RENALCONSULT

Hyponatremia: Potomania and Overcorrection

Recently, we had a patient admitted for Q with a serum sodium level of 117 mEq/L. One of the hospi- talists mentioned “beer poto- mania” in the differential. Not wanting to look dumb, I just agreed. What is beer potoma- nia, and how is it related to low serum sodium? Potomania is the excessive consumption of alcoholic bever- ages; beer potomania is used to refer to a dilutional hyponatremia caused by excessive consumption 1 Source Science / Werner Mike and Carol Credit: of beer. First recognized in 1971, Hyponatremia is generally defined as a serum sodium level of less than 135 this cause of hyponatremia is not mEq/L. When it occurs, water is drawn into the cells, causing the brain to the most common but should be swell (shown at right, in contrast to a normal brain at left). in the differential if the patient is a heavy imbiber who pres- weakness, and gait disturbance nosed more often? There are a lot ents with encephalopathy and with an average serum sodium of beer bingers out there!” Good low serum sodium. concentration of 108 mEq/L.3 question. Let’s review the patho- When considering this diag- Other abnormal lab results con- physiology of beer potomania. nosis, keep in mind that hypona- sistent with this diagnosis include When patients have poor protein tremia is common among chron- (mean potassium, and solute (food, ) ic alcoholics and can be due 3 mEq/L) and low blood urea ni- intake, they can experience wa- to conditions such as , trogen and urine sodium levels.2,3 ter intoxication with smaller- congestive heart failure, syndrome Another fairly consistent find- than-usual volumes of fluid. The of inappropriate antidiuretic hor- ing is a recent personal history of kidneys need a certain amount mone (SIADH) secretion, and hy- (more than about of solute to facilitate free water povolemia. Less common but still 5 L, or 14 cans of beer, in 24 hours) clearance (the ability to clear ex- belonging in the differential are and/or history of illness (vomit- cess fluid from the body). A lack pseudohyponatremia secondary ing, diarrhea) that predisposed of adequate solute results in a to alcohol-induced severe hyper- the patient to a rapid drop in se- buildup of free water in the vascu- triglyceridemia and cerebral salt rum sodium levels.2 lar system, leading to a dilutional wasting syndrome.2,3 Based on the information hyponatremia.3 Beer potomania usually mani- presented thus far, you may ask, Free water clearance is depen- fests as altered mental status, “Why haven’t I seen this diag- dent on both solute excretion and the ability to dilute urine. Some- Renal Consult is edited by Jane S. Davis, CRNP, DNP, a member of the Clinician Reviews editorial board, who is an NP in the Division of Nephrology at the University of Alabama at one consuming an average diet Birmingham and is the communications chairperson for the National Foundation’s will excrete 600 to 900 mOsm/d Council of Advanced Practitioners (NKF-CAP); and Kim Zuber, PA-C, MSPS, DFAAPA, who is a PA of solute. This osmolar load in- with Metropolitan Nephrology in Alexandria, Virginia, and Clinton, Maryland; she is also past chair of the NKF-CAP. This month’s responses were authored by Kristina Unterseher, MSN, cludes urea generated from protein FNP, CNN-NP, who practices at Peacehealth St. John Medical Center in Longview, Washington. (10 g of protein produces about

