GI: AAA, Appendicitis, SBO & LBO Flashcards
What diameter of the abdominal aorta defines an abdominal aortic aneurysm (AAA)?
> 3cm
Morality rate of a ruptured AAA?
80%
What diameter of the abdominal aorta is defined as a ‘significant risk of rupture’ and is treated as a time critical medical emergency?
> 5cm
Give some risk factors for AAA
- Male (more often and at a younger age than women)
- Increased age
- Smoking (& COPD)
- HTN
- FH of AAA
- Existing CVD
Risk of rupture in males vs females?
Despite AAA being more common in males, the risk of rupture is more common in females and can occur in aneurysms of a smaller diameter
Screening programme for AAA?
Current NHS screening programme is only for men.
Current NICE guidance is that ALL men over 65 be offered screening and all women over 70 with risk factors be offered screening for AAAs.
Do diabetics undergo AAA screening earlier?
No - diabetes mellitus does not confer a higher risk of developing a AAA or of it rupturing when diagnosed.
Who is AAA screening routinely offered to?
Men aged >65 y/o
What investigation is used for AAA screening?
US
When can AAA screening be considered in women?
In women aged >70y with risk factors
What aorta diameter is referred to a vascular team during screening?
> 3cm –> refer to vascular
> 5.5cm –> refer urgently
Symptoms of an AAA (not ruptured)?
- often asymptomatic
- pulsatile and expansile mass in the abdomen when palpated with both hands
what is investigation of choice in diagnosing AAA?
1st line: US.
CT angiogram gives a more detailed picture of the aneurysm and helps guide elective surgery to repair the aneurysm.
Classfication of an AAA:
a) normal
b) small aneurysm
b) medium aneurysm
d) large aneurysm
a) <3cm
b) 3-4.4 cm
c) 4.5-5.4 cm
d) >5.5 cm
Management of an AAA (not ruptured)?
1) Treat reversible risk factors (to reduce risk of progression):
- Stop smoking
- Healthy diet and exercise
- Optimising the management of hypertension, diabetes and hyperlipidaemia
2) Screening and surveillance programme (follow up scans)
3) Elective repair
How often should patients have follow up scans if they have an AAA of 3-4.4cm?
Yearly
How often should patients have follow up scans if they have an AAA of 4.5-5.4cm?
3 monthly
Who is an elective repair for AAA considered in?
1) Symptomatic aneurysm
2) Diameter growing >1cm per year
3) Diameter >5.5cm
What is involved in an elective surgical repair of an AAA?
Inserting an artificial “graft” into the section of the aorta affected by the aneurysm.
There are two methods for inserting the graft:
1) Open repair via a laparotomy
2) Endovascular aneurysm repair (EVAR) using a stent inserted via the femoral arteries
Driving rules for AAA?
1) Inform the DVLA if they have an aneurysm above 6cm
2) Stop driving if it is above 6.5cm
3) Stricter rules apply to drivers of heavy vehicles (e.g., bus or lorry drivers)
What size AAA must patients inform the DVLA?
> 6cm
Presentation of a ruptured AAA?
1) Pain:
- May be back or loin pain
- May be severe abdo pain that radiates to the back
2) CVS failure:
- Significant haemorrhage
- Progressive tachycarida & hypotension (shock) - poorly responsive to fluid resuscitation
3) Pulsatile and expansile mass in the abdomen
4) Distal ischaemia
5) Collapse, LOC & death
What is permissive hypotension?
The strategy of aiming for a lower than normal blood pressure when performing fluid resuscitation.
The theory is that increasing the blood pressure may increase blood loss.
What investigation is used to diagnose or exclude ruptured AAA in haemodynamically stable patients?
CT angiogram (gold standard imaging in patients with known AAA with suspected rupture)
Investigations in suspected ruptured AAA?
1) Imaging (CT angiogram)
2) FBC: to ascertain whether there is a low platelet count which may require transfusion and affect surgical bleeding risk.
3) U&Es: if treated endovascularly the patient will be exposed to large volumes of contrast and pre-existing renal failure may contraindicate this
4) Coagulation screen
5) Blood grouping
Differentials for an AAA?
- Back pain
- Acute pancreatitis: measure serum amylase or lipase in all patients presenting with acute abdominal or upper back pain.
- Renal colic: consider abdo US
- Lower limb ischaemia
What are the 3 main treatment options for ruptured AAAs?
1) open surgical repair
2) endovascular aneurysm repair (EVAR)
3) palliative care
What are classed as ‘low rupture risk’ AAAs?
Asymptomatic, aortic diameter < 5.5cm (i.e. small and medium aneurysms)
What is acute appendicitis typically caused by?
It is typically caused by infection secondary to luminal obstruction with faecolith, impacted normal stool, lymphoid hyperplasia or a tumour.
What is the most common abdominal surgical emergency worldwide?
Acute appendicitis
What is the appendix? What does it arise from?
a small, thin tube arising from the caecum.
Pathophysiology of appendicitis?
1) Pathogens can get trapped due to obstruction at the point where the appendix meets the bowel.
2) Trapping of pathogens leads to infection and inflammation.
3) The inflammation may proceed to gangrene and rupture.
4) When the appendix ruptures, faecal contents and infective material are released into the peritoneal cavity.
5) This leads to peritonitis, which is inflammation of the peritoneal lining.
Risk factors for appendicitis?
1) Male sex
2) Age 10-20 y/o
3) Positive FH
4) Caucasian
What are 4 causes of luminal obstruction of the appendix (that can lead to appendicitis)?
