Na

Question 1

Hypernatremia
definition? most common cause?
Hx & PE?

Answer 1

Serum sodium > 145 mEq/L + caused by free water loss
thirst, neurologic symptoms including
altered mental status, weakness, focal neurologic deficits, and seizures.

Question 2

Hypernatremia causes?

Answer 2

Hypernatremia causes— The 6 D’s
Diuresis
Dehydration
Diabetes insipidus
Docs (iatrogenic)
Diarrhea
Disease (eg, kidney, sickle cell)

Question 3

hypernatremia + hypovolemic with unstable vital signs

Answer 3

use isotonic 0.9% NaCl before correcting free water deficits then replace the deficit.
Use isotonic 0.9% NaCl until the patient is euvolemic, even with stable
vital signs.

Question 4

Hypernatremia + normal volume

status and asymptomatic

Answer 4

Use isotonic 0.9% NaCl until the patient is euvolemic, even with stable
vital signs.
* D5W, 0.45% NaCl or enteral fluids.
this is for deficit !

Question 5

Determine free water deficit

Answer 5

Water deficit =

Total body water × ( 1 - [serum Na/140] ).

Question 6

Determine rate of replacement.

Answer 6

Correction of chronic hypernatremia(> 48 hours) should be accomplished gradually over 48–72 hours (≤ 0.5 mEq/L/h) to prevent neurologic damage secondary to cerebral edema.

Question 7

Isovolemic hypernatremia treatment

Answer 7

Patients with diabetes insipidus require vasopressin, low sodium diet, and thiazide diuretics. Prescribe oral fluids, or if the patient cannot drink, give D5W.

Question 8

Hypervolemic hypernatremia treatment

Answer 8

hypernatremia—Give diuretics (such as furosemide, to correct volume status) and D5W (to achieve normal sodium concentration) to remove excess sodium. Dialyze patients with renal failure.

Question 9

hypernatremia causes

how to diagnose DI from external losses ?

Answer 9

urine osm<300 -> rise in urine osm with decompression following water restriction -> central DI
urine osm<300 -> No rise in urine osm with decompression following water restriction -> nephrogenic DI

urine osm>600 -> external losses -> vomit, diarrhea, NGT, insensible loss
urin osm> 600 -> Na gain -> hypertonic saline

Question 10

hyponatremia
definition? most common cause?
Hx & PE?

Answer 10

Serum sodium < 135 mEq/L.
most commonly caused by ↑ ADH
May be asymptomatic or may present with confusion, lethargy, muscle cramps, and nausea.
■ Can progress to seizures, coma, or brainstem herniation.

Question 11

Hyponatremia and hypernatremia are caused by…

Hypovolemia and hypervolemia are caused by …

Answer 11

Hyponatremia and hypernatremia are caused by too much or too little water.
Hypovolemia and hypervolemia are caused by too little or too much sodium.

Question 12

Isotonic hyponatremia causes

Answer 12

hyperlipidemia, hyperproteinemia, monitol

Question 13

causes of:
hypotonic hypovolemic hyponatremia
+
FENa > 2%

Answer 13

Diuretics
urinary obstruction 
Adrenal insufficiency 
RTA
M.Ac

Question 14

Causes of:
hypotonic hypovolemic hyponatremia
+
FENa<1%

Answer 14

GI loss
skin loss
third spacing

Question 15

Causes of:
Isovolemic hypotonic hyponatremia
+
urine Osm. > 100

Answer 15

SIADH
hypothyroidism
glucocorticoid deficiency

Question 16

Causes of:
Isovolemic hypotonic hyponatremia
+
urine Osm. < 100

Answer 16

primary polydipsia

beer potomania

Question 17

causes of:
hyervolemic hypotonic hyponatremia
+
FENa < 1%

Answer 17

cirrhosis
CHF
nephrotic syndrome

Question 18

causes of:
hypervolemic hypotonic hyponatremia
+
FENa >2 %

Answer 18

AKI

Chronic renal failure

Question 19

Hypertonic hyponatremia causes

Answer 19

glucose
monitol
contrast

Question 20

Serum Osmorality

Answer 20

Serum Osm. =

2 x Serum Na)+ (BUN/28)+(Glucose/18

Question 21

Correct sodium in hyperglycemia.

Answer 21

Sodium decreases by 1.6 mEq/L for

every 100 mg/dL elevation in glucose.

Question 22

hyponatremia treatment principles

Answer 22

Hypervolemic and euvolemic: water restriction ± diuretics
Hypovolemic: N.S
severe hyponatremia (Na < 120 mEq/L): 3% hypertonic saline, particularly if symptomatic Correct chronic hyponatremia (> 72 hours’ duration) slowly (< 8−10 mEq/L/day) to prevent osmotic demyelination syndrome

Question 23

Osmotic demyelination syndrome symptoms?

Answer 23

symptoms include paraparesis/quadriparesis, dysarthria, and coma

Question 24

A 29-year-old woman with a history
of bipolar disorder presents to the
emergency department with altered
mental status. On exam, she has
dry mucous membranes and ↓ skin
turgor with a BP of 92/40 mm Hg and
HR of 106 bpm. Her serum sodium
level is 154 mEq/L. What is the next
best step in management?

Answer 24

This patient probably has
rhabdomyolysis, and the urine
dipstick is detecting myoglobin.
He should be managed with saline
hydration, mannitol, bicarbonate, and
an ECG to rule out life-threatening
hyperkalemia.