A hiatal hernia occurs when part of the stomach — or occasionally other abdominal organs — pushes upward through the diaphragmatic hiatus (the small opening that normally allows only the esophagus to pass through the diaphragm) into the chest cavity. Hiatal hernias are extremely common, affecting an estimated 15–20% of the adult population in Western countries, and are frequently discovered incidentally on imaging. They range from small and entirely asymptomatic to large and clinically significant, with the largest types carrying risk of serious complications.
Hiatal hernias are the most common structural cause of gastroesophageal reflux disease (GERD) — by allowing the gastroesophageal junction to ride above the diaphragm, they impair the lower esophageal sphincter mechanism and permit stomach acid to reflux freely into the esophagus. Chronic acid exposure from uncontrolled reflux can lead to Barrett's esophagus — a metaplastic change in esophageal lining that carries risk of esophageal adenocarcinoma. Hiatal hernias are also frequently identified as incidental findings on MRI performed for biliary disease, pancreatic evaluation, or MALS workup — where the diaphragmatic and upper abdominal anatomy is in the field of view. Large paraesophageal hernias may cause significant gastric volvulus — twisting of the intrathoracic stomach — which can progress to strangulation and requires urgent surgery.
Causes
Weakening of the diaphragmatic hiatus.
The diaphragmatic hiatus is maintained by the phrenoesophageal membrane — a fibromuscular sheet that anchors the gastroesophageal junction below the diaphragm and allows the esophagus to move during swallowing while preventing upward herniation of the stomach. As this membrane ages and weakens — a process accelerated by chronic increases in intra-abdominal pressure — the hiatal opening gradually enlarges, allowing the GEJ and progressively more of the stomach to herniate superiorly into the posterior mediastinum. The process is typically gradual over years and is often discovered only when cross-sectional imaging is performed for another reason.
Other contributing factors.
Obesity is the most important modifiable risk factor — increased intra-abdominal pressure from excess adipose tissue chronically stresses the phrenoesophageal membrane, and weight loss can reduce hernia size and reflux severity. Pregnancy similarly elevates intra-abdominal pressure and predisposes to hiatal hernia development. Chronic cough (from asthma, COPD, or chronic smoking), chronic constipation with straining, and repetitive heavy lifting all produce sustained Valsalva-type pressure elevations that stretch the hiatus over time. Prior upper abdominal surgery — including fundoplication, gastric bypass, and esophagectomy — can disrupt the normal hiatal anatomy. Congenital diaphragmatic weakness and connective tissue disorders (Ehlers-Danlos syndrome, Marfan syndrome) predispose to larger hernias at younger ages. Prevalence increases markedly with age.
Symptoms
The majority of sliding hiatal hernias (Type I) produce no symptoms attributable to the hernia itself — they are discovered incidentally and require no treatment. When symptoms occur, they almost always result from impaired lower esophageal sphincter function and gastroesophageal reflux: heartburn (burning substernal discomfort, typically worse after meals and when lying flat), acid regurgitation, chronic cough from aspiration of refluxed acid into the airways, laryngitis, hoarseness, and chronic throat clearing. Dysphagia (difficulty swallowing) occurs when large hernias cause extrinsic compression of the esophagus or when esophagitis and stricturing have developed.
Paraesophageal hernias (Type II–IV) carry a different and more serious symptom profile. As the stomach herniates into the chest alongside the esophagus, it can rotate — producing gastric volvulus, where the stomach twists on its long axis (organoaxial) or mesentery (mesenteroaxial). Volvulus causes severe chest pain, inability to vomit despite nausea (Borchardt's triad: chest pain, retching without vomiting, inability to pass a nasogastric tube), and dysphagia. Incarceration — when the herniated stomach becomes trapped in the chest without blood supply — is a surgical emergency producing severe pain and requiring urgent operative reduction. Large hernias also cause early satiety, chest pressure, postprandial dyspnea, and anemia from chronic mucosal erosion (Cameron lesions — linear erosions at the level of the diaphragmatic hiatus).
Diagnosis
Upper endoscopy (EGD) is the most direct diagnostic study — it directly visualizes the hernia (the GEJ is above the diaphragmatic impression), grades associated esophagitis, and identifies Barrett's esophagus or Cameron lesions. Barium esophagogram with fluoroscopy demonstrates the hernia anatomy, GEJ position, associated reflux, and gastric volvulus in real time during swallowing. Esophageal manometry assesses lower esophageal sphincter pressure and esophageal motility when surgery is planned.
