A hiatal hernia can cause anemia, and in many cases it does so through a mechanism that goes undetected for months or even years. The culprit is usually a set of small erosions or ulcers that form inside the hernia sac, known as Cameron lesions. These lesions bleed slowly enough that you may never notice blood in your stool, but over time they drain your body’s iron stores and drive down your red blood cell count. In patients with iron deficiency anemia, a large hiatal hernia turns out to be the underlying cause in roughly 5 to 9 percent of cases, a figure that surprises many clinicians and patients alike.
How a Hiatal Hernia Causes Bleeding
A hiatal hernia occurs when part of the stomach pushes upward through the hiatus, the natural opening in the diaphragm that the esophagus passes through. This displaced portion of the stomach is now subject to forces it was never designed to withstand. Every time you breathe, swallow, or cough, the herniated stomach slides against the muscular rim of the diaphragm. The gradient between the positive pressure inside your abdomen and the negative pressure in your chest adds an extra back-and-forth sliding motion at the junction where the stomach meets the esophagus.
This constant mechanical friction damages the lining of the stomach at the point where it rubs against the diaphragmatic opening. The result is Cameron lesions: linear erosions or shallow ulcers that develop along the mucosal folds trapped within the hernia sac.1The American Journal of Case Reports. A 61-Year-Old Woman with Chronic Iron-Deficiency Anemia Due to a Cameron Lesion and a Response to Oral Application of Combined Poloxamer 407 with Hyaluronic Acid and Chondroitin Sulfate Following Single Treatment with Pantoprazole: A Case Report The bleeding from these erosions is typically slow and chronic rather than dramatic. You would not vomit blood or see red in the toilet. Instead, tiny amounts of blood seep into the digestive tract day after day, and because the losses are invisible, they go unnoticed until a blood test reveals low hemoglobin and depleted iron stores.2World Journal of Gastrointestinal Surgery. Paraesophageal hernia and iron deficiency anemia: Mechanisms, diagnostics and therapy
Historically, Cameron lesions have been recognized as a cause of chronic gastrointestinal bleeding with associated iron deficiency anemia.3PubMed. Hiatal hernia with cameron ulcers and erosions The anemia that develops is specifically iron deficiency anemia, the kind caused by blood loss rather than by a nutritional gap or a bone marrow problem. Your body uses iron to make hemoglobin, and when you’re losing small amounts of blood every day, your iron reserves eventually run out. Once they do, your hemoglobin drops and you start feeling the classic symptoms of anemia: fatigue, weakness, shortness of breath on exertion, pallor, and sometimes dizziness.
Why Hernia Size Matters
Not every hiatal hernia causes anemia. The risk depends heavily on how large the hernia is. Small sliding hernias, the kind found incidentally on imaging or during an endoscopy for heartburn, rarely produce enough mechanical trauma to cause significant bleeding. The connection between hernia and anemia becomes clinically meaningful when the hernia is large, meaning a substantial portion of the stomach has migrated above the diaphragm.
Cameron lesions are found in about 5 percent of patients with a hiatal hernia who undergo upper endoscopy, and that number climbs as hernia size increases.4Open Access Macedonian Journal of Medical Sciences. Large Hiatal Hernia Associated with Cameron Ulcers and Consecutive Sideropenic Anemia: Case Presentation In about two-thirds of those cases, multiple lesions are present rather than a single erosion, which compounds the blood loss. A prospective study of patients with iron deficiency anemia found that a large hiatal hernia was the likely cause of the anemia in about 9 percent of them, with median hemoglobin values at diagnosis hovering around 7.9 g/dL, well below the normal range, and ferritin values essentially bottomed out at 6 micrograms per liter.5PubMed Central. Large hiatal hernia in patients with iron deficiency anaemia: a prospective study on prevalence and treatment Cameron erosions were present in a third of those patients.
Paraesophageal hernias, the type in which part of the stomach herniates alongside the esophagus rather than simply sliding upward, carry a particularly high risk for this problem. Giant paraesophageal hernias, where the stomach or even other organs rotate into the chest cavity, frequently present with anemia as one of their defining symptoms alongside pain, heartburn, and difficulty swallowing.6Journal of Clinical & Medical Surgery. Laparoscopic Surgical Treatment of Hiatal Hernia with Gastric Volvulus: Report of a Case In one surgical series, more than a quarter of patients with massive hiatal hernias had iron deficiency anemia at the time of their repair.7PubMed Central. Laparoscopic hiatal hernia repair for treating patients with massive hiatal hernia and iron-deficiency anaemia
Why This Diagnosis Gets Missed
One of the most frustrating aspects of the hiatal hernia-anemia connection is how often it goes unrecognized, even when patients undergo the right tests. Cameron lesions are small, sometimes subtle, and sit in a location that is easy to overlook during a standard upper endoscopy. The endoscope needs to be positioned carefully to visualize the area where the stomach folds press against the diaphragmatic hiatus. A routine forward-viewing pass through the stomach may glide right past them.