1) Faecaliths
2) Lymphoid hyperplasia
3) Foreign bodies
4) Tumours
What is the most common cause of luminal obstruction causing appendicitis?
Faecaliths
What are faecalith?
Hardened faecal matter
4 most common bacteria implicated in appendicitis?
1) E. coli
2) Bacteriodes
3) Streptococcus
4) Enterobacter species
Clinical features of appendicitis?
1) Abdominal pain:
- central that localises to the RIF
- tenderness at McBurney’s point
- pain worse on coughing or going over speed bumps
2) N&V:
- once or twice but marked and persistent vomiting is unusual
3) Low grade fever: usually 37.5-38 degrees
4) Loss of appetite (anorexia)
5) Rovsing’s sign
6) Guarding on abdominal palpation
7) Rebound tenderness in the RIF
8) Percussion tenderness
9) Psoas sign
What is Rovsing’s sign?
Palpation of the left iliac fossa causes pain in the RIF)
What is MucBurney’s point?
Tefers to a specific area one third of the distance from the anterior superior iliac spine (ASIS) to the umbilicus.
What is rebound tenderness?
Increased pain when suddenly releasing the pressure of deep palpation
What is percussion tenderness?
pain and tenderness when percussing the abdomen
What does rebound tenderness & percussion tenderness indicate?
Peritonitis: potentially indicating a ruptured appendix.
What is psoas sign?
pain on extending hip (if retrocaecal appendix)
How is a diagnosis of appendicitis typically made?
Raised inflammatory markers + compatible history and examination findings
Other potential investigations in appendicitis?
1) Inflammatory markers
2) CT scan: can be useful in confirming the diagnosis, particularly where another diagnosis is more likely.
3) US scan: often used in female patients to exclude ovarian and gynaecological pathology (or in children where CT scan is less appropriate)
4) Urine analysis: exclude pregnancy in women, renal colic and urinary tract infection
When a patient has a clinical presentation suggestive of appendicitis, but investigations are negative, what is the next investigation?
Perform a diagnostic laparoscopy: to visualise the appendix directly.
Key differentials of appendicitis?
Gynae:
1) Ectopic pregnancy
2) Ovarian cysts
3) Ovarian torsion
4) PID
GI:
1) Mesenteric adenitis
2) Meckel’s diverticulum
3) IBD
4) Acute cholecystitis
Urology:
1) Testicular torsion
2) Ureteric stones
3) UTI
Important test in any female of reproductive age presenting with abdo pain?
Pregnancy test
What investigation can be used to differentiate between appendicitis and gynaecological conditions?
US scan
Similarities & differences between appendicitis and ectopic pregnancy?
Similarities: both can cause right iliac fossa pain, nausea/vomiting and fever
Differences: ectopic pregnancies typically present with a 6-8 week history of amenorrhoea with or without vaginal bleeding and a positive pregnancy test
Similarities & differences between appendicitis and ovarian torsion?
Similarities: both can cause right iliac fossa pain and nausea and vomiting
Differences: a palpable adnexal mass is felt in 50-70% of cases of ovarian torsion
Similarities & differences between appendicitis and acute mesenteric adenitis?
Similarities: both can cause lower abdominal pain with guarding
Differences: mesenteric adenitis typically occurs in children after a viral upper respiratory tract infection and it does not cause localised tenderness
Who does mesenteric adenitis typically affect?
children and young adults under 20 years old.
What does mesenteric adenitis typically follow?
Viral URTI or tonsilitis
Similarities & differences between appendicitis and meckel’s diverticulitis?
Similarities: both can cause periumbilical pain which localises to the right iliac fossa and peritonitis
Differences: Meckel’s diverticulitis is clinically indistinguishable from acute appendicitis and is often identified when a normal appendix is found during laparoscopic appendicectomy
What is Meckel’s diverticulum?
Meckel’s diverticulum is a malformation of the distal ileum that occurs in around 2% of the population.
It is usually asymptomatic and does not require any treatment. However, it can bleed, become inflamed, rupture or cause a volvulus or intussusception.
What is mesenteric adenitis?
Mesenteric adenitis describes inflamed abdominal lymph nodes.
What is an appendix mass?
An appendix mass occurs when the omentum surrounds and sticks to the inflamed appendix, forming a mass in the right iliac fossa.
Management of an appendix mass?
This is typically managed conservatively with supportive treatment and antibiotics, followed by appendicectomy once the acute condition has resolved.
Management of acute appendicitis?
1) emergency admission under surgical team
2) appendicectomy (typically done laparoscopically)
3) if perforation: copious abdominal lavage.
What are some complications of appendicitis?
1) Perforation
2) Abscess formation
3) Phlegmon
4) Peritonitis
5) Post op complications
6) Sepsis
What is a phlegmon?
A phlegmon is an inflammatory mass formed by a localized infection and oedema, often seen in the early stages of appendiceal perforation.
It can cause localized tenderness, and fever.
Signs of peritonitis?
severe abdominal pain, tenderness, guarding, and fever.
Management of peritonitis?
Prompt surgical intervention (appendectomy and peritoneal lavage), intravenous antibiotics, and supportive care, including fluid resuscitation and analgesia.
Examples of post appendicectomy complications?
- Bleeding, infection, pain and scars
- Damage to bowel, bladder or other organs
- Removal of a normal appendix
- Anaesthetic risks
- Venous thromboembolism (deep vein thrombosis or pulmonary embolism)