From the Guidelines
The most appropriate next diagnostic step for this patient is a CT scan of the abdomen, as it is the most sensitive and specific imaging modality for evaluating the severity of the obstruction, identifying the etiology and site of the obstruction, and detecting complications such as ischemia, volvulus, or perforation. The patient's presentation with severe abdominal pain, nausea, vomiting, abdominal distention, and severe diffuse tenderness, along with laboratory results showing leukocytosis, hypernatremia, and impaired renal function, suggests a high-grade small bowel obstruction (SBO) with potential complications 1. According to the ACR Appropriateness Criteria for suspected small-bowel obstruction, early imaging diagnosis and intervention are critical for successful treatment and minimization of mortality, which can be as high as 25% in the setting of ischemia 1. While an abdominal X-ray may be a useful initial imaging study, it is not sufficient to evaluate the severity of the obstruction or detect complications, and a CT scan is recommended as the next step in diagnosis 1. The use of CT scan is supported by the 2017 WSES guidelines for management of intra-abdominal infections, which recommend a step-up approach for diagnosis from clinical and laboratory examination to imaging examination, and suggest that CT may be very useful especially when the diagnosis is uncertain 1. In this case, given the patient's severe symptoms and laboratory results, a CT scan is the most appropriate next diagnostic step to guide further management and potential surgical intervention. Key benefits of a CT scan include its high sensitivity and specificity for detecting complications, its ability to evaluate the severity of the obstruction, and its non-invasive nature, which reduces the risk of complications compared to other imaging modalities 1. Overall, a CT scan is the best next step in diagnosis for this patient, as it will provide the most accurate and comprehensive information to guide further management and treatment.
From the Research
Diagnostic Approach
The patient's symptoms, including severe abdominal pain, nausea, vomiting, abdominal distention, and severe diffuse tenderness, along with laboratory results showing leukocytosis, hypernatremia, and impaired renal function, suggest a serious underlying condition. The most appropriate next diagnostic step would be to perform imaging studies to help determine the cause of these symptoms.
Imaging Options
- Computed Tomography (CT) scan: According to 2, CT is the primary technique for diagnosing acute abdominal pain, as it provides an accurate and reproducible diagnosis in urgent conditions.
- Ultrasonography (US): While US can be useful in certain cases, such as suspected acute cholecystitis, it may not be as effective in diagnosing other causes of acute abdominal pain 2.
- Plain radiography: This modality has limited use in diagnosing acute abdominal pain, except in cases of suspected bowel obstruction 2, 3.
- Magnetic Resonance (MR) imaging: Although MR imaging is a promising alternative to CT, its use in acute abdominal pain is still limited due to sparse data 2.
Clinical Evaluation and Imaging
- Clinical evaluation alone may not be sufficient to diagnose the cause of non-traumatic acute abdomen, and imaging studies can increase the accuracy of pre-operative diagnosis 3.
- The choice of imaging modality depends on the patient's symptoms, laboratory results, and clinical evaluation, and should be guided by current recommendations and appropriateness criteria 4, 5.
- Knowledge of pathognomonic imaging signs is essential for radiologists to make a correct diagnosis 6.