The numbers here are striking. In a systematic review of published cases, as many as 69 percent of patients had undergone one or more previous upper endoscopies before anyone identified Cameron lesions as the cause of their anemia.8Clinics and Research in Hepatology and Gastroenterology. Clinical challenge Cameron lesions: A still overlooked diagnosis. Case report and systematic review of literature That means most of these patients had already been scoped, told the endoscopy was unremarkable, and sent off for additional workups looking for other explanations for their low blood counts. Some received repeated colonoscopies, capsule endoscopies, or even bone marrow biopsies before the real cause was found.
Proper diagnosis requires a deliberate inspection technique: the endoscopist needs to examine the hernia sac from multiple angles, including a retroflexed view looking back at the hiatal opening, where the diaphragm applies the most pressure to the gastric wall.9American Journal of Case Reports. A 61-Year-Old Woman with Chronic Iron-Deficiency Anemia Due to a Cameron Lesion If your doctor already knows you have a hiatal hernia, this targeted look is straightforward. The problem arises when anemia is being investigated without that knowledge, or when the endoscopist isn’t specifically thinking about Cameron lesions as a possibility. Awareness of the condition is, frankly, the most important diagnostic tool.
What to Watch For
The tricky thing about anemia caused by a hiatal hernia is that the symptoms overlap almost completely with anemia from any other cause. You feel tired, you get winded climbing stairs, your skin may look paler than usual, and you might notice brittle nails or cravings for ice. None of those signs point specifically to a hiatal hernia. And because the bleeding is occult, meaning hidden, you won’t see any visible evidence of it.
The clue that points toward a hiatal hernia rather than some other explanation is usually the pattern of the anemia itself. If blood tests keep showing low iron (low ferritin, low serum iron, high total iron-binding capacity) and your doctor can’t find the source despite a colonoscopy and standard endoscopy, a large hiatal hernia should be on the list of suspects. This is especially true if you’re an older adult, the demographic most likely to have both large hernias and iron deficiency anemia. If you already know you have a hiatal hernia and you’ve been told your iron is low, connecting those two pieces of information is the critical step that often gets skipped.
Some patients also have reflux symptoms like heartburn or regurgitation, but not all do. Giant paraesophageal hernias sometimes cause a feeling of chest fullness, difficulty swallowing, or early satiety because the stomach is physically displaced. When anemia appears alongside any of these symptoms, the hernia becomes the prime suspect.
Treatment Without Surgery
For patients whose anemia is caught early and whose hernia is not causing severe complications, medical management is the first line of treatment. This typically involves two things: a proton pump inhibitor to reduce stomach acid and allow the erosions to heal, and iron supplementation to replenish depleted stores. If you’re already taking a PPI once daily, the recommendation is to increase the dose or switch to twice-daily dosing. Similarly, if you’re already taking iron but your levels haven’t improved, the dose should go up.10The American Journal of Case Reports. A 61-Year-Old Woman with Chronic Iron-Deficiency Anemia Due to a Cameron Lesion and a Response to Oral Application of Combined Poloxamer 407 with Hyaluronic Acid and Chondroitin Sulfate Following Single Treatment with Pantoprazole: A Case Report – Section: Management
Medical treatment can improve hemoglobin levels, but there is an important limitation: it doesn’t fix the hernia. The mechanical friction that caused the Cameron lesions in the first place is still happening. So while PPIs and iron can stabilize the anemia, the lesions may recur once medications are stopped or the hernia progresses. For patients with smaller hernias or mild anemia, this approach may be perfectly sufficient for years. For those with large hernias and recurrent or refractory anemia, medication alone tends to be a holding pattern rather than a cure.
When Surgery Becomes the Answer
Surgical repair of the hiatal hernia addresses the root cause. By pulling the stomach back down into the abdomen and tightening the hiatal opening, the mechanical trauma that produces Cameron lesions is eliminated. The evidence on surgical outcomes for this specific problem is genuinely encouraging.
In a multicenter study using matched patient comparisons, unexplained iron deficiency anemia resolved in more than 90 percent of patients following paraesophageal hernia repair. Those results held up over time, even in patients who had some degree of anatomical recurrence of the hernia on follow-up imaging.11PubMed Central. Surgical repair of paraesophageal hernia resolves unexplained iron deficiency anemia in the vast majority of patients: a propensity-matched multicenter study A separate surgical series found a nearly identical rate: anemia resolved in about 94 percent of patients after laparoscopic hiatal hernia repair, with a mean follow-up of five years. The two patients whose anemia did not resolve had experienced hernia recurrence and needed ongoing iron supplementation.7PubMed Central. Laparoscopic hiatal hernia repair for treating patients with massive hiatal hernia and iron-deficiency anaemia
Another study compared patients managed with medication alone to those who underwent surgery. Both groups saw improvement in hemoglobin levels, but the surgical group achieved normalized hemoglobin, were able to stop taking iron supplements and PPIs, and reported better quality of life. The benefits appeared durable over the study’s follow-up period.12Foregut: The Journal of the American Foregut Society. Changes in Hemoglobin Levels in Patients with Hiatal Hernia and Anemia Demonstrates a Durable Resolution When Surgery Utilized Based on these findings, hernia repair should be seriously considered for any patient with unexplained or medication-resistant iron deficiency anemia and a large hiatal hernia.
