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Hypokalemia: Possible Diagnosis


hypokalemia diagnosis

Background

  • Potassium is the major intracellular cation with 98% of the total body potassium in the intracellular compartment and only 2% located extracellularly (plasma).  The serum potassium level is a measure of the 2% that is  present in the extracellular space.
  • Hypokalemia is defined as a serum potassium concentration of less than 3.5 mEq/L [normal range: 3.5-5 mEq/L].
  • Hypokalemia classification:
    Mild (3-3.4 mEq/L)
    Moderate (2.5 - 2.9 mEq/L)
    Severe (< 2.5 mEq/L)
  • The patient's BMI has little effect when determining the amount of potassium required to reach a target level.  Conversely,  renal disease can profoundly impact the amount of potassium required.

Required Entries


Data points:


Potassium below 3.5 mEq/L (ruled out pseudohypokalemia) AND:


24hr urinary K+ excretion:
 

Alternative (more practical)


Perform a spot urine potassium-to-creatinine ratio from a spot urine specimen (Uk:Ucr):  
 Ratio: 


Blood pressure:

Plasma bicarbonate concentration:





Answer the following questions:

History or evidence suggestive of transcellular shifts? 

 Is the patient receiving any of the following medications

  • β-Adrenergic agonists (bronchodilators etc).
  • Decongestants
  • Xanthines (theophylline, caffiene)
  • Insulin administration or excess
  • Amphotericin B
  • Acute Glucose load
  • Verapamil Overdose
  • Chloroquine (Aralen) intoxication
  • Barium or cesium Overdose

Are any of the following medical conditions present?

  • Delirium Tremens
  • Head Injury
  • Myocardial Ischemia
  • Refeeding Syndrome
  • Metabolic Alkalosis
  • Familial hypokalemic periodic paralysis
  • Anabolic states
  • Thyrotoxicosis
  • Hypothermia


heart

 
 






Key Reference top of page

Aboujamous H. et al. Evaluation of the Change in Serum Potassium Levels after Potassium Administration. J Clin Nephrol Ren Care 2016, 2:013.

  • Because the potassium content of gastric secretion (5–10 mEq/L) is much less than that of the intestinal secretion (up to 90 mEq/L), loss of a large volume of gastric secretion is needed to produce substantial potassium depletion.
  • In an asymptomatic hypokalemic patient with no apparent causes for potassium depletion or transcellular redistribution, pseudohypokalemia should be excluded before pursuing an intensive evaluation.
  • Transcellular redistribution of potassium may, however, significantly alter the relationship between serum concentration and total body deficit. Therefore, potassium repletion should be guided by close monitoring of serum concentrations and analysis
  • Hypokalaemia can result from increased loss, transcellular shift, or decreased intake of potassium. Increased potassium loss (through the kidney or gastrointestinal tract) is the most common cause of hypokalaemia.
  • Less frequently, hypokalaemia can occur as a result of shift of potassium from the extracellular space into cells.
  • Rarely, hypokalemia can result from decreased intake of potassium.




References top of page

 

  1. Aboujamous et al. Evaluation of the Change in Serum Potassium Levels after Potassium Administration. J Clin Nephrol Ren Care 2016, 2:013,
  2. Asmar A, Mohandas R, Wingo CS. A Physiologic-Based Approach to the Treatment of a Patient With Hypokalemia. Am J Kidney Dis. 2012 September ; 60(3): 492–497.
  3. Cohn JN, Kowey PR, et al. New guidelines for potassium replacement in clinical practice: A contemporary review by the National Council on Potassium in Clinical Practice. Arch Intern MED/VOL 160, SEP 11, 2000.
  4. Gennari FJ. Disorders of potassium homeostasis: Hypokalemia and hyperkalemia. Crit Care Clin. 2002;18(2):273-288.
  5. Gennari FJ. Hypokalemia. N Engl J Med. 1998;339(7):451-458.
  6. Kamel KS, Quaggin S, Scheich A, et al. Disorders of potassium homeostasis: an approach based on pathophysiology. Am J Kidney Dis 1994;24:597–613.
  7. Kardalas E, et al. Hypokalemia: a clinical update. Endocrine Connections (2018) 7, R135–R146.
  8. Kim GH, Han JS. Therapeutic approach to hypokalemia. Nephron. 2002;92(suppl 1):28-32.
  9. Lippi G, Favaloro EJ, Montagnana M, Guidi GC. Prevalence of hypokalaemia:the experience of a large academic hospital. Intern Med J. 2010;40(4):315-316.
  10. Rastergar A, Soleimani M. Hypokalaemia and hyperkalaemia. Postgrad Med J 2001;77:759–764.
  11. Viera AJ, Wouk N. Potassium Disorders: Hypokalemia and Hyperkalemia.Am Fam Physician. 2015;92(6):487-495.
  12. Weiner ID, Wingo CS. Hypokalemia-consequences, causes, and correction. J Am Soc Nephrol. 1997;8(7):1179-1188.
Hypokalemia Possible Diagnosis