The Commonest Hernias Flashcards
What is a hiatal hernia?
protrusion of abdominal contents, most commonly the abdominal oesophagus, cardia and part of the stomach through the oesophageal hiatus into the caudal mediastinum
How many types of hiatal hernia are there?
4
Define type I hiatal hernia
Known as a sliding hiatal hernia, the gastro-oesophageal junction herniates.
Define type II hiatal hernia
Part of the stomach herniates but the gastro-oesophageal junction remains.
Define type III hiatal hernia
The gastro-oesophageal junction and part of the stomach herniates.
Define type IV hiatal hernia
Other abdominal organs in addition to the stomach herniate.
Which type of hiatal hernia is most common?
Type I
Are hiatal hernias typically congenital or acquired?
Congenital
Congenital hiatal hernias have been well recognised in what breed?
Shar Pei
Young dog breeds that have been recognised as having hiatal hernia? (2)
English bulldog
French dog
How obstruction of the upper airway could contribute to development of a hiatal hernia?
An upper airway obstruction a greater negative pressure must be generated to move air from the atmosphere into the thorax.
The resulting pressure differential between the abdomen and thorax is greater during inspiration in these circumstances and this pressure differential may be great enough for the abdominal oesophagus and cardia to be pushed (or sucked) into the thorax.
How common is a hiatal hernia 2ry to laryngeal paralysis (same pathophysiology as BOAS)?
Rare
How common is hiatal hernia 2ry to trauma of diaphragm muscles/nerves?
Rare
How common is hiatal hernia 2ry to tetanus?
Rare
What are some of the potential consequences of malpositioning of the gastro-oesophageal junction? (3)
- Reduced pressure of the gastro-oesophageal sphincter with resulting gastro-oesophageal reflux
- Oesophagitis and oesophageal dysmotility
- Slow passage of food from the caudal oesophagus to the stomach similarly resulting in oesophagitis and oesophageal dysmotility.
Clinical signs of hiatal hernia? (6)
note: can be assymptomatic
- Regurgitation of saliva (“white foam or froth”) or undigested food (differentiate from vomiting by presence/absence of abdominal effort)
- Hypersalivation, usually associated with feeding
- Gulping, swallowing
- Vomiting
- Poor body condition/weight loss
- Respiratory signs (tachypnea, dyspnea, cough, etc if secondary aspiration pneumonitis or pneumonia)
Which food may hiatal hernia be worse with?
Chunky/dry food
If congenital or 2ry to BOAS when do clinical signs of hiatal hernias develop?
First few months/years
Why is diagnosing a sliding hiatal hernia difficult?
As the diagnosis will not be evident when the hernia is reduced
How to aid hiatal hernia diagnosis?
By increasing abdominal pressure (by applying pressure to the abdomen or elevating the hindlimbs) to encourage herniation.
What is the preferred diagnosis of hiatal hernia? why?
A fluoroscopic barium swallow study is the preferred method of diagnosis as it allows real time assessment of oesophageal motility and gastric regurgitation
Cons of fluoroscopy? (2)
- Exposure to vet
- Conscious patient
What may be seen on thoracic imaging to diagnose a hiatal hernia?
A soft tissue/gas opacity within the mediastinum in the caudodorsal thorax (where the oesophagus is located)
Oesopagoscopy:
What is seen with a hiatal hernia is a gastroesophgeal herniation is present at the time?
A pink “mass” within the distal oesophagus.
Other than a mass, what might be seen in distal oesophagus with hiatal hernia and oesophagoscopy?
Oesophagitits
In these dogs where the clinical signs are consistent with hiatal hernia, if other differential diagnoses have been excluded and there has been no response to symptomatic treatment, how can diagnosis be confirmed?
Exploratory celiotomy
How MECHANISMS treat 2ry reflux oesophagtitis (3)
Reducing gastric acid secretion:
Protection of the oesophageal mucosa -
Improving lower oesophageal sphincter tone:
Reducing gastric acid secretion: Pharacology (2) and examples (3,1)
Antacids - Histamine H2 receptor blockers: famotidine, ranitidine, cimetidine;
Inhibition of H+/K+-ATPase - omeprazole
Protection of the oesophageal mucosa - drug that can be used?
Sucralfate
Improving lower oesophageal sphincter tone- Pharmacology (1) and drugs that can be used (2)
Prokinetics to enhance gastric emptying rate and increase lower oesophageal sphincter tone - cisapride, metoclopramide.
How can diet help treat hiatal hernia?
Low fat diet, slurry/soft consistency, small frequent meals, postural feeding.
Medical treatment of hiatal hernias
- 2ry reflux oesophagititis
- Diet modification
- Improve upper airway obstruct
- trx 2ry pneumonia
How long should a patient be stabilized medically before proceeding to surgery for a hiatal hernia?
2-4 weeks
Hiatal hernia sx is approached via a midline cranial ceoliotomy, what is performed (4)
- Diaphragmatic hiatal reduction and phrenoplasty
- Oesophagopexy
- Left sided gastropexy
Hiatal hernia reapir:
what ligament is cut to allow retraction of the left lateral lobe of the liver to allow observation of the oesophageal hiatus?
Left triangular ligament of the liver
How to identify oesophagus during hiatal hernia repair?
Pass orogastric tube
During hiatal hernia repair; how to free the oesophaus from diaphragm ventrally?
CARE - why?
- Carefully cut the phrenico-oesophageal ligament ventrally to free the oesophagus from the diaphragm ventrally
- CARE: to preserve the vagal trunks and oesophageal vessels.
During hiatal hernia repair before cutting the phrenico- oesophaeal ligament; warn the anaesthetists, why?
A pneumothorax is created at this point in the surgery, the anaesthetist has been advised of and prepared for this.
Following surgical approach; how the hernia then repaired
- Retract the cardia caudally.
- Reduce the size of the hiatus by pre-placing 3-5 sutures of 3 metric polydioxanone or polypropylene in a cruciate mattress or single interrupted pattern across the left and right diaphragmatic crura at the oesophageal hiatus.
- Tie these sutures with the large bore orogastric tube in place, starting at the ventral aspect of the hiatus and progressing dorsally.
After reducing a hiatal hernia; how large should the hiatus be?
To allow passage of stomach tube
How to perform an oesophagopexy?
By circumferentially placing single interrupted sutures using 2 or 3 metric suture material as described above between the free edge of the hiatus and the lateral and ventral aspects of the oesophagus.
What traction should be on the stomach following gastropexy after hiatal hernia repair?
Mild caudal traction on the stomach.