clinicianreviews.com SEPTEMBER 2014 • Clinician Reviews 19 RENALCONSULT

50 mOsm of urea), along with later, she was readmitted for The National dietary sodium and potassium. mental status changes, and Kidney The maximum capacity for uri- MRI showed brain swelling. Foundation nary dilution is 50 mOsm/L. In a The neurologist stated this Council of nutritionally sound person, a lot was a result of the initial treat- Advanced Practitioners' of fluid—about 20 L—would be ment for her hyponatremia. (NKF-CAP) required to overwhelm the body’s How is this possible? mission is to capacity for urinary dilution.2 The cause-and-effect relation- serve as an advisory resource for the However, when you don’t eat, ship between rapid correction of NKF, nurse practitioners, physician the body starts to break down tis- chronic hyponatremia and sub- assistants, clinical nurse specialists, and the community in advancing sue to create energy to survive. sequent development of neuro- the care, treatment, and education This catabolism creates 100 to 150 logic problems was discovered of patients with kidney disease and mOsm/d of urea, allowing you in the late 1970s. Central pontine their families. CAP is an advocate to continue to appropriately ex- and extrapontine myelinolysis for professional development, crete a moderate amount of fluid (known as osmotic demyelination research, and health policies that impact the delivery of patient care in spite of poor solute intake ... as syndrome or ODS) is a neurologic and professional practice. For more long as you are not drinking ex- condition that can occur from information on NKF-CAP, visit cessive amounts of water.5 rapid sodium correction. It is di- www.kidney.org/CAP Alcoholics get a moderate agnosed by MRI, which shows hy- amount of their calories via beer perintense lesions on T2-weight- first two to three hours. Do not consumption and do not expe- ed images. Clinical signs include exceed 10 mEq/L in 24 hours or rience this endogenous protein upper motor neuron signs, pseu- 18 mEq/L in 48 hours. Exceeding breakdown or its resultant low dobulbar palsy, spastic quadripa- these limits puts patients at high urea/solute level. With low solute resis, and mental status changes risk for ODS. In fact, even when intake, dramatically lower fluid ranging from mild confusion to staying within these parameters, intake (about 14 cans of beer) will coma.2 there is some risk for overcor- overwhelm the kidneys’ ability Treatment for hyponatremia rection. It is always better to go to clear excess free water in the should be guided by symptom slowly.2,3 body.2 Fortunately, most heavy management.2,3 If a patient is as- In the patient with hyponatre- beer drinkers continue to eat at ymptomatic, a simple and effec- mia due to low solute intake (eg, least modestly, which is sufficient tive strategy is to keep NPO for beer potomania), diuresis can to avoid this rare type of hypona- 24 hours, except for medications. start spontaneously after a period tremia. Chronic alcoholics who Simple food and fluid restriction of food and fluid restriction. It can go on a drinking binge beyond will likely increase the serum so- also be initiated with just a small their normal baseline alcohol dium level because of obligate amount of solute. For example, consumption, or who develop a solute losses and urinary electro- administering an IV antibiotic flulike illness that causes elec- lyte free water loss.2,4 While the with a base solution of 100 mL of trolyte depletion (via diarrhea or first instinct is to feed these pa- normal saline or a “banana bag” vomiting), are at higher risk for tients, as they often appear mal- (an IV solution containing 0.5 to beer potomania. nourished, this can cause a solute 1 L of normal saline with multi- load leading to a too-rapid so- vitamins/minerals that cause the A clinic patient of mine dium correction. After 24 hours, if fluid to be yellow) can produce was recently admitted intake restriction is not effective, several liters of diuresis.2 Once Q to the hospital with use 0.5% normal saline but with you open the floodgate, you can hyponatremia (serum sodium, limited dosing orders, as usual unintentionally cause too-rapid 115 mEq/L). She was treated saline dosing can cause too rapid correction that could lead to ODS. with 2 L of normal saline and a correction.2 In chronic hyponatremic pa- discharged home 48 hours For symptomatic patients tients, low antidiuretic hormone later, at her baseline mental (confusion, seizures, coma), the (ADH) levels are often found; thus status with a serum sodium goal is to initially elevate sodium when a solute is introduced, there level of 132 mEq/L. Two days by 1 to 2 mEq/L per hour for the is little ADH in the system to pro- continued on page 22 >>

20 Clinician Reviews • SEPTEMBER 2014 clinicianreviews.com ® Priority Updates from the Research Literature from the Family Physicians Inquiries Network PURLs

Why You Shouldn’t Start b-Blockers Before Surgery A new meta-analysis finds that initiatingb -blockers before surgery increases patients’ risk for death. Anne Mounsey, MD, Jodi M. Roque, MD, Mari Egan, MD

