[ Na+] COI Disclosure OBJECTIVES. By the end of the session, and upon further learning and reflection participants should be able to:

Transcription

1 COI Disclosure Busting Myths and de-mist-ifying its Assessment & Management Peter Loewen B.Sc.(Pharm), ACPR, Pharm.D., FCSHP Faculty of Pharmaceutical Sciences The University of British Columbia Lower Mainland Pharmacy Services OBJECTIVES By the end of the session, and upon further learning and reflection participants should be able to: 1. Correctly use the terms hypovolemia and dehydration. 2. Demonstrate an APPROACH to evaluating in a patient and its potential cause. 3. Describe drug-related causes of and treatment approaches tuned to the cause. 4. Diagnose or rule out SIADH and implement a treatment approach if detected.

2 is COMMON has CLINICAL CONSEQUENCES mortality, CNS, hip fracture, heart failure economic impacts Patterson JH. Hospital Pharmacy 2011;46:S3 S10. Zilberberg MD et al. Curr Med Res Opin 2008;24: Upadhyay A, et al. Am J Med 2006;119:S30 5 Waikar SS, et al. Am J Med 2009;122: Wald R, et al. Arch. Intern. Med. 2010;170:294 and Heart Failure Where s your water? Total body water (TBW) = 0.6* x total body weight *More precisely: 0.45 for elderly female, 0.5 for non-elderly female or elderly male, 0.6 for non-elderly male. Intracellular fluid (ICF) Extracellular fluid (ECF) Intracellular osmolality must be maintained for cells to function. Plasma osmolality will be sacrificed in either direction to achieve this. H2O freely crosses cell membranes. Na+ doesn t. Intracellular osmoles are mostly large proteins that don t move. H 2 O cell membrane interstitial water H 2 O Na+ intravascular water 2/3 1/3 3/4 1/4 Patterson JH. Hospital Pharmacy 2011;46:S3 S10.

3 DRUG THERAPY CASE KP is a 77 y/o M brought to ED from home because of increasing lethargy and confusion over the past 48 hours. He has had diarrhea for the past 4 days subsequent to a course of cefuroxime for mild CAP, and has been receiving HCTZ 25 mg/d for one year for ISH. PMH: HTN. CAP. O/E: Oriented x /60 supine, 75/45 standing. HR 65 supine, 80 standing. Postural dizziness. JVP <2cm ASA. Assess the ICF Serum [Na+] mmol/l Assess the ICF Serum [Na+] mmol/l hypernatremia ( ICF) hyponatremia ( ICF) hypernatremia ( ICF) hyponatremia ( ICF) assess the ECF

4 assess the ECF assess the ECF CASE KP is a 77 y/o M brought to ED from home because of increasing lethargy and confusion over the past 48 hours. He has had diarrhea for the past 4 days subsequent to a course of cefuroxime for mild CAP, and has been receiving HCTZ 25 mg/d for one year for ISH. PMH: HTN. CAP. O/E: Oriented x /60 supine, 75/45 standing. HR 65 supine, 80 standing. Postural dizziness. JVP <2cm ASA.

5 In hypovolemic, is the Na+ in the NS raising your patient s serum [Na+]? Zarychanski R, et al. JAMA 2013;309: ADH ICF ECF How does excess ICF cause hyponatremia? H2O goes in Intracellular tonicity decreases Need to maintain normal intracellular tonicity H2O moves [Na+] IV

6 How does loss of ICF cause hypernatremia? H2O leaves [loop diuretics, fever] ICF Need to Intracellular maintain tonicity normal increases intracellular tonicity ECF H2O moves [Na+] IV How much water should you drink? How much water should you drink? What makes you thirsty?

7 SITUATION Hey, pharmacist, I ve got a patient here with a serum Na of 122 and they re on [insert any drug name that starts with c ]. I think they ve probably got SIADH. Fix it, please. assess the ECF in a non-hypovolemic patient... Does my patient have SIADH? Holm EA, et al. South. Med. J. 2009;102:380 4.

8 CASE RQ is a 67 y/o white M admitted from home for general malaise and increasing confusion for one week. PMH: Carcinoma of the bronchus (surgical resection and radiation therapy) 4 months ago; Mild HTN x 5 y (metoprolol 100 mg po bid); Depression (diagnosed 4 months ago and treated with fluoxetine 50 mg/d) O/E: Moderately obese, disoriented white male. BP 150/85 supine, 145/85 standing. HR 70 supine, 75 standing. Temp 36.8C, Wt. 100 kg, JVP 3 cm ASA. Managing SIADH 1. Identify & remove cause 2. H2O restriction (<1000 or <500 ml/d) 3. Furosemide 4. Salt liberalization (eg, >10g/d) 5. Fludrocortisone 6. Lithium / Demeclocycline / Tolvaptan Managing SIADH EVEREST QUEST SALT 1 & 2 6 RCTs (N=2747) comparing low-na diets (1.8 g/day) with normal Na diets (2.8 g/d) in patients with systolic HF HF readmission 1.83 ( ) Mortality 1.95 ( ) Sudden death 1.72 ( ) HF death 2.23 ( ) EVEREST. JAMA 2007;297: QUEST. Cardiovasc Drugs Ther 2011;25 Suppl 1:S33 45 SALT 1 & 2. NEJM 2006;355: Dinicolantonio JJ, et al. Heart 2013; ( /heartjnl )

9 CASE ID: 74 year old M admitted 1 week ago for failure to thrive. On admission his [Na+] was 128. Today it s 133. Putting it all together... PMH: HTN, chronic angina, MI 5 years ago. MPTA: ramipril 5mg, ASA 81mg/d, metoprolol 100mg bid, atorvastatin 80mg/d. Can ramipril cause hyponatremia? COURSE: He got some volume in ED, ramipril was continued, and today is [Na] is 133. Someone sometime in the intervening days wondered whether he had SIADH and ordered urine electrolytes: Na+ was 14, UOsm was 512. Busting Myths and de-mist-ifying its Assessment & Management Peter Loewen B.Sc.(Pharm), ACPR, Pharm.D., FCSHP Faculty of Pharmaceutical Sciences The University of British Columbia Lower Mainland Pharmacy Services

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