood decrease below the normal levels. Clinically it is defined as plasma potassium levels <3.5mEq/L.
Potassium is a positively charged ion present in the body as a major intracellular (inside the cells) ion. Its concentration the plasma is very small compared to its concentration inside the cells. So, even a small change in the plasma reflects as a huge change in the concentration in terms of percentage, and therefore even small fluctuations can have life-threatening consequences.
Potassium may be reduced due to inadequate intake or excessive loss of potassium. As the concentration of the ion reduces the plasma, potassium inside the cells tends to come out to compensate for the difference in concentration. As the cells lose a positively charged ion, they become relatively negatively charged which finally boils down to the fact that they become very difficult to stimulate ie the cell functions become lazy.
This change is relatively unapparent in most of the cells but is significant in brain cells and muscle cells, especially in the heart and intestinal muscle.
What are the symptoms of Hypokalemia?
- Muscle weakness, reduced reflexes, reduces tone of muscles.
- New arrhythmias in the heart muscle
- ECG changes: U waves, Flattened T waves, depressed ST segment
- Constipation, paralytic ileus (decreased intestinal movement)
- Reduced urine formation due to reduced filtration in the kidney (reduced GFR)
- Increased ammonia production by the kidney
- Reduced Aldosteron production by the adrenal gland
- Metabolic alkalosis (decreased acidity of the body)
What are the risk factors for Hypokalemia?
Elderly population with an aged kidney is susceptible to developing electrolyte imbalance, and potassium is no exception for the rule. High risk is for those elderly who are:
- Under treatment with diuretics
- Diabetics with poor control (diabetic keto acidosis)
- Hormonal imbalances (Cushing’s disease, Addison’s disease, thyroid disease)
- Alcoholics with liver failure
- Kidney disease
- Heart disease
- Laxative addicts
- Bedridden patients whose dietary requirements of potassium is not adequately met by the caregivers.
What are the causes of Hypokalemia?
- Inadequate intake
- Diet with reduced potassium content
- Intravenous fluids without potassium
- Loss from the digestive system
- Tumors of the large intestine (villous adenoma)
- Urinary diversion created into the colon.
- Intestinal obstruction
- Ileus (decreased intestinal movement)
- Fluid collection in the bowel
3. Loss in urine
- Primary aldosteronism
- Bartter’s syndrome
- Gitelman’s syndrome
- Liver failure (cirrhosis)
- Kidney failure (nephrotic syndrome)
- Heart failure
What are the complications with Hypokalemia?
- Cardiac arrhythmias (rhythm abnormalities of heart)
- Muscle weakness, respiratory weakness leading to hypoxia (decreased oxygen in the body)
- Confusion and slowing of reflexes
- Abdominal distention due to paralytic ileus (decreased intestinal movement)
- Death due to cardiac rhythm abnormalities
How is Hypokalemia diagnosed?
In an elderly patient with history suggestive of risk factors, Hypokalemia is a fairly easy clinical diagnosis. The commonly undertaken investigations are:
- Estimation of serum potassium
- Estimation of pH
- Evaluation of ECG
What is the treatment for Hypokalemia?
Every 1 mEq/L fall in plasma potassium is equivalent to 100-200 mEq of potassium from the body.
Oral replacement is indicated if the correction is to be slowly given, that is in a relatively stable patient.
Intravenous replacement is indicated when the patient has severe life-threatening symptoms or is unable to take oral medications. In severely symptomatic patients, the correction should ideally be given in an ICU setting with due cardiac monitoring.
Diet and Rehabilitation
No supplements should be taken without the knowledge of the treating physician, since in old age the aged kidney is not perfectly equipped to handle rapid electrolyte changes. It is likely that an elderly patient is on some kind of medication acting on either kidney or the heart. In such a case, self-medication may prove to be extremely dangerous.
Diets rich in potassium are all fruits and vegetables. The patient is advised to consume generous amounts of fresh fruits and vegetables. Potassium supplements are given in case of chronic losses from the digestive or urinary tracts.
The caregivers of the elderly have an important role in monitoring the intake of potassium and in ensuring that the patient adheres to any drug regimen that has been prescribed by the treating physician.
How to Prevent Hypokalemia?
- Use of potassium-sparing diuretics with the high sealing ones
- Monitoring serum potassium levels in elderly seeking any long term treatment.
- Strict control of diabetes mellitus.
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