08-09-2010, 10:13 AM
A 72-year-old skilled nursing care facility resident with dementia is brought to the emergency department 2 days after the onset of fever, confusion, and generalized weakness. His symptoms began following irrigation of his urinary catheter, which was not draining well. He has chronic obstructive pulmonary disease and osteoarthritis. He appears lethargic. His temperature is 36.2°C (97.2°F), pulse is 110/min, and blood pressure is 90/50 mm Hg. Examination shows a supple neck. There are Heberden nodes on the hands. Breath sounds are decreased throughout the lungs with no dullness. Cranial nerves are intact. Deep tendon reflexes are normal. Laboratory studies show:
Hematocrit
50%
Leukocyte count
15,400/mm3
Segmented neutrophils
74%
Bands
4%
Lymphocytes
22%
Serum
ƒNa+
134 mEq/L
ƒK+
4.2 mEq/L
ƒCl−
86 mEq/L
ƒHCO3−
24 mEq/L
Urea nitrogen
12 mg/dL
Creatinine
1.1 mg/dL
An ECG shows sinus tachycardia with some flattening of ST-T segments. Which of the following is the most likely explanation for his hypotension?
A
) Decreased cardiac contractility
B
) Decreased systemic vascular resistance
C
) Deficiency of mineralocorticoids
D
) Impaired vagal reflexes
E
) Impaired venous return
Hematocrit
50%
Leukocyte count
15,400/mm3
Segmented neutrophils
74%
Bands
4%
Lymphocytes
22%
Serum
ƒNa+
134 mEq/L
ƒK+
4.2 mEq/L
ƒCl−
86 mEq/L
ƒHCO3−
24 mEq/L
Urea nitrogen
12 mg/dL
Creatinine
1.1 mg/dL
An ECG shows sinus tachycardia with some flattening of ST-T segments. Which of the following is the most likely explanation for his hypotension?
A
) Decreased cardiac contractility
B
) Decreased systemic vascular resistance
C
) Deficiency of mineralocorticoids
D
) Impaired vagal reflexes
E
) Impaired venous return
