Hypokalemic periodic paralysis: Difference between revisions

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==Background==
==Background==
*Autosomal dominant channelopathy<ref>June-Bum Kim, MD, PhD. Channelopathies. Korean J Pediatr. 2014 Jan;57(1):1-18 [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3935107/ Full Text]</ref>
*Autosomal dominant channelopathy<ref>June-Bum Kim, MD, PhD. Channelopathies. Korean J Pediatr. 2014 Jan;57(1):1-18 [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3935107/ Full Text]</ref>
*Symptoms include muscle weakness or paralysis with associated hypokalemia (though potassium levels can be normal), sometimes painful though often painless. Weakness can be from hand to leg to complete paralysis.
*Acquired [[hypokalemia]] from barium poisoning, hyperthyroidism, renal disorders, and GI losses<ref>Ahlawat SK and Sachdev A. Hypokalemic paralysis. Postgrad Med J. 1999; 75(882):193-197.</ref>
*Triggered by strenuous exercise, high carbohydrate meal, high sodium meals, sudden changes in temperature or emotional stress
*Attacks can last several hours to several days
*Most first attacks happen by age 16
*Most first attacks happen by age 16
*Young males, Asian
*There is no decrease in total body potassium. Blood potassium level is normal between attacks.<ref>Mount DB, Zandi-Nejad K. Disorders of potassium balance. In Taal MW, Chertow GM, Marsden PA, et al., eds. Brenner and Rector’s The Kidney. 9th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 17.</ref>
*There is no decrease in total body potassium. Blood potassium level is normal between attacks.<ref>Mount DB, Zandi-Nejad K. Disorders of potassium balance. In Taal MW, Chertow GM, Marsden PA, et al., eds. Brenner and Rector’s The Kidney. 9th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 17.</ref>
*Associations
**[[Thyrotoxicosis]] (thyrotoxicosis periodic paralysis)
**[[Steroids]]
**[[ETOH]]
**Renal disease


==Differential Diagnosis==
==Clinical Features==
*[[Guillan Barre]] - Deep tendon reflexes spared, CN 7 spared
===Symptoms===
*[[Thyrotoxic Periodic Paralysis]] - Distinguished by thyroid studies
*Muscle [[weakness]] or paralysis with associated hypokalemia (though potassium levels can be normal)
*[[Multiple Sclerosis]]
*Sometimes [[myalgia|painful]] though often painless
*[[Myasthenia Gravis]]
*Weakness can be from hand to leg to complete paralysis
*[[Conversion Disorder]]
===History===
*Spinal Impingement/[[Epidural Abscess]]
*Strenuous exercise
*[[ALS]]
*High carbohydrate meal
*[[NMS]]
*High sodium meals
*[[Serotonin Syndrome]]
*Sudden changes in temperature
 
*Emotional stress
==Physical Exam==
*Attacks can last several hours to several days
===Physical Exam===
*Reflexes are decreased or absent<ref name="Chinnery">Chinnery PF. Muscle diseases. In: Goldman L, Schafer AI, eds. Goldman’s Cecil Medicine. 24th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 429.</ref>
*Reflexes are decreased or absent<ref name="Chinnery">Chinnery PF. Muscle diseases. In: Goldman L, Schafer AI, eds. Goldman’s Cecil Medicine. 24th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 429.</ref>
*Shoulders and hips, are involved more often than the arms and legs.<ref name="Chinnery"></ref>
*Shoulders and hips, are involved more often than the arms and legs.<ref name="Chinnery"></ref>
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*There should not be myoclonus or spasticity
*There should not be myoclonus or spasticity


==Treatment==
==Differential Diagnosis==
{{Weakness DDX}}
 
==Evaluation==
===Labs===
*Chemistry (potassium)
*Magnesium
*Thyroid function tests for first presentation
 
===ECG Findings===
*Sinus [[bradycardia]]
*[[ECG]] signs of hypokalemia may be present but not always diagnostic<ref>Hypokalemic Periodic Paralysis. Periodic Paralysis International. http://hkpp.org/physicians/hypokalemic_pp</ref>
**U waves in leads II, V-2, V-3, and V-4
**Progressive flattening of T waves and depression of ST segment
**Prolongation of the PR and QT intervals
 
