passmed Flashcards
(49 cards)
Ischaemia to lower GIT can cause what 3 conditions
- Acute mesenteric ischaemia
- Chronic mesenteric ischaemia
- Ischaemic Colitis
Bowel ischaemia: common predisposing factors
- incr age
- AF - esp Mes Isch
- Other causes of emboli - endocarditis, malignancy
- CVD RF - smoking, HTN, diabetes
- Cocaine - isch colitis sometimes seen in young pts after cocaine use
Bowel ischaemia: common features
- abdominal pain - in acute mesenteric ischaemia this is often of sudden onset, severe and out-of-keeping with physical exam findings
- rectal bleeding
- D
- F
- bloods typically show an elevated WBC assoc with a lactic acidosis
Acute mesenteric ischaemia cause, pres, Ix + Mx
CAUSE: typically caused by an EMBOLISM resulting in occlusion of an artery which supplies the SMALL BOWEL, for example the SMA. Classically patients have a hx of AF.
PRES: abdo pain is typically severe (morphine might not even help), of sudden onset and out-of-keeping with physical exam findings.
IX: AMI causes RAISED LACTATE = VBG = 1st line ix
MX: urgent surgery is usu req
-poor prognosis, especially if surgery delayed
Chronic mesenteric ischaemia
relatively rare clinical diagnosis due to it’s non-specific features and may be thought of as ‘intestinal angina’. Colickly, intermittent abdominal pain occurs.
Ischaemic Colitis: define, Ix, Mx
= ACUTE but TRANSIENT compromise in the blood flow to the LARGE BOWEL –> inflamm, ulceration and haemorrhage
-It is more likely to occur in ‘WATERSHED’ areas such as the splenic flexure that are located at the borders of the territory supplied by the superior and inferior mesenteric arteries.
IX: ‘THUMBPRINTING’ may be seen on AXR due to mucosal oedema/haemorrhage
MX: - usually supportive
- surgery may be required in a minority of cases if conservative measures fail.
- Indications would include generalised peritonitis, perforation or ongoing haemorrhage
HNPCC inheritance + mutations
ADom
- most common form of inherited colon cancer (also causes endometrial C)
- 90% dev C - often proximal colon
- mutations in DNA mismatch repair
- genes: MSH2 (60%), MLH1 (30%)
HNPCC what criteria to aid dx
Amsterdam Criteria:
- at least 3 fam members with colon c
- cases span at least 2 generations
- at least 1 case dx before 50Y
FAP inheritance + gene
rare ADom
- mutation in TSG = APC - Chromosome 5
- develop colon carcinoma from 100s of polyps (also duodenal T)
- variant of FAP = Gardners Syndrome (=polyps + osteomas of skull + mandible, retinal pigmentation, thyroid C + epidermal cysts on the skin
oesophageal C - adenocarcinoma
most common type in UK/US
location - LOWER THIRD - near gastrooesophageal jtn
RF: GORD, Barrets O, Smoking Achalasia, Obesity
oesophageal C - SCC
most common in developing world
location - UPPER 2/3 of oesophagus
RF: smoking, alcohol, achalasia, Plummer-Vinson Syndrome, diets rich in nitrosamines
oesophageal C - Mx
surgical resection = IVOR LEWIS TYPE OESOPHAGECTOMY (often with adjuvant chemo)
-biggest surgical challenge= anastomotic leak - with intrathoracic anastomosis –> mediastinitis
C.Diff – > pseudomembranous colitis causes, features + dx
G+ rod –> prod exotoxin –> PSM Colitis
- C.diff cause = clindamycin, 2nd/3rd gen cephalosporins PPIs
- feat: D, abdo pain, RAISED WCC, severe toxic megacolon
- dx: detect CDT in stool
- exposure: C.diff antigen positivity shows exposure to bacteria NOT current infection
C.DIff usual MX - V, F, V+M
1st - oral VANC 10d
2nd - oral fidaxomicin
3rd - oral vanc +/- IV metro
C.Diff recurrence Mx
recurs in 20%, incr to 50% after 2nd ep
- WITHIN 12w of sx resolution: oral fidaxomicin
- AFTER 12w of sx resolution: oral vanc OR fidaxomicin
C.Diff LIFE THREATENING Mx
- ORAL vancomycin AND IV metronidazole
- specialist advice - surgery may be considered
Hereditary Haemochromatosis blood findings - 2 RAISED 1 LOW - Chromsome 6 - A.REC
RAISED - transferrin saturation + ferritin
LOW - TIBC
NB. ferritin is v sensitive for IRON OVERLOAD
perianal fistulae define
inflamm tract bet anal canal + perianal skin
perianal fistulae gold std ix
MRI
-determine if there is an abscess and if fistula simple (low) or complex (high - passes through or above muscle layers)
perianal fistulae mx
(symptomatic) - MED - oral metronidazole , infliximab = anti - TNF
SURG - seton or fistulotomy
oesophageal disorders 1: Plummer Vinson syndrome TRIAD. (DIG) + Tx
- Dysphagia (secondary to oesophageal webs)
- IDA
- Glossitis
- Tx: IRON supplementation + DILATATION of WEBS
oesophageal disorders 2: Mallory Weiss Syndrome
severe vomiting –> painful mucosal lacerations at the gastrooesophageal jtn –> haematemesis
-common in alcoholics
oesophageal disorders 3: Boerhaave Syndrome
severe vomiting –> oesophageal RUPTURE
Ascites define
ABN ACCUMULATION of fluid in ABDOMEN
