HYPONATREMIAWORKSHOP

D6STA. ANA – TANGCO

Dr. Monzon

Salient featuresHISTORY• 60 year old female• cc: vomiting • Fever, dysuria, frequency•Headache, body malaise, nausea• (-) epigastric pain, diarrhea• (-) smoker and alcohol beverage drinker• (+) HPN on telmisartan 40 mg and

hydrocholothiazide 12.5 mg

Salient featuresPHYSICAL EXAMINATION• wheel-chair-borne•Orthostatic hypotension

LABORATORY FINDINGS•Presence of infection▫Leukocytosis with predominance of neutrophils▫Slightly turbid urine▫Hyaline cast, Pyuria, Bacteruria

• Increased serum creatinine•Decreased serum sodium = hyponatremia

GUIDE QUESTIONS

1. What is you diagnosis?

HYPOTONIC HYPONATREMIA

• a plasma Na+ concentration less than 135 mmol/ L (patient: 123 mmol/L)

1. What is the basis for your diagnosis?

▫Infection/ Fever▫Vomiting▫Nausea ▫Frequency▫Serum Na = 123mmol/L▫Orthostatic hypotension▫Medications▫Neurologic manifestations

Basis for diagnosis

•Vomiting ▫Results in disturbances in acid-base balance,

dehydration and electrolyte depletion▫Na+ loss

• Infection ▫fever sweating Na+ loss

• Frequency ▫Na+ loss in urine

Basis for diagnosis•Nausea ▫ ADH H2O retention hypoosmolarity

•Serum Na+ 123 mmol/L = Hyponatremia

•Orthostatic hypotension▫Sustained drop in systolic pressure (≥ 20 mmHg)

or diastolic pressure (≥ 10 mmHg) within 3 minutes of standing

▫In nonneurogenic causes (i.e. hypovolemia) the BP drop is accompanied by a compensatory increase in HR (>15bpm)

Basis for diagnosis

• Medications▫Telmisartan - ARB

angiotensin II Na+ reabsorption in tubules Na + excretion Na + loss

▫Hydrochlorothiazide - Diuretic “diuretics-induced hyponatremia” is almost always

due to thiazide diuretics Na + reabsorption in tubules Na + excretion

Na+ loss

** Creatinine levels may increase when ACE inhibitors (ACEI) or angiotensin-II receptor blockers (ARBs)

Basis for diagnosis

• Neurologic symptoms▫Related to osmotic water shift increased ICF

volume (cerebral edema)▫Severity is dependent on rate of onset and

absolute decrease in plasma Na concentration▫As plasma concentration falls…

Nausea, body malaise, headache, lethargy, confusion and obtundation

▫Plasma concentration < 120 mmol/L Stupor, seizures, coma

2. What other laboratory tests are needed to be requested for the patient?

4 laboratory findings provide useful information for the diagnosis of hyponatremia▫Serum osmolality▫Urine osmolality▫Urine Na+ concentration▫Urine K+ concentration

▫Serum glucose & lipid profile*

Plasma OsmolalityHigh Low

Hyperglycemia

Mannitol

Normal

Maximal volume of maximally dilute urine (<100mosmol/kg)

Hyperproteinemia

Hyperlipidemia

Bladder Irrigation

Primary polydipsia

Reset osmostatECF Volume

Increased

SIADH

Exclude hypothyroidism

Exclude adrenal insufficiency

NormalDecreased

Heart Failure

Hepatic Cirrhosis

Nephrotic Syndrome

Renal Insufficiency

Urine Na Concentration

<10mmol/L

>20mmol/L

Extrarenal Na loss

Remote diuretic use

Remote vomiting

Na wasting nephropathy

Hypoaldosteronism

Diuretic

Vomiting

NoYes

2. What other laboratory tests are needed to be requested for the patient?

a. Serum osmolarity▫confirmation of true hypoosmolar hyponatremia▫determines fluid status to establish classification

of hyponatremia abnormally low in patients with hypoosmolar

hyponatremia normal or elevated in patients with hypertonic

hyponatremia due to serum hyperglycemia.

Serum osmolarity

Normal Range: 280 to 300mOsm/kg

Total osmolality (mOsm) = 2 (Na + K) + Glucose(mg/dl)/18 + BUN(mg/dl)/2.8

= 2(123 + 3.7) + 98/18 + 20/2.8 = 2(126.7) + 5.44 + 7.14= 265.98

Hypotonic Hyponatremia

2. What other laboratory tests are needed to be requested for the patient?

b. Urine osmolality▫may be helpful in establishing the diagnosis of

SIADH▫The appropriate renal response to hypoosmolality

is to excrete the maximum volume of dilute urine▫Patients with other forms of hyponatremia and

appropriately depressed levels of ADH have urine osmolarities below 100 mOsm/L.

2. What other laboratory tests are needed to be requested for the patient?

c. Urine Sodium Level▫to identify renal from nonrenal causes

If due to nonrenal causes eg, vomiting, diarrhea, fistulas, GI drainage, third

spacing of fluids have avid renal absorption of tubular sodium and urine

sodium levels of less than 20 mEq/L If due to renal causes

eg, diuretics, salt-losing nephropathy, aldosterone deficiency

have inappropriately elevated urine sodium levels in excess of 20 mEq/L.

