Lecture 4 - Hernias Flashcards
Visceral pain
Pain that results from:
- Visceral stretching
- Visceral inflammation
- Visceral ischaemia
No somatic innervation therefore pain is:
- poorly localised
- often in midline
Nausea
Vomiting
Sweating
Spinal level of sympathetic innervation to gut
T5- L2
How are the presynaptic splanchnic nerves formed?
The preganglionic sympathetic fibres pass through the sympathetic chain without synapsing.
They amalgamate to form the presynapytic splanchnic nerves
3 presynaptic splanchnic nerves
Greater splanchnic nerve (T5 - T9)
Lesser splanchnic nerve (T10-T11)
Least splanchnic nerve (T12)
4 prevertebral ganglia
Coeliac
Renal
Superior mesenteric
Inferior mesenteric
Foregut pain
T5-T9 - Greater splanchnic nerve
Midline epigastric pain
Poorly localised
From: Liver Gallbladder, Stomach Spleen Kidney
Midgut pain
- E.g. Caecul volvulus stimulates general visceral afferents
- Afferents to superior mesenteric ganglion
- To lesser splanchnic nerve (T10-T11)
- Sympathetic chain
- Dorsal horn of spine
- Converge with somatic afferents at T10-T11
- Brain interprets T10 - T11 dermatome pain in the peri-umbilical area
Hernia
Protrusion of part of the abdominal contents beyond the confines of the normal abdominal wall
Types of hernias
Direct
Indirect
Incarcerated
Not incarcerated
Hernias that are not incarcerated
Fullness/ swelling
Gets larger when intraabdominal pressure increases
Aches
Incarcerated hernias
Cannot be pushed back
Painful
Nausea and vomiting + signs of bowel obtruction
Systemic problems- bowel becomes ischaemic due to compromised blood supply
Causes of hernias
Weakness in the containing cavity
- congenital
- post surgery (incisional hernia)
- Normal points of weakness
Anything that increases intra- abdominal pressure:
- Obesity
- Weightlifting
- Chronic constipation or coughing (smoker)
Components of a hernia
Sac- pouch of peritoneum
Contents - structure within the abdominal cavity e.g. bowel or omentum
Coveringss - layers of the abdominal wall through which the hernia has passed
- External oblique
- Internal oblique
- Transversus abdominis
- Transversalis fascia
Weaknesses of the abdominal wall
Femoral canal
Inguinal canal
Previous incisions
Umbilicus
Inguinal canal
Oblique passage through the lower abdominal wall.
In males - abdomen to the testes where the testes passed through the inguinal canal from the abdomen to the scrotum
In females - Round ligament goes from the uterus to the labrium majora
Processus vaginalis
Pouch of peritoneum in males that obliterates once the testes have moved down.
Becomes the tunica vaginalis
Gubernaculum
Condensed band of mesenchyme that links the inferior portion of the testes to the labioscrotal swelling
Becomes the scrotal ligament
What occurs if the processus vaginalis doesn’t close?
There is a connection between the peritoneal cavity and the scrotum which can be the site of fluid collection and infection
Borders of the inguinal canal
Anterior wall - External oblique
Posterior wall - Transversalis fascia and conjoint tendon
Medially = internal oblique and transversus abdominis
Floor - Inguinal ligament and lacunar ligament medially
Roof - Conjoint tendon
Indirect hernias
Travel through the deep ring
Traverse the inguinal canal and exit the superficial ring
If it exits the superficial ring, can cause a scrotal hernia if the processus vaginalis is patent
Direct hernias
Bulges directly through the abdominal wall through Hasselbach’s triangle in the vicinity of the superficial inguinal ring
Percentage of abdominal hernias that are inguinal
75%
Percentage of hernias that are indirect and the proportion of males to females
50%
Males 7x more likely
Percentage of abdominal hernias that direct
25%
Which type of hernia protrudes laterally to the inferior epigastric vessels?
Indirect
Which type of hernia protrudes medially to the inferior epigastric vessels?
Direct
Borders of Hesselbachs triangle
Medial - Rectus abdominis
Roof - Inferior epigastric vessels
Floor - inguinal ligament
Femoral hernias
More common in females
Easily incarcerated and irreducible
Contents protrudes through the femoral ring of the femoral canal out of the saphenous ring
Borders of the femoral ring
Laterally - Femoral vein
Medially - Lacunar ligament
Omphalocele (4)
Failure of the midgut to return to the abdomen during development
Viscera persists outside the abdominal cavity within the umbilical ring covered in peritoneum
Feeding can occur
The abdominal cavity may not grow to correct the size to accommodate the viscera
How to treat an omphalocele
Can surgically operate and push viscera back in
Mortality rate is high as often associated with other genetic problems
Gastroschisis (6)
Defect in the ventral abdominal wall
The abdominal viscera are not covered in peritoneum - exposed to amniotic fluid
Problems with gut development - atresia, inflamed or short
Feeding problems
Better survival rates that omphalocele as not associated with other genetic factors
Defect can close at birth - push back in stepwise
Umbilical hernia
Commonly in infants
Hernia bulges at the umbilicus
Not painful
80-90% close by 3 yrs old
Paraumbilical hernia
Acquired in adults
Through linear alba in the region of the umbilicus
More common in females
Caused by obesity as there is an increase in intra-abdominal pressure
Presentation of para umbilical hernias
Based around what happens to the loops of bowel
- if trapped:
Pain
Vomiting
Sepsis
Incarcerated
Stuck - irreducible
Pain
Sepsis
Tissue breakdown
Strangulated
Blood supply is disrupted and can lead to tissue necrosis
