Multiple-Choice Questions on Cellular Dehydration, Dehydration, and Electrolyte Imbalances for NLE Exams
Question 1
A 75-year-old patient presents with confusion, dry mucous membranes, and decreased skin turgor. Which assessment finding is MOST reliable for diagnosing moderate to severe dehydration in this elderly patient?
A. Decreased skin turgor alone
B. Presence of at least four signs: confusion, non-fluent speech, extremity weakness, dry mucous membranes, dry tongue, furrowed tongue, sunken eyes
C. Postural hypotension only
D. Urine specific gravity measurement
Correct Answer: B
Rationale: According to ESPEN guidelines, in older adults with volume depletion following fluid and salt loss, a person with at least four of the following seven signs is likely to have moderate to severe volume depletion: confusion, non-fluent speech, extremity weakness, dry mucous membranes, dry tongue, furrowed tongue, and sunken eyes 1. Individual signs are subtle and unreliable in elderly patients 1. This systematic approach provides better diagnostic accuracy than single clinical findings. The combination of multiple clinical signs improves sensitivity and specificity for detecting significant dehydration in the geriatric population 1.
Question 2
A patient with diabetic ketoacidosis (DKA) has a blood glucose of 280 mg/dL, venous pH of 7.15, and serum bicarbonate of 12 mEq/L. What is the PRIORITY nursing intervention?
A. Administer subcutaneous insulin immediately
B. Begin aggressive fluid resuscitation with isotonic saline at 15-20 mL/kg/hour
C. Administer sodium bicarbonate intravenously
D. Restrict fluid intake to prevent cerebral edema
Correct Answer: B
Rationale: The American Diabetes Association recommends beginning aggressive fluid resuscitation with isotonic saline at 15-20 mL/kg/hour as the initial priority to restore circulatory volume and tissue perfusion in DKA 2. Management goals include restoration of circulatory volume first, followed by resolution of hyperglycemia and correction of electrolyte imbalances 1. Insulin therapy follows after initial fluid resuscitation is established. Bicarbonate therapy is not recommended except when pH <6.9 2.
Question 3
A postoperative patient develops hypernatremia (Na+ 152 mmol/L). What is the MAXIMUM recommended rate of sodium correction to prevent complications?
A. 5 mmol/L per 24 hours
B. 10-15 mmol/L per 24 hours
C. 20 mmol/L per 24 hours
D. 25-30 mmol/L per 24 hours
Correct Answer: B
Rationale: ESPGHAN/ESPEN guidelines recommend a reduction rate of 10-15 mmol/L per 24 hours for hypernatremia correction 1. Rapid correction of hypernatremia may induce cerebral edema, seizures, and neurological injury 1. The slower correction rate allows cellular adaptation and prevents osmotic shifts that can damage brain tissue. Monitoring should include frequent serum sodium measurements and neurological assessments during correction 1.
Question 4
A preterm infant on parenteral nutrition develops serum potassium of 7.2 mmol/L with normal urine output. What type of hyperkalemia is this, and what is the appropriate nursing action?
A. Oliguric hyperkalemia; restrict all potassium intake
B. Non-oliguric hyperkalemia (NOHK); check urine potassium and avoid excessive potassium in PN
C. Pseudohyperkalemia; no intervention needed
D. Renal failure; prepare for dialysis
Correct Answer: B
Rationale: ESPGHAN/ESPEN guidelines identify non-oliguric hyperkalemia (NOHK) in very low birth weight infants, which can develop in the absence of oliguria with normal diuresis and urine potassium >20 mmol/L 1. Risk factors include lack of antenatal corticosteroids, systemic acidosis, and birth asphyxia 1. This condition requires identification to avoid excessive potassium intake in parenteral nutrition. Severe hyperkalemia (K >7 mmol/L) requires prompt intervention but differs from oliguric hyperkalemia, which shows urine potassium <20 mmol/L 1.
Question 5
A patient with severe ulcerative colitis is admitted with profuse diarrhea. Which electrolyte supplementation is MOST critical to prevent toxic dilatation?
A. Sodium chloride 40 mmol/day
B. Calcium gluconate 20 mmol/day
C. Potassium supplementation of at least 60 mmol/day
D. Magnesium sulfate 10 mmol/day
Correct Answer: C
Rationale: European guidelines for ulcerative colitis management recommend potassium supplementation of at least 60 mmol/day in severe UC with diarrhea 1. Hypokalemia or hypomagnesemia can promote toxic dilatation, a life-threatening complication 1. Intravenous fluid and electrolyte replacement is essential to correct and prevent dehydration and electrolyte imbalance in severe UC 1. Adequate potassium replacement prevents cardiac arrhythmias and reduces the risk of colonic dilatation 1.
