mechanical obstructive disorders

what is a mechanical disorder?

any condition that physically blocks or narrows a passage within the body, preventing the normal flow of substances like air, blood, or digestive contents

what are the two types of small bowel obstructive

1. mechanical

2. functional

what are common causes of mechanical small bowel obstruction?

1. adhesions

2. hernia

3. tumor

what is a functional small bowel obstruction?

a failure of muscles or nerves that leads to a disruption in motility of ingesta

what can functional small bowel obstruction be caused by?

1. electrolyte imbalances

2. nerve damage

3. infection

4. inflammation

why is classifying mechanical obstructions so important?

helps determine severity, prognosis, and treatment approach

what are the different ways we categorize mechanical obstructions?

1. anatomical region affected

2. based on cause

3. degree of obstruction

4. vascular compromise

5. duration of onset

6. etiology

what is the pathogenesis of mechanical obstructions?

1. initial obstruction and luminal distension

2. increased intraluminal pressure and reduce motility

3. mucosal injury and bacterial overgrowth

4. venous congestion and ischemia

5. systemic effects

6. endotoxemia nad septic shock

what are the gastrointestinal signs associated with mechanical obstructions?

1. vomiting

2. abdominal distension and pain

3. anorexia and dehydration

4. tenesmus

5. absence of feces or diarrhea

what are the systemic signs associated with mechanical obstructions?

1. weakness

2. lethargy

3. fever

4. shock

what are the most common diagnostic tests used to diagnose mechanical obstructions?

1. abdominal radiographs

2. abdominal ultrasound

3. GI endoscopy

4. exploratory surgery

5. physical examination (CRUCIAL)

what are non-surgical treatments used for obstructive disorders?

1. fluid therapy

2. dietary management

3. medical management

what are surgical treatments used for obstructive disorders?

1. exploratory laparotomy

2. gastrotomy

3. enterotomy

4. resection and anastomosis

what are indications for conservative treatment of obstructive disorders?

1. partial obstructions

2. stable patients

3. non-life threatening obstructions

what are indications for surgical treatment of obstructive disorders?

1. complete obstructions

2. unstable patients

3. life threatening obstructions

4. failure of conservative management

MCQ: A cat is brought to your clinic for persistent vomiting, lethargy, and abdominal discomfort. On examination, the cat appears unstable, showing signs of dehydration, tachycardia, and painful abdomen. Radiographs confirm the presence of a needle lodged in the stomach or intestines. Would conservative management be appropriate for this patient?

no

what are the complications of untreated obstructions?

1. perforation and peritonitis

2. severe dehydration and electrolyte imbalance

3. sepsis and systemic infections

4. strangulation and tissue necrosis

5. death if untreated

constipation

the infrequent, incomplete or difficult evacuation of feces, which are typically dry and hard

what can constipation progress to if left untreated?

1. obstipation

2. megacolon

obstipation

a severe and intractable form of constipation caused by prolonged retention of hard, dry feces

what are the predisposing factors to constipation

1. diet and environment

2. mechanical obstructions

3. neuromuscular dysfunction

4. metabolic and endocrine conditions

5. drugs and medication

what dietary and environmental factors can lead to constipation?

1. low fiber

2. dehydration 

3. lack of exercise

4. stress and behavioral issues

what is the pathogenesis of constipation?

1. inadequate colonic motility

2. fecal retention and dehydration

3. colonic distension and weakening of muscle

4. mucosal injury and secondary inflammation

5. obstipation (if untreated)

what are the clinical signs of constipation?

1. infrequent or absent defecation

2. straining

3. painful defecation

4. lethargy and anorexia

5. vomiting (severe cases)

what do we use in the diagnosis of constipation?

1. history and physical examination

2. imaging

3. laboratory tests

what imaging can we use to diagnosis constipation?

1. abdominal radiographs

2. ultrasound

3. contrast studies (barium enema)

what species is most effected by constipation?

cats

what is a major cause of constipation in cats?

idiopathic megacolon

what is constipation in dogs commonly associated with?