2. What other laboratory tests are needed to be requested for the patient?

d. Urine Potassium Level▫Potassium levels often change with sodium levels▫↓ Na+, ↑K+

2. What other laboratory tests are needed to be requested for the patient?

•Serum glucose concentration▫Several physiologic states (e.g. hyperglycemia) exist

in which correct laboratory analysis yields low serum sodium levels, but these levels do not reflect a true hypoosmolar state.

▫Accumulation of extracellular glucose induces a shift of free water from the intracellular space to the extracellular space

▫Serum sodium concentration is diluted by a factor of 1.6 mEq/L for each 100 mg/dL increase above normal serum glucose concentration

GOALS:1.To raise the plasma Na+ concentration y restricting

water intake and promoting water loss2.To correct underlying disorder

MANAGEMENT • Check vital signs every 2 hrs• Check for changes neurologic status – seizures• Treat with Isotonic Saline (0.9 NaCl – 154 meq/L)• Calculate sodium deficit

3. How will you manage the patient’s hyponatremia?

Calculation of sodium deficit:

Target Na: 125 – 135 mEq/L (average: 130 meq/L)

Na deficit = 0.6 x wt. in kg X (desired Na – actual Na)

= 0.6 x (50 kg) x (130 – 123)

= 210 mEq/L

Correction rate: <0.5 meq/L/hr• First 8 hrs – 50% of calculated Na• Next 16 hrs – other 50%• Risk of development of Osmotic demyelination syndrome

in rapid correction of hyponatremia

•Do not give hypertonic saline may result to overcorrection Central Pontine

Myelinosis

•Do not give hypotonic fluids until serum Na is > 125 mg/L

• Correct K+ deficit

3. How will you manage the patient’s hyponatremia?

RT, 60 y/o female

Physical Exam

• Conscious, coherent, wheel-chair-borne•Weight 50 kg•Vital signs ▫BP: 120/80 supine; 90/60 sitting▫CR: 90/min supine; 105/min sitting▫RR: 20/min▫T: 37o C

•Warm, dry skin, dry buccal mucosa, no active dermatoses

•

•Pink, palpebral conjunctivae, anicteric sclera•Supple neck, JVP 3 cm at 30o angle•Symmetrical chest expansion, clear breath sounds•Adynamic precordium, AB 5th at LICS, MCL, no

murmurs• Flabby abdomen, w/ normoactive bowel sounds,

soft, non-tender•Extremities: (-) edema, pulses full and equal•Neurological exam: normal

Physical Exam

Drugs

Generic name Type of drug Indication

Paracetamol NSAIDs analgesic, antipyretic

Telmisartan ARB essential HPN

Hydrochloro-thiazide

Diuretic HPN

Amlodipine CCB HPN & angina

Laboratory results: CBC

RESULTS N.V.

Hemoglobin 0.132 g/dL 12 – 16 g/dL ↓

Hematocrit 0. 35 0.36 -0.46 ↓

WBC 12.5 x 109/L 4.5 – 11 x 109/L ↑

Neutrophils 0.88 0.40 – 0.70 ↑

Lymphocytes 0.12 0.22 – 0.44 ↓

** Increased WBC with predominance of neutrophils indicate presence of bacterial infection

Laboratory results

RESULTS N.V.

FBS 98 mg/dL < 100 mg/dL N

BUN 20 mg/dL 10 – 20 mg/dL N

Serum creatinine

0.9 mg/dL < 1.5 mg/dL ↑

Serum Na 123 mmol/L 136 – 145 mmol/L ↓

Serum K 3.7 mmol/L 3.5 - 5.0 mmol/L N

UrinalysisResult Normal

Appearance Yellow, slightly turbid ♥

Straw – dark yellow, clear – hazy

pH 6.0 4.5 – 7.8

Specific gravity

1.020 1.003-1.029

Albumin (-) (-)

Sugar (-) (-)

UrinalysisResult Normal

Hyaline casts 5/hpf ♥ 0-2/lpf

Pus cells 10-15/hpf ♥ Up to 5/hpf

RBC 2-5/hpf, non-dysmorphic

0-5/hpf

Epithelial cells Few Few

Bacteria Moderate ♥ (-)

Slightly turbid urine •Cloudy urine may not be pathologic•Turbidity may be due to precipitation of crystals

or non-pathologic amorphous salts

•Materials that can cause turbidity:▫Phosphate ▫ RBCs▫Uric acid ▫ Ammonium urates▫Leukocytes ▫ Bacterial growth▫Mucus ▫ Blood clots▫Contamination▫Increased number of epithelial cells

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Hyaline Casts

•Can indicate mild to severe renal disease when increased in numbers▫proteinuria of renal (eg., glomerular disease) ▫extra-renal (eg., overflow proteinuria as in

myeloma) origin.• Can be found in healthy individuals after heavy

exercise

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Pyuria

•Greater numbers of pus cells generally indicate the presence of an inflammatory process somewhere along the course of the urinary tract▫Acute infection of kidney (pyelonephritis)▫Cystitis (bladder)▫Urethritis (urethra)

•Pyuria often is caused by urinary tract infections, and often significant bacteria can be seen on sediment preps, indicating a need for bacterial culture.

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Bacteruria

•Can be contamination from external sources•Rapidly multiply in improper stored specimen•With increased WBCs, indicative of urinary tract

infection

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