General Surgery Flashcards
ASA Grade
The American Society of Anesthesiologists (ASA) grading system classifies the physical status of the patient for anaesthesia. Patients are given a grade to describe their current fitness prior to undergoing anaesthesia/surgery:
ASA I – normal healthy patient
ASA II – mild systemic disease
ASA III – severe systemic disease
ASA IV – severe systemic disease that constantly threatens life
ASA V – “moribund” and expected to die without the operation
ASA VI – declared brain-dead and undergoing an organ donation operation
E – this is used for emergency operations
Fasting before surgery
Patients undergo ‘fasting’ before surgery to ensure they have an empty stomach for the duration of their operation. The aim is to reduce the risk of reflux of food around the time of surgery (particularly during intubation and extubation), which subsequently can result in the patient aspirating their stomach contents into their lungs.
Fasting for an operation typically involves:
6 hours of no food or feeds before operation
2 hours no clear fluids (fully “nil by mouth”)
TOM TIP: When you assess an acutely unwell surgical patient, always consider whether there is any possibility they require emergency surgery. Acutely unwell surgical patients that potentially require emergency surgery are made nil by mouth and given maintenance IV fluids. Allowing them to eat and drink could have significant consequences if they need emergency surgery, and the anaesthetist and senior surgeon won’t be happy. This decision will often be reversed on the post-take ward round if the consultant or senior surgeon decides they are unlikely to need to go to theatre.
Medication changes and surgery
Follow local guidelines for medication alterations before and after an operation.
Anticoagulants need to be stopped before major surgery. The INR can be monitored in patients on warfarin to ensure it returns to normal before the operation. Warfarin can be rapidly reversed with vitamin K in acute scenarios. Treatment dose low molecular weight heparin or an unfractionated heparin infusion may be used to bridge the gap between stopping warfarin and surgery in higher-risk patients (e.g., mechanical heart valves or recent VTE), and stopped shortly before surgery depending on the risk of bleeding and thrombosis. DOACs (e.g., apixaban, rivaroxaban or dabigatran) are stopped 24-72 hours before surgery depending on the half-life, procedure and kidney function.
Oestrogen-containing contraception (e.g., the combined contraceptive pill) or hormone replacement therapy (e.g., in perimenopausal women) need to be stopped 4 weeks before surgery to reduce the risk of venous thromboembolism (NICE guidelines 2010).
Long-term corticosteroids, equivalent to more than 5mg of oral prednisolone, require additional management around the time of surgery. Surgery adds additional stress to the body, which normally increases steroid production. In patients on long-term steroids, there is adrenal suppression that prevents them from creating the extra steroids required to deal with this stress. Management involves:
Additional IV hydrocortisone at induction and for the immediate postoperative period (e.g., first 24 hours)
Doubling of their normal dose once they are eating and drinking for 24 – 72 hours depending on the operation
Diabetes and surgery
The stress of surgery increases blood sugar levels. However, fasting may lead to hypoglycaemia. In general, the risk of hypoglycaemia is greater than hyperglycaemia.
Certain oral anti-diabetic medications may need to be adjusted or omitted around surgery:
Sulfonylureas (e.g., gliclazide) can cause hypoglycaemia and are omitted until the patient is eating and drinking
Metformin is associated with lactic acidosis, particularly in patients with renal impairment
SGLT2 inhibitors (e.g., dapagliflozin) can cause diabetic ketoacidosis in dehydrated or acutely unwell patients
In patients on insulin going for surgery (follow the local policy):
Continue a lower dose (BNF recommends 80%) of their long-acting insulin
Stop short-acting insulin whilst fasting or not eating, until eating and drinking again
Have a variable rate insulin infusion alongside a glucose, sodium chloride and potassium infusion (“sliding-scale”) to carefully control their insulin, glucose and potassium balance
VTE prophylaxis and surgery
Every patient admitted to hospital should be assessed for their risk of venous thromboembolism (VTE). Surgery, particularly where the patient is likely to be immobilised (e.g., orthopaedic surgery), significantly increases the risk of venous thromboembolism. There are local and national policies on reducing the risk that involve:
Low molecular weight heparin (LMWH) such as enoxaparin
DOACs (e.g., apixaban or rivaroxaban) may be used as an alternative to LMWH
Intermittent pneumatic compression (inflating cuffs around the legs)
Anti-embolic compression stockings
Differential Diagnoses of Acute Abdominal Pain
It may be helpful to think of the causes as being related to pathology in the organs located in the area of the pain. Bear in mind the pain may not always be localised in the typical area, so keep an open mind for other possible differentials. This list is not exhaustive, and always keep your mind open to other possible differentials.
