GI pathology


Hypertrophic pyloric stenosis


Narrowing of distal lumen (pyloric canal in stomach) due to thickening of circular muscle of the wall in the stomachVomiting (non-bilous)More common in females than males


Duodenal atresia/stenosis


Lack of recanalization; mess-up in rotation, volvulus, gastroschisis, and other factors--the lumen of the duodenum doesn't reopenAtresia: In upper duodenum;Blood supply to region is compromised and segment will die resulting in complete loss of region; gut obstructions from this, 25% in duodeunum, 50% in ileumStenosis: in lower duodenum; blood supply in compromised resulting in narrowing of that region


Annular pancreas


Formation of bi-lobed ventral pancreatic bud that migrates around duodenum in opposite directionsStrangulation of duodenumDuodenal stenosis or atresia


Meckel's diverticulum


Stalk of yolk sac left behind; congenital diverticulumFollows the rule of 2 (2% population, 2 in long, 2 ft proximal to ileocecal junction)Mucosa similar to adjacent ileumComplications include hemorrhage, intestinal obstruction, diverticulitis, and perforation


Gut duplication


Mostly in esophagus and ileocecla/ilela regions


Situs inversus


complete or partial (abdomen only) reversal of organs


Diabetes and motility


likely due to autonomic neuropathyImpaired gastric emptying (gastroparesis), altered pharyngeal and esophageal contractions


Essential fructosuria


Lack of fructokinase in liver and kidneyBenign disorder; symptoms are dependent on amount of fructose and sucrose intake


Hereditary fructose intolerance


Lack of aldolase B in liver, small intestine, and kidneyPotentially lethalSevere hypoglycemia and vomiting following fructose intakeFructose in infants-->vomiting, jaundice, hepatomegaly, hemorrhage, and hepatic failure


Hereditary fructose-1,6-bisphosphate deficiency


Severely impaired hepatic gluconeogenesisEpisodes of hypoglycemia, apnea, hyperventilation, ketosis, and lactic acidosisLethal in newbornsTriggered by fasting or infections in adults


Classic galactosemia


Defect in either galactose-1-phosphate uridyl transferase or galactokinaseVomiting and diarrhea following ingestion of milk; impaired liver functioning may lead to cirrhosis; hypergalactosemia; metabolic acidosis; urinary galactitol excretion and hyperaminoaciduria; can cause blindness and fatal liver damageRestrict galactose form diet


UDP-galactose-4-epimerase deficiency


Type I: benign; affects only RBCs and WBCsType II: affects multiple tissues and manifests symptoms similar to transferase deficiencyRestrict galactose from diet


lactose intolerance


usually due to loss of lactase (beta galactosidase)lactose isn't broken down completely in small intestine and it passes into large where bacteria metabolize it; cramping and flatulence; can also cause water retention in intestine and diarrheaControl diet


Straddle injury


Young boys; rupture urethra fromo urogenital diaphragm and spill either urine or blood into scarpa's fascia


Indirect inguinal hernia


Gut herniates through inguinal canal; bulge fills scrotum; lateral to inferior epigastric artery


Direct inguinal hernia


Usually due to pushing strainDirectly through the wall (inguinal traingle)Bulge does not typically fill scrotumMedial to inferior epigastric artery


Glucose-6-phosphate dehydrogenase deficiency


lack of enzyme so no pentose-phosphate pathway; reduced NADPH with secondary reductionin glutathione (GSH) which is required for RBC membrane and without it, hemolytic loss occurs and anemia resultsAdvantageous when in conjuction with malaria


I-cell disease


GlcNAc phosphotransferase deficiencyDefect in attachment of phosphate group to make mannose-6-phosphate (usually targets protein to the lysosome for degradation)Buildup of proteins causing progressive psychomotor retardation and early death


Branched chain ketoacdiuria "maple syrup urine disease"


Def in branched-chain keto acid dehydrogenase complexVomiting, convulsions and neonatal death; MR in survivors


Homocystinuria


Def in crystathionine beta synthaseMR, severe eye dxs, osteoporosis and frail bone structure


Alkaptonuria


Def in homogentistic acid oxidaseUrine darkens upon standing, prone to arthritis


Albinism


Tyrosinase in melanocytes is absentWhite hair, pink skin, no significant pigementation


hartnup's Disease


Defect in intestinal and renal transport and reasorption of neutral AAs (esp tryptophan)Ataxia, occular symptoms, emotional, pellegra like symptoms, nicotinamide (niacin) deficiency


Phenylketonuria (PKU)


