General - small bowel disease Flashcards
Hernia
Defined as the protrusion of part/whole of an organ or tissue through the wall of the cavity that normally contains it
Epigastric hernia
Occurs in the upper midline through the fibres of the linea alba
Typically secondary to raised chronic intra-abdominal pressure eg. obesity, pregnancy/ascites
Relatively common, mostly affecting middle-aged men
Typically asymptomatic, but may present as a midline mass that disappear when lying on the back
Paraumbilical hernia
Herniation through the linea alba around the umbilical region
Typically secondary to raised chronic intra-abdominal pressure & present as a lump around the umbilical region
Generally they contain pre-peritoneal fat although they can occasionally contain bowel
Spigelian hernia
Rare form of abdominal hernia that occurs at the semilunar line (the tendinous lateral border of the rectus) around the level of the arcuate line
Clinically, they present as a small tender mass at the lower lateral edge of the rectus abdominus
High risk of strangulation and so should be repaired urgently
Obturator hernia
Hernia of the pelvic floor, occurring through the obturator foramen, into the obturator canal
More common in women, typically in elderly patients
Classically present with a mass in the upper medial thigh & patient will often have features of small bowel obstruction
~50% of cases – compression of the obturator nerve = positive Howship-Romberg sign (hip and knee pain exacerbated by thigh extension, medial rotation and abduction)
Littre’s hernia
Herniation of a Meckel’s diverticulum
Most commonly occurs in the inguinal canal and many will become strangulated
Lumbar hernia
Rare posterior hernias, that typically occur spontaneously/iatrogenically following surgery
Present as a posterior mass, often with associated back pain
Richter’s hernia
Can occur at any other sites and is a partial herniation of bowel, whereby the anti-mesenteric border becomes strangulated -> only part of the lumen of the bowel is within the hernial sac
Patients will present with a tender irreducible mass at the herniating orifice and have varying levels of obstruction (often surgical emergencies)
Angiodysplasia
Most common vascular abnormality of the GI tract
Caused by the formation of arteriovenous malformations between previously healthy blood vessels
Most commonly in the caecum and ascending colon
Angiodysplasia pathophysiology
1) Acquired – begins as reduced submucosal venous drainage in the colon due to chronic and intermittent contraction of the colon, giving rise to dilated and tortuous veins, results in the loss of pre-capillary sphincter competency -> causes the formation of small arterio-venous communications
2) Congenital
Angiodysplasia clinical features
Asymptomatic
Painless occult PR bleeding
Acute haemorrhage
Degree of symptoms will depend upon the location and severity of the malformation (upper GI = haematemesis or melena, lower GI = more likely to present as haematochezia)
Angiodysplasia investigations
Lab tests – blood tests, group and save/crossmatch
Imaging – upper GI endoscopy and/or colonoscopy depending on the suspected site of bleeding
Wireless capsule endoscopy for small bowel bleeds
Overt angiodysplastic bleed – mesenteric angiography may be required to confirm the location of a lesion in order to plan for intervention as necessary
Angiodysplasia management
Patients admitted with angiodysplasia can be treated conservatively – bed-rest, IV fluid support, potential tranexamic acid
Persistent/severe cases:
1) Endoscopy – argon plasma coagulation
2) Mesenteric angiography – used for small bowel lesions that cannot be treated endoscopically
Surgical management – resection and anastomosis of the affected segment of bowel is necessary
Angiodysplasia complications
Mainly related to treatment – re-bleeding post therapy is common
Endoscopic techniques – bowel perforation
Mesenteric angiography – haematoma formation, arterial dissection, thrombosis & bowel ischaemia
Femoral hernia
Abdominal viscera/omentum passes through the femoral ring and into the potential space of the femoral canal
More common in women than men
Femoral hernia risk factors
Female
Pregnancy
Raised intra-abdominal pressure
Increasing age
Femoral hernia clinical features
Small lump in the groin
30% of femoral hernia cases will present as an emergency – obstruction/strangulation
Important to identify the exact location of the lump in the groin
- Femoral hernia: found infero-lateral to the pubic tubercle
- Inguinal hernia: found supero-medial to the pubic tubercle
Femoral hernia investigations
Radiological – ultrasound scanning, CT abdomen-pelvis
Femoral hernia management
Should be managed surgically, ideally within 2 weeks of presentation due to the high risk of strangulation
Two different approaches:
- Low approach: incision is made below the inguinal ligament
- High approach: incision is made above the inguinal ligament, preferred in an emergency
Operation involves reducing the hernia and then narrowing the femoral ring
Femoral hernia complications
Risk of strangulation
Obstruction
Gastroenteritis
Inflammation of the GI tract, usually considered infective in origin
Gastroenteritis risk factors
Poor food preparation
Immunocompromised
Poor personal hygiene
Gastroenteritis clinical features
Cramp-like abdominal pain
Diarrhoea
May be associated vomiting, night sweats & weight loss reported
Features from the history – bowel movements, affected family/friends, recent travel abroad, recent use of antibiotics within the previous four weeks