Generalised abdominal pain:
Peritonitis
Ruptured abdominal aortic aneurysm
Intestinal obstruction
Ischaemic colitis
Right upper quadrant pain:
Biliary colic
Acute cholecystitis
Acute cholangitis
Epigastric pain:
Acute gastritis
Peptic ulcer disease
Pancreatitis
Ruptured abdominal aortic aneurysm
Central abdominal pain:
Ruptured abdominal aortic aneurysm
Intestinal obstruction
Ischaemic colitis
Early stages of appendicitis
Right iliac fossa pain:
Acute appendicitis
Ectopic pregnancy
Ruptured ovarian cyst
Ovarian torsion
Meckel’s diverticulitis
Left iliac fossa pain:
Diverticulitis
Ectopic pregnancy
Ruptured ovarian cyst
Ovarian torsion
Suprapubic pain:
Lower urinary tract infection
Acute urinary retention
Pelvic inflammatory disease
Prostatitis
Loin to groin pain:
Renal colic (kidney stones)
Ruptured abdominal aortic aneurysm
Pyelonephritis
Testicular pain:
Testicular torsion
Epididymo-orchitis
Peritonitis
Peritonitis refers to inflammation of the peritoneum, the lining of the abdomen. The signs of peritonitis are:
Guarding – involuntary tensing of the abdominal wall muscles when palpated to protect the painful area below
Rigidity – involuntary persistent tightness / tensing of the abdominal wall muscles
Rebound tenderness – rapidly releasing pressure on the abdomen creates worse pain than the pressure itself
Coughing test – asking the patient to cough to see if it results in pain in the abdomen
Percussion tenderness – pain and tenderness when percussing the abdomen
Localised peritonitis is caused by underlying organ inflammation, for example, appendicitis or cholecystitis.
Generalised peritonitis may be caused by perforation of an abdominal organ (e.g., perforated duodenal ulcer or ruptured appendix) releasing the contents into the peritoneal cavity and causing generalised inflammation of the peritoneum.
Spontaneous bacterial peritonitis is associated with spontaneous infection of ascites in patients with liver disease. This is treated with broad-spectrum antibiotics and carries a poor prognosis.
Initial assessment of acute abdominal pain
Initial assessment of an acutely unwell patient is with an ABCDE approach, assessing and treating:
A – Airway: Ensure the patient’s airway is patent and secure.
B – Breathing: Assess the breathing, respiratory rate and oxygen saturations. Listen to the lungs. Provide oxygen if required.
C – Circulation: Assess the blood pressure, heart rate, heart sounds and perfusion (e.g., capillary refill time). Gain IV access (wide-bore cannulae are better), take bloods and provide an IV bolus of fluid if required.
D – Disability: Assess the consciousness level using AVPU or GCS scoring systems. Check the blood glucose level.
E – Exposure: Finish the full assessment, including examination of the abdomen.
TOM TIP: When asked “how would you manage this acute presentation?” in an exam or teaching session, the obvious and easy answer to start with is “I would start with an ABCDE approach”. This is a good answer because it shows you are considering the immediate assessment and stabilisation of the unwell patient ahead of jumping to more definitive management that would come after the initial assessment (such as “I would perform an immediate right hemicolectomy”). It is not such a good answer for patients that are not acutely unwell, so don’t use it in these scenarios, for example, if a GP supervisor asked how you would manage a patient presenting with a patch of psoriasis.
Investigating acute abdominal pain
The following investigations are useful for obtaining a diagnosis and preparing the patient for theatre.
Full blood count (FBC) gives an indication of bleeding (drop in Hb) and infection / inflammation (raised WBC).
Urea and electrolytes (U&Es) give an indication of electrolyte imbalance and kidney function (useful prior to CT scans, as they require a contrast injection that can damage kidneys).
Liver function tests (LFTs) give an indication of the state of the biliary and hepatic system.
C-reative protein (CRP) gives an indication of inflammation and infection.
Amylase gives an indication of inflammation of the pancreas in acute pancreatitis.
International normalised ratio (INR) gives an indication of the synthetic function of the liver and is essential in establishing their coagulation prior to procedures.
Serum calcium is required to score acute pancreatitis and for other reasons (e.g., clotting and cardiac function).
Serum human chorionic gonadotropin (hCG) or urine pregnancy test is essential in females of child bearing age.
Arterial blood gas (ABG) analysis will show the lactate (an indication of tissue ischaemia) and pO2 (used for scoring in acute pancreatitis).
Serum lactate gives an indication of tissue ischaemia. It is a product of anaerobic respiration and can also be raised in dehydration or hypoxia. Lactate is also available on an ABG result as mentioned above.
Group and save is essential prior to theatre in case the patient requires a blood transfusion.
Blood cultures if infection is suspected.
Abdominal x-ray can provide evidence of bowel obstruction by showing dilated bowel loops.