1. pelvic fractures

2. tumors

3. prostate enlargement

4. diets that consist of bones

which breeds have congenital pelvic narrowing that can be a cause of constipation?

boston terriers and bulldogs

why is it important to differentiate straining?

important to determine if it is from constipation or from urinary problems (potential life threatening) especially in cats

what are the treatments for mild to moderate cases of constipation?

1. dietary adjustments

2. hydration support

3. laxatives and stool softeners

4. motility enhancers 

5. regular exercise 

6. enemas

what are the treatments for severe cases of constipation?

1. manual evacuation (enemas and digital removal)

2. IV fluids and electrolyte correction

3. surgical intervention depending on cause

what is megacolon?

a condition where the colon becomes abnormally enlarged and loses its ability to function properly

what is foreign body obstruction?

occurs when an ingested or penetrating object blocks normal flow through the gastrointestinal (GI) tract

what is the most common site in the GI tract for foreign body obstruction?

jejunum because of its length

what are the two main categories of foreign bodies?

1. non-linear

2. linear

what species are non-linear foreign bodies common in?

dogs

what are examples of non-linear foreign bodies?

1. toys

2. corn cobs

3. bones

4. socks

5. rocks

non-linear foreign body

a single, solid object that causes complete or partial obstruction

linear foreign body

a long, string-like material that becomes anchored at one point while the rest of it moves through the intestines

what are some examples of linear foreign bodies?

1. string

2. thread

3. ribbon

4. tinsel

what animals are linear foreign bodies common in?

cats

where can linear foreign bodies be found in the animal?

anchor around the base of the tongue, pylorus,

or at more distal sites in GIT.

what does a linear foreign body result in?

gathering and pleating of the intestine

(plication) around the foreign object which causes partial to complete obstruction

should we ever pull a string from the mouth?

NO!

how can we further classify foreign body obstructions?

1. degree of obstruction

2. location of obstruction along the intestinal tract

3. pathophysiological alterations

where in the body would a foreign body obstruction be located if classified as proximal?

esophagus, stomach, or small intestines

where in the body would a foreign body obstruction be located if classified as distal?

large intestines, colon, or rectum

what are predisposing factors of foreign body obstructions?

1. behavioral factors

2. age and breed disposition

3. dietary and medical factors

4. environmental factors 

5. specific risk factors in cats (string and hairballs)

what is the pathogenesis of foreign body obstructions?

1. obstruction occurs

2. distension and mucosal damage

3. iscehmia and necrosis

4. bacterial translocation and sepsis

5. systemic complications and death (if left untreated)

what are the clinical signs of a foreign body obstruction?

1. vomiting 

2. abdominal pain

3. dehydration

4. loss of appetite

5. diarrhea

6. lethargy

what diagnostic tests can be conducted to help diagnose foreign body obstructions?

1. bloodwork

2. radiography

3. ultrasound

what do most treatments of foreign body obstructions require?

surgical or endoscopic treatment

gastrotomy

opening the stomach

enterotomy

opening the intestine

what may be required if there is significant damage from a foreign body obstruction?

resection and anastomosis

MCQ: A 2-year-old indoor cat presents with straining to defecate, decreased appetite, and firm stool in the colon on palpation. Has a history of mild constipation but no vomiting or severe discomfort. what is the most appropriate type of treatment in this case?

conservative treatment

MCQ: 1-year-old Labrador Retriever who swallowed a tennis ball. Dog is lethargic, vomiting, and has severe abdominal pain. what is the most appropriate type of treatment in this case?

surgical (aggressive) treatment

MCQ: 5-month-old kitten ingested a string 24 hours ago. The kitten is still playful but has occasional vomiting and mild abdominal discomfort. what is the most appropriate type of treatment in this case?

