Final Flashcards
What are the different types of macronutrients in the diet?
Carbohydrates - Seen in sugar, flour, fruits, vegetables, dairy products, cellulose, etc. This is a big energy source for humans.
Lipids - Triacylglycerol makes up more than 90% of dietary fat. These provide satiety, add flavor, and aroma to the diet. This is an efficient energy source.
Proteins - Meat
What are the processes of macronutrient digestion and absorption?
Carbohydrates - α-amylase in the saliva and pancreatic juice hydrolyzes starch and glycogen into maltose and maltotriose. There are enzymes in the small intestine as well (Maltase converts maltose/maltotriose -> glucose; Sucrase converts sucrose -> Glucose and fructose; Lactase converts lactose -> glucose and galactose). We need these enzymes because only monosaccharides are absorbed in the body.
- Indigestible carbs may be broken down by bacterial enzymes which result in short-chain fatty acids, resulting in diarrhea, gas, etc.
Lipids - Fats need to be solubilized in order to be digested. This is done by bile acids. Gastric and pancreatic lipases hydrolyze triacylglycerol to fatty acids and monoacylglycerol. Esterases are also used to hydrolyze monoacylglycerol and cholesterol ester.
Proteins - The low pH of gastric juice denatures proteins. Pepsins are also used for the digestion in the stomach. Peptidases on the surface on the intestine digest proteins to produce free amino acids and di- and tripeptides. Intracellular peptidases inside the intestine transport amino acids and hydrolyze the di and tripeptidases. Only free amino acids are released into the blood.
What is the utilization of macronutrients after absorption?
Carbs - Used as a major energy source and is used to generate many metabolic intermediates.
Lipids - Chylomicrons deliver lipid to peripheral tissues. Muscle uses fat as an energy source, then excess fat is stored in adipose tissues.
Proteins - Used as an essential structural component. Also, they make up enzymes, hormones, plasma proteins, antibodies, and more. We are protein based.
How are excess macronutrients converted and stored?
Carbs - Excess carbs are converted to glycogen and triacylglyerol
Lipids - Excess fat is stored in adipose tissues.
Proteins - Excess protein is used as a source of energy. Glucogenic amino acids are converted to glucose and ketogenic amino acids are converted to keto acids and fatty acids. Eventually, it’s converted to triacylglycerol to be stored in adipose tissue.
How can you calculate the calorie contents of food?
Carbohydrates - 4 kcal/g
Lipids - 9kcal/g
Proteins - 4kcal/g
What are the essential macronutrients?
Essential fatty acids: Used to synthesize eicosanoids.
- Omega-3 (ω-3) fatty acids: α-Linolenic acid (18:3) in vegetable oils, Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in fish oids.
- Omega-6 (ω-6) fatty acids: Linoleic acid in corn oil, Arachidonic acid in meat and fish.
Essential amino acids:
- Arginine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Valine.
- Conditionally essential: Cysteine, Glutamine, Glycine, Proline, Tyrosine
What are the health consequences of having insufficient essential macronutrients?
Not enough essential amino acids: If we don’t get these from the diet, new proteins can’t be made without breaking down other body proteins.
No enough lipids: These are important in regulating BP, blood clotting, and immune functions, so we need these to keep out body processes balanced.
What are human energy reserves?
- We have excess energy stored mostly as fat in adipose tissue.
- Glycogen in the liver is used to maintain blood glucose levels.
- Glycogen in the muscle is used for exercise
What is the regulation of metabolism under well-fed, early fasting, and fasting states?
Well-fed: Insulin is released and is chemoregulating everything. Glycolysis is happening to break down glucose, glycogen is being made from the glucose. Amino acids are being broken down to make other products, fatty acids are being made. No glucose is being made!!
Early fasting: Glucagon is released (not insulin). Glycogen is being broken down to supply the body with glucose. Gluconeogenesis is happening due to the Cori and Alanine cycle. No amino acids are being broken down.
Fasting: Glucagon is released. The liver is working really hard to make glucose. Protein is used as a major carbon and nitrogen source (use Alanine and Glutamine). Lipolysis is happening in adipose tissue so that we are using fat as energy. Ketogenesis is happening because the amount of glucose in the body is not sufficient to supply the brain. We also see hypothyroidism.
What is caloric homeostasis in a human?
Caloric homeostasis is when we have constant availability of fuels in the blood so that our body has whatever resources it needs.
