From the Guidelines
The most effective way to diagnose an abdominal hernia, particularly a diaphragmatic hernia, is through a CT scan of the chest and abdomen, as it is the diagnostic gold standard with a sensitivity and specificity of 14–82% and 87%, respectively 1. When diagnosing abdominal hernias, a thorough physical examination by a healthcare provider is the initial diagnostic step. The patient is examined while standing and lying down, and asked to cough or strain to make the hernia more visible or palpable. For suspected inguinal hernias, the doctor will typically insert a finger into the scrotum and ask the patient to cough to feel for any abnormal protrusion. However, for diaphragmatic hernias, physical examination may not be sufficient, and imaging studies become necessary.
- A chest X-ray can be useful, especially in cases where the diagnosis is uncertain, as it can show abnormal bowel gas patterns, air-fluid levels, or an abnormal lucency or soft tissue opacity with deviation of the mediastinum, or hemidiaphragm elevation 1.
- Nevertheless, CT scan is the most accurate imaging modality for diagnosing diaphragmatic hernias, as it can evaluate the intrathoracic complications of the herniated abdominal organs and provide detailed anatomical information 1.
- The various radiological findings that can be seen on a CT scan include diaphragmatic discontinuity, segmental non-recognition of the diaphragm, “Dangling diaphragm” sign, “Dependent viscera” sign, intrathoracic herniation of abdominal contents, “Collar sign”, contiguous injuries of both sides of the diaphragm, elevated abdominal organs, thickened diaphragm, thoracic fluid, abutting intra-abdominal viscera, hypo-attenuated hemidiaphragm, and associated fractured ribs 1.
- CT scan findings of ischemia include forward displacement of the gastric bubble, the missing of the gastric folds, the absence of gastric walls contrast enhancement, intestinal wall thickening with target enhancement, spontaneous hyper-density of the intestinal wall, lack of enhancement after injection of iodinated contrast agent, and parietal pneumatosis with portal and mesenteric venous gas 1.
From the Research
Diagnostic Methods for Abdominal Hernia
- Abdominal imaging is often the first clue to the correct diagnosis of abdominal hernia, with CT scans being a common method for diagnosis 2, 3.
- CT findings can be subtle or confusing, but familiarity with a broad range of imaging appearances can help radiologists make an early and specific diagnosis of abdominal hernia 2.
- Ultrasound is also a valuable tool in the diagnosis of abdominal wall hernias, particularly in cases where the diagnosis is unclear or in post-operative patients 4.
- Ultrasound can help confirm clinical findings, alter the diagnosis, and change the treatment plan, making it a useful adjunctive tool in the diagnosis of abdominal wall hernias 4.
Imaging Modalities for Abdominal Hernia Diagnosis
- CT is the imaging modality of choice for the assessment of a known adult abdominal hernia in both elective and acute circumstances 5.
- Ultrasound is useful for adult groin assessment and is the imaging modality of choice for pediatric abdominal wall hernia assessment 5.
- MRI is beneficial when there is reasonable concern that a patient's symptoms could be attributable to a hernia or a musculoskeletal source 5.
- Fluoroscopic herniography is a sensitive radiologic investigation for patients with groin pain in whom a hernia is suspected but in whom a hernia cannot be identified at physical examination 5.
Challenges in Diagnosing Abdominal Hernia
- Internal hernias can be difficult to diagnose, both clinically and with imaging, and require careful assessment for closed-loop small-bowel obstruction and abnormally located bowel loops 5.
- Abdominal hernias can simulate a mass or cyst in ultrasonography and CT scans, and careful demonstration of intraperitoneal communication through a muscular defect or a herniated bowel loop within the hernia is necessary to avoid misdiagnosis 6.