what are the causes of anal fistula? and what do most start off as?
start as perianal abscess: sepsis in anal gland - force out through canal to perianal skin or vaginal skin
what is the difference between a low and high anal fistula?
low: fistula does not cross the sphincter muscles above the dentate line
high: fistula does cross the sphincter muscles above the dentate line
what are the symptoms and signs of acute perianal abscess?
rapid onset perianal pain
skin: swollen, red
systemic: fever, tachycardia
what investigations need to be done for anal fistula?
1. PR, perineum
2. EUA - probe through external opening of fistula to identify the tract and internal opening
3. end anal ultrasound with H202 if cant find tract with EUA
5. flexi sig: if suspect colorectal DISEASE e.g. crohns
treatment of anal fistula
medical: antibiotics, anti inflame (if IBD)
surgical: drain acute sepsis
low fistula: lay OPEN track by putting metal probe into fistula and cut through tissue onto probe
then remove all granulation tissue, allow to heal SPONTANEOUSLY (secondary intention) = FISTULOTOMY
high fistula: SETON - large silk suture passed through fistula track and tied off on outside. TIGHTEN every 2 weeks so it cuts through to surface, with fistula healing by SCAR tissue behind it. cant lay open high fistula as will damage sphincters
what is goodsall's rule about anal fistula?
it determines the path of the fistula track between openings
if anterior external opening: means fistula runs directly in a straight line into anal canal
if posterior external opening: the internal opening is always at 6o'clock i.e. it curves to the posterior midline of the canal
what are haemorrhoids?
spongy vascular cushions which line the anus and contribute to anal closure at 3, 7, 11 which are attached by smooth muscle and elastic tissue but are prone to displacement and disruption and can protrude to form piles
what factors make haemorrhoids protrude?
effect of gravity (our erect posture)
increased anal tone
effects of straining at stool due to constipation
all make the vascular cushions bulky and loose and so protrude to make piles
what colour is bleeding from piles and why?
bright red, as blood loss is from capillaries of the underlying lamina propria.
why are haemorrhoids generally painless, and when can they become painful?
painless: no sensory fibres above dentate line (squamomucosal junction)
painful: if they thrombose when they protrude and are gripped by the anal sphincter, blocking venous return
what are the causes of haemorrhoids
constipation with prolonged straining
congestion from a pelvic tumour, pregnancy, CCF, portal hypertension
differential anal pain
where are piles located and why?
3, 7, 11 oclock lithotomy position
this is where the superior rectal vein branches enter the muscle
why is having piles sometimes a vicious cycle?
the vascular cushions protrude through a TIGHT anus
become more congested
so hypertrophy again to protrude again more READILY
the protrusions then strangulate as tight anus
what is the classification of haemorrhoids
1st degree: remain in rectum
2nd degree: prolapse through anus on defaecation but spontaneously reduce
3rd degree: prolapse through anus on defaecation but need manual digital reduction
4th degree: remain persistently prolapsed
what may a patient with haemorrhoids complain of?
bright red rectal bleeding, coating stools or dripping into pain after defaecation
mild incontinence of flatus as there is imperfect closure of anal cushions
what actions needs to be taken in any rectal bleeding?
sigmoidoscopy: rectal pathology up to rectosigmoid junction
what is the treatment of haemorrhoids?
conservative: stool softener
inject sclerosant: 5% phenol in almond oil injected into pile above dentate line. this shrinks the H and causes scar formation SE: impotence, prostatitis
rubber band ligation: SE bleeding, infection. cheap but needs skill
Infra red coagulation: coagulates vessels and tethers mucosa to subcut tissue
haemorroidectomy: excision of piles and ligation of vascular pedicles. day case may need 2 wks off work. SE haemorrhage or stenosis
pre-op: 1 wks lactulose and metronidazole reduces pain and time off work
what are the complications of haemorrhoids?
what is the differential diagnosis of haemorrhoids?
perianal haematoma: rupture of small vein that drains anus, may see blue tinge under skin
anal fissure: tear in mucosa of anal canal
which chromosome is the AFP gene on? and what type of inheritance?
how is Peutz-Jeghers syndrome recognised clinically?
pigmented lesions on lips
what sort of antibiotic use do you worry about fungal infections?
PROLONGED antibiotic use (not prophylaxis)
name a contraindication to internal drainage of pancreatic pseudocyst
what clinical feature is present in over 75% of patients with pancreatic pseudocyst?
palpable abdo mass
what are the complications of acute pyelonephritis which doesn't improve with antibiotics? how to Ix and Rx this?
obstructed infected kidney: pyonephrosis
Ix: IVU or US
Rx: urgent nephrostomy drainage
what would manometry of achalasia show?
high pressure non relaxing LOS
what can cause diverticula to become inflamed?
what are the complications of diverticular disease? and how to treat them?
1 diverticulitis: altered bowel habit LIF colic, pyrexa, high WCC, high CRP/ESR, localised or generalised peritonism. bed rest, NBM, iv fluids, analgesia, antibiotics
2 perforation: ileum, peritonitis +/- shock. may need laparotomy Hartmann's (temporary colostomy and partial colectomy).
3 form fistulae into adjacent structures: enterocolic, colovaginal, colovesical (pneumaturia, intractable UTI). Rx: colonic resection
4 bleed: sudden and painLESS. bleeding stops with berets. may need transfusion. Rx: embolisation/colonic resection after locate bleeding points by angio/colonoscopy. diathermy and local adrenaline injection prevent need for surgery
5 abscess: swinging fever, high WCC, may have localising signs. Rx: antibiotics, US drainage
if crohn's disease is suspected what are the 2 first investigations needed to be done?
which patients are more prone to diverticular disease at an early age?
what is thought to cause diverticula and how?
low fibre: leads to high intraluminal pressures which force mucosa to herniate through muscle layers of the gut at weak points,
adjacent to PENETRATING VESSELS
where do diverticula occur?
why are diverticula prone to perforation?
muscle atrophy so no muscular layer
what is the differential for bright red PR bleed in elderly?
angiodysplasia: submucosal AVM. but most in right colon. do mesenteric angiography to diagnose angiodysplasia as it shows early filling at the site of lesion, then extravasation. do therapeutic embolisation during active bleeding.