Usually a defect in Phe hydroxylaseAbility to converte Phe to tyrosine is inhibitedLight color of skin, eyes, and internal tissues because melanin is made fromo tyrosineDiet low in Phe and total protein for first couple years


Ketoacidosis


fasting or severe dieting; can also occur when DM is not well-controlledHigh levels of ketone bodies in blood is ketonemia (in urine, it's ketonuria)Can be fatal in diabetics


Multiple Sclerosis


Demyelinating disease (loss of phospholipids and sphingolipids from white matter); lipid composition of white resembles thaty of gray; CSF shows high phospholipid levels


Sphingolipidoses (lipid storage diseases)


Genetic defect in catabolism of lipids containing sphingosine; defects in lysosomal degradation pathway of sphingolipidsComplex lipids containing ceramide accumulate in cells (esp neurons) causing neurodegeneration; rate of synthesis of stored lipids is normal thoughSome success with enzyme replacement and bone marrow transplantation


Tay-Sachs


Type of SphingolipidosesDeficit in hexosaminidase ACermide lipid accumulatesNormal development, then nerve cells fill with fat; deterioration; blindness; uanble to swallow due to muscle atrophy; msot die within 5 years


Splenic vein thrombosis


Can result in pancreatitis; presents with abdominal pain; rare


Duodenal ulcers


95% occur in posterior wall of the first portion; remember that the pancreas is back there as well


Oropharyngeal dysphagia


Most commonly caused by stroke; seen in Parkinson's, MS, myasthenia gravis, and end-stage dementiainability of difficulty swallowing; difficulty moving food from front of mouth to posterior oropharynx to esophagus


Esophageal dysphagia


Disordered peristaltic motility of the esophagus; msot commonly caused by achlasia or sclerodermaInability or difficulty swallowing; pt complains of food getting stuck


Obstructive dysphagis


Most commonly caused by strictures, schatzki's ring, or external compression on the esophagus by tumor or vasculatureInability or difficulty swallowing; pt complains of food getting stuck; phsyical obstruction to movement of bolus through esophagusRemove object causing obstruction


Schatzki's ring


Commonly caused by relfuxScar tissue forms bandsDilators are often used to dilate the esophagus and break the rings; may need repeat tretaments due to regrowth


Scleroderma


Chronic dx characterized by diffuse fibrosis of the skin and internal organs (esp esophagus)4 times more common in women than men; in 3 to 6th decade


Gastroparesis


Common in diabetics, hypothyroidism, post-operative, parkinson's, and various infectionsChronicIntermittent n/v, early satiety, bloating and upper abdominal discomfort, gastric reteention of 60% after 2+ hours or 10% after 4 hours; may be caused by autonomic neuropathyPharmacotherapy; avoid opiates; eat small frequent meals; avoid gas


IBS


abnormal motor functionDisorder of bowel motilityl may have constipation-predominant or diarrhea-predominant2/3 womenDiagnosis of exclusionAvoid dietary triggers; take anti-diarrheal, anti-constipation, serotonin receptor agonists (increase motility) and antagonists (to decrease motility); depending on what type you have


Constipation


Persistent, difficult, infrequent, seemingly incomplete defecationWide variability of normal bowel habits makes it difficult to define (<3 bm/week)Eat a fiber-rich dieat, adequate fluid intake, appropriate bowel habits and training, avoid constipating drugs, increase activity, bulk-forming agents, laxatives, and stool softeners


narcotic bowel


Opiate receptors in the bowel significantly slow down motility when activated by reducing response to excitatory NTs causing constipation


Pseudo-obstruction (ileus)


Commonly caused by surgery, infection, inflammation, or medsSigns and symptoms of intestinal bowel obstruction with no mechanical cause; air-filled bowelMost common type is paralytic ileusGive it time/IV fluid/electrolyte replacement; gastric decompression (remove air); may require surgery


Hirschsprung disease


Congenital abnormality of the small bowel caused by incomplete migration of neural crest cells resulting in loss of innervationColon from internal anal sphincter in a proximal direction (of variable length) remains permanently contracted; gut segment proximal to this dilates1/5000 live birthsSurgical correction to remove piece of bowel


Viral gastroenteritis


Cuased by norwalk or rotavirusAcute diarrheaNorwalk is mainly in the winter (24-48 hrs)Rotavirus is mainly in infants and childhood; severe if it penetrates the epithelium


Osmotic diarrhea


Due to ingestion (osmotic laxatives), maldigestion (pancreatic and lactase def), and malabsorption (carb. malabsorption and congenital chloridorrhea)Watery diarrhea, high osmolal gap (>50); if fecal pH<6, due to carb malabsorption; if increased fecal mG, due to laxative abuse


