10/12- Abdominal Pain and Constipation

Question 1

How is pain sensed in the diaphragm?

• Receptors
• Stimuli
• Sensation

Answer 1

Mechanoreceptors (stretch)

• Torsion, rapid distention of a hollow viscus, forceful muscular contractions, and rapid stretching of solid organ serosa or capsule

Chemoreceptors

• Substances released in response to local mech injury, inflammation, ischemia, necrosis
• Chemical substances released include: H+ and K+ ions, histamine, serotonin, bradykinin and other vasoactive amines, substance P, calcitonin gene-related peptide, prostaglandins, and leukotrienes

Sensed as:

• Dull, cramping, burning, poorly localized, and more gradual in onset and longer in duration than somatic pain
• Secondary autonomic effects such as sweating, restlessness, nausea, vomiting, perspiration, and pallor often accompany

Question 2

Describe abdominal pain due to visceral receptors?

Answer 2

• Abdominal organs transmit sensory afferents to both sides of the spinal cord
• Visceral pain is usually perceived to be in the midline, in the epigastrium, periumbilical region, or hypogastrium

Question 3

Describe somatic/parietal pain

• Nerve fibers involved
• Location
• Sensation
• Aggravated by
• Location

Answer 3

• A-delta fibers
• Abdominal wall and peritoneum
• More intense, sharp, sudden, well-localized pain
• Aggravated by movement or vibration
• Lateralization possible because each side separately innervated

Question 4

What are reflexive responses to somatic/parietal abdominal pain?

Answer 4

• Involuntary guarding
• Abdominal rigidity

Question 5

How can quality of pain give you a clue to the cause of the abdominal pain?

Answer 5

Obstruction of Viscera

• Crampy, but can be constant
• Diffuse, or periumbilical if of small bowel

Peritonitis

• Steady, achy
• Directly over inflamed area
• Better with laying still

Question 6

What causes referred pain?

• What neurons involved
• What may cause it

Answer 6

• Visceral afferent neurons and somatic afferent neurons from different area converge on second order neurons
• May have embryological origin

CAUSES:

• Cholecystitis -> shoulders or scapula
• Pancreatitis and perforated GU -> back
• Abdominal pain from non-abdominal organs
• Zoster -> Abdominal wall pain
• MI -> Epigastric pain
• MI or pneumonia -> Upper abdominal pain

Question 7

How does localization vary by cause with abdominal pain?

Answer 7

• Visceral pain: localization unreliable
• Parietal pain: reliable location
• Most organs are bilaterally, symmetrically innervated

(EXCEPT: gallbladder, ascending/descending colon)

Question 8

Difference between acute/chronic or recurrent abdominal pain?

Answer 8

• Acute = under 24 hrs, usually sudden onset

Question 9

Rigidity upon palpation of the abdomen suggests what?

Answer 9

Peritonitis

Question 10

Rebound tenderness suggests what?

Answer 10

Peritonitis

Question 11

Absence of bowel sounds may indicate what conditions?

Answer 11

• Peritonitis
• Perforation
• Obstruction

Question 12

High pitched bowel sounds may indicate what?

Answer 12

• SBO
• Ileus

Question 13

What to look for on lab testing when working up abdominal pain?

Answer 13

• CBC: anemia, leukocytosis, leukopenia
• CMP: assess metabolic state, assess hepatobiliary disease
• Lipase (amylase): elevated in acute pancreatitis
• Pregnancy test for childbearing age women

Question 14

When is x-ray useful in evaluating abdominal pain?

Answer 14

“Acute Abdominal Series”: Upright chest, Upright abd film, Supine abd film

Useful in:

• Suspected perforation
• Bowel obstruction
• Severe constipation
• Kidney stones
• Colonic pseudo-obstruction
• Sigmoid volvulus

Pros: fast, inexpensive, widely available

Cons: limited view

Question 15

When is US useful in evaluating abdominal pain?

Answer 15

• Cholelithiasis
• Biliary evaluation
• Abscesses
• Aortic aneurysm
• Ectopic pregnancy

Pros: readily available, inexpensive

Cons: limited evaluation, operator dependent, can be time consuming

Question 16

When is CT useful in evaluating abdominal pain?

