Monday, September 29, 2008

32 - surgical cases mcqs - 1


CASE 1 :


Twenty-four hours after colon resection, urine

output in a 70-year-old man is 10 mL/h. Blood

chemistry analysis reveals sodium, 138 mEq/L;

potassium, 6 mEq/L; chloride, 100 mEq/L; bicarbonate,

14 mEq/L. His metabolic abnormality

is characterized by which of the following?

(A) Abdominal distension

(B) Peaked T waves

(C) Narrow QRS complex

(D) Cardiac arrest in systole

(E) J wave or Osborne wave


ANSWER:


(B) Hyperkalemia can manifest by GI or

cardiovascular signs. GI symptoms include

nausea, vomiting, intestinal colic, and diarrhea.

Abdominal distension as a result of paralytic

ileus is due to hypokalemia. An ECG is useful

to monitor potassium levels. Hyperkalemia

is characterized by peaked T waves. ECG

changes also include ST-segment depression,

widened QRS complex, and heart block.

Cardiac arrest occurs in diastole with increasing

levels of potassium. Osborne (J) wave is

seen in hypothermia.


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