A 65-Year-Old Man Comes to the Emergency Department Due to Acute

question 237

Multiple Choice

A 65-year-old man comes to the emergency department due to acute right flank pain.  The pain started an hour ago and he has vomited twice.  The pain is 10 on a scale of 0-10 in severity, is crampy, and waxes and wanes.  The patient has never before had similar pain.  He reports passing "sand" occasionally in his urine.  Medical history is significant for obesity, hyperlipidemia, hypertension, gout, and claustrophobia.  The patient does not use tobacco, alcohol, or illicit drugs.  He is afebrile.  Blood pressure is 160/100 mm Hg, pulse is 98/min, and respirations are 16/min.  BMI is 54 kg/m².  The abdomen is obese and bowel sounds are decreased.  Mild tenderness is present over the right flank.  Urinalysis shows hematuria and a urine pH of 5.  Abdominal ultrasonogram shows right-sided hydronephrosis and dilation of the proximal ureter.  Which of the following is the most likely cause of this patient's current symptoms?

• A)Decreased intestinal absorption of oxalate
• B)Increased release of calcium from bone
• C)Increased urinary excretion of calcium and phosphorus
• D)Presence of urea-splitting bacteria
• E)Supersaturation of urine with uric acid

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Definitions:

Concentration Gradient

Difference in the relative abundance of a substance among regions of a container; allows the substance to diffuse from an area of higher concentration to an area of lower concentration.

Diffusion

The movement of molecules from an area of higher concentration to an area of lower concentration, a fundamental process in biology and chemistry.

Negatively Charged

Having more electrons than protons, resulting in a net charge that is less than zero.

Protein Anions

Negatively charged proteins that play various roles in cellular functions, including maintaining cell structure and function.