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Zorluk: OrtaOrdering Imaging Studies

A 28-year-old woman with a 4-year history of ulcerative colitis presents to the emergency department with a 3-day history of progressively worsening abdominal pain and frequent, large-volume bloody diarrhea. Over the past 24 hours, she has also developed chills and profound weakness. Her current medications include mesalamine, which she states she stopped taking a month ago. Her temperature is 39.2°C (102.6°F), blood pressure is 92/58 mmHg, pulse is 128/min, and respirations are 22/min. Physical examination reveals a markedly distended abdomen that is diffusely tender to palpation with voluntary guarding. Percussion demonstrates severe tympany, and bowel sounds are absent. Laboratory studies show a leukocyte count of 18,500/mm³ and a hemoglobin of 9.2 g/dL. Which of the following is the most appropriate initial imaging study to evaluate this patient's current condition?

  1. A
    Computed tomography of the abdomen and pelvis with oral and intravenous contrast
  2. B
    Transabdominal ultrasonography of the abdomen
  3. C
    Magnetic resonance enterography
  4. D
    Fluoroscopic contrast enema
  5. Plain abdominal radiographyCevap

Cevap

Plain abdominal radiography is the most appropriate initial imaging study.
The correct answer is plain abdominal radiography because it is the fastest, safest, and most cost-effective initial imaging modality to confirm a clinical suspicion of toxic megacolon. It can immediately demonstrate the characteristic continuous dilation of the colon (most often the transverse colon measuring greater than 6 cm) and the loss of normal haustral markings. Furthermore, it serves the critical function of identifying free intraperitoneal air, which would indicate a bowel perforation and the need for emergent surgical exploration. In an unstable patient, obtaining a bedside or rapid plain film does not compromise ongoing resuscitation efforts.

Adım Adım Çözüm

1
Identify the primary clinical syndrome from the patient's presentation.
The patient has a known history of ulcerative colitis and presents with systemic toxicity (fever, tachycardia, hypotension, leukocytosis) alongside acute severe colitis (bloody diarrhea, abdominal distention, tympany). This constellation strongly suggests toxic megacolon.
Recognizing the life-threatening complication of inflammatory bowel disease dictates the urgency and type of diagnostic workup.
2
Select the optimal initial diagnostic test based on the suspected diagnosis.
Plain abdominal radiography is chosen as the first-line imaging study.
Plain films can rapidly and non-invasively confirm toxic megacolon (typically showing a transverse colon dilated > 6 cm with loss of haustra) and rule out free air, guiding immediate surgical and medical management without delaying care.

Anahtar Kavram

In patients with suspected toxic megacolon, plain abdominal radiography is the rapid, non-invasive, and most appropriate initial diagnostic imaging study to evaluate colonic dilation and rule out frank perforation.
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