Secretory diarrhea


Caused by bacterial enterotoxins (e.coli and cholerae) and secretagogues (bile acids, FAs, ethanol, carcinoid syndrome, gastrinoma, and calcitonin)Watery diarrhea; when they stop eatch, diarrhea continues


Disorderd motility diarrhea


Due to change in transit timeSlow: fistulas, strictures, and diabetic neuropathyRapid: intestinal resection, IBS, hyperthyroidism, and post-vagotomy


Scurvy


def in Vitamin CRare in US; smoking is risk factorPoor collagen synthesis and wound healing; skeletal changes due to insufficient osteoid matrix


Riboflavin deficiency


Common, but pts rarely seek medical attentionOcular symptoms, frontal headaches, cheliosis, palor at angles of mouth, cracks/fissures, glossitis


Protein-energy malnutiriton (PEM)


either due to inadequate intake of protein (somatic or visceral) or calories to meet the body's needsCommon in underdeveloped countries; can be fatal; in developed countries, seen with poverty, alcoholism, ignorance, acute or chronic illness, and voluntary diet restriction


Marasmus (sub-type of PEM)


def of total food intake (somatic protein compartment)Spindly legs and arms, stunted growth, anemia, infections and defects in immunity, multi-vitamin def, serum albumin normal to slightly reduced


Kwashiorkor (sub-type of PEM)


Def of protein intake (visceral protein compartment)Babies who are weaned early and fed exclusively carb diet; also caused by chronic diarrhea, protein losing enteropathies, and nephrotic syndromeApathy, listlessness, loss of appetite, enlargened fatty liver, hypoalbuminemia, altering zones of hyperpigmentation, stunted growth, anemia, infections and defects in immunity, multi-vitamin deficiencies


Cachexia (sub-type of PEM)


marasmus-like PEM seen in AIDS, cancer, and end-stage lung diseasesDepletion of subcutaneous fat, muscle wasting, and ankle edema


Kwashiorkor-like PEM (subptype of PEM)


usualyl seen with severe trauma, burns, and sepsis


Anorexia nervosa


self-induced starvation, amenorrhea, decreased thyroid hormone release and boen density, anemia, lymphopenia, hypoalbuminemia, cold intolerance, bradycardia, constipation, scaly skin, prone to hypokalemia (increases risk of sudden death)


Bulimia


Binge eating followed by induced vomiting, menstrual irregularities, complications of chronic vomiting, pulmonary aspiration of gastric contents, esophageal and cardiac rupture allowing bacteria into mediastinum, also prone to hypokalemia and sudden death


Carotenemia


Excess vit A precursorsYellow-orange skin with white sclera (difference from jaundice)


Rickets


vit D deficiencypredisposed to fractures, bowed legs, can be mistaken for abuse


Beriberi


thiamine deficiencyDry (toe drop, common in alcoholics, pernicious vomiting during pregnancy, diseases that imapir appetite or cause diarrhea; can cause heart failure due to edema and hemorrhage into mammillary body)Wet (CV problems)


Wernicke-Korsakoff syndrome


thiamine deficiency causing brain problems (encephalopathy)


Pellagra


Niacin deficiency (B3)Dermatitis, diarrhea, dementia--classic picture of hands


Squamous cell carcinoma of the esophagus


smoking and alcohol; poor prognosisl common in males and AAs; geographic distribution (Asia, Africa, S. America)Pt complains of difficulty swallowing, heartburn, wgt loss


Adenocarcinoma of the esophagus


smoking and alcohol; poor prognosis; geographic variation (Asia, Africa, S. America)GERD-->Barrett's esopagus (10-20 times more likely)--occurs in lower esophagusResults from metaplasiaPt complains of difficults swallowing, heartburn, and wgt loss


Barrett esophagus


Intestinal metaplasia of the esophagusNormal linining is squamous; chronic exposure to gastric reflux leads to metaplasia and columnar epithelium; incidence is on the rise


Gastric carcinoma


H. pylori, AI gastritis, metaplasia, food, familial factors, gastric adenoma (benign tumor); more frequent in Asia, E. Europe, Africa, and S. America; decreasing incidencePoor prognosis (early detection helps-Japan)Aysmptomatic until too late, wgt loss, anorexia, abdominal pain, and Krukenburg tumor (of the ovaries--metastasis)Most are adenocarcinoma (diffuse signet ring type)


Gastric adenoma


Benign tumor; premalignant; adjacent gasric mucosa may develop cancer in 30% of cases


