Lecture 4: GI Elimination 2

Lecture 4: GI Elimination 2 GI Congenital Malformations · Esophageal atresia · Tracheoesophageal fistula (TEF or TE fistula) · S&S: compromised airway, choking, vomiting, lack of stool due to no GI continuum Small Intestine · 20 ft long (6m), 1 inch diameter · 3 parts: ↳ duodenum ↳ jejunum ↳ ileum · major function: absorption of nutrients Large Intestine · 5 ft long (1.5 m), 3 inch diameter · 4 parts: ↳ ascending colon ↳ transverse colon ↳ descending colon ↳ sigmoid colon · major function: re-absorption of water Carbohydrate, Protein, and Fat Metabolism ① Carbs · carbohydrate → monosaccharides (simple sugars) → glucose + galactose · broken down by salivary amylase, pancreatic juices, brush border enzymes (maltase + lactase) · once broken down they travel through the blood stream to the liver → systemic · note: broken sugars cause osmotic movement of water into intestines, causing diarrhea (eg. lactose intolerance) ② Proteins · protein → amino acid chains · HCI converts pepsinogen into pepsin to break down proteins in the stomach ↳ pepsinogen is secreted from gastric chief cells ↳ further broken down by pancreatic juices · once broken down they travel through the blood stream to the liver → systemic ③ Fats · Fats → triglycerides → Fatty acids · broken down by bilingual lipase, emulsification of fats through bile, and pancreatic juices · once broken down they travel through lymphatic circulation → systemic ~ - - Hirschsprung Disease · innervation issue due to lack of parasympathetic ganglia in wall of large intestine · lacks the ability for GI movement or peristalsis (likely fecal impaction) Tx: pull-through procedure Review of IBD: Inflammatory Bowel Disease (IBD) · environmental factors cause immune system to malfunction, leading to inflammation · risk factors: family history · S&S: anorexia, diarrhea, nausea · trigger: endogenous host flora is recognized as noxious antigen * · Crohn's disease: Entire GI is inflamed, characteristic patchy lesions and sores in mouth * · Ulcerative colitis: continuous inflammation inside the colon · diagnosis: endoscopy or colonoscopy ↳ may see fistula or adhesion to body wall by improper healing/fusion · treatment: Sulfasalazine ↳ also biologics and glucocorticoids - - Celiac Disease · "gluten sensitive enteropathy" · gluten triggered immune disorder where T-cells form a response to alpha-gliadin (gluten component) causing severe inflammation and loss of villi ↳ not always at birth, can happen over time . S&S: anorexia, bloating, diarrhea, malnutrition · diagnosis: serology, biopsy (endoscopic) · treatment: avoid gluten - C. difficile Infection · G + bacteria, opportunistic · causes damage to stomach lining (b/c of toxin), and contaminates stool · highly contagious! · S&S: severe diarrhea, blood or pus in stool, fever, abdominal pain, dehydration · empiric treatment: metronidazole, vancomycin E. coli Infection G· E. coli is often ingested through undercooked meat, contaminated vegetables, contaminated water, or unwashed hands · S&S: diarrhea, pain, fever, (GI symptomology) · complications: hemolytic uremic syndrome (HUS) due to shiga toxin · treatment: supportive, rehydration Antidiarrheals Diarrhea is a Symptom! · increased frequency and fluidity of loose/unformed stool · opioid-based, high efficacy ↳ CNS depression in high closes (sedating effect) · caused by inflammation, infectious organisms, or drugs * · Mu2 receptor agonists → decreased peristalsis · Acute: <2 weeks, sudden onset · Drugs: Opioid + atropine · Chronic: >4 weeks, long-term disease or drug tx ↳ Lomotil (diphenoxylate atropine) · complications: electrolyte imbalance, dehydration, ↳ Imodium (loperamide HCI) malabsorption - meperidine (Demerol)+ atropine ↳ rehydration is a must! Types of rehydration in slides manum Constipation is a Symptom! · decrease in the frequency and number of bowel movements · alterations in peristalsis or intestinal innervation impacting colon motor function · can be caused by lack of dietary fibre or fluid intake · treatment: laxatives (5 types) Laxatives ① Bulk-forming agents · pull water and bulk into stool w/fiber · drug: Metamucil (psyllium) ↳ prophylactic: takes 1-2 days for effect ↳ water intake w/drug ↳ most PO, some PR (not systemic) ② Stool Softeners · pull water and fat into stool · drug: Colace (Docusate Sodium) ↳ prophylactic, decreased straining ↳ requires good renal function for excretion ↳ post MI or post surgery ③ Osmotics (& Saline) · pulls water into stool · drugs: Milk of Magnesia, Lactulose, GoLytely ↳ pre-procedural ↳ potent, fast-acting (1-3 hours or less) · note: Milk of Magnesia is renally excreted & Lactulose is contraindicated in lactose intolerance - - - ④ Stimulants / Irritants · increase peristalsis through ep3 receptor of smooth muscle · drugs: Dulcolax, Senna (Exlax, Senokot), Castor oil ↳ s/e: N&V, cramping ↳ do not use on obstruction for risk of perforation ↳ NOT first choice ⑤ Miscellaneous · lubricating · drugs: Mineral oil, glycerine (PR) ↳ note: used with other treatments - - Cathartics · NOT a laxative · it is an enema (inserting saline up rectum to help constipation) · used pre-procedural for bowel preparation ~ Bloating · gas, farting, burping · dietary ingestion causing abdominal discomfort · drugs: ↳ Gas X (simethicone) - surfactant that breaks surface tension of bubbles ↳ Beano (alpha-d-galactosidase) - carb enzyme increases digestion into simple sugars Nausea & Vomiting · the vomiting center in the medulla recieves stimuli from chemoreceptor trigger zone (CTZ), organs, body etc. ↳ CTZ outside of BBB where stimuli can trigger GI and diaphragm contractions → emesis · There are many types of stimuli such as GI infections, food poisoning, stress, motion sickness, and pain · protective mechanism Motion Sickness / Morning Sickness · There are 2 types of drugs: ① H1 Antihistamines ↳ antagonizes receptors of vestibular excitation → some sedating effects ↳ drugs: - dimenhydrinate (Gravol): diphenhydramine + chlorotheophyline - mecizine (Dramamine) Morning sickness - diclectin: doxylamine + pyridoxine hydrochloride (vitamin B6) ② Antimuscarinic Anticholinergics ↳ reduce vestibular excitation (some affinity for H1 receptors) ↳ drugs: scopolamine (Hyoscine) - transdermal patch - - Drug-induced & Chemotherapy + Visceral Pain Nausea · targets 5HT3 (serotonin) antagonists · drug: ondansetron (zofran) ↳ px only, PO, IV GI Pain Nausea · targets D2 receptor antagonism → stimulates GI motility · drug class: Phenothiazines ↳ drugs: metoclopramide (Maxeran, Reglan), prochlorperazine (Stemetil) - px only, PO, IV, SC - s/e of sedation Chemotherapy, Chronic Disease, Challenges type Nausea · targets CB1 and CB2 agonism for a systemic calming effect · Cannabinoids (THC & CBD) ↳ drugs: - dronabinol (Marinol) - Cesamet/Nabilone - cannabis · Agonism affects other neurotransmitters, dose dependent: Serotonin, GABA, Dopamine u m