Fluid & Electrolytes

A 74-year-old postoperative patient is hypotensive and tachycardic with dry mucous membranes. Which initial fluid is most appropriate for resuscitation?

A 58-year-old man with septic shock received 30 mL/kg crystalloid. MAP remains 58 mmHg. What is the next best step?

A 67-year-old woman has serum Na 118 mEq/L, confusion, and seizures. What is the most appropriate immediate therapy?

A 45-year-old man with chronic SIADH (Na 124 mEq/L) is euvolemic and asymptomatic. What is first-line management?

A 70-kg man with Na 152 mEq/L is alert and hemodynamically stable. What fluid is best for gradual correction?

A 63-year-old woman with glucose 520 mg/dL has measured Na 130 mEq/L. What is the corrected sodium (use +1.6 per 100 mg/dL >100)?

A 32-year-old with severe hypokalemia (K 2.2 mEq/L) and U-waves on ECG requires IV replacement. What is correct?

A 60-year-old on ACE inhibitor presents with K 6.8 mEq/L and peaked T-waves. What is the first priority?

A 55-year-old with CKD and K 7.2 mEq/L remains hyperkalemic despite calcium, insulin/dextrose, and nebulized albuterol. Next step?

A 78-year-old with vomiting and contraction alkalosis (Cl 88, HCO₃⁻ 34) needs fluid therapy. Best choice?

A 35-year-old burn patient (80 kg) with 20% TBSA requires Parkland resuscitation. What is the 8-hour volume?

A 44-year-old with DKA: glucose 480, K 3.0, anion gap 28. What is the immediate next step before insulin?

Which acid-base compensation is correctly estimated by Winter’s formula?

A 50-year-old with anion gap acidosis (AG 26, HCO₃⁻ 10). ΔAG=14; ΔHCO₃=14. Interpretation?

A 63-year-old with hypercalcemia of malignancy (Ca 14.8 mg/dL) is dehydrated and confused. Best initial management?

A 29-year-old ICU patient develops hypocalcemia (tetany) during massive transfusion. Cause?

A 40-year-old with post-op polyuria (>4 L/day) and serum Na 151 mEq/L has dilute urine. Best next step?

A 54-year-old with SIADH has serum osmolality 260 mOsm/kg, urine osmolality 600, urine Na 45, euvolemic exam. Likely diagnosis?

A 66-year-old with hypernatremia (Na 160) needs free water. Estimated water deficit for a 70-kg man (TBW 0.6)?

A 58-year-old with lactic acidosis (pH 7.05) remains hypotensive despite vasopressors/fluids. Role of bicarbonate?

A 42-year-old with tumor lysis syndrome has K 6.1, phosphate 7.5, Ca 6.9, uric acid 12. Best immediate management?

A 37-year-old post-thyroidectomy patient develops perioral numbness and carpopedal spasm. Labs show low Ca and high phosphate. Best acute therapy?

A 50-year-old cirrhotic with tense ascites has serum Na 126, urine Na 8, low urine volume. Diagnosis?

A 62-year-old post-TURP becomes confused; Na 114 mEq/L, low serum osmolality. Most likely cause?

A 28-year-old with persistent hypokalemia despite replacement most likely needs which additional therapy?

A 71-year-old with diarrhea develops non–anion gap metabolic acidosis. What urine test helps distinguish renal vs GI bicarbonate loss?

A 64-year-old on large-volume normal saline develops hyperchloremic acidosis. Preferred fluid to reduce this risk?

A 35-year-old with high-output ileostomy (2.5 L/day) has dizziness and hyponatremia. Best oral strategy?

A 57-year-old with pancreatico-cutaneous fistula has non–anion gap metabolic acidosis. Why?

A 25-year-old trauma patient requires massive transfusion protocol. Which electrolyte issue must be proactively managed?

A 52-year-old with CKD has chronic metabolic acidosis (HCO₃⁻ 18). What outpatient therapy improves outcomes?

A 34-year-old ICU patient has measured serum osmolality 330 mOsm/kg; Na 140, glucose 90, BUN 14. Is there an osmolar gap?

A 45-year-old alcoholic with confusion and seizures after starting tube feeds shows phosphate 1.1 mg/dL. Diagnosis?

A 69-year-old with pneumonia has Na 122 mEq/L, euvolemia, urine osmolality 500. Target daily sodium correction?

A 31-year-old with hyponatremia overcorrects after hypertonic saline. What can safely re-lower Na?

A 56-year-old with COPD has chronic CO₂ retention. ABG after diuresis: pH 7.52, PaCO₂ 52, HCO₃⁻ 42. Primary disorder?

A 62-year-old post-pituitary surgery has high urine output and rising Na. Serum osmolality high; urine osmolality 90. Best test/therapy combo?

A 75-year-old with heart failure has hyponatremia (Na 126) and signs of volume overload. Best initial approach?

A 48-year-old with suspected pseudohyperkalemia after traumatic blood draw shows K 6.1 without ECG changes. Next step?

A 66-year-old malnourished patient starting TPN is at high risk of electrolyte shifts. Best prevention strategy?

A 64-year-old septic patient remains hypotensive after 30 mL/kg crystalloid. Which hemodynamic target best guides further fluids?

A 22-year-old marathon runner presents with headache and confusion after excessive water intake; Na 122 mEq/L. Most likely mechanism?

A 78-year-old with GI bleed receives 3 L NS rapidly; now HCO₃⁻ 18 and Cl 114. Which change reduces this acidosis risk?

A 58-year-old with severe hyperkalemia (K 7.0) after ACEI overdose is given calcium, insulin/dextrose, and albuterol. Which additional temporizing therapy shifts K intracellularly?

A 35-year-old postoperative patient has non–anion gap metabolic acidosis with urine anion gap +35. Likely cause?

A 70-kg patient needs maintenance fluids while NPO without major losses. Which is appropriate?

A 60-year-old with chronic hyponatremia (Na 121) overcorrected by 10 mEq/L in 12 hours. Best evidence-based action?

A 50-year-old trauma patient with TBI requires resuscitation. Which statement is most accurate?

A 39-year-old with pancreatitis has Ca 7.5 mg/dL (corrected Ca normal) and albumin 2.0 g/dL. What explains the value?

A 72-year-old post-gastrectomy has persistent metabolic alkalosis and hypokalemia. Best treatment?

A 63-year-old cirrhotic with ascites and Na 124 is started on tolvaptan. What is the key safety measure?

A 46-year-old with nephrogenic DI from lithium needs chronic management. Best option?

A 55-year-old ICU patient on TPN develops hypophosphatemia, weakness, and arrhythmias. Primary mechanism?

A 68-year-old with septic shock has low ScvO₂ after fluids and norepinephrine. Most appropriate next step?

A 44-year-old with hypomagnesemia (Mg 1.0 mg/dL) and torsades requires acute therapy. What is indicated?

A 30-year-old with severe hypokalemia (K 2.4) via peripheral access only. Safe maximum infusion rate?

A 75-year-old with HFrEF and CKD has hypervolemic hyponatremia. Which combination is most appropriate initially?

A 52-year-old with DKA after initial saline resuscitation now has glucose 240 mg/dL and persistent ketosis. Appropriate fluid change?