Erect chest x-ray can demonstrate air under the diaphragm when there is an intra-abdominal perforation. This is caused by air within the peritoneal cavity (pneumoperitoneum).
Abdominal ultrasound can be useful in checking for gallstones, biliary duct dilatation and gynaecological pathology.
CT scans are often required to identify the cause of an acute abdomen and determine correct management.
Managing acute abdominal pain
Initial management involves:
ABCDE assessment
Alert seniors of unwell patients: escalating to the registrar, consultant and critical care as required
Nil by mouth if surgery may be required or they have features of bowel obstruction
NG tube in cases of bowel obstruction
IV fluids if required for resuscitation or maintenance
IV antibiotics if infection is suspected
Analgesia as required for pain management
Arranging investigations as required (e.g., bloods, group and save and scans)
Venous thromboembolism risk assessment and prescription if indicated
Prescribing regular medication on the drug chart if they are being admitted (some may need to be withheld)
Patients being admitted to an acute surgical unit will usually be seen by a junior doctor, then reviewed by the surgical registrar if required. A consultant will then review that patient on the post-take ward round, creating a management plan that is then carried out by the junior doctors. This may involve further investigations, preparations for surgery or discharge depending on the presentation.
Further management steps if the patient requires surgery:
Taking consent for surgery (by someone suitably qualified)
Review by an anaesthetist
Putting on the theatre list
Crossmatch units of blood if required
Appendicitis
Appendicitis is inflammation of the appendix. The peak incidence of appendicitis is in patients aged 10 to 20 years. It can occur at any age but is less common in young children and adults over 50 years.
Pathophysiology of appendicitis
The appendix is a small, thin tube arising from the caecum. It is located at the point where the three teniae coli meet (the teniae coli are longitudinal muscles that run the length of the large intestine). There is a single opening to the appendix that connects it to the bowel, and it leads to a dead end.
Pathogens can get trapped due to obstruction at the point where the appendix meets the bowel. Trapping of pathogens leads to infection and inflammation. The inflammation may proceed to gangrene and rupture. When the appendix ruptures, faecal contents and infective material are released into the peritoneal cavity. This leads to peritonitis, which is inflammation of the peritoneal lining.
Signs and symptoms of appendicitis
The key presenting feature of appendicitis is abdominal pain. This typically starts as central abdominal pain that moves down to the right iliac fossa (RIF) within the first 24 hours, eventually becoming localised in the RIF. On palpation of the abdomen, there is tenderness at McBurney’s point. McBurney’s point refers to a specific area one third of the distance from the anterior superior iliac spine (ASIS) to the umbilicus.
Other classic features are:
Loss of appetite (anorexia)
Nausea and vomiting
Low-grade fever
Rovsing’s sign (palpation of the left iliac fossa causes pain in the RIF)
Guarding on abdominal palpation
Rebound tenderness in the RIF (increased pain when suddenly releasing the pressure of deep palpation)
Percussion tenderness (pain and tenderness when percussing the abdomen)
Rebound tenderness and percussion tenderness suggest peritonitis, potentially indicating a ruptured appendix.
Diagnosing appendicitis
Diagnosis is based on the clinical presentation and raised inflammatory markers. Performing a CT scan can be useful in confirming the diagnosis, particularly where another diagnosis is more likely. An ultrasound scan is often used in female patients to exclude ovarian and gynaecological pathology. Ultrasound can also be useful in children, where a CT scan is less appropriate due to the dose of radiation.
Appendicitis is mostly a clinical diagnosis (meaning it is based on signs and symptoms rather than diagnostic tests). Where the diagnosis is unclear, a period of observation may be used, with repeated examinations over time to see whether the symptoms resolve or worsen.
When a patient has a clinical presentation suggestive of appendicitis, but investigations are negative, the next step is to perform a diagnostic laparoscopy to visualise the appendix directly. The surgeon can proceed to an appendicectomy during the same procedure, if indicated.
Differential diagnoses to appendicitis
Ectopic Pregnancy
Consider ectopic pregnancy in females of childbearing age. This is a gynaecological emergency with a relatively high mortality if mismanaged. A serum or urine human chorionic gonadotropin (hCG) to exclude pregnancy is essential.
Ovarian Cysts
Ovarian cysts can cause pelvic and iliac fossa pain, particularly with rupture or torsion.
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.
Mesenteric Adenitis
Mesenteric adenitis describes inflamed abdominal lymph nodes. It presents with abdominal pain, usually in younger children, and is often associated with tonsillitis or an upper respiratory tract infection. No specific treatment is required.
TOM TIP: When seeing females of child-bearing age assume they are pregnant until proven otherwise with a pregnancy test. This is especially important in patients with abdominal pain (where ectopic pregnancy is a key differential), or where you are requesting x-rays or CT scans. Serum HCG is typically part of the normal abdominal pain blood panel in A&E.
