Thrombosed Hemorrhoid · What Is It, Causes, Diagnosis, Treatment, and More

Hemorrhoidal disease, most commonly known as hemorrhoids, arises from an abnormal distension of the hemorrhoidal veins that lie underneath the mucosa of the lower rectum and anus. Although the word “hemorrhoids” is frequently used to refer to hemorrhoidal disease, hemorrhoids are actually normal clusters of highly vascular structures, smooth muscle, and elastic connective tissue that form the anal cushions. Their main function is to protect the anal sphincter and help prevent incontinence when the abdominal pressure increases, such as when sneezing or coughing.  

In some individuals, these anal cushions can become swollen or protrude through the anal canal, leading to what is commonly known as hemorrhoids or piles. A thrombosed hemorrhoid occurs when a blood clot forms inside a hemorrhoidal vein, obstructing blood flow and causing a painful swelling of the anal tissues. Thrombosed hemorrhoids are not dangerous, but they can be very painful and cause rectal bleeding if they become ulcerated. 

There are two kinds of hemorrhoids: internal hemorrhoids, which develop in the lower rectum, above the dentate line, and external hemorrhoids, which develop on the verge of the anal canal, below the dentate line. Almost all thrombosed hemorrhoids are external, but thrombosis of internal hemorrhoids is also possible.  

Initially, hemorrhoidal disease can develop as a result of a combination of factors, including the weakening of the supportive connective tissue within the anal cushions, reduced blood flow to the perianal area, and increased intra-abdominal pressure.  

Risk factors associated with the development of hemorrhoids include a history of constipation, prolonged straining during bowel movements, heavy lifting, sitting for a long period of time, obesity, and pregnancy. Once hemorrhoids have developed, blood pooling within the blood vessels can contribute to the formation of a blood clot, resulting in thrombosis. 

Diagnosis of thrombosed external hemorrhoids can be suspected in individuals with a history of sudden intense pain in the anal region, along with the detection upon physical examination of a painful lump or swelling of the perianal tissues. Inspection of the anus will exclude the presence of a prolapsing internal hemorrhoid. A digital rectal exam may be performed to check for blood in the stool, as well as exclude the presence of a rectal mass or internal hemorrhoids. If the digital exam is inconclusive, the anal canal can be examined with the help of an anoscope, which is an illuminated speculum that can be used to visualize the lower rectum. Finally, if there’s clinical evidence of rectal bleeding, a colonoscopy or sigmoidoscopy may be performed to rule out other causes of bleeding, such as inflammatory bowel disease, colorectal polyps, or cancer.  

Treatment of thrombosed hemorrhoids is aimed at relieving the pain and speeding recovery time, as the body is generally able to reabsorb the blood clot even without treatment. Conservative measures like oral or topical pain relievers and warm water sitz baths several times a day are the preferred treatment in most cases. In addition, constipation or straining can be relieved by increasing fluid and dietary fiber intake, as well as taking fiber supplements and stool softeners, thus reducing the chance of developing hemorrhoids in the future. 

In individuals with severe pain, surgical excision of the blood clot may be recommended within the first 24–48 hours from onset. While surgical excision can provide rapid pain relief for severe cases, it's not as universally recommended as it used to be, as even minor procedures like incision and drainage may not always be effective and can have recurrence or healing issues. Most clinical guidelines now lean towards conservative management, even in early stages, unless the pain is very intense and significantly impairs quality of life. 

Surgical excision or drainage of the blood clot is a procedure that can entail significant risks, such as incomplete removal of the blood clot, uncontrollable bleeding, and infection of the perianal tissues, which is why it should always be performed by a trained clinician. Surgical excision or drainage of the blood clot begins by numbing the affected area with local anesthesia and then performing a circumferential incision to remove the clot.