Anorectal disease Flashcards
Anal cancer risk factors
Anoreceptive sex
Syphilis
Anal warts/cervical cancer (HPV)
Immunosuppression
Anal cancer pathology
Mainly SCC
Above pectinate line: columnar epithelium, lymph drainage to internal iliac nodes & portal venous drainage –> hepatic mets
Below pectinate line: squamous epithelium, lymph drainage to superficial inguinal nodes & caval venous drainage –> pulmonary mets
Colorectal/anal tumour presentation
Abdominal mass, abdominal pain, haemorrhage, perforation, fistula Right sided (proximal): more asymptomatic, iron deficiency anaemia/weight loss Left sided (distal): PR blood/mucus, altered bowel habit, tenesmus, obstruction/mass on PR Anal: bleeding, pain, changes in bowel habit, pruritis ani, masses/stricture
The role of anal sphincters in maintaining faecal continence
Runs from superior aspect of pelvic diaphragm to anus, normally collapsed
Internal anal sphincter: involuntary, surrounding upper 2/3 of anal canal
Tonic contraction stimulated by sympathetic fibres from superior rectal/hypogastric plexus
Parasympathetic fibres inhibit tonic contraction: contraction of puborectalis/external anal sphincter maintains continence
External anal sphincter surrounds the lower 2/3 of the anal canal: voluntary control, mediated by inferior rectal nerve (S4)
Haemorrhoids pathology
Anal cushions: smooth muscle with subepithelial anastomoses of rectal arteries/veins (3, 7, 11 o’clock from lithotomy position)
Haemarrhoids: prolapsed anal cushions
Arise due to breakdown of smooth muscle layer (muscularis mucosae)
Superior rectal vein drains into inferior mesenteric (portal) therefore anal cushion anastomoses are porto-caval anastomoses. In portal hypertension = ano-rectal varices
Haemorrhoids commonly arise in the absense of portal hypertension
Haemorrhoids aetiology
Mainly idiopathic
Increased anal tone (chronic constipation)
Factors that cause congestion of superior rectal veins (cardiac failure, pregnancy, rectal carcinoma, raised IAP)
Haemorrhoids classification
1st degree: confined to anal canal, do not prolapse
2nd degree: prolapse on defecation, reduce spontaneously
3rd degree: prolapse on defecation, manually reducible
4th degree: remain prolapsed at all times
Haemorrhoids symptoms
Rectal bleeding Prolapse Mucous discharge Pruritus ani Pain if piles become thrombosed
Haemorrhoids complications
Anaemia: severe/continued bleeding
Thrombosis: strangulated by anal sphincter –> venous return occluded –> swollen, purple, tense haemorrhoids (painful)
Thrombosed piles fibrose within 2-3w = spontaneous cure
Haemorrhoids investigation
Abdo exam: palpable masses/enlarged liver?
Rectal exam: any prolapse?
Proctoscopy/rigid sigmoidoscopy: visualise, assess for higher lesions
Colonoscopy/flexi-sigmoidoscopy: if more sinister pathology suspected
Rectal bleeding differentials
Haemorrhoids: most common Anal fissure: skin tag, tenderness Diverticulitis: LIF symptoms Rectal cancer: tenesmus, PR bleeding Colon cancer: blood mixed with stool Ulcerative colitis: abdo pain, urgency Crohn's: weight loss, chronic diarrhoea Massive upper GI bleed: malaena + haematemsis Trauma Ischaemic/infective colitis Angiodysplasia
Types of perianal infections
Anorectal abscesses: gut organisms, crohn’s, DM, malignancy
Pilonidal sinus: obstruction of natal cleft hair follicles/ingrown hair –> abscess formation/pilonidal sinus
Perianal warts
Anal fissure symptoms + O/E
Pain, worse on defecation, lasting for hrs afterwards
Associated constipation
Pruritis ani
Bleeding on defecation
O/E: midline longitudinal tear + mucosal tag
What are the causes of proctitis?
Crohn’s/UC
C. Diff
Where are anorectal abscesses located?
Perianal, Ischiorectal, Pelvirectal, Intersphincteric
Caused by E. coli or S. aureus
