Hypokalemic periodic paralysis: Difference between revisions
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< | ==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> | ||
*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> | |||
*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> | |||
*Associations | |||
**[[Thyrotoxicosis]] (thyrotoxicosis periodic paralysis) | |||
**[[Steroids]] | |||
**[[ETOH]] | |||
**Renal disease | |||
==Clinical Features== | |||
===Symptoms=== | |||
*Muscle [[weakness]] or paralysis with associated hypokalemia (though potassium levels can be normal) | |||
*Sometimes [[myalgia|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<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> | |||
*There is flaccid paralysis rather than hypertonia | |||
*There should not be myoclonus or spasticity | |||
==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 | |||
*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: | |||
**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== | ||
*[[Hypokalemia]] | |||
==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
- Thyrotoxicosis (thyrotoxicosis periodic paralysis)
- Steroids
- ETOH
- Renal disease
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
- Neuromuscular weakness
- Upper motor neuron:
- CVA
- Hemorrhagic stroke
- Multiple sclerosis
- Amyotrophic Lateral Sclerosis (ALS) (upper and lower motor neuron)
- Lower motor neuron:
- Spinal and bulbar muscular atrophy (Kennedy's syndrome)
- Spinal cord disease:
- Infection (Epidural abscess)
- Infarction/ischemia
- Trauma (Spinal Cord Syndromes)
- Inflammation (Transverse Myelitis)
- Degenerative (Spinal muscular atrophy)
- Tumor
- Peripheral nerve disease:
- Neuromuscular junction disease:
- Muscle disease:
- Rhabdomyolysis
- Dermatomyositis
- Polymyositis
- Alcoholic myopathy
- Upper motor neuron:
- Non-neuromuscular weakness
- Can't miss diagnoses:
- ACS
- Arrhythmia/Syncope
- Severe infection/Sepsis
- Hypoglycemia
- Periodic paralysis (electrolyte disturbance, K, Mg, Ca)
- Respiratory failure
- Emergent Diagnoses:
- Symptomatic Anemia
- Severe dehydration
- Hypothyroidism
- Polypharmacy
- Malignancy
- Aortic disease - occlusion, stenosis, dissection
- Other causes of weakness and paralysis
- Acute intermittent porphyria (ascending weakness)
- Can't miss diagnoses:
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
- ↑ June-Bum Kim, MD, PhD. Channelopathies. Korean J Pediatr. 2014 Jan;57(1):1-18 Full Text
- ↑ Ahlawat SK and Sachdev A. Hypokalemic paralysis. Postgrad Med J. 1999; 75(882):193-197.
- ↑ 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.
- ↑ 4.0 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.
- ↑ Hypokalemic Periodic Paralysis. Periodic Paralysis International. http://hkpp.org/physicians/hypokalemic_pp
- ↑ 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.