Chapter review

Bring the chapter together

Start with the case synthesis, answered in 3 separate parts, then work through mixed case-based questions. Every answer explains the clue that matters and why the closest alternative fails.

Case synthesis

Bringing it together: one patient, three compartments

A 56-year-old man with alcoholic cirrhosis has tense ascites and pitting ankle edema; albumin 2.0 g/dL, Na⁺ 129 mEq/L, urine Na⁺ 8 mEq/L. Tonight he vomits a large amount of bright red blood. In the emergency department he is cold and clammy, pulse 124/min, BP 82/50 mm Hg, neck veins flat. Hemoglobin is 13.2 g/dL (13.5 a week ago). Na⁺ 130, Cl⁻ 100, HCO₃⁻ 16 mEq/L; lactate 6 mmol/L; PaCO₂ 31 mm Hg.

  1. 1. Where the fluid went before the bleed

    Why does he have ascites, edema and a low sodium at the same time?

  2. 2. The bleed

    Why is his hemoglobin almost unchanged, and what is his hemodynamic profile?

  3. 3. The acid

    His anion gap is 130 − (100 + 16) = 14. What does it mean?

Answer all 3 parts to see how they connect.L4 p.11, 27, 32, 43

Mixed case review

Morphology, mechanism and application. Some items need two sections at once.

0 of 16 correct
  1. Q1Diuretic-induced metabolic alkalosisConnects 4.3 + 4.4Midterm sim. p.13–14L4 p.29

    A 54-year-old woman's blood pressure is 154/90 mm Hg on the right arm and 155/93 mm Hg on the left. Weight loss over 2 months has not helped, and she starts a thiazide diuretic.

    Which arterial blood gas is most likely once the thiazide is acting?

  2. Q2SIADH: compartmentsConnects 4.2 + 4.3L4 p.10, 19

    A 63-year-old man with small cell carcinoma of the lung has a serum Na⁺ of 118 mEq/L, plasma osmolality 248 mOsm/kg, urine osmolality 560 mOsm/kg and no edema.

    Which change in the compartments fits?

  3. Q3Potassium in DKAConnects 4.2 + 4.3 + 4.4L4 p.16, 21

    A 16-year-old girl in diabetic ketoacidosis has pH 7.10, glucose 610 mg/dL and K⁺ 5.8 mEq/L.

    Which statement about her potassium is correct?

  4. Q4Paradoxical aciduria in vomitingConnects 4.3 + 4.4L4 p.29

    A 5-week-old boy has had projectile, non-bilious vomiting after every feed for a week; an olive-sized mass is felt in the epigastrium. Na⁺ 134, K⁺ 2.9, Cl⁻ 86, HCO₃⁻ 34 mEq/L. His urine pH is 5.5.

    Why is his urine acidic despite the alkalosis?

  5. Q5Hypervolemic hyponatremia and edemaConnects 4.2 + 4.5L4 p.11, 32

    A 59-year-old man with alcoholic cirrhosis has tense ascites and ankle edema. Serum Na⁺ 127 mEq/L, albumin 2.2 g/dL, urine Na⁺ 6 mEq/L.

    Which statement explains both the edema and the low sodium?

  6. Q6Isotonic loss with normal-gap acidosisConnects 4.1 + 4.2 + 4.4L4 p.5, 28

    A 25-year-old with cholera has passed about 10 L of rice-water stool. BP 80/50 mm Hg, dry mucosa. Na⁺ 140, Cl⁻ 115, HCO₃⁻ 15, K⁺ 3.1 mEq/L.

    Which pair describes his fluid and acid–base status?

  7. Q7Salicylate: mixed disorderConnects 4.4L4 p.27, 30

    A 70-year-old woman taking large doses of aspirin for arthritis is confused and breathing fast and complains of ringing in her ears. pH 7.46, PaCO₂ 22 mm Hg, HCO₃⁻ 15 mEq/L; Na⁺ 139, Cl⁻ 102 mEq/L.

    What is the acid–base diagnosis?

  8. Q8Obstructive shock from PEConnects 4.6 + 4.7L4 p.37, 49–50

    Eight days after hip fracture repair, a 77-year-old woman collapses while getting out of bed. BP 70/40 mm Hg, pulse 130/min, distended neck veins, clear lungs, SpO₂ 84%.

    Which hemodynamic profile is expected (CO · SVR · CVP · PCWP)?

  9. Q9DIC in sepsisConnects 4.6 + 4.7L4 p.47

    A 19-year-old student with meningococcal sepsis develops spreading purpura and oozes from every venipuncture site on day 2.

    Which laboratory pattern is expected?

  10. Q10ARDS as permeability edemaConnects 4.5 + 4.7L4 p.33, 47

    Two days into septic shock from pneumonia, a 45-year-old man needs more and more oxygen. Chest radiograph shows bilateral infiltrates; PCWP is 10 mm Hg; bronchoalveolar fluid is protein-rich.

    What kind of pulmonary edema is this?

  11. Q11Effective vs ineffective osmolesConnects 4.1 + 4.2L4 p.3

    A neurosurgeon gives intravenous mannitol to a patient with raised intracranial pressure. A student asks why urea, which raises plasma osmolality just as much per osmole, is not used instead.

    What is the best answer?

  12. Q12Aldosterone, potassium and acidConnects 4.3 + 4.4L4 p.22, 28–29

    A 66-year-old man with diabetic nephropathy has K⁺ 6.1 mEq/L, Na⁺ 137, Cl⁻ 112, HCO₃⁻ 17 mEq/L. Renin and aldosterone are both low.

    What best explains his hyperkalemia and acidosis?

  13. Q13Hypercoagulability in nephrotic syndromeConnects 4.5 + 4.6L4 p.32, 34

    A 34-year-old woman with nephrotic syndrome from membranous nephropathy (albumin 1.8 g/dL) develops sudden flank pain, hematuria and a swollen left leg.

    Why is she prone to thrombosis?

  14. Q14Combined acidosis in cardiac arrestConnects 4.4 + 4.7L4 p.30

    Ten minutes after the return of a pulse following cardiac arrest, a man's gas shows pH 6.95, PaCO₂ 70 mm Hg, HCO₃⁻ 15 mEq/L; Na⁺ 140, Cl⁻ 101 mEq/L; lactate 12 mmol/L.

    What is the acid–base diagnosis?

  15. Q15Correcting hypernatremia too fastConnects 4.2 + 4.3L4 p.12, 14, 17

    A 3-year-old with central diabetes insipidus after craniopharyngioma surgery has had a serum Na⁺ of 162 mEq/L for three days. He is given 5% dextrose rapidly, and his sodium falls to 146 mEq/L in 8 hours. He then has a seizure.

    What happened?

  16. Q16Thrombus → embolus → infarctConnects 4.6L4 p.38L1 p.33

    A 72-year-old woman with atrial fibrillation who stopped her anticoagulant has sudden left flank pain and hematuria. CT shows a wedge-shaped, non-enhancing area at the periphery of the left kidney.

    Which sequence explains it?

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