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Zorluk: OrtaNephrology

Match each patient's laboratory profile with the most likely underlying clinical etiology.

  • ABG: pH 7.257.25, pCO 2_2 2424 mmHg, HCO 3−_3^- 1010 mEq/L. Serum: Na +^+ 140140 mEq/L, Cl −^- 105105 mEq/LUncontrolled type 1 diabetes mellitus
  • ABG: pH 7.527.52, pCO 2_2 4848 mmHg, HCO 3−_3^- 3838 mEq/L. Urine Cl −^- 88 mEq/LHyperemesis gravidarum
  • ABG: pH 7.287.28, pCO 2_2 6060 mmHg, HCO 3−_3^- 2626 mEq/LAcute heroin overdose
  • ABG: pH 7.317.31, pCO 2_2 3030 mmHg, HCO 3−_3^- 1515 mEq/L. Serum: Na +^+ 135135 mEq/L, Cl −^- 112112 mEq/LSevere infectious diarrhea
  • ABG: pH 7.447.44, pCO 2_2 2828 mmHg, HCO 3−_3^- 1919 mEq/LNormal third-trimester pregnancy

Cevap

The correct matches require calculating the anion gap and assessing respiratory compensation chronicity to identify the primary acid-base disorder and its etiology.
Each laboratory profile represents a classic presentation of a primary acid-base disorder with appropriate physiologic compensation. Matching them accurately requires systematic calculation of the anion gap, expected compensation formulas, and an understanding of volume status via urine electrolytes.

Adım Adım Çözüm

1
Calculate the anion gap (Na+−(Cl−+HCO3−)\text{Na}^+ - (\text{Cl}^- + \text{HCO}_3^-)) for the metabolic acidosis profiles (Profiles 1 and 4).
Profile 1 has an AG of 2525 mEq/L (HAGMA), while Profile 4 has an AG of 88 mEq/L (NAGMA).
Differentiating HAGMA from NAGMA isolates uncontrolled diabetes (HAGMA) from severe diarrhea (NAGMA).
2
Evaluate the metabolic alkalosis profile (Profile 2) using urine chloride.
Profile 2 shows a low urine chloride (88 mEq/L).
Low urine chloride (<20< 20 mEq/L) indicates a saline-responsive alkalosis, typically caused by upper gastrointestinal fluid loss such as hyperemesis gravidarum.
3
Analyze the ratio of change in pCO 2_2 to HCO 3−_3^- for the respiratory disorders (Profiles 3 and 5) to determine acuity.
Profile 3 shows an acute 11:1010 ratio of HCO 3−_3^- increase to pCO 2_2 increase. Profile 5 shows a chronic 44:1010 to 55:1010 ratio of HCO 3−_3^- decrease to pCO 2_2 decrease.
This distinguishes the acute hypoventilation of a heroin overdose from the chronic, progesterone-driven hyperventilation of a normal third-trimester pregnancy.

Anahtar Kavram

Interpretation of arterial blood gases and electrolyte panels to diagnose specific acid-base disorders
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Konular

Nephrology

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