Hemorrhoids: Can Colonoscopy Misdiagnose Internal Issues?

Hemorrhoids discovered after colonoscopy?

Hello doctor, I recently underwent a colonoscopy because I noticed blood in my stool.
After the procedure, I was diagnosed with internal hemorrhoids.
I would like to ask if there is a possibility that the colonoscopy could have made an incorrect diagnosis, as hemorrhoids are typically located near the anus, while mine are in the rectum.
I found some information online stating that internal hemorrhoids are mostly located close to the anal canal, which makes me a bit anxious about whether there was a misdiagnosis.

1.
What is the accuracy of a colonoscopy?
2.
Can internal hemorrhoids be located in the rectum?
These are my main questions.
Thank you, and I hope the doctor can provide some answers.
I've been really worried about this lately.

Chen, 20~29 year old female. Ask Date: 2020/07/21

Dr. Ke Fangxu reply Surgery

There are two anatomical locations in the structure of the anus that need to be clarified.
The first is the anal glands, which are located at the junction of the anus and the external environment.
The second is the dentate line, which marks the boundary between the rectal mucosa and the anus.
The area between these two locations is referred to as the anal canal, where hemorrhoids can occur, consisting of a complex of vascular plexuses and connective tissue.
This area is located in the anal canal and is not related to the rectum.
The accuracy of colonoscopy should not be questioned, and at the age of 22, the likelihood of developing colorectal cancer is very low, so there is no need for excessive worry.

Reply Date: 2020/07/21

More Info

Understanding hemorrhoids and the diagnostic capabilities of colonoscopy is crucial for patients experiencing symptoms such as rectal bleeding. Hemorrhoids, which are swollen veins in the lower rectum and anus, can be classified into two main types: internal and external. Internal hemorrhoids are located inside the rectum and are typically not visible unless they prolapse outside the anal canal. External hemorrhoids, on the other hand, are located under the skin around the anus and can be seen or felt.

1. Accuracy of Colonoscopy: Colonoscopy is considered a highly accurate diagnostic tool for evaluating the lower gastrointestinal tract, including the rectum and colon. It allows for direct visualization of the mucosal lining and the ability to perform biopsies if necessary. The sensitivity of colonoscopy for detecting abnormalities, including hemorrhoids, polyps, and malignancies, is generally high, often exceeding 90%. However, like any medical procedure, it is not infallible. Factors such as the skill of the operator, the quality of bowel preparation, and the presence of overlapping conditions can affect the results. In some cases, internal hemorrhoids may be missed if they are not actively bleeding or if they are small and not protruding.

2. Location of Internal Hemorrhoids: It is indeed possible for internal hemorrhoids to be located higher up in the rectum, not just near the anal canal. While they are most commonly found within the lower rectum, they can extend further up. The classification of internal hemorrhoids is often based on their degree of prolapse rather than their exact location. For example, Grade I internal hemorrhoids do not prolapse, while Grade II may prolapse during straining but reduce spontaneously. Grade III hemorrhoids require manual reduction, and Grade IV are permanently prolapsed.

Given your concerns, it’s important to understand that the presence of internal hemorrhoids does not rule out other potential issues. If you are experiencing persistent symptoms such as rectal bleeding, it is advisable to follow up with your healthcare provider. They may recommend further evaluation, which could include repeat colonoscopy or other imaging studies, especially if there are changes in your symptoms or if new symptoms arise.

In summary, while colonoscopy is a reliable diagnostic tool, it is not without limitations. Internal hemorrhoids can indeed be located within the rectum, and their diagnosis can sometimes be complicated by other conditions. If you have lingering concerns or symptoms, do not hesitate to seek further medical advice. Your health and peace of mind are paramount, and addressing these issues with your healthcare provider can help clarify your situation and guide appropriate management.

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