PRACTICE CHANGER in the process of being updated, up to 30 days postop. Metoprolol Do not routinely initiate b-block- came from the DECREASE (Dutch was used in five trials, bisoprolol ers in patients undergoing inter- Echocardiographic Cardiac Risk in one trial, atenolol in two trials, mediate- or high-risk noncardiac Evaluation Applying Stress Echo- and propranolol in one trial. The surgery. b-Blockers appear to cardiography) trials. These trials primary endpoint was all-cause increase the 30-day risk for all- have been discredited due to se- mortality within 30 days. cause mortality.1 rious methodologic flaws, includ- A total of 5,264 patients were ing falsified descriptions of how randomly assigned to receive b- STRENGTH OF RECOMMENDATION outcomes were determined and blockers and 5,265 to placebo. A: Based on meta-analysis of fictitious databases.3 There were 162 deaths in the b- nine randomized controlled trials A new meta-analysis conduct- blocker group and 129 deaths in (RCTs).1 ed by Bouri et al1 that excluded the placebo group. Patients who the DECREASE trials found that, received b-blockers had a 27% ILLUSTRATIVE CASE although preoperative b-blockers increased risk for all-cause mor- A 67-year-old woman with diabe- reduce the rate of certain nonfatal tality (risk ratio [RR] = 1.27). The tes, hypertension, and hyperlipid- outcomes, they increase the risk number needed to harm was 160. emia presents for evaluation prior for death and stroke. Six of the studies also evalu- to a total hip arthroplasty. She is ated rates of nonfatal MI, nonfatal not taking a b-blocker. Should you STUDY SUMMARY stroke, and hypotension. b-Block- prescribe one? Preop b-blockers do more ers lowered the risk for nonfatal harm than good MI (RR = 0.73) but increased the urrent guidelines from the Bouri et al1 conducted a meta- risk for nonfatal stroke (RR = 1.73) CAmerican College of Cardi- analysis of published RCTs eval- and hypotension (RR = 1.51). ology Foundation (ACCF) and uating preoperative b-blockers This meta-analysis was domi- the American Heart Associa- versus placebo for patients un- nated by the 2008 Peri-Operative tion (AHA) recommend starting dergoing noncardiac surgery. Of ISchemic Evaluation (POISE) b-blockers to prevent cardiac the 11 studies that met eligibility trial, an RCT that compared pla- events in patients about to under- criteria, two were the discredited cebo to extended-release meto- go intermediate- or high-risk sur- DECREASE trials. Thus, Bouri et prolol (100 mg 2 to 4 h before gery or vascular surgery who have al1 analyzed nine high-quality surgery, followed by 200 mg/d a history of inducible ischemia, RCTs that included 10,529 pa- for 30 d), in 8,351 patients with, coronary artery disease (CAD), or tients. or at risk for, atherosclerotic dis- at least one risk factor for CAD.2 Most studies included patients ease.4 While b-blockers reduced However, the majority of the evi- undergoing vascular surgery. the risk for MI and atrial fibrilla- dence for these guidelines, which Some studies also included intra- tion, they increased the risk for were published in 2009 and are abdominal, intrathoracic, neuro- mortality and stroke, likely due surgic, orthopedic, urologic, and to drug-induced hypotension. Anne Mounsey and Jodi M. Roque are in gynecologic surgeries. b-Blockers The slightly larger-than-typical the Department of Family Medicine at the were started no more than a day doses of b-blockers used in this University of North Carolina at Chapel Hill. Mari Egan is in the Department of Family before surgery and were discon- study may have contributed to Medicine at the University of Chicago. tinued at hospital discharge or the excess mortality. continued on next page >> clinicianreviews.com SEPTEMBER 2014 • Clinician Reviews 21 PURLs®