Glucose is heavily regulated. If it falls below 1.5mM, coma and death will happen. If we have too much, it can cause dehydration, hyperglycemic coma, and other complications.
What are examples of malnutrition?
Marasmus - Inadequate intake of both protein and energy, causing a thin wasted appearance. The child will be small for his/her age.
Kwashiorkor - Inadequate intake of protein with adequate energy intake. This happens mainly in children 1-3 years old. They can’t synthesize proteins (inc. digestive enzymes), so they aren’t able to break down carbs. They will have lots of swelling, which makes them deceptively plump.
What do these mean: EAR, RDA, AI, and UL
EAR - Estimated average requirement. This represents the amount of nutrient that satisfies 50% of the population.
RDA - Recommended dietary allowance. This is 2 standard deviations away from the EAR (so it satisfies 98% of the population).
AI - Adequate intake. This is used when scientific evidence isn’t enough to set an EAR, so approximations of average nutrient intake are from a healthy population.
UL - Tolerable upper intake levels. If you pass this amount, there will be toxicity.
What are the fat-soluble vitamins and what are the water-soluble vitamins?
Fat soluble - Vitamin A, D, E, K
Water soluble - Vitamin Bs, C
What are the biochemical roles of the 7 B vitamins + Vitamin C?
- Thiamin (B1): Thiamin pyrophosphate functions as a cofactor in enzymatic catalysis. Thiamin triphosphate functions within the nerve impulse in peripheral nerve membranes.
- Riboflavin (B2): Precursor of cofactors that are used in redox reactions (FAD, FMN).
- Niacin (B3): These are converted to the cofactors NAD and NADP.
- Pyridoxine (B6): Converted to cofactor pyridoxal phosphate that functions in transamination reactions of AA metabolism, synthesis of neurotransmitters, and synthesis of sphingolipids.
- Biotin (B7): Is a cofactor in activation of CO2 in carboxylase enzymes.
- Folic acid (B9): converted to a one-carbon carrier in enzyme reactions. Used in the synthesis of amino acids and nucleotides and is essential for DNA synthesis and cellular proliferation.
- Cobalamin (B12): Required for two reaction in humans.
- Vitamin C: Ascorbic acid. Cofactor for several oxidases and is a reducing agent.
What diseases can result from deficiency of a vitamin?
Vitamin A: Deficiency can result in night blindness.
Vitamin D: Rickets in young children, osteomalacia in adults.
Thiamin (B1): Severe deficiency is called beriberi.
Niacin (B3): Severe deficiency is called pellagra.
Pyridoxine (B6) has mid and severe deficiency symptoms.
Folic acid (B9): Deficiency can result in increased risk of birth defects.
Cobalamin (B12): Causes accumulation of homocysteine and methylmalonic acid, which causes anemia and neurological damage.
Vitamin C: Capillary fragility can result from a mild deficiency. Scurvy may result from a severe deficiency.
Calcium: Osteoporosis
Iron: Anemia
Iodine: Goiter (enlargement of thyroid gland), cretinism (severely stunted physical and mental growth).
Zinc: Poor growth and impairment of sexual development. Also may cause poor wound healing, dermatitis, and impaired immune function.
Copper: Anemia, bone demineralization, blood vessel fragility.
What are the symptoms of vitamin or mineral deficiencies?
Thiamin (B1) deficiency, Beriberi, is characterized by muscular atrophy and weakness.
Riboflavin (B2) deficiency has symptoms including angular cheilitis, glossitis, and scaly dermatitis.
Niacin (B3) deficiency, Pellagra, has characteristics of dermatitis, diarrhea, and dementia
Mild Pyridoxine (B6) deficiency has symptoms of irritability, nervousness, and depression. Severe pyridoxine deficiency is seen with peripheral neuropathy and convulsions.
Folic acid deficiency can be seems in patients who are anemic. They can also cause birth defects (neural tube defect).
Capillary fragility (from mild Vit C deficiency) has symptoms of easy bruising and decreased immunocompetence. Scurvy (severe Vit C deficiency) has symptoms of decreased wound healing, osteoporosis, hemorrhaging, and anemia.
Ca2+ deficiency may cause osteoporosis or muscle cramps.
What are common food sources for vitamins and minerals?
Vitamin A: Dark green and yellow vegetables, liver, egg yolk, butter, whole milk.