Appendix Mass
An appendix mass occurs when the omentum surrounds and sticks to the inflamed appendix, forming a mass in the right iliac fossa. This is typically managed conservatively with supportive treatment and antibiotics, followed by appendicectomy once the acute condition has resolved.
Managing appendicitis
Patients with suspected appendicitis need emergency admission to hospital under the surgical team.
Removal of the inflamed appendix (appendicectomy) is the definitive management for acute appendicitis. Laparoscopic surgery is associated with fewer risks and faster recovery compared to open surgery.
Complications of appendicectomy
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)
TOM TIP: Older children, for example, those aged above 10 years, will often be managed by adult general surgical teams at local hospitals, provided there is a paediatric department in the hospital. This means you may end up visiting the paediatrics ward whilst on your adult surgery rotations. It is worth making friends with paediatric doctors and nurses, who can be very helpful if you are unsure about pain relief or IV fluids prescriptions in children, as this is quite different to adults.
Bowel Obstruction
A bowel obstruction refers to when the passage of food, fluids and gas, through the intestines becomes blocked. Small bowel obstruction is more common than large bowel obstruction. Obstruction results in a build up of gas and faecal matter proximal to the obstruction (before the obstruction). This causes back-pressure, resulting in vomiting and dilatation of the intestines proximal to the obstruction. Bowel obstruction is a surgical emergency.
The gastrointestinal tract secretes fluid that is later absorbed in the colon. When there is an obstruction, and fluid cannot reach the colon, it cannot be reabsorbed. As a result, there is fluid loss from the intravascular space into the gastrointestinal tract. This leads to hypovolaemia and shock. This abnormal loss of fluid is referred to as third-spacing. The higher up the intestine the obstruction, the greater the fluid losses as there is less bowel over which the fluid can be reabsorbed.
Causes of bowel obstruction
The “big three” causes account for around 90% of cases:
Adhesions (small bowel)
Hernias (small bowel)
Malignancy (large bowel)
Other causes include:
Volvulus (large bowel)
Diverticular disease
Strictures (e.g., secondary to Crohn’s disease)
Intussusception (in young children aged 6 months to 2 years)
TOM TIP: Learn to recite the “big three” causes of obstruction without any hesitation. These are the three causes of bowel obstruction you should produce if asked on a ward round or in an OSCE examination. When patients present with symptoms of bowel obstruction, don’t just think about obstruction, but also consider what the cause of the obstruction would be. Ask about hernias, change in bowel habit, weight loss and PR bleeding (bowel cancer) and about previous abdominal surgery that may have resulted in adhesions.
Adhesions
Adhesions are pieces of scar tissue that bind the abdominal contents together. They can cause kinking or squeezing of the bowel, leading to obstruction. Adhesions typically cause obstruction in the small bowel, rather than the large bowel.
The main causes of intestinal adhesions are:
Abdominal or pelvic surgery (particularly open surgery)
Peritonitis
Abdominal or pelvic infections (e.g., pelvic inflammatory disease)
Endometriosis
Less commonly, they can be congenital or secondary to radiotherapy treatment.
Closed-loop obstruction
Closed-loop obstruction describes a situation where there are two points of obstruction along the bowel; meaning that there is a middle section sandwiched between two points of obstruction. This might happen with:
Adhesions that compress two areas of bowel
Hernias that isolate a section of bowel blocking either end
Volvulus where the twist isolates a section of intestine
A single point of obstruction in the large bowel, with an ileocaecal valve that is competent
A competent ileocaecal valve does not allow any movement back into the ileum from the caecum. When there is a large bowel obstruction and a competent ileocaecal valve, a section of bowel becomes isolated and the contents cannot flow in either direction.
The contents of a “closed-loop” section of bowel do not have an open end where they can drain and decompress. Therefore, the closed-loop section will inevitably continue to expand, leading to ischaemia and perforation. Closed-loop obstruction requires emergency surgery.
Presentation of bowel obstruction
The key features of bowel obstruction are:
Vomiting (particularly green bilious vomiting)
Abdominal distention
Diffuse abdominal pain
Absolute constipation and lack of flatulence
“Tinkling” bowel sounds may be heard in early bowel obstruction
Abdominal X-ray of bowel obstruction
The key x-ray finding in bowel obstruction is distended loops of bowel.
The upper limits of the normal diameter of bowel are:
3 cm small bowel
6 cm colon
9 cm caecum
Valvulae conniventes are present in the small bowel and are mucosal folds that form lines extending the full width of the bowel. These are seen on an abdominal x-ray as lines across the entire width of the bowel.
