LS4 Electr Gen

Management of Hyponatremia in the ER Mabel Vasnaik, Consultant & Head Dept of Emergency Medicine Manipal Hospital, Bangalore.

Overview. Causes Symptoms Treatment Complications of Hyponatremia.

What electrolyte abnormality do you expect?. Case.

Total body Na content is between 40 & 50 mEq /kg ECF (98%) 135- 145 mEq /l Serum Na conc < 135 mEq /l 2 nd most common electrolyte abnormality.

Severity of symptoms depend on 2 factors Severity of hyponatremia Acuity of onset The lower the Na & faster the ↓, the more symptomatic a patient will become. Symptoms are often vague and non-specific headache, irritability, lethargy, confusion, agitation or unstable gait leading to a fall..

Hypovolemic Hyponatremia • Gastrointestinal loss (vomiting, diarrhea ) • Renal loss (diuretic therapy, adrenal insufficiency) Euvolemic Hyponatremia • SIADH (neoplastic disease, CNS disorders, drugs, etc.) • Glucocorticoid insufficiency (pituitary disorders) • Overdrinking (athletes, polydipsia, beer potomania ) Hypervolemic Hyponatremia • Congestive heart failure • Chronic kidney disease/ • Nephrotic syndrome.

Measured and calculated plasma osmolality Osmolarity ( mosm /L)= 2x Na + gluc /18+BUN/2.8= 275- 295 Osmolarity = No of osmoles per l of soln Osmolality = No of osmoles per kg of solvent True hyponatremia - plasma osmolality ↓ Factitious hyponatremia - plasma osmolality ↑/normal.

Hypertonic Hyponatremia. Large quantities of osmotically active solutes accumulate in the ECF space Net movement of water from ICF to ECF E.g. hyperglycemia Correct cause Add 1.6-2.4mEq/l to measured Na for every 100 mg/dl of increase in glucose.

Isotonic Hyponatremia. Hyperlipidemia Hyperproteinemia Treatment not required.

Hypovolemic Renal- diuretic use Extrarenal - GI losses Hypervolemic Urine Na >20 – Renal failure with impaired water excretion Urine Na <20 – CCF, nephrotic syndrome, cirrhosis Euvolemic ( Urine Na >20) SIADH, hypothyroid, stress.

Bedside clinical assessment POCUS is an accurate tool for proper volume evaluation, and may be used as an adjunct to physical examination for hyponatremic patients. POCUS gives a good idea whether the patient is significantly hypovolemic or hypervolemic.

Treat neurologic emergencies related to hyponatremia with hypertonic saline Assess the intravascular volume Prevent worsening hyponatremia Prevent rapid overcorrection with the Rule of 100s Ascertain the cause.

What now?. Case Progression. Patient suffers a grand mal seizure STAT serum sodium 108 mEq/L.

3% saline 100cc IV over 10min. If no clinical improvement, repeat a 2 nd bolus over 50 mins . Check serum Na. If 3% NS is not readily available give 1 amp NaHCO3 over 5 min..

6 in 6 hrs for severe symptoms, then stop. If you need to rapidly increase serum Na due to a neurologic emergency do not correct more than 6mmol. 6 a day Na should not increase more than 6mmol/day. Different ranges are cited. Targeting 6 is a conservative approach which helps to stay within the safe range..

Calculate sodium deficit: Deficit = (desired [Na + ] – current [Na + ])  0.5  body weight (in men, use 0.6  body weight in calculation). Calculate volume of 3% NaCl (513 mEq Na + /L) required to correct deficit. Infuse 3% NaCl to increase serum sodium to desired levels..

Calculate sodium deficit —  sodium 4 mEq /L in 4 hours, current Na + 108 mEq /L. Deficit = (112 mEq /L – 108 mEq /L)  0.5  70 kg = 140 mEq Determine volume of 3% NaCl to be administered. Volume = 140 mEq  513 mEq /L = 0.27 L (270 mL) of 3% NaCl 3. Administer solution over 4 hours (67 mL/h) to increase serum sodium 4 mEq over 4 hours..

Volume resuscitate with 0.9% NaCl . Check Na levels Once BP is normal and if serum Na< 120 start 3% saline slow infusion Serum Na should rise not more than 0.5 mq / hr or 6-10 mEq /day Treat the underlying cause.

Hypervolemic & hyponatremia. Na restriction Water restriction Diuretics..

Euvolemic patients with hyponatremia. Management should concentrate on preventing worsening hyponatremia. Treatment depends on how symptomatic the patient is Depends on Na levels.

Once baseline volume status is corrected goal is to prevent further exacerbation of hyponatremia. Strict fluid restriction & saline locking the IV. Water can literally kill your patient with hyponatremia!.

Prevent Rapid Overcorrection: The Rule of 100s. Free water diuresis that results after fluid administration causes rapid Na increase. Monitor input/ output with Foleys catheter. If urine output >100cc/ hr , send STAT urine osmolarity and urine Na If urine osmolarity <100, give 1 ug DDAVP IV DDAVP minimizes water excretion during the correction of hyponatremia during water diuresis. Continue steps 2-3 as per urine output.

Indication for DDAVP in patients with hyponatremia.

Ascertain the Cause of Hyponatremia Correcting Hypokalemia Can Help Improve Hyponatremia Demeclocycline 600 – 1200mg daily in patients with refractory hyponatremia . Demeclocycline is a bacteriostatic antibiotic (tetracycline group) Causes diuresis and nephrogenic diabetes insipidus Hence currently used to treat sustained hyponatremia in patients with SIADH.

Cerebral edema should be considered in all patients with either severe hyponatremia or a rapid ↓of serum Na concentration & altered level of consciousness. Measurement of the optic nerve diameter with POCUS, and a CT brain may show effacement of the sulci. If you suspect cerebral edema, administer 3% saline..

Formerly known as CPM, ODS can occur after rapid over-correction of hyponatremia. Clinical diagnosis with a delayed presentation up to 7 days. Symptoms vary & depend on which structure in the brain demyelinates. Most commonly affects the pons, cerebellum or basal ganglia can also be affected. Common symptoms are ataxia, quadriplegia, cranial nerve palsies, & the ‘locked-in’ syndrome. Risk factors for ODS: Elderly, malnourished state chronic severe hyponatremia, hypokalemia.

Assess and manage the intravascular volume Prevent the Na from increasing any further Fluid restriction: make the patient NPO and stop IV fluids Give DDAVP 1 microgram IV.

Arginine Vasopressin Antagonists. Treats hyponatremia through V2 antagonism of AVP in the renal collecting ducts. This effect results in excretion of free water Conivaptan : Euvolemic ( dilutional ) & hypervolemic hyponatremia. ↑ urine output of free water, with little electrolyte loss. Tolvaptan : Hypervolemic & euvolemic hyponatremia serum Na < 125 mEq /L that has resisted correction with fluid restriction. Used for hyponatremia associated with CCF, cirrhosis, SIADH..

Hyponatremia is a common electrolyte disorder Important to find out the volume status of the patient Na correction should not exceed 10 mEq /24 hours Important to also diagnose and treat the cause Slow and adequate correction will prempt complications..

Thank you. 30.