Question

A patient presents with unexplained severe hypernatremia (plasma Na⁺ = 168 mmol/L). Laboratory test results reveal the following:

                Blood pressure = 85/60

                Plasma renin = 3.0 (normal = 1.0)

                Plasma ADH = 40 pg/ml (normal = 3.0 pg/ml)

                Plasma aldosterone = 12 ng/100 ml (normal = 6 ng/100 ml)

Which of the following is the most likely reason for her hypernatremia?

                A. Nephrogenic diabetes insipidus

                B. Central diabetes insipidus

                C. Inappropriate ADH syndrome

                D. Increased aldosterone secretion

                E. Increased renin secretion

69. A patient arrives at your office and appears to be dehydrated. Laboratory tests indicate that he is hyponatremic, with a plasma sodium concentration of 125 mmol/L and a plasma osmolarity of 250 mOsm/L. You decide to slowly administer 1.0 liter of 3% sodium chloride. His body weight was 70 kilograms before giving the fluid. Assume the following values:

                Intracellular fluid volume = 40% of body weight before fluid administration

Extracellular fluid volume = 15% of body weight before fluid administration (he is dehydrated and has lower than normal extracellular fluid volume)

                Molecular wt of NaCl = 58.5 gm/mole

                No excretion of water or electrolytes

Calculate his approximate plasma osmolarity after administration of the NaCl solution and after osmotic equilibrium.

                A. 257 mOsm/L

                B. 270 mOsm/L

                C. 282 mOsm/L

                D. 305 mOsm/L

                E. 320 mOsm/L

57. An elderly patient complains of muscle weakness and lethargy. Analysis of a urine specimen reveals a sodium ion concentration of 600 mmol/L and an osmolarity of 1200 mOsm/L. Additional laboratory tests provide the following information:

                Plasma Na⁺ concentration = 167 mmol/liter

                Plasma renin = 4.0 (normal =1.0)

                Plasma ADH = 60 pg/ml (normal = 3.0 pg/ml)

                Plasma aldosterone = 15 ng/100 ml (normal = 6 ng/100 ml)

Which of the following is the most likely reason for this patient's hypernatremia?

                A. Dehydration

                B. Inappropriate ADH syndrome

                C. Nephrogenic diabetes insipidus

                D. Primary aldosteronis

Which of the following would likely lead to the most severe hyponatremia?

                A. Restriction of fluid intake

                B. Excessive antidiuretic hormone (ADH) secretion

                C. Excess aldosterone secretion

                D. Administration of 2 liters of 3% sodium chloride solution

Answer 1

Question no 68

Answer is Option a nephrogenic diabetes incipidous

Yes it is nephrogenic diabetes incipidous as the amount of sodium in blood us increased but the concurrent increase in blood volume is not increased . This show's abnormalities in the action of ADH . Aldosterone cause increased sodium absorption . This is not compensated by intake of water so BP is low . So Option b,c,d and e are wrong

So the inability of ADH to act on nephron is the reason for this condition