Haustra are like pouches formed by the muscles in the walls of the large bowel. They form lines that do not extend the full width of the bowel. These are seen on an abdominal x-ray as lines that extend only part of the way across the bowel.
Initial management of bowel obstruction
As with any unwell patient, start with an ABCDE approach. Patients with bowel obstruction may be haemodynamically unstable and require urgent intervention if they have developed:
Hypovolaemic shock due to fluid stuck in the bowel rather than the intravascular space (third-spacing)
Bowel ischaemia
Bowel perforation
Sepsis
A full set of bloods are required, as with any acute abdomen. Key things to look out for with bowel obstruction are:
Electrolyte imbalances (U&Es)
Metabolic alkalosis due to vomiting stomach acid (venous blood gas)
Bowel ischaemia (raised lactate – either on a venous blood gas or laboratory sample)
The initial management of bowel obstruction is casually described as “drip and suck”:
Nil by mouth (don’t put food or fluids in if there is a blockage)
IV fluids to hydrate the patient and correct electrolyte imbalances
NG tube with free drainage to allow stomach contents to freely drain and reduce the risk of vomiting and aspiration
Abdominal x-ray may be the initial imaging investigation. However, depending on the signs and symptoms, this may be skipped, and the patient sent straight for a CT scan.
Erect chest x-ray can demonstrate air under the diaphragm when there is an intra-abdominal perforation.
A contrast abdominal CT scan is usually required to confirm the diagnosis of bowel obstruction and establish the site and cause of the obstruction. It can also be used to diagnose an intra-abdominal perforation, if present.
Surgical intervention in bowel obstruction
Conservative management may be used in the first instance in stable patients with obstruction secondary to adhesions or volvulus. Where this fails, surgery is required.
The definitive management of bowel obstruction is with surgery (either laparoscopy or laparotomy) to correct the underlying cause:
Exploratory surgery in patients with an unclear underlying cause
Adhesiolysis to treat adhesions
Hernia repair
Emergency resection of the obstructing tumour
Stents may be inserted into the bowel (during a colonoscopy) in patients with obstruction due to a tumour. Stents hold the tumour out of the way, creating space for the bowel contents to move through.
Ileus
Ileus is a condition affecting the small bowel, where the normal peristalsis that pushes the contents along the length of the intestines, temporarily stops. It may be referred to as paralytic ileus or adynamic ileus.
Pseudo-obstruction is a term used to describe a functional obstruction of the large bowel, where patients present with intestinal obstruction, but no mechanical cause is found. This is less common than ileus affecting the small bowel.
Causes of ileus
There is a long list of things that can make the bowel unhappy, leading to ileus. Common causes are:
Injury to the bowel
Handling of the bowel during surgery
Inflammation or infection in, or nearby, the bowel (e.g., peritonitis, appendicitis, pancreatitis or pneumonia)
Electrolyte imbalance (e.g., hypokalaemia or hyponatraemia)
The most common time you will see ileus is following abdominal surgery. This usually resolves with supportive care within a few days.
Signs and symptoms of ileus
The signs and symptoms are akin to bowel obstruction, with:
Vomiting (particularly green bilious vomiting)
Abdominal distention
Diffuse abdominal pain
Absolute constipation and lack of flatulence
Absent bowel sounds (as opposed to the “tinkling” bowel sounds of mechanical obstruction)
Managing ileus
The ileus will usually resolve with treatment of the underlying cause. Management involves supportive care.
Supportive care involves:
Nil by mouth or limited sips of water
NG tube if vomiting
IV fluids to prevent dehydration and correct the electrolyte imbalances
Mobilisation to helps stimulate peristalsis
Total parenteral nutrition (TPN) may be required whilst waiting for the bowel to regain function
Volvulus
Volvulus is a condition where the bowel twists around itself and the mesentery that it is attached to. The mesentery is the membranous peritoneal tissue that creates a connection between the bowel and the posterior abdominal wall. The bowel gets its blood supply from the mesentery (through the mesenteric arteries).
Twisting in the bowel leads to a closed-loop bowel obstruction, where a section of bowel is isolated by obstruction on either side.
The blood vessels that supply the bowel can be involved, cutting off the blood supply to the bowel, which leads to bowel ischaemia. Ischaemia leads to death of the bowel tissue (necrosis), and bowel perforation.
Types of volvulus
There are two main types of volvulus depending on the area affected:
Sigmoid volvulus
Caecal volvulus
Sigmoid volvulus is more common and tends to affect older patients. The twist affects the sigmoid colon. A key cause is chronic constipation and lengthening of the mesentery attached to the sigmoid colon. The sigmoid colon becomes overloaded with faeces, causing it to sink downwards causing a twist. It is also associated with a high fibre diet and the excessive use of laxatives.
Caecal volvulus is less common and tends to affect younger patients. The twist occurs in the caecum.
