Acute Water IntoxicationDecember 17, 2003Bruce R. Wall, MD

Good old fashioned nephrology (with a large dose of pulmonary) Most nephrologists would chose to evaluate and treat a SODIUM of 110 mEq/L rather than a BUN of 110mg%Be careful what you ask for you just might get it Lt.Col. Theodore R. Wall, USMC, RetiredPatient admitted from ER with hyponatremia and respiratory failure no problem

Todays lecture:Chronic polydipsia not this caseCase presentationLaboratory reviewBrief discussion of water intoxication Pulmonary aspects @ Dr Weinmeister

Input minus output equals accumulation75 kg male60% water = approx 45 Liters TBW

Intracellular Extracellular 30 L 15 L 280mosm/kg 280mosm/kg [K+] 140mEq/l [Na+] 140mEq/l

How much water was ingested?Initial TB solute: 280 X 45 =12,600 mosmolInitial ECF solute: 280 X 15 = 4,200 mosmolInitial intracellular: 12600 4200 = 8,400 mosmol

NEW TBW : 45kg + 6 kg = 51 kgNEW TB OSM: 12,600 / 51kg = 251mosm/kgNEW ECF volume: 4200 / 251 = 16.7kgNEW intracellular volume: 8400 / 251 = 33.4kg

How much water?Assume an ingestion of 6 liters: serum osmolality of 251mosmol/kg

Estimated nadir [Na+] = osmolality / 2 = 125.5mEq

Effective Posm is approximately 2 X [Na+]

Case Presentation21 year old AAM student at SMUCC: can not be obtained (intubation)History obtained from family membersPatient was asked to drink 3 - 4 gallons of water (with hot sauce), as part of a fraternity hazing on Friday eveningPost ingestion, patient was confused, and became less responsiveAt 4AM, patient developed a seizure, yet was not transported to Presby ER until 7AM

Hospital day:oneProfound shock/hypotension poor response to high dose pressor medicationsImmediate respiratory failure with severe agitation and hypoxemia; endotracheal intubation confirmed drowningTransfer to ICU maximal support: 100% oxygen, maximum PEEP, IV norepinephrineInitial SODIUM = 126mEq/L (IV @KO NS)

Case presentation: continuedPast medical history: noneSocial history: 2 year football player for Austin College. No drug or alcohol history Mother arrived from Houston; Father arrived from US Virgin Islands (lives in Wash D.C.)Medications: IV pressors, antibioticsROS: not available

Physical exam:BP 100/60 on very high dose IV pressors; pulse 110 sinus tachycardia; R per vent; high pressuresVery muscular patient, intubated PO, who eventually developed subQ crepitation from barotraumaHEENT: mild swelling; anicteric NECK: WNLLUNGS: bilateral breath sounds; increased rate COR: no murmur, increased HRABD: benign, although later the CT was abnormalExt: no cyanosis; warm; slowly progressive edemaNeuro: unresponsive pupils; ? signs of herniation prompted use of IV mannitol

Admit labsWBC 17K 76%neutrophils, 6%lymphs Hgb/Hct 13.2g%/38% Plts 380KUrinalysis: 2+ blood, few RBCs, 360mOs/kgInitial Serum Osm: 272, falling to 263 in 8hrsToxicology screen negative for tylenol, PCP, ethylene glycol, MDMA, salicylate, ethanol, cocaine, barbiturates, and narcoticsCXR: ? RUL pneumoniaCT Head: cerebral edema, especially in retrospect

Additional admit labs:Calcium 8.6mg/dl Phos 4.2g/dlTotal protein 7.6g/dl Albumin 4.8g/dlAlk phos 63 LFTs mildly elevatedINITIAL CPK 2100INITIAL BUN 10mg% CREAT 1.0mg%ANION GAP 21Therefore, working diagnosis of (+) AG lactic acidosis from seizure, 3 hours PTA

