INTERACTIVE CASE DISCUSSION Fluid and Electrolyte Disorders Part II.
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INTERACTIVE CASE DISCUSSION Fluid and Electrolyte Disorders Part II
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Transcript of INTERACTIVE CASE DISCUSSION Fluid and Electrolyte Disorders Part II.
INTERACTIVE CASE DISCUSSION
Fluid and Electrolyte Disorders
Part II
Fluid and Electrolytes Part II
CASE # 1: • 60 y/o male with ischemic cardiomyopathy and
CHF. Admitted because of orthopnea.• 150/60, HR=120/min, RR = 38/min• JVP = 20 (); bibasal inspiratory crackles• S3 gallop; ascites; pedal edema• Na = 125meq/L ()• Posm = 270 mosm/kg ()• Uosm = 500 mosm/kg
Fluid and Electrolytes Part II
Question # 1: Describe the patient’s fluid and electrolyte status.
A. Na deficit, water deficit
B. Na deficit, water excess
C. Na excess, water deficit
D. Na excess,water excess
Fluid and Electrolytes Part II
Answer #1: Na excess, water excess
• Hyponatremic (Na=125) hence he has water excess.
• Hypervolemia on physical examination ( BP, JVP,crackles, ascites, edema ) hence he has Na excess.
Fluid and Electrolytes Part II
REMEMBER !
Serum Na Na balance
Serum Na = Water balance
Volume status = Na balance
Fluid and Electrolytes Part II
Question # 2: How will you approach the problem of hyponatremia?
HYPONATREMIAPlasma Osmolality
(285-295)
High•Hyperglycemia•Mannitol
Normal•Hyperproteinemia•Hyperlipidemia•Bladder irrigaton
LowTrue Hyponatremia
MaximallyDilute urine
Singer, 2001
HYPONATREMIA
Maximally dilute urine
Uosm < 100
No Yes
Primary polydipsiaReset osmostat
ECF Volume
Singer, 2001
HYPONATREMIA
Increased Normal Decreased
ECF Volume
CHFCirrhosisRenal failureNephrosis
HypothyroidHypoadrenalSIADH
Urine Na
Singer, 2001
HYPONATREMIA
Urine Na
UNa < 10 meq/L UNa > 20 meq/L
Extrarenal Na lossRemote diureticsRemote vomiting
Na wasting nephropathyHypoaldosteronismDiureticsVomiting
Singer, 2001
Fluid and Electrolytes Part II
Question # 3: What is the most likely cause of hyponatremia in this patient?
A. Congestive heart failureB. DiureticsC. HypothyroidismD. Syndrome of Inappropriate ADH
secretion (SIADH)
Fluid and Electrolytes Part II
Answer # 3: Congestive heart failure
• Low Posm excludes pseudohypoNa.
• Uosm > 100 (500) hence not primary polydipsia or reset osmostat
• Volume status increased (Na excess)
• Compatible with CHF
Fluid and Electrolytes Part II
CASE # 2: 30 y/o 70kg male suffered a skull fracture due to MVA.
• 86/60,HR=110/min.• JVP = 4, poor skin turgor• Dry mucosa, no edema• Na = 168 meq/L• Posm = 350mosm/kg; Uosm = 80mosm/kg• 24 hr urine output = 4 liters
Fluid and Electrolytes Part II
Question # 4: Describe the patient’s fluid and electrolyte status.
A. Na deficit, water deficit
B. Na deficit, water excess
C. Na excess, water deficit
D. Na excess, water excess
Fluid and Electrolytes Part II
Answer # 4: Na deficit, water deficit
• Hypernatremic ( Na = 168) hence he has water deficit.
• Hypovolemic on physical examination ( BP, JVP,poor skin turgor, drymucosa) hence he has Na deficit.
Fluid and Electrolytes Part II
REMEMBER !
Serum Na Na balance
Serum Na = Water balance
Volume status = Na balance
Fluid and Electrolytes Part II
Question # 5: Calculate the amount of water deficit in this patient.
Fluid and Electrolytes Part II
Answer # 5: 7 liters
Water deficit
= Plasma Na – 140/140 X ( 0.5 X BW )
= 168 – 140/140 X ( 0.5 X 70 )
= 7 liters.
Fluid and Electrolytes Part II
Question # 6: How will you approach the problem of hypernatremia?
HYPERNATREMIAECF Volume
Increased Not increased
Administration of Hypertonic NaCl andNaHCO3
Minimum volumeof maximallyconcentrated urine(Uosm)
Singer, 2001
HYPERNATREMIA
UOsm > 800
No Yes
Insensible H2O lossGI H20 lossRemote renal H2O loss
Urine osmolarexcretion rate
Singer, 2001
HYPERNATREMIAUrine osmolar excretionrate > 750 mosm/day
YesNo
Osmotic diuresisDiuretic
Renal responseto desmopressin
UOsm Uosm no
Central DI Nephrogenic DI
Singer, 2001
Fluid and Electrolytes Part II
Question # 7: What is the most likely cause of the patient’s hyperNa?
A. Diabetes insipidus
B. GI water losses
C. IV hypertonic NaCl
D. Osmotic diuresis
Fluid and Electrolytes Part II
Answer # 7: Diabetes insipidus• Not hypervolemic hence not IV hypertonic
NaCl.• Uosm < 100 (dilute) hence not extrarenal
water losses (GI losses).• Urine osmolar excretion rate = Uosm X U
volume; 80mosm/kg x 4 liters/d = 320 mosm/d (< 750mosm/d); hence not osmotic diuresis.
Fluid and Electrolytes Part II
Question # 8: The patient was given a dose of desmopressin (ADH analog). The Uosm after the dose is 800 mosm/kg. What is the cause of the diabetes insipidus?
A. Central diabetes insipidus
B. Nephrogenic diabetes insipidus
Fluid and Electrolytes Part II
Answer # 8: Central DI
• The Uosm increased after the desmopressin dose. The Uosm will not change even after repeated desmopressin doses in patients with nephrogenic DI.