Risk factors for volvulus
Neuropsychiatric disorders (e.g., Parkinson’s)
Nursing home residents
Chronic constipation
High fibre diet
Pregnancy
Adhesions
Presentation of volvulus
The signs and symptoms are akin to bowel obstruction, with:
Vomiting (particularly green bilious vomiting)
Abdominal distention
Diffuse abdominal pain
Absolute constipation and lack of flatulence
Diagnosing volvulus
Abdominal x-ray can show the “coffee bean” sign in sigmoid volvulus, where the dilated and twisted sigmoid colon looks like a giant coffee bean.
A contrast CT scan is the investigation of choice to confirm the diagnosis and identify other pathology.
TOM TIP: Remember the “coffee bean” sign for your MCQ exams. It is worth looking up photographs so that you can recognise it and immediately know the diagnosis (sigmoid volvulus) if it comes up.
Managing volvulus
The initial management is the same as with bowel obstruction (nil by mouth, NG tube and IV fluids).
Conservative management with endoscopic decompression can be attempted in patients with sigmoid volvulus (without peritonitis). A flexible sigmoidoscope is inserted carefully, with the patient in the left lateral position, resulting in a correction of the volvulus. A flatus tube / rectal tube is left in place temporarily to help decompress the bowel and is later removed. There is a risk of recurrence (around 60%).
Surgical management involves:
Laparotomy (open abdominal surgery)
Hartmann’s procedure for sigmoid volvulus (removal of the rectosigmoid colon and formation of a colostomy)
Ileocaecal resection or right hemicolectomy for caecal volvulus
Hernias
Hernias occur when there is a weak point in a cavity wall, usually affecting the muscle or fascia. This weakness allows a body organ (e.g., bowel) that would normally be contained within that cavity to pass through the cavity wall.
Presentation of hernias
There are many types of hernias that present differently depending on where they are and what organs are involved.
The typical features of an abdominal wall hernia are:
A soft lump protruding from the abdominal wall
The lump may be reducible (it can be pushed back into the normal place)
The lump may protrude on coughing (raising intra-abdominal pressure) or standing (pulled out by gravity)
Aching, pulling or dragging sensation
Complications of hernias
Incarceration is where the hernia cannot be reduced back into the proper position (it is irreducible). The bowel is trapped in the herniated position. Incarceration can lead to obstruction and strangulation of the hernia.
Obstruction is where a hernia causes a blockage in the passage of faeces through the bowel. Obstruction presents with vomiting, generalised abdominal pain and absolute constipation (not passing faeces or flatus).
Strangulation is where a hernia is non-reducible (it is trapped with the bowel protruding) and the base of the hernia becomes so tight that it cuts off the blood supply, causing ischaemia. This will present with significant pain and tenderness at the hernia site. Strangulation is a surgical emergency. The bowel will die quickly (within hours) if not corrected with surgery. There will also be a mechanical obstruction when this occurs.
TOM TIP: Hernias that have a wide neck, meaning that the size of the opening that allows abdominal contents through is large, are at lower risk of complications. While the contents can easily pass out of this opening, they can also easily be put back, which puts them at a lower risk of incarceration, obstruction and strangulation. When assessing a hernia, always comment on the size of the neck/defect (narrow or wide), as this will help formulate a risk assessment and management plan for the hernia (such as how urgently they need to be operated on).
Richter’s Hernia
A Richter’s hernia is a very specific situation that can occur in any abdominal hernia. This is where only part of the bowel wall and lumen herniate through the defect, with the other side of that section of the bowel remaining within the peritoneal cavity. They can become strangulated, where the blood supply to that portion of the bowel wall is constricted and cut off. Strangulated Richter’s hernias will progress very rapidly to ischaemia and necrosis and should be operated on immediately.
Maydl’s Hernia
Maydl’s hernia refers to a specific situation where two different loops of bowel are contained within the hernia.
General management options of abdominal wall hernias
There are general principles of management that apply to abdominal wall hernias. These are:
Conservative management
Tension-free repair (surgery)
Tension repair (surgery)
Conservative management involves leaving the hernia alone. This is most appropriate when the hernia has a wide neck (low risk of complications) and in patients that are not good candidates for surgery due to co-morbidities.
Tension-free repair involves placing a mesh over the defect in the abdominal wall. The mesh is sutured to the muscles and tissues on either side of the defect, covering it and preventing herniation of the cavity contents. Over time, tissues grow into the mesh and provide extra support. This has a lower recurrence rate compared with tension repair, but there may be complications associated with the mesh (e.g., chronic pain).
Tension repair involves a surgical operation to suture the muscles and tissue on either side of the defect back together. Tension repairs are rarely performed and have been largely replaced by tension-free repairs. The hernia is held closed (to heal there) by sutures applying tension. This can cause pain and there is a relatively high recurrence rate of the hernia.