Question 6
A pregnant patient at 10 weeks gestation presents with hyperemesis gravidarum. Which laboratory finding indicates the need for immediate hospitalization and IV fluid therapy?
A. Weight loss of 3% of prepregnancy weight
B. Serum sodium of 138 mmol/L
C. Signs of dehydration with electrolyte imbalances and weight loss >5% of prepregnancy weight
D. Mild ketonuria on urinalysis
Correct Answer: C
Rationale: AGA guidelines define hyperemesis gravidarum as intractable NVP that leads to dehydration, weight loss >5% of prepregnancy weight, and electrolyte imbalances 1. The goals of management include prevention of dehydration and correction of electrolyte abnormalities 1. Physical examination should focus on signs of dehydration including orthostatic hypotension, decreased skin turgor, and dry mucous membranes 1. Laboratory evaluation focuses on the extent of dehydration, nutritional deficiencies, and electrolyte imbalances 1.
Question 7
A patient with multiple myeloma develops acute renal failure. What is the MOST important preventive measure to maintain renal function?
A. Restrict fluid intake to 1 liter per day
B. Maintain high urine output of 3 liters per day and correct dehydration promptly
C. Administer nephrotoxic antibiotics prophylactically
D. Encourage bed rest and limit activity
Correct Answer: B
Rationale: Italian Society of Hematology guidelines recommend maintaining a high urine output (3 L/day) to prevent renal failure in patients with Bence Jones proteinuria 1. Prompt treatment of hypercalcemia and correction of dehydration and electrolyte imbalance are crucial 1. Renal failure should be prevented by avoiding dehydration and nephrotoxic drugs 1. Patients with rapidly progressive renal failure should be rehydrated with intravenous fluids (saline) to achieve urine flow over 3 liters per day 1.
Question 8
A patient in DKA has initial serum potassium of 3.0 mEq/L. What is the PRIORITY action before starting insulin therapy?
A. Begin insulin infusion immediately at 0.1 units/kg/hour
B. Delay insulin therapy and aggressively replace potassium first
C. Start insulin at half the usual dose
D. Administer sodium bicarbonate to correct acidosis
Correct Answer: B
Rationale: The American Diabetes Association advises delaying insulin therapy and aggressively replacing potassium first if initial potassium is <3.3 mEq/L to prevent fatal cardiac arrhythmias 2. Insulin drives potassium into cells, which can precipitate life-threatening hypokalemia in patients with already low serum potassium 2. Once serum potassium falls below 5.5 mEq/L and adequate urine output is confirmed, 20-30 mEq potassium per liter of IV fluid should be added to maintain serum potassium 4-5 mEq/L 2.
Question 9
An elderly patient on diuretic therapy develops volume depletion after an episode of gastroenteritis. Which route of fluid administration is recommended for mild to moderate dehydration?
A. Intravenous fluids only
B. Oral, nasogastric, subcutaneous, or intravenous isotonic fluids
C. Hypotonic fluids intravenously
D. Restrict fluids until vomiting stops
Correct Answer: B
Rationale: ESPEN guidelines recommend that older adults with mild/moderate/severe volume depletion should receive isotonic fluids orally, nasogastrically, subcutaneously, or intravenously 1. Treatment aims to replace lost water and electrolytes with isotonic fluids 1. The elderly are at increased risk for adverse outcomes from dehydration, especially when on diuretic medications 1. Subcutaneous infusion (hypodermoclysis) provides an effective option for treating mild to moderate dehydration in nursing homes and at home 3.
Question 10
A patient with DKA has blood glucose of 180 mg/dL after 6 hours of treatment, but venous pH remains 7.25 and bicarbonate is 14 mEq/L. What is the appropriate nursing action?
A. Discontinue insulin infusion since glucose is normalized
B. Add dextrose to IV fluids and continue insulin infusion to clear ketones
C. Increase insulin infusion rate
D. Administer sodium bicarbonate
Correct Answer: B
Rationale: The American Diabetes Association recommends adding dextrose to IV fluids to prevent hypoglycemia when blood glucose falls below 200-250 mg/dL, while continuing insulin infusion to clear ketones 2. DKA is considered resolved when glucose <200 mg/dL AND venous pH >7.3 AND serum bicarbonate ≥18 mEq/L 2. Ketonemia typically takes longer to clear than hyperglycemia, requiring continued monitoring and insulin therapy 2. Discontinuing insulin prematurely before ketoacidosis resolves can lead to recurrence 2.