Vitamin D: Vit D milk, saltwater fish, liver, egg yolk
Vitamin E: Vegetable oils rich in polyunsaturated fatty acids
Vitamin K: Green vegetables, Vit K2 is synthesized by intestinal bacteria.
Riboflavin (B2): Milk, meat, eggs, cereal products.
Niacin (B3): Meats, peanuts, enriched cereals.
Pyridoxine (B6): Meat, vegetables, whole-grain cereals
Biotin (B7): Found in lots of food sources.
Folic acid (B9): Rich in lots of food sources.
Calcium: Dairy products, nuts, beans, seeds, seaweeds.
Iodine: Added to salt. Good natural source is seafood.
What populations are at risk of vitamin deficiency?
- Populations that rely exclusively on polished rice for food or alcoholics are at risk to get beriberi (Thiamin deficiency)
- Chronic alcoholics also are at risk of Riboflavin deficiency.
- Alcoholics, pts with severe malabsorption, and the elderly are on very restricted diets.
- If raw egg white is consumed regularly or is a woman is pregnant the person may be at risk of biotin deficiency.
- Alcoholics are at risk of folic acid deficiencies.
- Patients with severe malabsorption diseases and long term vegetarians are at risk of cobalamin deficiencies.
- Smokers may be at risk of a vit C deficiency.
- Low-income children and adult females are at risk of a calcium deficiency.
- Menstruating females are at risk of an iron deficiency.
What is the pharmacological mechanism of warfarin?
Warfarin inhibits the Vit K epoxide reductase that activates vitamin K. Without the active Vitamin K Hydroquinone, The carboxyglutamate is not made, which is needed for blood clotting.
What are the biochemical roles of the 4 trace minerals?
Iodine: Synthesis of thyroid hormones.
Zinc: Needed for metalloenzymes and zinc finger proteins.
Copper: Needed for many enzymes.
Selenium: Used during translation.
What are the biochemical roles of the 4 fat soluble vitamins?
- Vit A: Retinol, retinal, retinoic acid. Retinol can act as a light sensor. Retinoic acid can function as a steroid hormone that regulates cell growth and differentiation. Carotenoids are effective antioxidants.
- Vit D: Function as steroid hormones that maintain calcium homeostasis. It is produced in the skin from sun exposure.
- Vit E: Tocopherols and tocotrienols. These are antioxidants that protect unsaturated fatty acids. They reduce the risk of CVD by preventing the oxidation of LDLs.
- Vit K: Needed for post-translational modification of glutamic acid residues to carboxyglutamic acid residues, which allow proteins to bind to Ca2+. They are essential for blood clotting and bone mineralization.
What are the biochemical roles of calcium and iron?
- Calcium: Makes bones, is a second messenger, required for enzymes, essential for blood coagulation and muscle contraction.
- Iron: Required for O2 transport, energy metabolism, cell proliferation, immune defense.
What are some important parts of GI anatomy and what is the physiological control of acid secretion in the stomach?
Anatomy:
- Stomach (the acid sterilizes the contents we eat): The lower esophageal sphincter is important. If it’s too lose, the acid will go up into the esophagus. The stomach has a multi layer lining of muscle that facilitates digestion.
- Duodenum: This is where digestion begins. Digestive enzymes start to break down food.
- Jejunum
- Anal canal
Physiological control of GI secretions: First, G-cells produce gastrin. This gastrin travels through the blood stream and bind to ECL cells in the fundus of the stomach. In the ECL cell, histamine is released and it binds to receptors on the intestinal parietal cells (along with some gastrin and ACh). This binding pulls K+ out of the stomach and exchanges it for H+. This is the proton pump that contributes to the acidity of the luminal acid secretion. When the acid reaches a certain point, somatostatin is produced and shuts down gastrin production.
What salts are used as antacids (4), what is their acid neutralizing capacity, and what side effects are associated with them?
Antacids - Ingest a weak base to reduce the acid content of the stomach.
NaHCO3 - High neutralizing capacity, side effects include systemic alkalosis and fluid retention
CaCO3 - Moderate neutralizing capacity, side effects include hypercalcemia, kidney stones, and milk-alkali syndrome; Ex. Tums
Al(OH)3 - High neutralizing capacity, side effects include constipation and hypophosphatemia
Mg(OH)2 - Diarrhea
What is the mechanism by which PPIs inhibit acid secretion and how can you recognize their chemical structure?
PPIs irreversibly inhibits the ATPase that exhanges K+ for H+ in the parietal cells. This means the acid is not produced.
