Hypokalemia

Original Editors - Kara Lawless from Bellarmine University's Pathophysiology of Complex Patient Problems project.

Top Contributors - Kara Lawless, Elaine Lonnemann, Lucinda hampton, Admin, Kim Jackson, Wendy Walker and WikiSysop  

Definition/Description

One of the most common electrolyte disturbances seen in clinical practice is hypokalemia. Hypokalemia is known as a electrolyte imbalance that is lower than normal level of potassium in your bloodstream.

• A normal blood potassium is 3.6 to 5.2 mmol/L.
• Severe and life threatening hypokalemia level is known as <2.5mmol/L.

Potassium helps control how our muscles, heart, and digestive system work. Hypokalemia occurs when your body loses too much potassium or does not absorb enough from food.

Etiology

A variety of etiologies can result in hypokalemia. These etiologies can be placed into the following categories:

1. Decreased potassium intake
2. Transcellular shifts (increased intracellular uptake)
3. Increased potassium loss (skin, gastrointestinal, and renal losses)

Epidemiology

In general, hypokalemia is associated with diagnoses of cardiac disease, renal failure, malnutrition, and shock. Hypothermia and increased blood cell production (for example, leukemia) are additional risk factors for developing hypokalemia.

• Hypokalemia is more common in hospitalized patients, up to 15%, as a result of other pathologies.
• Only 3% of the outpatient population is found to have Hypokalemia. 
• There has been no significant difference in prevalence between gender and race.

Characteristics/Clinical

An individual with Hypokalemia may exhibit signs of the following:

• Abnormal heart rhythyms
• Constipation
• Fatigue
• Muscle Damage
• Muscle Weakness or spasms
• Paralysis
• Nausea and vomiting
• Polyuria, nocturia or polydipsia
• Altered mental status
• Signs of Ileus
• Hypotension
• Cardia arrest
• Bradycardia or Tachycardia
• Premature atrial or ventricular beats
• Hypoventilation/Respiratory distress
• Respiratory failure
• Lethargy
• Edema (Cushingoid appearance)

Associated Co-morbidities

Hypokalemia may present as a result of:

• Chronic Kidney Failure
• Diabetic Ketoacidosis
• Diarrhea/Vomiting
• Excessive Sweating
• Excessive use of laxatives
• Prescription Diuretic Pills
• Primary Aldosteronism
• Liddle Syndrome
• Cushing Syndrome
• Bartter Syndrome
• Fanconi Syndrome
• Bulimia
• Eating large amounts of licorice, herbal teas or chewing tobacco
• Magnesium Deficiency
• Glue Sniffing
• Alcoholism (poor appetite and/or vomiting)
• Amphotericin B therapy
• Hypothermia

Diagnostic Tests/Lab Tests/Lab Values

Hypokalemia is commonly found in a blood test, with <3.5mmol/L as mild hypokalemia and <2.5mmol/L as severe hypokalmia.

In severe cases, a 12-lead electrocardiogram may be necessary if to check for cardiac arrythymias. Findings such as T-wave flattening or prominent U waves will result in hospital admission. Other tests may include:

• arterial blood gas
• basic or comprehensive metabolic panel

Blood tests will also be administered to check the following:

• glucose
• magnesium
• calcium
• sodium
• phosphorus
• thyroxine
• aldosterone levels.

Systemic Involvement

Systems Affected

Systems	Impairments
Cardiovascular	Cardiac Arrythmias, Hypotension, Premature Artrial or Ventricular Contractions, Bradycardia/Tachycardia/3
Pulmonary	Respiratory Failure or complete paralysis in cases <2.5mmol/L
Musculoskeletal	Muscle weakness, cramping or paralysis.
Genitourinary	Polyuria or sexual dysfunction.

Management

The overarching goals of therapy for hypokalemia are to prevent or treat life-threatening complications, replace the potassium deficit, and to diagnose and correct the underlying cause.

Management of the underlying disease or contributing factors constitutes the cornerstone of therapeutic approach. Potassium should be gradually replaced, preferably by oral administration if clinically feasible. In cases of severe/symptomatic hypokalemia and cardiac complications, i.v. administration with continuous ECG monitoring is recommended. In some patients, such as in endocrine related hypokalemia cases, multidisciplinary diagnostic and therapeutic approach is needed.

Physical Therapy Management

Hypokalemia is not managed primarily by a physical therapist. Physical therapists should be mindful of common signs of symptoms of hypokalemia when working with patients.

• Potassium levels < 3.2 mEq/L is contraindicated for physical therapy intervention due to the potential for arrhythmia . Due to muscle weakness and cramping, exercise is not effective during the state of hypokalemia.
• Patients should be monitored for potassium levels in order to determine the appropriate time to participate in Physical Therapy.

Differential Diagnosis

• Bartter syndrome
• Hyperthyroidism and thyrotoxicosis
• Hypocalcemia
• Hypochloremic alkalosis
• Hypomagnesemia
• Iatrogenic Cushing syndrome
• Metabolic alkalosis
  

References

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