Answer 16

Chest, Abdomen, Pelvis

Useful in:

• Pancreatic disease
• Retroperitoneal collections
• Intra-abdominal abcess
• Some vascular processes
• Trauma-induced hematomas
• Ischemia
• Inflammation (IBD, Diverticulitis)

Pros: excellent images, widely accessible, relatively fast

Cons: Expensive, radiation exposure

Question 17

What is the key demographic for biliary disease?

Answer 17

4Fs:

• Fat
• Forty
• Female
• Fertile

Question 18

Where is pain from biliary disease experienced?

Answer 18

Postprandial RUQ pain

• Biliary colic intermittent

Question 19

What are types of biliary disease/co-conditions?

Answer 19

Acute cholecystitis

• 95% due to cholelithiasis
• Obstruction of the gallbladder leads to inflammation

Choledocholithiasis

• Stone in CBD
• Can cause pancreatitis

Cholangitis

• Charcot’s triad: pain, jaundice, fever
• Reynold’s pentad: triad + hypoTN and change in mental status

Question 20

In what condition is Charcot’s triad/Reynold’s pentad observed?

Answer 20

Cholangitis

Question 21

Causes of upper abdominal pain?

Answer 21

Biliary disease

• Acute cholecystitis
• Choledocholithiasis
• Cholangitis

Peptic ulcer disease

Acute pancreatitis

Question 22

Describe peptic ulcer disease?

• Location
• Improved when
• Complications
• Signs

Answer 22

• Epigastric, improved after eating
• “Acute abdomen” if perforated Peritonitis/Peritoneal signs
• Rigid abdomen
• Lack of bowel sounds

Question 23

Describe peptic ulcer disease

• Most common causes
• Presentation
• Diagnostic criteria

Treatment

Answer 23

Most common causes:

• ETOH
• Gallstones

Presents with

• Epigastric pain radiating to the back
• Associated nausea and vomiting

Diagnostic criteria

• Elevated lipase (amylase)
• Clinical presentation
• CT characteristic findings

Treatment:

• IVF
• Opiates

Question 24

What may cause lower abdominal pain?

Answer 24

• Appendicitis
• Diverticulitis

Diffuse abdominal pain sydnromes:

• Mesenteric ischemia
• Mesenteric embolism
• Mesenteric thrombosis
• Low flow mesenteric ischemia
• Small bowel obstruction

Question 25

Describe appendicitis - What is it - Presentation - Diagnosis - Treatment

Answer 25

- #1 cause of acute abdominal pain in US - Obstruction and inflammation of appendix _Presents with_ - Periumbilical pain, anorexia, +/- vomiting - Pain migrates to right lower quadrant Diagnose by clinical presentation and imaging Treatment is surgical

Question 26

Describe diverticulitis - Disease progression - What is it - Complications - Presentation - Treatment

Answer 26

- Diverticulosis common, diverticulitis rare (5%) - Occurs when diverticulum is obstructed with stool causing inflammation - Usually sigmoid - May progress to peritonitis or abscess: “complicated” _Presents with_ - Left lower quadrant pain, fever, obstipation - Leukocytosis _Treatment:_ - NPO - Antibiotics

Question 27

What are some causes of diffuse abdominal pain syndromes?

Answer 27

- Mesenteric ischemia (embolism)

Question 28

Describe mesenteric ischemia/embolism - Most common causes - Presentation - Exam findings - Complications

Answer 28

- Usually cardiac in origin: a.fib, mural thrombus _Presents with_ - Sudden, severe abdominal pain - Vomiting Early examination unremarkable (pain out of proportion to examination) _May develop:_ - Acidosis - Infarction - Leukocytosis

Question 29

Describe mesenteric thrombosis - Causes - Presentation

Answer 29

_Due to:_ - Atherosclerosis, usually at SMA _May describe:_ - Intestinal angina - Weight loss

Question 30

Describe low flow mesenteric ischemia: - Causes - Presentation

Answer 30

- Reduced cardiac output - Shock - Dehydration

Question 31

Describe small bowel obstruction: - Causes - Presentation - Diagnosis - Treatment

Answer 31

- Usually from postoperative adhesions - Malignancy, volvulus, intussusception _Presents with_ - Crampy, intermittent, midabdominal pain - Vomiting - Abdominal distension - Obstipation Acute abdominal series: dilated loops of small bowel with air-fluid levels _Treatment:_ - NPO - IV hydration - NGT ….surgery

Question 32

What is normal as far as bowel habits?