An MRI of the abdomen most commonly identifies hiatal hernias as incidental findings during imaging for other abdominal conditions. MRI precisely characterizes hernia type and size — the relationship of the GEJ to the diaphragm, the volume of intrathoracic stomach, and the presence of additional herniated organs (colon, small bowel, or spleen in Type IV hernias). MRI is particularly valuable for characterizing gastric volvulus — the rotational anatomy of the intrathoracic stomach on axial and coronal sequences identifies organoaxial vs. mesenteroaxial volvulus — and for pre-surgical planning of large or recurrent hernias. MRI also evaluates adjacent structures including the lower esophagus, mediastinum, and diaphragm for findings that would influence the surgical approach.
Classification
Hiatal hernias are classified into four anatomic types that differ in mechanism, risk profile, and management.
- Type I — Sliding hiatal hernia: By far the most common (~95% of hiatal hernias). The GEJ and proximal stomach slide upward through the hiatus when intra-abdominal pressure rises. The GEJ is above the diaphragm. Strongly associated with GERD. Rarely requires surgery unless reflux is refractory or severe. The hernia often reduces spontaneously when upright.
- Type II — Pure paraesophageal hernia: The GEJ remains in its normal infradiaphragmatic position, but a portion of the gastric fundus herniates alongside the esophagus through a separate defect. Uncommon. At risk for volvulus and strangulation — elective surgical repair typically recommended even if asymptomatic.
- Type III — Mixed: Combines Type I and II features — both the GEJ and a portion of the fundus have herniated through the hiatus. The most common large hiatal hernia type. High complication risk; surgical repair recommended.
- Type IV — Complex giant hernia: Very large defect with herniation of additional organs beyond stomach — most commonly colon, small bowel, or spleen — into the chest. Highest complication risk. Urgent repair when symptomatic; elective repair in fit patients even when asymptomatic.
Treatments
Treatment is guided by hernia type, symptom severity, and complication risk.
Lifestyle modification and medication: Type I sliding hernias with GERD symptoms are managed medically in the majority of patients. Proton pump inhibitors (PPIs — omeprazole, pantoprazole, esomeprazole) effectively suppress gastric acid and heal esophagitis in most cases. H2 blockers (famotidine) provide supplemental nighttime acid suppression. Lifestyle modifications — weight loss, smaller and more frequent meals, avoiding meals within 3 hours of bedtime, elevating the head of the bed 6–8 inches on blocks (not just extra pillows), and avoiding dietary triggers (citrus, caffeine, alcohol, fatty foods, chocolate) — reduce reflux burden. These measures treat the symptoms of reflux but do not reduce the hernia itself.
Laparoscopic surgical repair.
Surgery is recommended for: paraesophageal hernias (Types II–IV) regardless of symptoms due to volvulus and strangulation risk; large Type I hernias with refractory reflux despite maximal medical therapy; reflux confirmed objectively on pH testing in patients wishing to discontinue PPI therapy; and complicated hernias with esophagitis, stricture, Barrett's esophagus, or Cameron lesion anemia. The standard procedure is laparoscopic hiatal hernia repair — reducing the hernia sac contents back into the abdomen, reapproximating the diaphragmatic crura with sutures, and performing a Nissen fundoplication (360° wrap of the gastric fundus around the lower esophagus) to restore the anti-reflux barrier. Partial fundoplication (Toupet, 270°) is preferred when esophageal dysmotility is identified on preoperative manometry. Mesh reinforcement of the hiatal closure reduces early recurrence rates for large defects but carries rare mesh-related complications.
Emergency treatment of incarceration or strangulation.
Acute gastric incarceration or volvulus with strangulation is a surgical emergency — urgent reduction and repair is performed, with bowel resection if ischemic tissue is not viable. Mortality is significantly higher for emergency repair than elective surgery, which is why asymptomatic paraesophageal hernias are typically repaired electively in fit patients rather than watching for an emergency.
Long-term follow-up.
Patients with GERD on chronic PPI therapy require surveillance endoscopy for Barrett's esophagus every 3–5 years. Patients with known Barrett's undergo more frequent surveillance with biopsies. After surgical repair, long-term symptom assessment and occasional imaging confirm durability of the repair — hernia recurrence rates of 10–30% at 5 years are reported even at experienced centers, underscoring the importance of long-term follow-up.
Get an MRI to Confirm Your Diagnosis
Before surgical planning or starting treatment, a clear MRI diagnosis ensures the right path forward. First Look MRI offers self-pay Abdomen MRI scans — no doctor's order or insurance required — at our locations in Georgia, Texas, and Colorado.