PPIS all have the S=O that ends up covalently binding with the H+ pump. They also have the double ring structure. These are prodrugs that are activated by acidic pH inside the parietal cell.
Ex. Esomeprazole, lansoprazole, Pantoprazole
Some risks: infection, Vit B12 defiency, Ca2+ deficiency
What is the role of mucosal protective agents and what is their mechanism of action?
Sucralfate polymerizes to form a protective barrier at the ulcer site. Misoprostol is a prostaglandin analog that has cryoprotectant effects, like enhanced mucus and bicarbonate secretion, and reduced acid secretion.
Ex Misoprostol, Sucralfate
What is the rationale for antibiotic treatment of ulcers?
Many ulcers are use to an infection by gram-negative bacteria. They break the mucus down which provide an opportunity for an H. Pylori infection. So, antibiotics would work to eradicate this infection.
Common antibiotics used: Metronidazole, Tetracycline, Amoxicillin, Clarithromycin
What are examples of drug classes that increase GI motility (2) and what are their mechanisms of action?
Laxatives - Bulk and osmotic laxatives draw water into the stool by forming polymer chains, which stretches the intestine, leading to contraction and relaxation. Stool softeners get incorporated into the stool to make passage easier and decrease water absorption. They also lubricate the lower bowl to reduce fecal impaction. Secretory/stimulant laxatives cause irritation of the mucosa, which affects fluid secretion/absorption balance and induces peristalsis.
Prokinetics - These act on the cholinergic motor neuron. Metoclopramide is a D2 receptor antagonist that leads to an increase in ACh release. Prucalopride is a 5HT4 receptor agonist. It’s a GPCR that leads to increased cAMP, which releases ACh (smooth muscle stimulated). Chloride Channel Activators, Linaclotide (GC-C) and Lubiprostone (ClC2) for example, lead to increased Cl- in the gut, leading to increased Na+, leading to increased H2O, which stimulates peristalsis. Sodium/hydrogen exchanger inhibition causes more Na+ to be in the lumen, leading to peristalsis.
What are examples of drug classes that reduce the GI motility (2), and what are their mechanisms of action?
Antidiarrheals - Opiates, like Dihenoxylate and Loperamide, inhibit presynaptic cholinergic nerves, leading to slowed peristalsis to increase water and electrolye absorption. 5HT3 receptor antagonists decrease colon motility.
Anti-emetics - 5HT3 receptor antagonists (ex. ondansetron) block the activity of afferent nerves from stomach and the SI, which activate the trigger center in the CNS. NK1 antagonists (ex. Aprepitant, Netupitant, and Rolapitant) antagonize receptors in the chemoreceptor trigger zone. Antihistamines/anticholinergics antagonize the muscarinic stimulation of peristalsis. Antipsychotics (D2 receptor antagonists) have anti-emetic, sedative, and antimuscarinic/antihistamine effects.
What is gastroesophageal reflux disease (GERD)?
GERD is when passage of gastric contents into the esophagus cause symptoms and/or damage to the esophagus.
What is the pathophysiology of GERD?
The lower esophageal sphincter usually relaxes when you swallow, then immediately closes up. With GERD, the sphincter is not as quick to close, and the liquid/acid can cause erosion in the esophagus and even food can come back up.
Increased acid production and gastric pressure, along with decreased esophageal clearance and gastric emptying contribute to the pathogenesis of GERD.
What are the symptoms (typical and atypical) and alarm symptoms of GERD?
Typical symptoms: Heartburn, regurgitation, belching, bloating, nausea, early satiety, hypersalivation, trouble sleeping
Atypical symptoms: Chronic cough, non-allergic asthma, hoarseness, dental enamel erosion, globus sensation
Alarm symptoms: Difficulty breathing, involuntary weight loss, vomiting, blood in stool, dysphagia, choking, chest pain, continual pain, painful swallowing
What are the risk factors and stressors of GERD?
Risk factors: overweight/obesity, diet, smoking, diabetes, asthma, pregnancy, delayed stomach emptying.
Food triggers for reflux: Coffee, chocolate, fatty foods, alcohol
Food triggers for heartburn: Spicy foods, acidic foods, carbonation
Medication triggers: Aspirin/NSAIDs, bisphosphonates, potassium chloride, iron, chemotherapy, anticholinergics, calcium channel blockers, tricyclic antidepressants, narcotics, barbiturates/benzodiazepines, nitrates, estrogen and progesterone
How do you diagnose GERD?