Inguinal hernias
Inguinal hernias present with a soft lump in the inguinal region (in the groin). There are two types:
Indirect inguinal hernia
Direct inguinal hernia
There are a number of differential diagnoses for a lump in the inguinal region:
Femoral hernia
Lymph node
Saphena varix (dilation of saphenous vein at junction with femoral vein in groin)
Femoral aneurysm
Abscess
Undescended / ectopic testes
Kidney transplant
Indirect inguinal hernia
An indirect inguinal hernia is where the bowel herniates through the inguinal canal.
The inguinal canal is a tube that runs between the deep inguinal ring (where it connects to the peritoneal cavity), and the superficial inguinal ring (where it connects to the scrotum).
In males, the inguinal canal is what allows the spermatic cord and its contents to travel from inside the peritoneal cavity, through the abdominal wall and into the scrotum.
In females, the round ligament is attached to the uterus and passes through the deep inguinal ring, inguinal canal and then attaches to the labia majora.
During fetal development, the processus vaginalis is a pouch of peritoneum that extends from the abdominal cavity through the inguinal canal. This allows the testes to descend from the abdominal cavity, through the inguinal canal and into the scrotum. Normally, after the testes descend through the inguinal canal, the deep inguinal ring closes and the processus vaginalis is obliterated. However, in some patients, the inguinal ring remains patent, and the processus vaginalis remains intact. This leaves a tract or tunnel from the abdominal contents, through the inguinal canal and into the scrotum. The bowel can herniate along this tract, creating an indirect inguinal hernia.
There is a specific finding of indirect inguinal hernias that help you differentiate them from a direct inguinal hernias. When an indirect hernia is reduced and pressure is applied (with two fingertips) to the deep inguinal ring (at the mid-way point from the ASIS to the pubic tubercle), the hernia will remain reduced.
Direct inguinal hernias
Direct inguinal hernias occur due to weakness in the abdominal wall at Hesselbach’s triangle. The hernia protrudes directly through the abdominal wall, through Hesselbach’s triangle (not along a canal or tract like an indirect inguinal hernia). Pressure over the deep inguinal ring will not stop the herniation.
Hesselbach’s triangle boundaries (RIP mnemonic):
R – Rectus abdominis muscle – medial border
I – Inferior epigastric vessels – superior / lateral border
P – Poupart’s ligament (inguinal ligament) – inferior border
Femoral hernias
Femoral hernias involve herniation of the abdominal contents through the femoral canal. This occurs below the inguinal ligament, at the top of the thigh.
The opening between the peritoneal cavity and the femoral canal is the femoral ring. The femoral ring leaves only a narrow opening for femoral hernias, putting femoral hernias at high risk of:
Incarceration
Obstruction
Strangulation
Boundaries of the femoral canal (FLIP mnemonic):
F – Femoral vein laterally
L – Lacunar ligament medially
I – Inguinal ligament anteriorly
P – Pectineal ligament posteriorly
Don’t get the femoral canal confused with the femoral triangle. The femoral triangle is a larger area at the top of the thigh that contains the femoral canal. You can remember the boundaries with the SAIL mnemonic:
S – Sartorius – lateral border
A – Adductor longus – medial border
IL – Inguinal Ligament – superior border
Use the NAVY-C mnemonic to remember the contents of the femoral triangle from lateral to medial across the top of the thigh:
N – Femoral Nerve
A – Femoral Artery
V – Femoral Vein
Y – Y-fronts
C – Femoral Canal (containing lymphatic vessels and nodes)
Incisional hernias
Incisional hernias occur at the site of an incision from previous surgery. They are due to weakness where the muscles and tissues were closed after a surgical incision. The bigger the incision, the higher the risk of a hernia forming. Medical co-morbidities put patients at higher risk due to poor healing.
Incisional hernias can be difficult to repair, with a high rate of recurrence. They are often left alone if they are large, with a wide neck and low risk of complications, particularly in patients with multiple co-morbidities.
Umbilical hernias
Umbilical hernias occur around the umbilicus due to a defect in the muscle around the umbilicus.
Umbilical hernias are common in neonates and can resolve spontaneously. They can also occur in older adults.
Epigastric hernias
An epigastric hernia is simply a hernia in the epigastric area (upper abdomen).
Spigelian hernias
A Spigelian hernia occurs between the lateral border of the rectus abdominis muscle and the linea semilunaris. This is the site of the spigelian fascia, which is an aponeurosis between the muscles of the abdominal wall. Usually, this occurs in the lower abdomen and may present with non-specific abdominal wall pain. There may not be a noticeable lump.
An ultrasound scan can help establish the diagnosis.
