From the Guidelines
For a patient presenting with left-sided abdominal pain, I strongly recommend starting with a CT Abdomen and Pelvis as the most useful examination, as it is accurate and guides appropriate management, regardless of patient sex or body habitus. This recommendation is based on the most recent and highest quality study, which suggests that CT is sensitive for small quantities of extraluminal intraperitoneal or retroperitoneal air, a critical finding indicating luminal perforation and often having surgical implications 1. The use of intravenous (IV) contrast material at CT can improve the characterization and detection of bowel wall pathology, pericolic abnormalities, vascular pathology, and intraabdominal fluid collections.
Some key points to consider when evaluating left-sided abdominal pain include:
- The patient's age, sex, pain characteristics, associated symptoms, and medical history to efficiently identify the underlying cause and initiate appropriate treatment
- The potential causes of left-sided abdominal pain, including colonic diverticulitis, kidney stones, splenic issues, and gynecological causes in female patients of reproductive age
- The importance of identifying bowel obstruction or perforation, which can be life-threatening if not promptly treated
While other diagnostic tests, such as abdominal ultrasound and abdominal X-ray, may be useful in certain situations, CT Abdomen and Pelvis is the most recommended initial imaging study for left-sided abdominal pain, due to its high sensitivity and specificity for detecting various abdominal pathologies 1. Additionally, unenhanced CT can be accurate in the assessment of nonspecific acute abdominal pain in the emergency department, with similar accuracy to contrast-enhanced CT in patients aged 75 years or older 1.
It's worth noting that other studies, such as the one by Barat et al, have evaluated the use of unenhanced CT in the emergency department, and found it to be accurate in the assessment of nonspecific acute abdominal pain 1. However, the most recent and highest quality study recommends CT Abdomen and Pelvis as the most useful examination for left-sided abdominal pain 1.
From the Research
Diagnostic Testing for Left-Sided Abdominal Pain
The diagnosis of left-sided abdominal pain can be complex and requires a combination of clinical evaluation, laboratory tests, and imaging studies.
- The choice of diagnostic tests depends on the suspected cause of the pain, with computed tomography (CT) being a commonly used imaging modality for evaluating left-sided abdominal pain 2, 3.
- Ultrasound (US) can also be useful in the diagnosis of left-sided abdominal pain, particularly in patients with diverticulitis, as it can help identify local wall thickening of the colon and preservation of the US layer structure 2.
- Laboratory tests such as complete blood count, C-reactive protein, hepatobiliary markers, electrolytes, creatinine, glucose, urinalysis, lipase, and pregnancy testing may also be recommended to help guide the diagnosis 3.
- In some cases, endoscopy may be necessary to evaluate the colonic lumen and exclude potential malignancies, particularly in patients with a history of diverticulitis 4.
- A structured diagnostic approach, using algorithms based on the site of abdominal tenderness, can help prevent confusion and reduce unnecessary testing 5.
- Imaging studies, including CT, US, and magnetic resonance imaging, play a crucial role in establishing the diagnosis and extent of diverticulitis, as well as detecting any complications 2, 3, 6.
Specific Considerations for Diverticulitis
- CT is generally considered the imaging modality of choice for diagnosing diverticulitis, particularly in complicated cases or in obese patients 2, 6.
- US can be useful in the diagnosis of uncomplicated diverticulitis, particularly in non-obese patients, and can help identify signs such as local wall thickening and hyperechoic tissue surrounding the inflamed diverticulum 2.
- Early colonoscopy may be considered in patients with acute diverticulitis, particularly those with a protracted or unresolved course, to exclude potential malignancies 4.