Giới thiệu
Hemorrhoids_Disease Background 1Hemorrhoids are naturally occurring vascular structures located within the submucosa of the anal canal, consisting of loose connective tissue, smooth muscle (Treitz’s muscle) and blood vessels with numerous arteriovenous connections accounting for the bright red color of hemorrhoidal bleeding. These vascular cushions, which are believed to aid in stool continence by adding bulk to the anal canal, are typically located at three positions: Left lateral, right anterior and right posterior.
Dịch tễ học
Hemorrhoids affect approximately 4.4% of the global population, with the highest prevalence observed among individuals aged 45-65 years. It is a common condition that affects both men and women, though it is more prevalent in men. Several studies also found that people with higher socioeconomic status were the most frequently affected group due to dietary habits and physical inactivity.
Hemorrhoidal diseases are more common in the White than in the Black population. Based on a global prevalence study of hemorrhoids, the African region showed the highest point prevalence of hemorrhoidal disease, followed by the Americas, while the lowest prevalence was reported in Southeast Asia.
Sinh lý bệnh
Hemorrhoids are associated with conditions that increase intra-abdominal pressure (patients with ascites, an enlarged prostate or urethral stricture, chronic obstructive pulmonary disease [COPD], space-occupying intraabdominal lesion [eg ovarian tumor, large rectosigmoid carcinoma], pregnancy), leading to impaired venous return from the hemorrhoidal veins and a subsequent pathologic enlargement of the vascular cushions that results in symptomatic hemorrhoids. The passage of hard stools from a low-fiber diet can cause local tissue trauma, leading to bleeding. The Fibers of Treitz’s muscle that normally support the hemorrhoidal tissue may become weakened with advanced age, contributing to hemorrhoidal prolapse.
Yếu tố nguy cơ
Hemorrhoidal disease is frequently associated with several risk factors, that include a low-fiber diet, chronic constipation or diarrhea, delayed bowel movements, inadequate hydration, family history, pregnancy, lack of physical activity, obesity, spinal cord injuries, and prolonged straining during defecation. Prolonged straining during bowel movements, obesity, pregnancy, and a sedentary lifestyle contribute to increased pressure in the hemorrhoidal veins, leading to swelling and inflammation, while a low-fiber diet and chronic constipation further increase the risk of hemorrhoid development.
Phân loại
Hemorrhoids_Disease Background 2External and Internal Hemorrhoids
Hemorrhoids are classified according to their location relative to the dentate line.
External Hemorrhoids
External hemorrhoids are located closer to the anal verge and are covered with squamous epithelium. These produce symptoms only when thrombosed or when they give rise to large skin tags, which make hygiene difficult. The common symptoms are anal pain of acute onset and a palpable lump in the perianal area with itching and discomfort during thrombosis. Thrombosed external hemorrhoids may present as painful non-reducible lumps at the anal verge.
Internal Hemorrhoids
Internal hemorrhoids originate above the dentate line and are covered with rectal or transitional mucosa. These do not cause cutaneous pain, though thrombosed or strangulated internal hemorrhoids may cause severe pain. The prominent symptom is painless bleeding during defecation, but patients may also complain of itching, burning, moisture, swelling, prolapse, pain, difficulty with perianal hygiene, and the feeling of sitting on a foreign object. Prolapse of internal hemorrhoids may cause bleeding, mucus discharge, fecal soiling and anal pruritus. With internally prolapsing internal hemorrhoids, patients may describe a sensation of fullness, an urge to defecate or a sensation of incomplete defecation while with complete prolapse, patients may complain of a mass or lump, soiling or wetness.