A 34-year-old man comes to the emergency department with severe abdominal pain. He describes the pain as "sharp" and "unbearable." It is located in the lower left abdomen and radiates to the groin. He has vomited twice since it began. The patient has no burning with urination. He is afebrile. He has difficulty lying still on the examination table due to the discomfort. Mucous membranes appear slightly dry. Lungs are clear to auscultation. Heart sounds are normal and there are no murmurs or gallops. The abdomen is soft and nontender to palpation. Inspection and palpation show normal genitalia. Extremities have no cyanosis, clubbing, or edema. Which of the following is the most appropriate test to diagnose this patient's condition?

Question

A 34-year-old man comes to the emergency department with severe abdominal pain.  He describes the pain as "sharp" and "unbearable."  It is located in the lower left abdomen and radiates to the groin.  He has vomited twice since it began.  The patient has no burning with urination.  He is afebrile.  He has difficulty lying still on the examination table due to the discomfort.  Mucous membranes appear slightly dry.  Lungs are clear to auscultation.  Heart sounds are normal and there are no murmurs or gallops.  The abdomen is soft and nontender to palpation.  Inspection and palpation show normal genitalia.  Extremities have no cyanosis, clubbing, or edema.  Which of the following is the most appropriate test to diagnose this patient's condition?

Quizplus · Accepted Answer

This patient, with severe left lower abdominal pain radiating to the groin, vomiting, and unremarkable findings on abdominal examination, has typical features of obstructive ureterolithiasis. Acute obstruction of the ureter at the ureterovesical junction produces severe flank pain that radiates to the perineum, penis, scrotum, or inner thigh. Patients with ureteral stones are often writhing in pain and unable to sit still in the examination room. Obstruction of hollow viscera often produces severe pain that is colicky in nature and poorly localized. Other causes of visceral pain include obstruction of the small intestine, colon, common bile duct, gall bladder, or urinary bladder, each of which produces a characteristic pattern of referred pain. characteristic pattern of referred pain The preferred modalities for diagnosing a ureteral stone are ultrasonography or noncontrast spiral CT scan of the abdomen and pelvis. Ultrasonography provides good imaging of the kidney and the proximal ureter and has lower radiation exposure. It is preferred in patients with a low likelihood of alternate diagnosis and in pregnant patients. However, it can also miss small stones, and its quality is dependent on the technician's expertise. (Choice A) Abdominal and pelvic x-ray (kidney-ureter-bladder study) will identify radiopaque, calcium-containing stones. Other types of urinary stones, accounting for at least 15% of cases, are not visible on plain x-ray. This method can also miss small stones at the ureterovesical junction. X-ray gives no information about obstruction of the ureter or kidney. However, it may be useful in serial follow-up of stones in the kidney or renal pelvis. (Choice C) Amylase and lipase help in the diagnosis of acute pancreatitis. In acute pancreatitis, pain typically radiates to the back (upper lumbar region). (Choice D) Colonoscopy is usually not performed in patients with acute abdominal pain due to the risk of perforation. If colonic obstruction is suspected and there is no evidence of perforation, a contrast enema study (barium or water-soluble contrast) can be diagnostic. (Choice E) Contrast is not required to visualize ureteral stones. A noncontrast CT of the abdomen and pelvis can be obtained quickly, is very sensitive and specific, can visualize small or non-calcium stones, and may identify other potential causes of abdominal pain. (Choice F) Exploratory laparotomy is indicated when there is evidence of peritonitis, as from a perforated viscus (free air under the diaphragm), ruptured aortic aneurysm, or abdominal trauma. Individuals with peritonitis typically lie still and avoid any movement that irritates the inflamed peritoneum. There are no physical signs of peritonitis, such as guarding, rigidity, or rebound tenderness, in this patient. (Choice G) An intravenous pyelogram (IVP) uses IV contrast and plain x-ray to visualize the urinary system. IVP was previously the test of choice for diagnosing urinary stones. However, due to the risk of contrast administration (eg, allergy, acute kidney injury), noncontrast CT is now preferred. (Choice H) Radioisotope (HIDA) scan is indicated in patients with acute cholecystitis when ultrasonography cannot definitively demonstrate obstruction at the neck of the gall bladder. In acute cholecystitis, pain is located predominantly in the upper abdomen and radiates to the tip of the right scapula or right shoulder. (Choice I) Urinalysis in patients with urinary stones will show microscopic or gross hematuria in over 90% of cases. However, the presence of hematuria is nonspecific. It is important to exclude coexistent urinary tract infection in patients with urinary calculi as this would significantly change management. This patient has no history of fever or dysuria to suggest an infection. Educational objective: Ureteral calculi may cause flank or abdominal pain radiating to the perineum, often with nausea and vomiting. Ultrasonography or a noncontrast spiral CT scan of the abdomen and pelvis are the imaging modalities of choice to confirm the diagnosis. Ultrasonography is preferred in pregnant patients to reduce radiation exposure. References: Imaging in diagnosis, treatment, and follow-up of stone patients. (http://www.ncbi.nlm.nih.gov/pubmed/19095204)

A 34-Year-Old Man Comes to the Emergency Department with Severe