==Management==
*Replace potassium appropriately - do not try to correct to normal level as once the muscles release potassium you will likely overcorrect
*Replace potassium appropriately - do not try to correct to normal level as once the muscles release potassium you will likely overcorrect
*Consider magnesium
*Consider [[propranolol]] 3 mg/kg PO, expect to see rise in potassium within 2 hours<ref>Lin SH and Lin YF. Propranolol rapidly reverses paralysis, hypokalemia, and hypophosphatemia in thyrotoxic periodic paralysis. Am J Kidney Dis. 2001 Mar;37(3):620-3.</ref>
**Only in hemodynamically stable patients without significant conduction block
**Beta blockers particularly helpful in thyrotoxicosis variant
*Long Term Treatment:  
*Long Term Treatment:  
**Should be initiated by primary physician but often includes eating a low carbohydrate diet and avoiding alcohol
**Should be initiated by primary physician but often includes eating a low carbohydrate diet and avoiding alcohol
**Medications to increase potassium: [[Acetazolamide]], [[Spironolactone]], Potassium tablets,
**Medications to increase potassium: [[Acetazolamide]], [[Spironolactone]], Potassium tablets


==Disposition==
==Disposition==
*Can be discharged from ED after potassium repletion and resolution of symptoms.
*Can be discharged from ED after potassium repletion and resolution of symptoms
 
*Consider admission if patient remains symptomatic


==See Also==
==See Also==
*[[Hypokalemia]]


==Sources==
==References==
<references/>
<references/>
[[Category:Neurology]]
[[Category:FEN]]

Latest revision as of 05:27, 20 August 2022

Background

  • Autosomal dominant channelopathy[1]
  • Acquired hypokalemia from barium poisoning, hyperthyroidism, renal disorders, and GI losses[2]
  • Most first attacks happen by age 16
  • Young males, Asian
  • There is no decrease in total body potassium. Blood potassium level is normal between attacks.[3]
  • Associations

Clinical Features

Symptoms

  • Muscle weakness or paralysis with associated hypokalemia (though potassium levels can be normal)
  • Sometimes painful though often painless
  • Weakness can be from hand to leg to complete paralysis

History

  • Strenuous exercise
  • High carbohydrate meal
  • High sodium meals
  • Sudden changes in temperature
  • Emotional stress
  • Attacks can last several hours to several days

Physical Exam

  • Reflexes are decreased or absent[4]
  • Shoulders and hips, are involved more often than the arms and legs.[4]
  • There is flaccid paralysis rather than hypertonia
  • There should not be myoclonus or spasticity

Differential Diagnosis

Weakness

Evaluation

Labs

  • Chemistry (potassium)
  • Magnesium
  • Thyroid function tests for first presentation

ECG Findings

  • Sinus bradycardia
  • ECG signs of hypokalemia may be present but not always diagnostic[5]
    • U waves in leads II, V-2, V-3, and V-4
    • Progressive flattening of T waves and depression of ST segment
    • Prolongation of the PR and QT intervals

Management

  • Replace potassium appropriately - do not try to correct to normal level as once the muscles release potassium you will likely overcorrect
  • Consider magnesium
  • Consider propranolol 3 mg/kg PO, expect to see rise in potassium within 2 hours[6]
    • Only in hemodynamically stable patients without significant conduction block
    • Beta blockers particularly helpful in thyrotoxicosis variant
  • Long Term Treatment:
    • Should be initiated by primary physician but often includes eating a low carbohydrate diet and avoiding alcohol
    • Medications to increase potassium: Acetazolamide, Spironolactone, Potassium tablets

Disposition

  • Can be discharged from ED after potassium repletion and resolution of symptoms
  • Consider admission if patient remains symptomatic

See Also

References

  1. ↑ June-Bum Kim, MD, PhD. Channelopathies. Korean J Pediatr. 2014 Jan;57(1):1-18 Full Text
  2. ↑ Ahlawat SK and Sachdev A. Hypokalemic paralysis. Postgrad Med J. 1999; 75(882):193-197.
  3. ↑ Mount DB, Zandi-Nejad K. Disorders of potassium balance. In Taal MW, Chertow GM, Marsden PA, et al., eds. Brenner and Rector’s The Kidney. 9th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 17.
  4. ↑ 4.0 4.1 Chinnery PF. Muscle diseases. In: Goldman L, Schafer AI, eds. Goldman’s Cecil Medicine. 24th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 429.
  5. ↑ Hypokalemic Periodic Paralysis. Periodic Paralysis International. http://hkpp.org/physicians/hypokalemic_pp
  6. ↑ Lin SH and Lin YF. Propranolol rapidly reverses paralysis, hypokalemia, and hypophosphatemia in thyrotoxic periodic paralysis. Am J Kidney Dis. 2001 Mar;37(3):620-3.
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