10/12- Abdominal Pain and Constipation Flashcards
How is pain sensed in the diaphragm?
- Receptors
- Stimuli
- Sensation
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
Describe abdominal pain due to visceral receptors?
- 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
Describe somatic/parietal pain
- Nerve fibers involved
- Location
- Sensation
- Aggravated by
- Location
- 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
What are reflexive responses to somatic/parietal abdominal pain?
- Involuntary guarding
- Abdominal rigidity
How can quality of pain give you a clue to the cause of the abdominal pain?
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
What causes referred pain?
- What neurons involved
- What may cause it
- 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
How does localization vary by cause with abdominal pain?
- Visceral pain: localization unreliable
- Parietal pain: reliable location
- Most organs are bilaterally, symmetrically innervated
(EXCEPT: gallbladder, ascending/descending colon)
Difference between acute/chronic or recurrent abdominal pain?
- Acute = under 24 hrs, usually sudden onset
Rigidity upon palpation of the abdomen suggests what?
Peritonitis
Rebound tenderness suggests what?
Peritonitis
Absence of bowel sounds may indicate what conditions?
- Peritonitis
- Perforation
- Obstruction
High pitched bowel sounds may indicate what?
- SBO
- Ileus
What to look for on lab testing when working up abdominal pain?
- CBC: anemia, leukocytosis, leukopenia
- CMP: assess metabolic state, assess hepatobiliary disease
- Lipase (amylase): elevated in acute pancreatitis
- Pregnancy test for childbearing age women
When is x-ray useful in evaluating abdominal pain?
“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
When is US useful in evaluating abdominal pain?
- Cholelithiasis
- Biliary evaluation
- Abscesses
- Aortic aneurysm
- Ectopic pregnancy
Pros: readily available, inexpensive
Cons: limited evaluation, operator dependent, can be time consuming
When is CT useful in evaluating abdominal pain?
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
What is the key demographic for biliary disease?
4Fs:
- Fat
- Forty
- Female
- Fertile
Where is pain from biliary disease experienced?
Postprandial RUQ pain
- Biliary colic intermittent
What are types of biliary disease/co-conditions?
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
In what condition is Charcot’s triad/Reynold’s pentad observed?
Cholangitis
Causes of upper abdominal pain?
Biliary disease
- Acute cholecystitis
- Choledocholithiasis
- Cholangitis
Peptic ulcer disease
Acute pancreatitis
Describe peptic ulcer disease?
- Location
- Improved when
- Complications
- Signs
- Epigastric, improved after eating
- “Acute abdomen” if perforated Peritonitis/Peritoneal signs
- Rigid abdomen
- Lack of bowel sounds
Describe peptic ulcer disease
- Most common causes
- Presentation
- Diagnostic criteria
Treatment
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
What may cause lower abdominal pain?
- Appendicitis
- Diverticulitis
Diffuse abdominal pain sydnromes:
- Mesenteric ischemia
- Mesenteric embolism
- Mesenteric thrombosis
- Low flow mesenteric ischemia
- Small bowel obstruction
Describe appendicitis
- What is it
- Presentation
- Diagnosis
- Treatment
- # 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
Describe diverticulitis
- Disease progression
- What is it
- Complications
- Presentation
- Treatment
- 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
What are some causes of diffuse abdominal pain syndromes?
- Mesenteric ischemia (embolism)
Describe mesenteric ischemia/embolism
- Most common causes
- Presentation
- Exam findings
- Complications
- 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
Describe mesenteric thrombosis
- Causes
- Presentation
Due to:
- Atherosclerosis, usually at SMA
May describe:
- Intestinal angina
- Weight loss
Describe low flow mesenteric ischemia:
- Causes
- Presentation
- Reduced cardiac output
- Shock
- Dehydration
Describe small bowel obstruction:
- Causes
- Presentation
- Diagnosis
- Treatment
- 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
What is normal as far as bowel habits?
- 2-3/day to 3/week
- Should be easy to pass
- Should feel relieved afterward
Pathophysiology of constipation: secondary?
- Colon disorders
- Metabolic disturbances
- Neurologic disorders
- Medications
Colon disorders:
- Strictures
- Anal fissure
- Proctitis
Metabolic disturbances:
- Hypercalcemia
- Hypothyroidism
- Diabetes
Neurologic disorders:
- Parkinsonism
- Spinal cord lesions
Medications:
- Antacids
- Opiates
- Iron
- CCBs
Pathophysiology of constipation: idiopathic?
- Slow transit
- Functional outlet obstruction
Describe slow transit as a cause of idiopathic constipation
- 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
Describe functional outlet obstruction as a cause of idiopathic constipation
- Ineffective opening of the anal canal or failure of the rectum to expel feces
- Pelvic floor dysfuction: lack of coordination or altered anatomy
What are alarm symptoms when working up constipation?
- Blood in the stool
- Weight loss
- Sudden onset of symptoms
What should be done on PE for constipation work up?
Abdominal exam:
- Distension
- Tenderness
- Fecal column
Anorectal exam:
- Examine perineum
- Cutaneoanal reflex (“anal wink”)
- Rectal mass
What labs should be run when working up constipation?
- CBC: check for anemia
- BMP: hypkalemia, hypercalcemia, diabetes
- TSH
- Not necessary in all pts
When should endoscopy and imaging be done for constipated pts?
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
What should be done for constipated pt if therapeutic trial does not yield improvement?
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
How can constipation be treated?
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
What are different laxatives/strategies?
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
How can you use biofeedback to treat constipation?
Pelvic floor dysfunction patients
Attempt regular defecation schedule
- Use suppositories or enemas
- Reward success
Biofeedback
- Relearn to interpret sensation
What are chloride secretagogues and how do they help in treating constipation?
Lubiprostone- opens chloride channels and increases luminal fluid secretion
What are systemic agents and how do they help in treating constipation?
- Methylnaltrexone in opiate induced constipation
- Blocks opiate receptors on the GI tract
What surgeries may be done to treat constipation?
- Colonic inertia
- Colectomy
