Examkin

Soru

Zorluk: OrtaNephrology

Match each patient's clinical presentation with the most likely corresponding arterial blood gas and basic metabolic panel profile.

  • A 22-year-old female with type 1 diabetes presenting with polyuria, vomiting, and fruity breath odor.pH 7.25, PaCO2\text{PaCO}_2 30 mm Hg, HCO3−\text{HCO}_3^- 14 mEq/L, Na+\text{Na}^+ 138 mEq/L, Cl−\text{Cl}^- 100 mEq/L
  • A 68-year-old male with severe chronic obstructive pulmonary disease presenting with worsening productive cough and lethargy.pH 7.28, PaCO2\text{PaCO}_2 70 mm Hg, HCO3−\text{HCO}_3^- 32 mEq/L, Na+\text{Na}^+ 140 mEq/L, Cl−\text{Cl}^- 98 mEq/L
  • A 19-year-old male experiencing an acute panic attack with circumoral numbness and carpopedal spasm.pH 7.55, PaCO2\text{PaCO}_2 24 mm Hg, HCO3−\text{HCO}_3^- 20 mEq/L, Na+\text{Na}^+ 140 mEq/L, Cl−\text{Cl}^- 106 mEq/L
  • A 45-year-old female with recurrent severe vomiting over one week due to gastric outlet obstruction.pH 7.52, PaCO2\text{PaCO}_2 48 mm Hg, HCO3−\text{HCO}_3^- 38 mEq/L, Na+\text{Na}^+ 138 mEq/L, Cl−\text{Cl}^- 88 mEq/L

Cevap

Diabetic ketoacidosis matches with the high anion gap metabolic acidosis profile; COPD exacerbation matches with the acute-on-chronic respiratory acidosis profile; panic attack matches with the acute respiratory alkalosis profile; and vomiting matches with the metabolic alkalosis profile.
Each clinical vignette provides a classic etiology for one of the four primary acid-base disorders. By interpreting the pH to determine the primary disturbance (acidosis vs. alkalosis), and then analyzing the PaCO2\text{PaCO}_2, HCO3−\text{HCO}_3^-, and anion gap, the correct laboratory profile can be definitively paired with the patient's presentation.

Adım Adım Çözüm

1
Analyze the first presentation (type 1 diabetes with vomiting and fruity breath).
Identify the primary acid-base disorder as high anion gap metabolic acidosis (HAGMA) secondary to diabetic ketoacidosis.
Ketone body production consumes bicarbonate (HCO3−\text{HCO}_3^-) and increases the anion gap.
2
Match HAGMA to the correct lab profile.
Select the profile with pH 7.25, HCO3−\text{HCO}_3^- 14 mEq/L, and an anion gap of 24.
The calculated anion gap (138−100−14=24138 - 100 - 14 = 24) confirms HAGMA, and the PaCO2\text{PaCO}_2 of 30 mm Hg reflects appropriate respiratory compensation per Winter's formula (1.5×14+8±2=29±21.5 \times 14 + 8 \pm 2 = 29 \pm 2).
3
Analyze the second presentation (COPD exacerbation).
Identify the primary disorder as respiratory acidosis with chronic partial metabolic compensation.
Airway obstruction causes CO2\text{CO}_2 retention, while chronic COPD leads to compensatory renal bicarbonate (HCO3−\text{HCO}_3^-) retention.
4
Match respiratory acidosis to the correct lab profile.
Select the profile with pH 7.28, PaCO2\text{PaCO}_2 70 mm Hg, and HCO3−\text{HCO}_3^- 32 mEq/L.
The elevated PaCO2\text{PaCO}_2 directly causes the acidosis, and the elevated bicarbonate indicates chronic renal compensation.
5
Analyze the third presentation (panic attack with hyperventilation).
Identify the primary disorder as acute respiratory alkalosis.
Tachypnea blows off excessive CO2\text{CO}_2, rapidly raising the blood pH.
6
Match acute respiratory alkalosis to the correct lab profile.
Select the profile with pH 7.55, PaCO2\text{PaCO}_2 24 mm Hg, and HCO3−\text{HCO}_3^- 20 mEq/L.
The low PaCO2\text{PaCO}_2 drives the alkalemia, and the small drop in bicarbonate represents acute cellular buffering.
7
Analyze the fourth presentation (severe recurrent vomiting).
Identify the primary disorder as metabolic alkalosis.
Loss of gastric hydrochloric acid (HCl\text{HCl}) directly leads to alkalosis and hypochloremia.
8
Match metabolic alkalosis to the correct lab profile.
Select the profile with pH 7.52, PaCO2\text{PaCO}_2 48 mm Hg, HCO3−\text{HCO}_3^- 38 mEq/L, and Cl−\text{Cl}^- 88 mEq/L.
The high bicarbonate defines the alkalosis, hypochloremia (Cl−\text{Cl}^- 88 mEq/L) reflects gastric losses, and the elevated PaCO2\text{PaCO}_2 indicates respiratory compensation.

Anahtar Kavram

Diagnosis of primary acid-base disorders by analyzing clinical history, pH, PaCO2, bicarbonate, and anion gap.
Bu soruyu puanla

Konular

Nephrology

Bu konudan daha fazla soru