Transcript Approach to the patient with electrolyte disorders Hypo

Approach to the patient with
electrolyte disorders
Hyponatremia-Hypernatremia
Zehra Eren, M.D.
LEARNING OBJECTIVES
• recall body water and fluid distribution
• recall serum osmolality
• recall etiology of hyponatremia and hypernatremia
• describe sing and symptoms of hyponatremia and
hypernatremia
• describe laboratory findings of hyponatremia and
hypernatremia
• explane treatment of hyponatremia and hypernatremia
Solute Composition of Body Water
• Predominant solutes in ECF:
Sodium (Na+)
Chloride (Cl−)
Bicarbonate (HCO3−)
• Predominant solutes in ICF:
Potassium (K+)
Protein−
Phosphate−
Osmolality
• Posm=2×plasma Na+ +
Glucose/18 + BUN/2.8
Osmolality
• Normal ECF osmolality: 280-290mOsm/kgH2O
• ECF and ICF are in osmotic equilibrium, at steady
state
• Vasopressin (antidiuretic hormone (ADH)
-osmotic stumuli
-nonosmotic stumuli: HF, Cirrhosis, vomiting,
postoperative pain, pregnancy
Hyponatremia
• Serum Na <135 mEq/L
European Society of Intensive Care Medicine (ESICM)
European Society of Endocrinology(ESE)
European Renal Association – European Dialysis and Transplant
Association (ERA–EDTA)
Hyponatremia
• Serum Na <135 mEq/L
Hyponatremia is a disorder of water balance
Dısorders of water and sodium balance
• Hyponatremia (too much water)
• Hypernatremia (too little water)
• Hypovolemia (too little sodium, the main extracellular
solute)
• Edema (too much sodium with associated water retention)
Hyponatremia
• almost always due to the oral or intravenous intake of water that
cannot be completely excreted
• impaired water excretion that is most often due to an inability
to suppress the release of antidiuretic hormone (ADH) or to
advanced renal failure
Diagnosis
• Volume status and serum osmolality are essential to
determine etiology
• Hyponatremia usually reflects excess water retention
relative to sodium rather than sodium deficiency, the
sodium concentration is not a measure of total body
sodium
• Hypotonic fluids commonly cause hyponatremia in
hospitalized patients
Differences between SIADH and
cerebral salt wasting
Sherlock M, O’Sullivan E, et all. The incidence and pathophysiology of hyponatraemia after
subarachnoid haemorrhage. Clinical Endocrinology; 2006, 64: 250–254
6.3. Which parameters to be used for differentiating
causes of hypotonic hyponatraemia?
Clinical practice guideline on
diagnosis and treatment of
hyponatraemia; Nephrol Dial
Transplant (2014) 0: 1–39
Symptoms and Sing of Hyponatremia
• symptoms depends on severity and acuity hyponatremia
• the symptoms reflect neurologic dysfunction induced by
cerebral edema and possible adaptive responses of brain cels
to osmotic swelling
• Nausea, malaise, headache, lethargy, seizures, coma,
respiratory arrest
• the physical examination should help categorize the patient's
volume status into hypovolemia, euvolemia, or
hypervolemia.
Classification of symptoms of hyponatraemia
Clinical practice guideline on diagnosis and treatment of
hyponatraemia; Nephrol Dial Transplant (2014) 0: 1–39
Adaptation of the brain to hypotonicity
Adrogue HJ & Madias NE. Hyponatremia. NEJM; 2000 342 1581–1589
Complications of hyponatraemia
Hyponatraemia with severe symptoms
7.2. Hyponatraemia with moderately
severe symptoms
7.3. Acute hyponatraemia without severe
or moderately severe symptoms
7.4. Chronic hyponatraemia without
severe or moderately severe symptoms
7.4. Chronic hyponatraemia without
severe or moderately severe symptoms
7.4. Chronic hyponatraemia without
severe or moderately severe symptoms
Na+ deficit ≈
body weight X 0.6 X
(desired plasma Na+ concentration –
plasma Na+ concentration)
1mg/dl/ h
10-12mg/dl /24h
Hypernatremia
• Serum Na>145 mEq/L
Symptoms and Sings of Hypernatremia
• Dehydrated patient → orthostatic hypotension and oliguria
• Rise in plasma Na and osmolality
→water movement out of the brain
→rupture of the cerebral veins
→focal intracerebral and subarachnoidal hemorrages→possible
ireversible neurologic damage
• Lethargy, weaknees, irritability, twitching, seuzures, coma
• Osmotic demyelination (uncommon)
Laboratory Findings
• Urine osmolality > 400 mosm/kg → renal water-conserving
ability is functioning (hypotonic fluid losses from excessive
sweating, the respiratory tract, or bowel movements and
lactulose)
• Urine osmolality < 250 mosm/kg → characteristic of DI
-Central DI: inadequate ADH release
-Nephrogenic DI: renal insensitivity to ADH
(lithium, demeclocycline, relief of urinary obstruction, interstitial
nephritis, hypercalcemia, and hypokalemia)
• Water deficit ≈
body weight X 0.6 X
(plasma Na concentration/
desired plasma Na concentration) - 1
Case 1
• A 72-year-old woman from a nursing home presents to the emergency
department with a change in her mental state over the past few hours.
She has a medical history of coronary artery disease and hypertension.
• Her medications include hydrochlorothiazide: 25 mg a day, and aspirin,
80 mg a day.
• On physical examination, she has decreased skin turgor, orthostatic
hypotension, and disorientation to time, place, and person without focal
neurologic deficits.
• Initial laboratory tests show a serum sodium level of 110 mmol/L;blood
urea nitrogen 65 mg/dL; creatinine 3.6mg/dL and plasma osmolality, 278
mOsm/kg of water.
• Her serum sodium level 2 months before admission was 135 mmol/L, and
her urine output was 400 mL a day.
Case2
• A 82-year-old women with Dementia, HTN and DM is
admitted for work-up of hyponatremia. Her sodium has
been 118 for the last 4 days.
• She is taking Paxil for depression and she is not on any
diuretics.
Case 3
• A 85 year-old male presents to the emergency room with
pneumonia. He has been febrile for several days and has had a
cough productive of yellow sputum.
• On physical exam he is a well-developed, thin male in moderate
respiratory distress. Blood pressure (supine) 120/86, pulse 74,
blood pressure 115/85, pulse 70, respirations 24. Temperature
was 39oC. Body weight 60 kg. Cardiopulmonary exam
demonstrated decreased breath sounds at the base of the right
lung.
• Sodium 120 mmol/L, Potassium 3.9, BUN 10 mg/dl ,
Creatinine 0.8 mg/dl, U Osmolality 500
mosm/kg, Glucose 90 70-110 mg/dl
Urine Sodium 60 mmol/L,Potassium 30 mmol/L,
Case4
• A 60 year-old male with alcoholic cirrhosis presents to your office
because of worsening edema.
• On physical exam the patient is a well-developed, poorly
nourished, jaundiced male in mild distress due to his anasarca.
Blood pressure (supine) 110/75, pulse 100, (standing) 90/60,
pulse 120, respirations 23 and he was afebrile. Body weight 80
kg. Cardiopulmonary exam was unremarkable. The abdomen was
remarkable for tense ascites and a shrunken liver. Lower
extremities had 3+ pitting edema.
• Sodium 127 mmol/L, Potassium 3.63mmol/L, BUN 35 mg/dl,
Creatinine 1.8 mg/dl, Glucose 105 mg/dl
• Urine Sodium 6 mmol/L
Osmolality 600 mosm/kg