Hyponatremia. Kara M. Olivier, NP

Transcription

1 Hyponatremia Kara M. Olivier, NP 22nd Annual Northeast Regional Nurse Practitioner Conference May 6-8, 2015

2 DISCLOSURES There has been no commercial support or sponsorship for this program. The planners and presenters have declared that no conflicts of interest exist. The program co-sponsors do not endorse any products in conjunction with any educational activity.

3 ACCREDITATION Boston College Connell School of Nursing Continuing Education Program is accredited as a provider of continuing nursing education by the American Nurses Association Massachusetts, an accredited approver by the American Nurses Credentialing Center s Commission on Accreditation.

4 SESSION OBJECTIVES Describe the etiology of SIADH. Discuss the clinical manifestations and medical management of patients with SIADH. Discuss the nursing implications in the care of patients with SIADH. 22nd Annual Northeast Regional Nurse Practitioner Conference May 6-8, 2015

5 The Bare Essentials of Hyponatremia and SIADH Kara M. Olivier, NP

6 Objectives Describe the etiology of hyponatremia and SIADH. Discuss the clinical manifestations and medical management. Discuss the nursing implications in the care of patients.

7 Overview What is the difference between hyponatremia and SIADH? Hyponatremia Low serum Na SIADH Low serum Na and low osmolality Result of excess water not Na deficiency

8 Defining Hyponatremia Abnormally low sodium level Electrolyte regulates water in and out of cells Normal serum sodium meq/l Hyponatremia is typically defined as a serum sodium concentration below 135 meq/l

9 Causes of Hyponatremia Poor oral/iv intake Over hydration Paraneoplastic syndrome from malignancy Medications or street drugs Adrenal insufficiency SIADH

10 Symptoms Serum 125 range Mild CNS symptoms Fatigue Lethargy Anorexia Nausea Muscle cramps

11 Symptoms Serum Na <125 Confusion Seizures Coma

12 Assessment Past and recent medical/surgical history Poor oral intake, thirsty Fevers, sweating Recent vomiting or diarrhea Urine output Orthostatic vital signs

13 Assessment Physical exam Skin turgor Mood changes Mucous membranes Axillary sweat Cardiovascular status

14 Should hospitalization be considered? Is the patient symptomatic (confused, seizures)? Is the hyponatremia severe ( <120 meq/ml)? Is the hyponatremia acute (was Na 145 several days ago and 125 now)? Repeat labs to confirm

15 Assessment Laboratory Urinalysis presence of hyaline casts or specific gravity >1.010 suggestive of intravascular hypovolemia Urine electrolytes urine sodium, urine creatinine and urine osmolality Urine Na <25 suggestive of hypovolemia with exception of patients on diuretics

16 Assessment Laboratory Cont d Serum BUN/Creatinine - >2.0 suggestive of intravascular hypovolemia None of the above are perfect. Consider all when deciding whether patient is intravasculary hypovolemic, euvolemic, hypervolemic

17 The Hypovolemic Patient Most frequently occurs in patients taking diuretics with recent decrease in PO intake. To manage patient Hold diuretics Hydrate intravascularly (oral and IV) Treat underlying cause

18 IV Hydration Tips Wait for lab results of serum Na prior to ordering aggressive IV hydration Rapid administration of IV fluid in setting of severe hyponatremia can lead to seizure, destruction of myelin sheath covering nerve cells in brain stem

19 The Hypervolemic Patient Most frequently seen in patients with congestive heart failure, cirrhosis, renal failure, psychogenic polydipsia. To manage this patient: Diuresis with loop diuretic (lasix, bumex) Consider ACE inhibitor based on patient tolerability

20 The Euvolemic Patient Most frequently seen in patients with SIADH, hypothyroidism, adrenal insufficiency, patients s/p stroke. To manage patient: Check serum osmolality, TSH, and serum cortisol

21 The Euvolemic Patient Management Continued: If urine osmolality >serum osmolality, then patient has SIADH If TSH high hypothyroidism should be considered If cortisol level is <18 consider adrenal insufficiency