Electrolytes day one, as serum osmolality fell from 272 to 263

Electrolytes: day 2

Hospital courseHemodynamics and oxygenation were tenuous on day onePatient was considered for extra-coporeal oxygenation therapy, resulting in a transfer from 3 ICU to 4 ICUPost transfer, his BP and PO2 IMPROVEDAbnormal CXR: bilateral infiltrates, air under R hemidiaphragmCT scan: larger amt of air surrounds tail of pancreas, (L) kidney, anterior aspect of psoas muscle, tracking down from mediastinum

Hospital course: continuedElectrolytes were normal, by hospital day 3EEG always showed electrical activity (patient had been severely hypoxemic, but never required ACLS)CNS began to improve by hospital day 4Ventilator support was weaned by day 7Transfer to floor day 8Discharged home day 10

CNS damage associated with acute hyponatremiaCPM: rare neurologic disorder reported in malnourished/alcoholic patientsMORE COMMON brain edema, with uncal and tonsillar herniation with diffuse cerebral demyelination secondary to increased intracranial pressure, with necrosis, and hypoxic brain damageCompression of medullary respiratory center because of brain swelling, above 5 to 8% of baseline volume can lead to herniation -- fixed pupils, hypoventilation, cardio instability, impaired temperature control, pituitary and hypothalamic infarction also possible

Water intoxication in cattleJ AFR VET ASSOC 1999 DEC; 70(4)Water intoxication is common in cattle, and also has been described in other domestic animals. Comprehensive description is lacking

Fatal water intoxication: Journal of Clinical Pathology Oct 2003 p 803DJ Farrell et al64 yo woman with known MV diseaseCompulsively drinking water, one evening, in range of 30 to 40 glassesHours later was described as hystericalFell asleep, and found dead next morningPostmortem: no tumor, bilateral pleural effusions, LVH with large heart; increased cortisols Na+ = 92meq/L (vitreous fluid, usually stable)Acute delirium, seizures, coma, and death

Autopsy case of rare iatrogenic water ingestion; Chen et al, Tongji Med Univ, Forensic Sci International: Nov 9521 yo female suicide attempt (powder scraped from 18 matches)1700 hrs: 3L of water 1730 hrs: 800ml1800 hrs: 4L of water, via NG tubeHeadache, dyspnea, cyanosis, then comaAutopsy: cerebellar herniation, Na+ 112, pulmonary edema, trachea and bronchial tubes full of fluid

Literature review: Forensic Science International (1995): continued534 papers over 17 years only 16 fatalities15 cases diagnosed during hospitalization for various types of psychosisWater intoxication is unusual in normal people, and death is even rarerCase report of death within 2.5 hrs is rare

Fatal child abuse by forced water intoxicationPediatrics 1999 JUN;103 Alan Arief,MD3 children punished by forced intoxication> 6 litersSeizures, emesis, coma, hypoxemia, average sodium 112mEq/LAutopsy confirmed cerebral edemaTried and convicted

Death by hyponatremia as result of water intoxication in a Army traineeMIL MED 1999 MAR;164Excessive water intake by athletes during endurance races, to prevent heat injury has been the recommendationDescribe a case of programmed drinking > 8 liters during initial trainingOne death, cerebral edema with seizure

Death by Water intoxication MIL MED 2002 May; 167

3 deaths in recruits, usual water load of 6 to 10 liters in 2 to 3 hrssafe limit probably 1 liter per hour

Chronic Polydipsia and hyponatremiaPsychiatric patients, especially schizophrenia, often have problems with water balance6% to 8% have a history compatible with compulsive water drinking; of these pts had intermittent symptoms of hyponatremiaNormal patients can excrete 10 to 15 liters/d by decreasing Uosm from 40 to 100 mosm/kgEpisodes of transient ADH release with acute psychotic episodesCarbamazepine and fluoxetine are associated with SIADH

Chronic polydipsiaThis is an uncommon clinical scenario, but does not apply to our current case (which is rare)Rx hypontremia with acute encephalopathy rate of correction 0.5 to 1 meq/l per hr (until a sodium of 120meq/l) Never actively correct > 130meq/l