When the Bleeding Is Not Slow
Most of the time, the anemia caused by a hiatal hernia develops gradually over weeks to months. But Cameron lesions can occasionally bleed more briskly, and in rare cases, they produce acute upper gastrointestinal bleeding with symptoms you cannot miss: vomiting blood, passing black tarry stools, rapid heart rate, or lightheadedness from sudden blood loss. Delayed treatment in these situations can lead to life-threatening hemorrhage.13PubMed Central. A Case of Cameron Lesions: An Overlooked Cause of Anemia in Patients With Gastrointestinal Bleeding and Hiatal Hernia
Large paraesophageal hernias can also lead to acute bleeding through a different mechanism entirely. When the stomach is significantly displaced and rotates within the hernia sac, the retching and vomiting that result can produce tears at the junction between the esophagus and the stomach, known as Mallory-Weiss tears. In one reported case, a nine-month-old infant with a type IV paraesophageal hernia, a rare and extreme variant where the stomach and other abdominal organs herniate into the chest, developed severe anemia from an actively bleeding Mallory-Weiss tear triggered by persistent vomiting.14PubMed Central. Type IV Paraesophageal Hernia With Mallory-Weiss Bleeding in an Infant: Endoscopic Hemostasis and Laparoscopic Repair Cases like this are unusual, but they illustrate that large hiatal hernias can produce bleeding through more than one pathway.
Who Is Most at Risk
The hiatal hernia-anemia connection disproportionately affects older adults. Hiatal hernias become more common with age as the diaphragmatic muscles weaken and connective tissue loosens. By some estimates, the majority of people over 60 have at least a small hiatal hernia, though most are asymptomatic. The hernias that cause anemia tend to be the larger ones, which also become more prevalent in older populations.
Women are affected more often than men, partly because women have lower baseline iron stores and are more susceptible to iron deficiency from any cause. Postmenopausal women who develop unexplained iron deficiency anemia are a group where a large hiatal hernia should be actively considered in the diagnostic workup, especially if colonoscopy and standard endoscopy have not revealed a source of bleeding.
People who take nonsteroidal anti-inflammatory drugs regularly also face higher risk. NSAIDs impair the stomach lining’s ability to protect and repair itself, so the mechanical trauma inflicted by a hiatal hernia on already-compromised mucosa can produce larger or more numerous erosions. If you have a known large hiatal hernia, chronic NSAID use is worth discussing with your doctor.
How Iron Absorption Can Be Affected Beyond Bleeding
While the dominant pathway from hiatal hernia to anemia runs through Cameron lesions and chronic blood loss, there is a less commonly discussed possibility. In very large hernias, the anatomy of the upper digestive tract is significantly distorted. The stomach’s position affects how efficiently food is mixed with acid and digestive enzymes, and iron absorption depends on an acidic environment in the stomach and upper small intestine. When a large hernia alters gastric motility or combines with long-term PPI use, which raises stomach pH, iron absorption from food can decline.
This is harder to quantify than the bleeding mechanism, and the published literature focuses overwhelmingly on Cameron lesions as the explanation for hernia-related anemia. But in patients whose anemia stubbornly persists despite no visible bleeding and adequate dietary iron intake, impaired absorption may be playing a contributing role. It is also worth noting that giant hernias occasionally involve not just the stomach but parts of the colon, duodenum, or even the pancreas herniating into the thorax.15ScienceDirect / Journal of Clinical Gerontology and Geriatrics. A case of giant hiatal hernia in an elderly patient: When stomach, duodenum, colon, and pancreas slide into thorax When the anatomy is that severely disrupted, the downstream effects on digestion and nutrient absorption become unpredictable.
Talking to Your Doctor
If you’ve been diagnosed with iron deficiency anemia and your initial workup hasn’t found a clear source of bleeding, ask whether you have a hiatal hernia. If you’ve had an upper endoscopy that was reported as normal, it may be worth asking whether the endoscopist specifically examined the hernia sac for Cameron lesions, given how frequently these erosions are missed on first-look examinations. Many patients cycle through repeated testing before someone connects the two conditions, and a direct conversation with your gastroenterologist about this specific possibility can short-circuit that process.
For patients who already know they have a large hiatal hernia and are being managed medically for anemia, periodic monitoring of hemoglobin and iron levels is important. If your numbers keep dipping despite consistent medication, surgical consultation is a reasonable next step. The evidence showing that hernia repair resolves anemia in the vast majority of cases is some of the most consistent data in this area of gastroenterology, and for the right patient, surgery can mean finally getting off iron supplements and feeling like yourself again.