surgical (aggressive) treatment

MCQ: 1-year-old Standard Poodle swallowed a LEGO piece an hour ago. The dog is bright, alert, and asymptomatic, with no vomiting or signs of distress. what is the most appropriate type of treatment in this case?

conservative treatment

hernia

a condition where an organ or tissue pushes through an abnormal opening but remains closed within a hernial sac formed by the peritoneum

what is required for there to be a true hernia?

there must be a hernial ring, sac, and contents involved

what is it required for it to be a false hernia?

lacks the hernial sac because the peritoneum is torn and organs move into abdominal position without being enclosed in a sac

direct hernias

occur through a rent in the body wall

indirect hernias

occur through an already existing ring, such as the inguinal ring or umbilical ring

what is the pathogenesis of hernias?

1. weakness or defect in the body wall

2. increased intra-abdominal pressure

3. herniation of abdominal contents

list the different types of hernias

1. umbilical hernia

2. inguinal hernia

3. scrotal hernia

4. perineal hernia

umbilical hernia

defect in the abdominal wall at the umbilicus, allowing abdominal contents to protrude

what is the cause of umbilical hernias?

failure of the umbilical ring to close after birth

what species are affected from umbilical hernias?

common in young animals of all species

what are the clinical signs of umbilical hernias?

1. soft, reducible swelling at umbilicus

2. may contain intestines or omentum

3. can become strangulated leading to pain and colic

what is the treatment of umbilical hernias?

small hernias may resolve on their own, larger ones may need surgical repair

what type of hernia is this?

umbilical hernia

inguinal hernia

protrusion of abdominal organs through the inguinal canal, forming a swelling near the groin

what is the cause of inguinal hernias?

weakness in the inguinal ring, allowing abdominal contents to pass through

what species are affected by inguinal hernias?

common in breeding males and occasionally in females during pregnancy

what are the clinical signs of inguinal hernia?

1. swelling in the inguinal region

2. if intestines trapped can lead to strangulation causing colic and pain

what is the treatment for inguinal hernias?

surgical correction usually required especially if strangulation is present

what type of hernia is this?

inguinal hernia

scrotal hernia

a condition where abdominal contents pass through the inguinal canal and into the scrotum

what is the cause of scrotal hernias?

genetic factors, acquired trauma, or a combination of both

what species are affected by scrotal hernias?

most common in boars, stallions, and dogs

what are the clinical signs of scrotal hernia?

1. unilateral or bilateral scrotal swelling

2. pain

3. testicular asymmetry

what is the treatment of scrotal hernia?

surgical castration often performed in severe cases

what type of hernia is shown?

scrotal hernia

perineal hernia

weakening or traumatic tear in the muscles of the area, resulting in the bladder, intestines, or fat pushing through the muscle to an abnormal position just under the skin

what are the causes of perineal hernia?

weakness of the pelvic diaphragm muscles, leading to displacement of abdominal organs

what species are affected by perineal hernias?

older intact male dogs

what are the clinical signs of perineal hernia?

1. swelling near anus

2. straining

3. constipation 

4. urinary problems

what is the treatment of perineal hernias?

surgical repair with reinforcement of the pelvic muscles

what type of hernia is shown?

perineal hernia

what is used in the diagnosis of inguinal hernia?

1. palpation of soft mass in groin

2. ultrasound and X rays

3. doppler ultrasound

what is used in teh diagnosis of umbilical hernia?

1. palpation of soft lump at belly button

2. ultrasound

what is used in the diagnosis of scrotal hernia?

1. swelling in scrotum (soft or firm)

2. ultrasound

what is used in the diagnosis of perineal hernia?

1. rectal exam (to see muscle weakness)

2. X-rays

3. ultrasound

when is emergency surgery required with hernias?

when intestines are trapped

which hernias is surgical repair always recommended?

scrotal and perineal hernias

what is the risk of complications of inguinal hernias?

high due to risk of strangulation

what is the risk of complications of umbilical hernias?

low most resolve on their own