Gastroenteritis investigations
Not necessary for most cases, as the condition is usually self-limiting
Stool culture is often warranted, esp in cases with blood/mucus, patient is immunocompromised, severe/persistent
Gastroenteritis management
Rehydration, encouraging oral fluid intake where possible
Education to prevent future episodes
Exclusion from work is usually 48 hours
Gastroenteritis viruses
Norovirus – most common form of viral gastroenteritis in adults
Rotavirus – severe diarrhoea among infants and young children
Adenovirus – common cause of diarrhoea in children
Gastroenteritis bacteria
Campylobacter – gram negative bacillus, most common cause of food poisoning
E. Coli – gram negative bacillus, typically transmitted through contaminated foodstuffs
Salmonella – gram negative flagellated bacillus, transmitted through undercooked poultry/raw eggs
Shigella – gram negative bacillus, commonly acquired from contaminated dairy products and water
Gastroenteritis bacterial toxins
Toxins from bacteria often cause an acute onset of diarrhoea & vomiting and symptoms tend to last less than 24 hours, common bacterial toxins can arise from:
- Staphylococcus aureus: typically found in meat or dairy products
- Bacillus cereus: usually found in reheated rice, rapid-onset vomiting and abdominal cramps
- Clostridium perfringes: re-heating meat dishes
- Vibrio cholera: acquired most commonly from contaminated water supplies
Gastroenteritis parasites
More common in travellers’ diarrhoea
Cryptosporidium: self-limiting watery diarrhoea and abdominal cramps
Entamoeba histolytica: becomes acquired from the ingestion of food/water contaminated with faeces
Giardia intestinalis: transmitted through direct contact or faeco-oral route
Schistosoma: acquired through contaminated water
Hospital-acquired gastroenteritis
C. difficile, a gram positive organism that can develop following the use of broad-spectrum antibiotics
Produce large amounts of exotoxins A & B
Severe bloody diarrhoea and has the potential to develop into toxic megacolon
Investigation – stool culture and C. difficile toxin testing
Treatment – IV fluid rehydration and oral metronidazole
Non-infective causes gastroenteritis
Radiation colitis
Inflammatory bowel disease
Microscopic colitis
Chronic ischaemic colitis – compromise in blood supply to the colon
Inguinal hernia
Occurs when abdominal cavity contents enter into the inguinal canal
Most common type of hernia
Direct inguinal hernia
Bowel enters the inguinal canal ‘directly’ through a weakness in the posterior wall of the canal (Hesselbach’s triangle)
Most commonly in older patients, often secondary to abdominal wall laxity/significant increase in intra-abdominal pressure
Indirect inguinal hernia
Bowel enters the inguinal canal via the deep inguinal ring
Arise from incomplete closure of the processus vaginalis, an outpouching of peritoneum allowing for embryonic testicular descent -> usually deemed congenital in origin
Indirect inguinal hernia risk factors
Male gender
Increasing age
Raised intra-abdominal pressure
High BMI
Inguinal hernia clinical features
Lump in the groin, which will initially disappear with minimal pressure/when the patient lies down
Specific features
- Cough impulse
- Location: inguinal hernia appear superomedial to the pubic tubercle
- Reducible: lying down/with gentle pressure
Inguinal hernia investigations
Hernia is typically a clinical diagnosis
Ultrasound scan is recommended as first line imaging
Patients with features of obstruction/strangulation – CT imaging
Inguinal hernia management
Symptomatic inguinal hernia should be offered surgical intervention
Surgical intervention
- Hernia repairs can be performed via open repair/laparoscopic repair
- Open mesh repairs are preferred for those with primary inguinal hernias
- Laparoscopic approach: bilateral or recurrent inguinal hernias
Inguinal hernia complications
Incarceration
Strangulation
Obstruction
Following repair: haematoma/seroma formation, recurrence, chronic pain or damage to vas deferens/testicular vessels
Small bowel tumours
Most arise from the duodenum & less commonly arise from the jejunum
Small bowel neoplasms can be either benign/malignant:
- Benign tumours – typically adenomas
- Malignant tumours – adenocarcinomas/neuroendocrine tumours
Small bowel tumours pathophysiology
Believed to arise from pre-existing adenomas through a sequential accumulation of genetic abnormalities
Tumour suppressor gene p53 and the oncogene KRAS have been implicated in over 50% cases
Small bowel tumours risk factors
Non-modifiable – increasing age, Crohn’s disease, coeliac disease, certain genetic conditions
Modifiable – smoking, obesity, low fibre intake, high intake of red meats and alcohol excess
Small bowel tumours clinical features
Initially asymptomatic
Cause small bowel obstruction due to luminal narrowing, less commonly present with PR bleeding
Examination – abdominal mass, cachexia, jaundice, hepatomegaly, ascites
Small bowel tumours investigations
Blood tests – elevated CEA levels, elevated 5-HIAA
Imaging – upper Gi endoscopy, MRI enterography
Majority of patients present with features of bowel obstruction, often the diagnosis is made via CT imaging
PET-CT imaging is useful is metastatic disease is suspected
Small bowel tumours management
Any symptomatic benign small bowel tumour should be resected either endoscopically/through surgical resection
Adjuvant chemotherapy is likely required for lymph node positive disease
Chemotherapy for metastatic disease
