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Dipika Aggarwal PGY 4 Neurology.  Teen aged male admitted with acute onset generalized weakness for 1 day duration  Woke up with diffuse weakness; no.

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Presentation on theme: "Dipika Aggarwal PGY 4 Neurology.  Teen aged male admitted with acute onset generalized weakness for 1 day duration  Woke up with diffuse weakness; no."— Presentation transcript:

1 Dipika Aggarwal PGY 4 Neurology

2  Teen aged male admitted with acute onset generalized weakness for 1 day duration  Woke up with diffuse weakness; no anti gravity strength in arms, unable to get out of bed  Proximal > distal weakness; bilaterally symmetrical  Denied diplopia, dysphagia, dysarthria, facial droop, drooling or change in level of consciousness 2

3  Denied any sensory complains  Denied trouble breathing, urinary or bowel incontinence  Denied any recent illness, trauma, travel or tick bite  One episode of non-bloody emesis prior to admission 3

4  PMH: similar episode four months earlier, admitted to OSH for 4-5 days, ?? Diagnosed with GBS, ?? treated with plasmapheresis, no LP/ EMG  PSH: none  Home meds: None  FH: HTN, migraine, DM, asthma, no similar problem in family members  SH: denies smoking, ETOH or illicit drug use 4

5  Vitals stable  General physical exam unremarkable  Neurological exam ◦ Mental status: AAO * 4 ◦ Speech : fluent with comprehension intact ◦ CN 2-12: PERRLA, EOMI, normal facial sensation and symmetry, normal facial strength, hearing intact, equal palatal elevation and tongue midline 5

6 ◦ Motor: Flaccid tone, motor strength 2/5 proximally and 3-4/5 distally BUE and BLE ◦ DTRs: Areflexic, toes downgoing ◦ Sensory: Intact to LT/PP/ Vibration and proprioception ◦ Unable to test for cerebellar function and gait 6

7 Where?? What?? 7

8  Hb - 14.6, WBC 6.1, Plt count 215  Sodium 143, K 1.3, Chloride 110, BUN 13, Creatinine 0.83, Glucose 151, Calcium 9.3, Magnesium 2.0, Phosphorus 2.4  CK 493, Aldolase 15.7 (on day 3)  TSH: 2.082, free T3 – 3.8, free T4 – 0.9  Urine lytes: unremarkable 8

9  Aggressive Potassium replacement  Started showing improvement in muscle strength on day 1  By day 2 – strength was 5/5 BUE and BLE  Diagnosed with familial hypokalemic periodic paralysis  Discharged with follow up care with Jayhawk clinic 9

10  Non dystrophic myotonias ◦ Myotonia congenita (CLCN1) ◦ Paramyotonia congenita (SCN4A) ◦ Sodium channel myotonias (potassium aggravated myotonias) (SCN4A)  Periodic paralyses ◦ Hypokalemic (CACNA1S/ SCN4A) ◦ Hyperkalemic (SCN4A) ◦ Anderson Tawil syndrome (KCNJ2) 10

11  Hypokalemic: ◦ Thyrotoxic periodic paralysis ◦ hyperaldosteronism ◦ RTA ◦ villous adenoma ◦ cocaine binge ◦ diuretics, licorice, steroids, ETOH  Hyperkalemic (k>7): ◦ hyporenemic hypoaldosteronism (DM/CRF) ◦ oral K, CRF, chronic heparin, rhabdomyolysis  Normakalemic: ◦ Guanidine, sleep paralysis, MG, TIA, conversion 11

12  HypoKPP1 and 2 - CACNA1S/ SCN4A gene  HypoKPP 1 is the most frequent form  1 in 100,000  Autosomal dominant inheritance pattern  M:F – 3 or 4:1  Onset: first 2 decades of life 12

13  Flaccid paralysis – mild focal weakness to severe generalized weakness  Occur anytime of the day; more common in morning  Absence of myotonia  Proximal > distal weakness; legs > arms  Sparing of facial, ventilatory and sphincter muscles  Lasts several hours to more than a day 13

