Hypokalemia


[1]

Definition/Description

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. Since potassium is critical to the proper functioning of nerve and muscle fibers, hypokalemia can require urgent medical attention. [2]

Prevalence

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

Characteristics/Clinical

An individual with Hypokalemia may exhibit signs of the following:

  • Abnormal heart rhythyms
  • Constipation
  • Fatigue
  • Muscle Damage
  • Muscle Weakness or spasms
  • Paralysis[2]
  • 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)[4]

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 [2]
  • Liddle Syndrome
  • Cushing Syndrome
  • Bartter Syndrome
  • Fanconi Syndrome
  • Bulimia [5]
  • Eating large amounts of licorice, herbal teas or chewing tobacco
  • Magnesium Deficiency
  • Glue Sniffing
  • Alcoholism (poor appetite and/or vomiting)
  • Amphotericin B therapy
  • Hypothermia [3]

Medications

In order to correct Hypokalemia, potassium supplements can be administered orally or intervenously.   

Oral preparations of potassium include:

  • 8m Eq KCl slow release tablets
  • 20 mEq KCl elixir
  • 20 mEq KCl powder
  • 25mEq KCl tablet

If the patient has severe hypokalemia (<2.5mmol/L) up to 40 m Eq/h of IV preparation will be administered. Close follow-up care is necessary with continuous ECG monitoring and serial potassium level cheacks. If higher amounts of potassium is administered, cardiac complication risks may increase. Thus, many insttitutions have set up policies that limit the amount of potassium that can be given per hour. Potassium levels must be measured every 1-3 hours.[4]

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.[2]

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.[3]

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.[5]

Etiology/Causes

Low potassium has many causes with the most common being excessive loss in urine or from the digestive tract. Very seldom it may be caused by not consuming enough potassium in your diet.[2] 

Other causes include excessive sweating or overuse of laxatives, diuretics, and alcoholism.[2]Certain medications (penicillin, nafcillin, cerbencillin, gentamicin, amphotericin B, foscarnet) are known to be possible causes, as well.Pathologies such as Cushing syndrome, Liddle Syndrome, Barrtter Syndrome and Fanconi Syndrome can all potentially casue low potassium levels.[5]

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.[2]

Medical Management (current best evidence)

Severe hypokalmeia levels that cause ECG changes such as T-wave flattening or prominent U waves require hospital admission. Mild hypokalemia (<3.5mmol/L) can be treated by taking potassium supplements by mouth, while severe cases (<2.5mmol/L) may need to receive potassium intravenously. Potassium supplements usually corrects the problem, however if hypokalemia is not addressed it may lead to serious heart problems that can be fatal.  [3]

Physical Therapy Management (current best evidence)

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.[6]

Thus, 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.

Differential Diagnosis

  •  Emesis
  • Nasogastric suctioning
  • Pyloric stenosis
  • Diarrhea 
  • Malabsorption
  • Villous adenoma 
  • Renal losses
  • Electrolyte abnormalities 
  • Hypomagnesemia
  • Endocrine abnormalities
  • Cushing disease or syndrome
  • Congenital adrenal hyperplasia 
  • Hyperaldosteronism 
  • High renin states
  • Increased mineralocorticoid –  chewing tobacco, licorice 
  • Intrinsic renal abnormalities
  • Bartter’s Syndrome
  • Gitelman’s Syndrome 
  • Renal tubular acidosis, types I or II [7]

Case Reports/ Case Studies

Hypokalemia Case Study


The syndrome of refractory watery diarrhea and hypokalemia in patients with a non-insulin—secreting islet cell tumor ☆: A further case study and review of the literature  http://www.sciencedirect.com/science/article/pii/0002934362901882
--Summary: Surgical removal of islet cell adenoma results in a decrease of severe diarrhea and a reduced risk of hypokalemia.


Hypokalemic nephropathy in anorexia nervosa http://connection.ebscohost.com/c/case-studies/67145420/hypokalemic-nephropathy-anorexia-nervosa

--summary: 25 year old female that has a history of multiple hospital admissions due to hypokalemia caused by chronic purging.

Resources

http://www.mayoclinic.com/health/low-potassium/MY00760

Recent Related Research (from Pubmed)

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References

  1. Hypokalemia [Internet]. 2012 [cited 2013 March 27] Available from:https://www.clinicalkey.com/topics/nephrology/hypokalemia.html
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Low Potassium(hypokalemia)[Internet]. 2012 August 10 [cited 2013 March 27] Available from:http://www.mayoclinic.com/health/low-potassium/MY00760
  3. 3.0 3.1 3.2 3.3 Hypokalemia [Internet]. 2012 [cited 2013 March 27] Available from:https://www.clinicalkey.com/topics/nephrology/hypokalemia.html#720089
  4. 4.0 4.1 Garth D.,Schraga E.Hypokalemia in emergency medicine.[homepage on the Internert]2012 April 13 [cited 2013 March 27] Available from: http://emedicine.medscape.com/article/767448-overview
  5. 5.0 5.1 5.2 Hypokalemia [Internet]. 2013 March 22 [cited 2013 March 27] Available from: http://www.nlm.nih.gov/medlineplus/ency/article/000479.htm
  6. Goodman CC. Fuller KS. In K Falk editor. Pathology: Implications for the Physical Therapist. St. Louis: Saunders Elsevier; 2009. pp.150, 157, 187-189, 480, 558, 927, 1243, 1640-1641
  7. Alessandro D. Alessandro M. What is the differential diagnosis of hypokalemia? [Internet] 2006 February 6. [cited 2013 April 4] Available from:http://www.pediatriceducation.org/2006/02/06/what-is-the-differential-diagnosis-of-hypokalemia/

see adding references tutorial.