Do a clinical history to help paint a full picture. If the patient has typical mild symptoms, clinical history + response to treatment = diagnosis. With pts who have alarm symptoms or those who don’t respond to therapy within 8 weeks of a PPI, consider other tests.
- Treat first, test later
- Other diagnosis tests: endoscopy, pH probe test, bernstein test, manometry
What are the non-pharmacological treatment options for GERD?
Lifestyle modifications
- Smoking cessation
- Exercise & weight loss
- Eat small, frequent meals
- Raise the head of the bed
- Eliminate trigger foods & increase water
- Avoid laying down after meals
What is the mechanism of action and use of GERD treatments?
We want to neutralize the acid and reduce gastric acid secretion.
PRN medications: Symptoms are just a couple of times per week. (refer if OTCs don’t work within 14 days)
- Antacids: Weak bases that neutralize gastric acid. Quick onset. Ex. Tums (Ca), Milk of Magnesia (Mg), Mixed
Scheduled medications:
- H2RAs: Reversibly inhibit histamine receptors. Ex. Famotidine, Cimetidine; Used for mild to moderate GERD, take 10-60 mins before a meal. Treatment is 6-12 weeks.
- PPIs: Irreversibly inhibits proton/potassium ATPase activity. Full effect is in 3-5 days
- Prokinetics: Enhance gastric motility/increases speed of gastric emptying. Blocks DA/5HT receptors.
What are the medical options for the treatment of GERD?
Surgery - Reinforces the lower esophageal sphincter. The top of the stomach is wrapped around the lower esophagus. This reduces regurgitation and acid back-flow.
Who qualifies? - If pt is contraindicated to PPI or if PPI + lifestyle modifications don’t control symptoms.
These don’t prevent cancer and they don’t prevent the need for long-term medications.
What are the treatment options for special populations in GERD?
Pregnancy: Lifestyle modifications
1. Antacids
2. Sucralfate & H2RAs (ranitidine, famotidine, cimetidine)
Last. PPI only for complications of GERD or treatment failure.
Lactation: PPIs and H2RAs are present in breastmilk, but there’s low risk to infants at standard doses.
Infants/Children: Non-pharm includes thickening of formula/foods, decreasing the volume of intake, milk free diet, and positioning therapy
- PPIs and H2RAs can be used for 4-8 weeks if child is diagnosed for GERD for esophagitis.
- Children shouldn’t use antacids chronically, and aluminum shouldn’t be used in children under 12.
- Simethicone and probiotics are safe and OTC.
What is the dosing, MOA, side effects, and drug interactions for antacids?
Dosing: PRN
- Tums: 1-4 tablets PRN up to 4x per day.
- Milk of Magnesia: 5-15 mL PRN
MOA: Neutralize acid.
Side effects: Nausea/Vomiting
- Calcium side effects: constipation, Milk-Alkali syndrome
- Mg side effects: Diarrhea, accumulation
- Al side effects: Constipation, confusion/neurotoxicity
Drug interactions: Take meds 2 hours before or 4-6 hours after antacids.
- HIV meds
- Digoxin
- Levothyroxine
- Azole antifungals
- Tetracyclines
- Fluroquinolones
- Steroids
- Iron
What is the dosing, MOA, side effects, and drug interactions of H2RAs?
Dosing: every day or twice a day
- Famotidine: 20, 40mg
- Cimetidine: 200, 400, 800mg
MOA: Reversibly inhibit histamine receptors.
Side effects: Headaches, dizziness/fatigue, constipation/abdominal pain, somnolence/confusion, agitation, thrombocytopenia
Drug interactions:
- Cimetidine has so many drug interactions it’s not used anymore.
** adjust the dose with pts who have renal impairment
What is the dosing, MOA, side effects, and drug interactions PPIs?
Dosing: Once daily dosing
MOA: Irreversibly inhibits proton/potassium ATPase activity. Prodrug.
Side effects: Headache, dizziness, constipation, diarrhea, nausea, abdominal pain, long-term concerns. These are pretty well tolerated.
Drug interactions: The most inhibition is with omeprazole and esomeprazole
- Reduce absorption of Ca2+, Vit C, and Iron.