14  Frequency: highly variable  Frequency decreases after age 30; may become attack free in 40s and 50s  Permanent fixed weakness or slowly progressive weakness more common with HypoKPP1  Attacks may be preceded by sensation of heaviness and or aching in the low back 14

15  Strenuous physical activity followed by rest or sleep  High carb diet  ETOH consumption  Emotional stress  Concurrent viral illness  Lack of sleep  Medications like beta agonists, corticosteroids, and insulin 15

16  Mutations in voltage sensor segment D2S4 of  1 subunit of skeletal muscle Ca channel gene, chromosome 1q  Arg528His, Arg1239His, Arg1239Gly  Less commonly SCN4A mutation enhances Na inactivation 16

17  The mutation slows the activation rate of L-type Ca current to 30% of NL  Reduced RYR1-mediated Ca release from SER  Reduced calcium current density  Impaired E-C coupling  ? role of K and ? inexcitability  Ca homeostasis change reduces ATP-dependent K channel current and leads to abnormal depolarization (Tricarico D et al 1999) 17

18  Serum K < 3.0mEq/L  Serum CK level elevated  EKG changes – U waves, flattening of T waves  Provocative testing - Intravenous glucose load/ insulin  Electrophysiology ◦ Sensory and motor NCS normal between attacks ◦ During attacks – small CMAP. Reduced insertional activity, fibs and positive sharp waves ◦ No myotonia on EMG ◦ Short/ long exercise test 18

19  Muscle biopsy reserved to atypical patients with normal provocative and gene testing  Vacuoles reflect permanent myopathy  Vacuoles represent proliferation, degeneration and autophagic destruction of T-tubules & SR  Large central vacuoles in hypokalemic PP 19

20 20

21  Reducing exposure to known triggers  Acute treatment – replacement of K  Acetazolamide – prevent attack recurrence and severity ◦ Acetazolamide may ppt weakness in HypoKPP2  Dichlorphenamide – no longer available  Triamterene and spironolactone 21

22  R/O secondary forms  Measure K + during attack  Provocative testing for PP: seldom done! o Hypo: gluc/insulin o Hyper: K +  Muscle Bx – vacuoles/dilated T-tubules  Electrophysiology o EMG o Short/long exercise tests  Genetics 22

23  More useful in MC  Baseline CMAP  Exercise 10 sec  Record CMAP immediately post exercise, then q 10 sec for 1 min.   CMAP in MC and PMC  PMC exacerbated by cold  No change in CMAP in HypoKPP 23 (Streib. Musc. Nerve. 1982; 5: 719-723) (Fournier. Ann. Neurol. 2004; 56: 650-661) (Fournier Neurology 2009)

24  Record ulnar CMAP Amp baseline  Exercise ADM 5 min  Check CMAP every 2 min. for 50 min  In PP (all types),  Amp immed post ex, over next 10-40 min, grad dec amp  In MC ↓ Amp immed post ex, rapid return to baseline  In PMC sustained ↓ Amp 24 (McManis. Musc. Nerve. 1986; 9: 704-710) (Fournier. Ann. Neurol. 2004; 56: 650-661)

25  Dr.Barohn’s presentation on “Muscle Channelopathies”  Anthony A.Amato and James A.Russell; Non dystrophic myotonias and periodic paralysis. Neuromuscular disorders 2008, Mc Graw Hill, Section II Chapter 29; 655-680  Burge JA, Hanna MG. Novel insights into the pathomechanisms of skeletal muscle channelopathies; Curr Neurol Neurosci Rep. 2012 Feb Vol 12:62-69  Hanna, Dipa L Raja Rayan and Michael G. Skeletal Muscle Channelopathies:Non Dystrophic Myotonias and Periodic Paralysis. Current Opinion in Neurology, 2010 Vol. 23: 466-476  neuromuscular.wustl.edu  Doreen Fialho and Michael G.Hanna. Periodic paralysis, Handbook of Clinical Neurology, 2007 Vol. 86 (3rd series), p 89-90 25


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