>> continued from previous page WHAT’S NEW riod, which is in line with current Cardiovascular Anesthesiologists; Society for Cardiovascular Angiography and Interven- Avoiding b-blockers in surgery ACCF/AHA guidelines. tions; Society for Vascular Medicine; Society patients will prevent deaths for Vascular Surgery; Fleisher LA, Beckman JA, Bouri et al1 found that while b- CHALLENGES Brown KA, et al. 2009 ACCF/AHA focused update on perioperative beta blockade incor- blockers protect against nonfa- TO IMPLEMENTATION porated into the ACC/AHA 2007 guidelines on tal MIs, they increase the risk for Reluctance to disregard perioperative cardiovascular evaluation and nonfatal strokes and death. This published guidelines care for noncardiac surgery. J Am Coll Cardiol. 2009;54:e13-e118. new meta-analysis challenges the Some clinicians may not be com- 3. Erasmus Medical Center Follow-up Investiga- ACCF/AHA recommendations by fortable ignoring the current tion Committee. Report on the 2012 follow- suggesting that abandoning the ACCF/AHA guidelines that make up investigation of possible breaches of aca- demic integrity (September 30, 2012). use of b-blockers for preoperative a Class IIA recommendation (it CardioBrief. Available at: http://cardiobrief. patients who aren’t already taking is reasonable to administer this files.wordpress.com/2012/10/integrity- them will prevent a substantial treatment) for the use of preop- report-2012-10-english-translation.pdf. Accessed August 14, 2014. number of perioperative deaths. erative b-blockade for patients 4. Devereaux PJ, Yang H, Yusuf S, et al; POISE 1 Bouri et al estimate that in the at risk for cardiovascular events Study Group. Effects of extended-release United Kingdom, where 47,286 who were not previously taking metoprolol succinate in patients undergoing non-cardiac surgery (POISE trial): a ran- deaths occur annually within 30 a b-blocker. This updated meta- domised controlled trial. Lancet. 2008; days of intermediate- or high-risk analysis excludes the discredited 371:1839-1847. procedures, the number of iatro- DECREASE trials and challenges genic deaths would drop by ap- us to act against these current ACKNOWLEDGEMENT The PURLs Surveillance System was supported in proximately 10,000 if b-blockers guidelines while we await updat- part by Grant Number UL1RR024999 from the were not used.1 ed recommendations. CR National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of CAVEATS REFERENCES the authors and does not necessarily represent the Don’t stop b-blockers in 1. Bouri S, Shun-Shin MJ, Cole GD, et al. Meta- official views of the National Center For Research patients who already take them analysis of secure randomised controlled trials Resources or the National Institutes of Health. of ß-blockade to prevent perioperative death in This meta-analysis did not evalu- non-cardiac surgery. Heart. 2014;100:456-464. Copyright © 2014. The Family Physicians Inquiries ate outcomes in patients who 2. American College of Cardiology Foundation/ Network. All rights reserved. were already taking b-blockers. American Heart Association Task Force on Practice Guidelines; American Society of Echo- Reprinted with permission from the Family Physi- These patients should continue to cardiography; American Society of Nuclear cians Inquiries Network and The Journal of Family take them in the perioperative pe- Cardiology; Heart Rhythm Society; Society of Practice. 2014;63(6):E15-E16.

RENALCONSULT >> continued from page 20 tect against excessive water loss with reduction of serum sodium REFERENCES and imbalance. At the levels.2,3 1. Hilden T, Swensen TL. Electrolyte disturbances in beer drinkers: a specific “hypo-osmolaity same time, excessive water loss While the treatment of hypo- syndrome.” Lancet. 1975;2(7928):245-246. can translate to higher sodium natremia at first glance seems 2. Sanghvi SR, Kellerman PS, Nanovic L. Beer levels and increase the risk for straightforward—replace that potomania: an unusual cause of hyponatremia at high risk of complications from rapid correc- cerebral edema. If rapid diuresis which is lost—it can actually tion. Am J Kidney Dis. 2007;50(4):673-680. occurs, an infusion of D5W (5% transform a seemingly simple 3. Bhattarai N, Poonam K, Panda M. Beer poto- dextrose in water) to match the problem into a complicated clini- mania: a case report. BMJ Case Rep. 2010; rate of urine output may prevent cal course requiring intensive 2010: bcr10.2009.2414. 4. Campbell M. Hyponatremia and central pon- a rapid serum sodium level rise. care, due to the need for frequent tine myelinolysis as a result of beer potomania: Frequent monitoring of serum monitoring and intervention. CR a case report. Prim Care Companion J Clin Psy- sodium levels is often necessary. Kristina Unterseher, MSN, FNP, CNN-NP chiatry. 2010;12(4):PCC.09100936. In instances where ODS is already Peacehealth St. John 5. Thaler SM, Teitelbaum I, Beri T. “Beer potoma- nia” in non-beer drinkers: effect of low dietary present, there are case studies of Medical Center solute intake. Am J Kidney Dis. 1998;31(6): improved neurologic outcomes Longview, WA 1028-1031.

22 Clinician Reviews • SEPTEMBER 2014 clinicianreviews.com