Diarrhea Flashcards
Definition of diarrhea
Passage of more than three unformed stools (Bristol stool forms 5-7 - soft blobs to water) in a 24 hr period
Prevalence of diarrhea
7-10% of cancer patients on admissiont o hospice, 6% of similar patients in hospital
Less common than constipation.
27% of symptomatic HIV infected patients
Definition of chronic diarrhea
Diarrhea persisting over 3 weeks
Causes of diarrhea in Palliative Care
Most common in Palliative patients:
- Imbalance of laxative tx (most common in palliative patients, especially when laxatives increased to treat constipation), but would typically resolved within 24-48 hrs of stopping laxatives. Restart at a lower dose.
- Malignant intestinal obstruction and fecal impaction (‘narcotic bowel syndrome’) resulting in overflow diarrhea. Note that partial obstruction may cause alternating constipation and diarrhea.
Others:
- Drugs (antacids, antibiotics, NSAIDs)
- Complications of antibiotics (lactose intolerance, c diff)
- Sorbitol in sugar free foods or enteral feeds
- GI infection, overgrowth of candida, C Diff
- Chemotherapy (5-FU, capecitabine, irinotecan) due to epithelial necrosis and inflammation leading to loss of absorptive surface
- Targeted therapies (bortzemib, erlotinim, everolimus, cetuximab, etc.)
- GVHD (may be life-threatening and become chronic) after stem cell transplant
- Radiation to abdomen or pelvis (2nd to 3rd week of tx due to damage of intestinal mucosa, malabsorption of bile salts
- Celiac plexus blockade (due to anatomical variations in innervation of the gut, blockade can result in excess bowel activity)
- Malabsorption related to pancreatic ca, or after gastrectomy/ileal resection. Results in steatorrhea.
- Bile salt malabsorption (Vagotomy causing increased fecal secretion of bile salts; ileal resection, esp over 100cm, where 97% of bile salts are re-absorbed)
- Total colectomy (partial usually no impact) - over 7 days begins to normalise, but patients still require an extra L of water and 7g of extra salt per day to compensate
- Secretory diarrhea from endocrine tumours secreting VIP or serotonin (pancreatic islet cels, adrenal tumours, bronchogenic CA, Zollinger-Ellison syndrome secreting gastrin, carcinoid tumour)
- Excessive dietary fibre from fruits and vegetables
History for diarrhea
Frequency and consistency
- Profuse and water: Colonic diarrhea
- Fatty, smelly: Steatorrhea (pancreatic or small intestinal cause)
- Diarrhea after constipation (fecal impaction)
Review of medications
- Ensure laxative dosing is regular
- Too much stimulants can cause colic and urency
- Too much stool softener can cause fecal leakage
- High doses of lactulose or docusate may cause colic or watery diarrhea
Ask about fever, blood in the stools, or dehydration (e.g. cytotoxic chemo, neutropenic enterocolitis)
Ask about immunotherapy (call Med Onc - can be life threatening, may occur months after cessation of tx but most common a few months after starting tx. Treatment is steroids, depending on therapy.)
Examination for diarrhea
- Rectal exam for fecal impaction
- Abdominal palpation for fecal masses
- Stool examination
Investigations for diarrhea
Anion Gap
- Stool osmo, sodium, and potassium to calculate anion gap (Stool osmo - (Na + K * 2)
Anion gap > 50mmol = Osmotic diarrhea (additional non-absorbed solute)
Anion gap < 50 = Secretory diarrhea (e.g. carcinoid, pancreatic islet cell tumours)
CBC, lytes, Cr etc. if persistent
C-diff if history of antibiotic use
Avoid culture if diarrhea occurs within 3 days of inpatient admission, as likely to be community-acquired bacterial pathogen or virus
Supportive Care for diarrhea
- Rehydration PRN (note oral is superior to IV when possible, solutions with lytes and glucose will facilitate active lyte transport across the gut wall)
- Consider clear liquids (flat lemonade or gingerale) with simple carbohydrates (crackers, toast) and reintroduce fats and proteins slowly as diarrhea resolves
- Note some infections can cause transient lactase deficiency - avoid dairy
In case of pyrexia, neutropenia, dehydration, or bloody stools:
- Inpatient management with IV support
- Octreotide with or without antidiarrheals
- Assessment for infection and antibiotics PRN
- In the case of neuropenia, consider candida infection
Pancreatic enzyme replacement for diarrhea
Pancrealipase - can be used for pancreatic insufficiency (chronic pancreatitis, pancreatic CA, DM, surgery, CF, Celiac)
Cholestyramine for diarrhea
Cholestyramine - bile acid binding resin effective in chologenic diarrhea
Occurs when there is insufficient resorption of bile acids through the small intestine due to resection of the terminal ileum gallbladder loss
Treatment for radiation-induced diarrhea
Loperamide first line (up to 2mg q2H), according to ASCO.
Treatment for chemotherapy induced diarrhea
Loperamide (initial dose 4mg, then mg q4h or after every unformed stool, NTE 16mg/day)
If severe or no resolution after 24-48H on loperamide, escalate to IVF with SC TID octreotide.
Treatment for Carcinoid diarrhea
- Treatment with selective somatostatin analogues (Octreotide)
- May also consider non-specific antidiarrheals, like loperamide, a trial of cholestyramine, or another SSA if octoretide is ineffective
Carcinoid Syndrome diarrhea (path, symptoms, treatment)
Patho:
- Increased production of serotonin
- Increased production of vasoactive intestinal polypeptide
Symptoms:
- Water stools
- Large volume (> 1L/day)
- Not affected by fasting
- Occurs day and night
- Stool frequency up to 20 times per day
- Associated with flushing
Treatment
- Octreotide (somatostatin analogue) is first line
Short GI Transit time diarrhea (Path, Symptoms, Treatment)
Patho
- Resection of the small bowel
- Loss of the ileocecal bowel
Symptoms
- bowel movements occur soon after meals
- Undigested or partially digested food in the stool
Treatment:
- Dietary adjustments (increase fibre, restrict fat), restriction of hypertonic fluids
- Loperamide
- Octreotide