Spigelian hernias generally have a narrower base, increasing the risk of incarceration, obstruction and strangulation.
Diastasis Recti
Diastasis recti may also be called rectus diastasis and recti divarication. It refers to a widening of the linea alba, the connective tissue that separates the rectus abdominis muscle, forming a larger gap between the rectus muscles. It is not technically a hernia. This gap becomes most prominent when the patient lies on their back and lifts their head. There is a protruding bulge along the middle of the abdomen.
The linea alba is the aponeurosis of the two sides of the rectus abdominis muscle. The gap is created because the linea alba is stretched and broad.
This can be congenital (in newborns) or due to weakness in the connective tissue, for example following pregnancy or in obese patients.
No treatment is required in most cases, but surgical repair is possible.
Obturator hernias
Obturator hernias are where the abdominal or pelvic contents herniate through the obturator foramen at the bottom of the pelvis. They occur due to a defect in the pelvic floor and are more common in women, particularly in older age, after multiple pregnancies and vaginal deliveries. They are often asymptomatic but may present with irritation to the obturator nerve, causing pain in the groin or medial thigh.
Howship–Romberg sign refers to pain extending from the inner thigh to the knee when the hip is internally rotated and is due to compression of the obturator nerve.
It can also present with complications of:
Incarceration
Obstruction
Strangulation
CT or MRI of the pelvis can establish the diagnosis. It may be found incidentally during pelvic surgery.
Hiatus hernias
An hiatus hernia refers to the herniation of the stomach up through the diaphragm. The diaphragm opening should be at the level of the lower oesophageal sphincter and should be fixed in place. A narrow opening helps to maintain the sphincter and stop acid and stomach contents refluxing into the oesophagus. When the opening of the diaphragm is wider, the stomach can enter through the diaphragm and the contents of the stomach can reflux into the oesophagus.
There are four types of hiatus hernia:
Type 1: Sliding
Type 2: Rolling
Type 3: Combination of sliding and rolling
Type 4: Large opening with additional abdominal organs entering the thorax
Sliding hiatus hernia is where the stomach slides up through the diaphragm, with the gastro-oesophageal junction passing up into the thorax.
Rolling hiatus hernia is where a separate portion of the stomach (i.e. the fundus), folds around and enters through the diaphragm opening, alongside the oesophagus
Type 4 refers to a large hernia that allows other intra-abdominal organs to pass through the diaphragm opening (e.g., bowel, pancreas or omentum).
Key risk factors are increasing age, obesity and pregnancy.
Hiatus hernias present with dyspepsia (indigestion), with symptoms of:
Heartburn
Acid reflux
Reflux of food
Burping
Bloating
Halitosis (bad breath)
Hiatus hernias can be intermittent, meaning they may not be seen on investigations. Hiatus hernias may be seen on:
Chest x-rays
CT scans
Endoscopy
Barium swallow testing
Treatment is either:
Conservative (with medical treatment of gastro-oesophageal reflux)
Surgical repair if there is a high risk of complications or symptoms are resistant to medical treatment
Surgery involves laparoscopic fundoplication. This involves tying the fundus of the stomach around the lower oesophagus to narrow the lower oesophageal sphincter.
Haemorrhoids
Haemorrhoids are enlarged anal vascular cushions. It is not clear why they become enlarged and swollen, but they are often associated with constipation and straining. They are also more common with pregnancy, obesity, increased age and increased intra-abdominal pressure (e.g., weightlifting or chronic coughing).
They often occur in pregnancy, most likely due to constipation, pressure from the baby in the pelvis and the effects of hormones that relax the connective tissues.
Anal Cushions
The anal cushions are specialised submucosal tissue that contain connections between the arteries and veins, making them very vascular. They are supported by smooth muscle and connective tissue. They help to control anal continence, along with the internal and external sphincters. The blood supply is from the rectal arteries.
The location of pathology at the anus is described as a clock face, as though the patient was in the lithotomy position (on their back with their legs raised). 12 o’clock is towards the genitals and 6 o’clock is towards the back. The anal cushions are usually located at 3, 7 and 11 o’clock.
Classifying haemorrhoids
The classification of haemorrhoids depends on their size and whether they prolapse from the anus:
1st degree: no prolapse
2nd degree: prolapse when straining and return on relaxing
3rd degree: prolapse when straining, do not return on relaxing, but can be pushed back
4th degree: prolapsed permanently
Symptoms of haemorrhoids
Haemorrhoids may be asymptomatic. They are often associated with constipation and straining.
A common presentation is with painless, bright red bleeding, typically on the toilet tissue or seen after opening the bowels. The blood is not mixed with the stool (this should make you think of an alternative diagnosis).
Other symptoms include:
Sore / itchy anus
Feeling a lump around or inside the anus