- These increase effect: Methotrexate, phenytoin, warfarin
- These decrease effect: Iron, bisphosphonates, HIV drugs
** don’t take OTC longer than 14 days at a time, Rx is used for 8 weeks, no tolerance seen, can increase to BID if needed, switch to different PPI if the first doesn’t work.
What are some risks and concerns associated with PPIs?
- C. diff: Highest risk is in pts who are older, chronic med conditions, also on broad spectrum antibiotics. For this reason, we want to use these at the lowest dose for the shortest duration.
- Bone density decrease/fractures: Increasingp pH may decrease calcium absorption, leading to fractures. Pts may want to be on calcium and Vit D supplements.
- Memory impairment
- Low B-12 and Mg lab values
What is the dose, MOA, and risks of metoclopramide?
Metoclopramide:
Dosing: 10-15mg QID 30 mins before meals
MOA: Enhances motility/increases gastric emptying; blocks DA/5HT receptors
Risks: Tremors, depression, HTN, proarrythmic effects
** mainly used in pts with comorbid gastroparesis
What is the pathophysiology of PUD?
PUD - Open sore in GI mucosa that extends into muscularis mucosae (gastric or duodenal).
When the aggressive factors (pepsin, NSAIDs, H. pylori, and gastric acid) outweigh protective factors (blood flow to mucosa, bicarbonate, prostaglandins and mucus), ulcers can form.
What are the risk factors associated with the development of PUD?
Risk factors for H. pylori -
- Birth in developing country
- Low socioeconomic status
- Crowded/unsanitary living conditions
- Unclean food/water
- Exposure to gastric contents
- Close contact within households
How do pts with PUD present clinically?
Signs and symptoms: 70% are asymptomatic
- Intermittent symptoms: abdominal pain, nausea, bloating, abdominal fullness, weight loss, early satiety.
Gastric ulcer: Acid production in response to food irritates the ulcer
Duodenal ulcer: Pain occurs 2-3 hours after eating as the food passes through the stomach and into the duodenum.
What is the MOA, dosing, and adverse effects for Bismuth quad therapy?
MOA: bismuth has topical bactericidal effects which improves ulcer healing by inhibiting aggressive factors and increasing protective factors.
Dosing: Different brands have different dosing. 10-14 days.
- Metronidazole 250mg QID
- Tetracycline 500mg QID
- Bismuth subsalicylate 262.4mg 2 tabs QID
- PPI BID
Adverse effects:
- Bismuth: darkening of stools and tongue
- Metronidazole: Avoid alcohol due to disulfiram-like reaction (vomit)
- Tetracycline: Photosensitivity
- Levofloxacin: Tendon rupture, mental status change, QTc prolongation
What is the treatment of PUD when caused by H. pylori and NSAIDs and how do they differ?
H. pylori - PPI + 2-3 antibiotics; PPI BID is the backbone of therapy
1. Bismuth quad therapy (PPI, bismuth, tetracycline, metronidazole) for 10-14 days.
- Levofloxacin triple therapy PPI BID
Maybe. Probiotics prophylaxis as a supplement to increase eradication rates.
NSAIDs - Treatment for 8 weeks if NSAID was stopped, 12 weeks if continued.
- PPIs: Daily dose
- H2RAs
- Sucralfate: forms barrier over an open ulcer; treatment only
How do you make a treatment plan for a patient with PUD (inc. dose, duration, monitoring, and education)?
- If the patient has antibiotic resistance, poor medication adherence, short duration of therapy, high bacterial load, or low intra-gastric pH, these may alter the therapeutic outcome.
- If one antibiotic doesn’t work, use a different one
- Determine if H. pylori or NSAIDs caused. If H. pylori, do bismuth quad therapy, if NSAID, do PPI.
Education: proper drug administration, avoid/management of adverse effects, avoid triggers, comply with treatment, reduce NSAID-relate complications
What is the MOA, dosing, and adverse effects for misoprostol?
MOA: prostaglandin E1 analog that increases mucus and bicarbonate secretion, surface active phospholipids, and gastric mucosal blood flow. Also inhibits acid secretion.
Dose: 200mcg QID with food
Side effects: diarrhea, abdominal cramping, N/V, flatulence, headache, BBW: abortifacient
** for prophylaxis only
What are the four main classifications of diarrhea?
Acute: Less than 14 days of diarrhea.
Persistent: More than 14 days of diarrhea.
Chronic: More than 30 days of diarrhea.
Chronic idiopathic: More than 4 weeks of loose stool with no identifiable cause.