22 The Euvolemic Patient Restrict free water to <1500 ml/day for mild abnormalities Restrict free water to <1000 ml/day for severe abnormalities If there is no response in two days consider further restriction Consult Endocrinology and/or Renal colleagues

23 SIADH SIADH causes include malignancy, recent surgery, medications Syndrome of inappropriate antidiuretic hormone (SIADH) is a disorder of water intoxication SIADH describes the inappropriate production and secretion of antidiuretic hormone (ADH)

24 Pathophysiology Abnormal metabolism of ADH causes increased water reabsorption in the renal tubules which leads to increased water retention and dilution

25 Pathophysiology Vasopressin is the biologically active form of ADH in humans Synthesized in the hypothalamus After synthesis transferred to posterior pituitary

26 Pathophysiology Vasopressin is stored until reflexes signal release into bloodstream. Major role is regulation of water reabsorption in renal tubules.

27 Pathophysiology Total body water is regulated primarily by reflexes that stimulate or inhibit ADH. Venous, cardiac and arterial baroreceptors sense pressure changes that control ADH secretion and to restore extravascular volume.

28 Pathophysiology In SIADH, receptors are overridden with the production and secretion of ADH that is not appropriate for homeostasis. The mechanism in SIADH is ectopic production of ADH which interferes with ability to stop thirst mechanism

29 Signs and Symptoms General Weakness, fatigue Neurologic Altered mental status, headache, lethargy, irritability, delirium, psychosis, personality changes, gait disturbance Cardiovascular Normotensive, regular rate, rhythm

30 Signs and Symptoms Gastrointestinal Anorexia, nausea, vomiting, diarrhea, excessive thirst, abdominal cramping. Renal Oliguria (<400 cc/24 hours), weight gain, incontinence.

31 Signs and Symptoms Musculoskeletal Muscle cramps Hypoactive reflexes Myoclonus

32 Physical Exam Absence of patient reported symptoms Dilution occurs on intravascular level Normal skin turgor Euvolemic Normotensive No peripheral or interstitial edema

33 Diagnostics Studies Electrolytes, BUN, creatinine, albumin and uric acid. Studies to r/o cardiac, hepatic, adrenal and thyroid causes should be considered.

34 Laboratory Values Serum sodium <130 meq/l Serum osmolality <280 mosm/kg Urine osmolality >500 mosm/kg Urine sodium >20 meq/l

35 Medical Management of SIADH Directed at treating the underlying pathology. Discontinuation of contributing medications In setting of malignancy goal is treatment with surgery, chemotherapy or radiation.

36 Medical Management of SIADH Treatment for mild SIADH (serum Na >125 meq/l) includes fluid restriction of ml/day. Fluid restriction often increases Na within 3-10 days. Loop diuretic when SIADH confirmed

37 Medical Management Demeclocycline acts on renal tubules as vasopressin antagonist Contraindicated with cirrhosis Increases Na within 3-4 days Eases strict fluid restriction

38 Medical Management Aquaretics Vasopressin receptor antagonist Promotes electrolyte sparing diuresis Approved in hospital setting Contraindicated hypovolemic patient Use mostly limited to heart failure patients and best use still in early studies

39 Medical Management Consider hypertonic saline (3%) for acute and symptomatic (seizures, coma) low Na Hypertonic saline 513 meq NaCl 1L NS 154 meq NaCl Administered over two to three hours.

40 Nursing Management Assessment of neuromuscular, cardiac, gastrointestinal and renal systems. Evaluation of fluid and electrolyte status Assess for signs and symptoms of hypovolemia or hypervolemia Review medications Monitor blood and urine chemistries

41 Key Take Home Points Recent medical and surgical history is going to be best first tool Wait for repeat serum Na before deciding on role and rate of rehydration Goal is to treat underlying cause

42 References Up-to-Date Harrison s Online

43 Contact Information Office Number: