Anal Haemorrhoids

Notes

Overview

Haemorrhoid Plexi are normal anatomical structures. However if they enlarge they can cause discomfort and pain. There are internal and external haemorrhoids. Internal are usually asymptomatic whereas external are often painful. The most common complications of hemorrhoids are heavy bleeding, chronic unremitting prolapse of mucosal tissue, strangulation, ulceration, and thrombosis.

Definition

Haemorrhoid plexus: venous drainage of the anal canal being at the haemorrhoid plexi. There is an internal and external haemorroid plexus. Dilatation of a haemorrhoid plexus causes haemorrhoids.
Haemorrhoids: collections of submucosal, fibrovascular, arteriovenous sinusoids that are part of the normal anorectum.

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Haemorrhoids Overview

Anorectal Anatomy

Overview

The hindgut makes up the last 1/3 of the transverse colon, the descending colon, sigmoid colon, rectum and part of the anus. The anal canal commences at the level where the rectum passes through the pelvic diaphragm and ends at the anal verge.

Layers of the rectum mucosa (from inner to outer)

Mucosa
Submucosa
Muscularis
- Outer longitudinal
- Inner Circular
Serous

Anal Sphincters

Internal sphincter
- Continuation of circular fibers of the colon. Thus, the internal sphincter is under autonomic control (Autonomic nervous system)
- Involuntary control
- Surrounds upper 3/4 of anal canal
External sphincter
- Voluntary control
- Surrounds entire length of anal canal
- Consists of three parts – subcutaneous, superficial and deep

Intersphincteric Plane

Between the external sphincter muscle laterally and the longitudinal muscle (inner sphincteric muscle) medially
Contains anal glands
The plance can be opened up surgically to provide access for operations on the sphincter muscles

Anal glands

Apocrine glands
Glands are occasionally infected and acts as a source of anal fistula

Pectinate line (dentate line)

Muco-cutaneous junction of anal canal
Divides anal canal into upper and lower lowers which differ in
- Blood supply
- Lymph drainage
- Nerve supply
Corresponds with position of anal valves
Situated at the middle of internal sphincter

PECTINATE LINE (DENTATE LINE)
Distinction	Above Pectinate line	Below Pectinate line
Embryological origin	Endoderm	Ectoderm
Epithelium	Colomnar epithelium	Stratified squamous epithelium
Lymph drainage	Internal iliac lymph node	Superficial inguinal lymph nodes
Artery	Superior rectal artery	Middle and inferior rectal arteries
Veins	Superior rectal veins	Middle and inferior rectal veins
Innervation	Inferior hypogastric plexus	Inferior rectal nerve
Haemorrhoids	Internal haemorrhoids	External haemorrhoids

Hilton’s Line also called while line/anocutaneous line indicates lower end of the internal sphincter. Ischiorectal abscess when communicates with anal canal usually opens at or below Hilton’s line.

Types

Internal Haemorrhoid Staging
I	Protudes slightly
II	Protrudes during straining and returns back to normal afterwards
III	Protrudes out of the anal canal and is reducible
IV	Non reducible prolapse

Internal Haemorrhoid occur above the pectinate line and can prolapse out of the anal canal. This is a late stage and requires surgery.

External haemorrhoid occur below the pectinate line and can form thrombus. A thrombosed external haemorrhoid is very painful but self resolves after 2 weeks. They can leave behind skin tags.

Risk Factors

Clinical Manifestation

Patients who present with any symptoms related to the anorectum need to be carefully evaluated to determine the cause. The most common manifestation of hemorrhoids is painless rectal bleeding associated with bowel movement, described by patients as blood drips into toilet bowl.

Internal Haemorrhoids

Usually not painful even if prolapsed or thrombosed because they occur above the dentate line
Painless rectal bleeding
Aching after a bowel movement
Fullness or discomfort feeling

External Haemorrhoids

Occur below the dentate line and so causes pain
Pain on defecation
Rectal bleeding
Thrombosed vein (VERY PAINFUL!)

Think

Although external thrombosed haemorrhoids causes severe pain, the presence of severe pain raises the possibility of other conditions, including anal fissure, perirectal or perivaginal infection, abscess, and other inflammatory processes.

Remember

Commonest age of onset is young adulthood.

Remember

Typically haemorrhoids occur in the same location as the main anal blood vessels pedicles (described as 3, 7 and 11 o’clock positions as seen in the supine position.

Differential Diagnosis

More information on clinical presentation of per rectal bleeding.

Investigations

Flexible sigmoidoscopy or colonoscopy may be appropriate if there is concern about the cause of symptoms. During a these procedures, haemorrhoid band ligation and haemorrhoidectomy can be performed.

Diagnosis

Diagnosis is usually by rigid sigmoidoscopy and proctoscopy.

Treatment

General treatment

Avoidance of constipation and straining
Ingest a sufficient amount of insoluble fiber
Sufficient water to avoid constipation and straining

Medical treatment

Bulking or softener laxatives
Sitz bath can be used to clean the butock area.
Steroid cream – temporary relief of some symptoms
Pramoxine (anti-itching) – temporary relief of some symptoms

Surgical treatment

Rubber band ligation – Stage I, II, III
Photocoagulation – Stage I, II
Sclerotherapy – Stage I, II
Haemorrhoidectomy – Stage IV
Thrombectomy of External Hemorrhoid

Remember

Avoid constipation/straining. Do not give laxatives. Exercise, diet and drink plenty water are good recommendations.

Complications and Prognosis

Complications

Anaemia
Pain
Heavy bleeding
Chronic unremitting prolapse of mucosal tissue
Strangulation
Ulceration
Thrombosis

Prognosis

External haemorrhoids usually self limiting and patients live with existing lump. Banding is a good treatment option with good outcome.

References

Jacobs, D. (2014). Hemorrhoids. NEJM. 371(10). 944-951.
Lohsiriwat, V. (2012). Hemorrhoids: From basic pathophysiology to clinical managemen. World Journal of Gastroenterology. 18 (17). 2009-2017.