Internal hemorrhoids are swollen veins located inside the rectum, similar to varicose veins found elsewhere in the body. Narrow stools, also called pencil-thin or ribbon-like stools, are bowel movements that appear significantly thinner than their usual diameter, often less than one inch wide. A consistent change to a narrower shape can sometimes indicate an underlying issue.
The Impact of Internal Hemorrhoids on Stool Shape
Internal hemorrhoids generally do not cause noticeable symptoms. However, if they become significantly enlarged or prolapsed, meaning they push through the anal opening, they might affect stool shape. A large internal hemorrhoid could create a partial obstruction in the rectal passage, causing stool to become narrower as it passes through, resulting in flatter or thinner stools.
However, this is not a common symptom of internal hemorrhoids, especially if they are small or not prolapsed. Bleeding, often painless and bright red on toilet tissue or in the toilet, is a far more frequent symptom. Therefore, if you primarily experience narrow stools without significant bleeding or other prominent hemorrhoid symptoms, other causes are more likely.
Other Reasons for Narrow Stools
Narrow stools can arise from various conditions, many more common or serious than hemorrhoids in causing this specific symptom. Dietary factors, such as a low-fiber diet, can lead to constipation, which might result in less bulky and narrower stools. Dehydration or insufficient fluid intake can also contribute to harder, smaller stools.
Irritable Bowel Syndrome (IBS) is a common disorder of the large intestine that can cause changes in stool size and shape, including narrower stools, particularly with constipation-predominant IBS. Other symptoms often accompany IBS, such as abdominal pain that improves after a bowel movement, bloating, gas, and mucus in the stool. Intestinal infections caused by certain bacteria or parasites can also lead to stringy or narrow stools, alongside symptoms like nausea, vomiting, cramps, and fatigue.
More concerning causes of persistent narrow stools include colorectal cancer, especially in individuals over 50. A cancerous growth or polyp in the colon or rectum can physically narrow the passage, forcing stool to become thinner. Diverticulitis, an inflammation or infection of small pouches in the digestive tract, or inflammatory bowel diseases like Crohn’s disease or ulcerative colitis, can also cause inflammation or strictures (narrowing) in the intestines, leading to changes in stool caliber.
Anal stenosis is a rare condition where the anal canal narrows due to scarring. This narrowing, often from surgical hemorrhoid removal or chronic conditions, can result in painful, narrow stools and constipation.
When to Consult a Doctor
Seeking medical attention is advisable if narrow stools persist for more than a week, or if accompanied by other concerning symptoms. Persistent changes in bowel habits, such as new onset of chronic diarrhea or constipation, warrant evaluation. Rectal bleeding, especially if the blood is dark, mixed with the stool, or if significant, should prompt an immediate doctor’s visit.
Unexplained weight loss, severe or persistent abdominal pain, chronic fatigue, or a family history of colon cancer are additional red flags that necessitate prompt medical consultation. These symptoms, when combined with narrow stools, could indicate a more serious underlying condition requiring professional diagnosis and treatment. A healthcare provider can perform a thorough examination, which may include a digital rectal exam or anoscopy, to determine the cause and rule out serious conditions.