What are the different pathological mechanisms (4) associated with diarrhea?
- if secretions or reabsorption isn’t balanced, then you may end up with either constipation or diarrhea.
- Secretory - Change in active ion transport by either a decrease in Na+ absorption or an increase in Cl- secretion into the lumen, drawing more water in the stool. Seen with large stool volumes (>L/day), not altered by fasting.
- Osmotic - Poorly absorbed substances are retained in the intestinal fluids, resulting in an influx of water and electrolytes into the lumen. This improves with fasting.
- Exudative - This is a subset of secretory (messed up ion transport), secondary to inflammatory diseases of the bowel. This is characterizes by large stool volumes.
- Altered intestinal transit - Moving too fast through the intestine, not enough time to absorb the fluid.
What are 3 infectious organisms that are commonly associated with causing diarrhea?
Bacterial - Salmonella, E. coli
Viral - Norovirus
What is the impact of diarrhea in the US and around the world?
Disrupts quality of life
Leading cause of death in children in 3rd world countries.
What are the clinical pictures, etiology, and treatment for acute diarrhea, chronic diarrhea, traveler’s diarrhea, and drug-induced diarrhea?
Acute:
- Clinical presentation: Small intestinal cramps, abdominal pain, N/V, head ache, chills
- Treatment: No fever/systemic symptoms: fluid replacement, loperamide/diphenoxylate/absorbent, and diet; Yes fever/systemic symptoms: check for parasites and if positive, use appropriate antibiotics. If negative, do symptomatic treatment.
Chronic:
- Clinical presentation: Weight loss, anorexia, weakness
- Treatment: Refer!! If diagnosis, treat the specific cause; If no diagnosis: Replete hydration, D/C potential drug inducer, adjust diet, Loperamide or absorbent.
Traveler’s diarrhea:
- Clinical presentation: Acute watery diarrhea, duration 2-3 days.
- Etiology: Infective, usually by bacteria
- Prevention: Bottled water, no prophylaxis antimicrobials (rifaximin if necessary), bismuth subsalicylate, be cautious
- Treatment: Oral rehydration solutions; Mild: Loperamide or BSS; Moderate: Maybe antibiotic, maybe loperamide as monotherapy or adjunct; Severe: Antibiotic treatment (single dose preferred), maybe loperamide as adjunct.
Drug-induced:
- Clinical presentation: Ranges from mild inconvenience to life-threatening antibiotic associated.
- Etiology: Decreases transit time leading to irregular absorption and secretion, alteration of bowel flora.
- Treatment: D/C causative agent, oral rehydration fluids, loperamide if needed.
What are the appropriate questions to ask a patient when they are complaining of diarrhea?
- When did symptoms begin?
- Frequency, consistency, and color of stool?
- Have you had similar bouts in the past?
- Any fever, N/V, malaise?
- Presence of abdominal pain and/or cramping?
- Anyone else with similar symptoms?
- Any recent travel outside of the US?
What are the non-pcol options for management of diarrhea?
- Manage the diet: Most important with osmotic diarrhea, BRAT diet (bananas, rice, applesauce, toast); Don’t stop the feeding in children with bacterial diarrhea
- Fluid/electrolyte replacement: Re-hydrate and prevent electrolyte disturbances. Ex. Pedialyte
What are the different therapeutic indications, advantages, disadvantages, side effect, and key pt counseling points for these diarrhea therapeutic agents: antimotility drugs, absorbents, antisecretory agents
Antimotility drugs: Activate mu opioid receptors to reduce peristalsis and increase segmentation.
- Shouldn’t be used long term, not to be used with C. diff
- Ex. Loperamide, Diphenoxylate/Atropine (Lomotil)
- Loperamide has cardiac risk associated, so it’s important not to exceed 16mg/day.
Absorbents: Adsorb nutrients, toxins, drugs, and digestive juices to provide symptomatic relief. Used for some pts with chronic diarrhea if they have trouble forming solid stools.
- Effectiveness is unproven.
- Ex. Psyllium (Metamucil)
Antisecretory: Reduces secretions in the gut
- Ex. Bismuth subsalicylate (don’t use in pts who shouldn’t take salicylates, also has antimicrobial and anti-inflammatory effects).
Also use antibiotics when needed (Bactrium, nystatin, azithromycin, etc.) and get recommended vaccines (rotarix, dukoral, typhim) to prevent.