Answer 32

- 2-3/day to 3/week - Should be easy to pass - Should feel relieved afterward

Question 33

Pathophysiology of constipation: secondary? - Colon disorders - Metabolic disturbances - Neurologic disorders - Medications

Answer 33

_Colon disorders:_ - Strictures - Anal fissure - Proctitis _Metabolic disturbances:_ - Hypercalcemia - Hypothyroidism - Diabetes _Neurologic disorders:_ - Parkinsonism - Spinal cord lesions _Medications:_ - Antacids - Opiates - Iron - CCBs

Question 34

Pathophysiology of constipation: idiopathic?

Answer 34

- Slow transit - Functional outlet obstruction

Question 35

Describe slow transit as a cause of idiopathic constipation

Answer 35

- Likely dysfunction of enteric smooth muscles or nerves - Usually longstanding - Longer exposure to mucosa will allow for more water absorption and fermentation by bacteria * Scybala * Bloating

Question 36

Describe functional outlet obstruction as a cause of idiopathic constipation

Answer 36

- Ineffective opening of the anal canal or failure of the rectum to expel feces - Pelvic floor dysfuction: lack of coordination or altered anatomy

Question 37

What are alarm symptoms when working up constipation?

Answer 37

- Blood in the stool - Weight loss - Sudden onset of symptoms

Question 38

What should be done on PE for constipation work up?

Answer 38

_Abdominal exam:_ - Distension - Tenderness - Fecal column _Anorectal exam:_ - Examine perineum - Cutaneoanal reflex ("anal wink") - Rectal mass

Question 39

What labs should be run when working up constipation?

Answer 39

- CBC: check for anemia - BMP: hypkalemia, hypercalcemia, diabetes - TSH - Not necessary in all pts

Question 40

When should endoscopy and imaging be done for constipated pts?

Answer 40

No need unless alarm symptoms - If rectal bleeding in pt under 45 yo (do sigmoidoscopy to rule out malignancy) - If alarm symptoms (bleeding, weight loss) or age \> 50, do colonoscopy - KUB can be done to evaluate for fecal loading

Question 41

What should be done for constipated pt if therapeutic trial does not yield improvement?

Answer 41

**Sitz Marker study** - Capsule with markers ingested and then serial xrays - If markers throughout the colon -\> slow transit - If markers in rectum -\> pelvic floor dysfunction **Defecography** **Anorectal manometry**

Question 42

How can constipation be treated?

Answer 42

**Fiber** - Dietary is difficult (20-30 g/day) - Supplementation - May cause gas and distension **Increase fluid and exercise** - Good idea, but no evidence **Laxatives** **Biofeedback** - Pelvic floor dysfunction pts - Attempt regular defecation schedule - Biofeedback Other: - **Chloride secretagogues** - **Systemic agents** - **Surgery**

Question 43

What are different laxatives/strategies?

Answer 43

**BULK** - Psyllium - Methycellulose - Wheat dextrin **Emollient** - Docusates - Mineral Oil **Osmotic** - Mg hydroxide - Phosphate salts - Lactulose - Sorbitol - Polyethylene glycol **Stimulants** - Castor Oil - Cascara fluid extract - Senna - Bisacodyl

Question 44

How can you use biofeedback to treat constipation?

Answer 44

**Pelvic floor dysfunction patients** **Attempt regular defecation schedule** - Use suppositories or enemas - Reward success **Biofeedback** - Relearn to interpret sensation

Question 45

What are chloride secretagogues and how do they help in treating constipation?

Answer 45

Lubiprostone- opens chloride channels and increases luminal fluid secretion

Question 46

What are systemic agents and how do they help in treating constipation?

Answer 46

- Methylnaltrexone in opiate induced constipation - Blocks opiate receptors on the GI tract

Question 47

What surgeries may be done to treat constipation?

Answer 47

- Colonic inertia - Colectomy