Crohn's disease


sub-type of IBDSkip lesions, 80% in small intestion (ileocecal junction), Ash-Jewish, Asian, and AA population; bimodal distTriad of symptoms: diarrhea, ab pain, 10+% wgt loss


Enteritis


bacterial, parasitic, viralPresent with inflammation and diarrheaFluids, electrolytes, and nutrition for treatment


Hyperplastic polyp


non-neoplastic polyp in colonPretty-star shaped growths


Hamartomatous polyp


non-neoplastic polyp of the colonLooks like a stalk of broccoli


Tubular adenoma


Most common polyp (40% of these become malignant)Usually small and predunculated; may be raised (look like broccoli)


Villous adenoma


Les common, and 10 times less likely to become malignant than tubular adenomalarger and sessile with a broader base; may be combined as tubulovillous


FAP (familial adenomatous polyposis)


stepwise accumulation of genetic mutationsPolyps start benign and then become malignantAttentuated: fewer polyps in right colon (secum)Garnder syndrome (FAP + osteomas, fibromas, epidermal cysts)Turcot syndrome: FAP + brain tumors


Colorectal carcinoma


Second in incidence to lung cancer in men and third to breast in womenRarely causes obstruction in right colon, does in left; with right colon, pt presents with microscopic bleeding, anemia (due to depletion in iron due to continuous bleeding); in left colon, pt presents with pencil like feces and constipationAdenocarcinoma is most common in bothCan be asymptomatic for years; colon more common in women and rectal more common in menMetastasis to local LNs, liver, lung (triple L)CEA (carcinoembryonic antigen) is a marker for tumor after surgery, not for primary detection


Carcinoid tumor


NE tumor of the GI tract and resp tract; most common in small intestine; size matters; secrete polypeptide hormones and biogenic amines (5-HT); present with 5-hydroxyindoleacetic acid in urine


Gastrointestinal stromal tumor (GIST)


Express mutated c-KIT and PDGFRAtumor of the GI system composed of stromal cells; benign or malignant; may occur anywhere from stomach to intestines (histologically, it looks like collagen/stroma w/lymphocyte infiltrates)Inhibitors of TK block growth


Gastrointestinal lymphoma


H pylori is a risk factorSecondary spreading to the GI from lymph nodes, primaryily originates in the GI tractGI is most common site of extranodal lymphomaStomach is most common site of GI lymphomasMost are MALTomas (respond well to H pylori therapy)


Acute pancreatitis


alcohol abuse and gall stones (50%)--caused by anything that obstructs the duct, causes acinar cell injury, defective intracellular transportactivation of lipolytic enzymes produces fat necrosis; activation of proteolytic enzymes activates chemotactic factors (inflam and leukocytosis) leading to fever; microvasc leakage leads to edema; endothelial injury leads to thrombosis and hemorrhageEpigastric pain of sudden onset, n/v, low-grade fever, dehydration, tender abdomen, xray shows sentinel loop, US shows gallstones and swelling; elevated amylase and lipase; decreased Ca; get ERCP


Pancreatic Pseudocyst


Complication of acute pancreatitisCyst with necrotic surface and no epithelium


Chronic pancreatitis


more common in men; alcohol abuse causes toxic effects directly to acinar cells and can cause spasms of sphincter of Oddi; caused by repeated bouts of acute pancreatitis and ductal obstructionsPresent with ab pain, calcifications and pseudocysts; pancreatic insufficiencies resulting in malabsorption, diabetes (destruction of islets of Langerhans)Ductal dilation on US; ERCP shows beadingTreat with low fat diet, no alcohol, enzyme supplementation, pain management, surgery to restore bile flow


Hiatal hernia


gastroesophageal junction protrudes through the esophageal hiatus with or without the stomachMimics the substernal pain of an MI but sitting up from supine position lessens the pain here


Esophageal varices


Caused by portal hypertension; small veins in esophagus become dilated; varices/dilation can rupture under stress leading to profuse hemorrhage


Achlasia


Absence of intinsic neurons in lower esophagus (cause or effect?)Dysmotility in lower esophagus causes upper esophagus hypertrophy and dilation; patients have recurrnet vomiting leading to malnutrition


Pyrosis


"heartburn" in abdominal part of esophagus


Cholecystitis


inflammation of the gall bladder; can spread to first part of duodenum with consequent adhesions to or perforating ulcerations of the duodenumPositive murphy's sign


Pancreatic adenocarcinoma


most common tumor of the pancreas; elderly; male predominance in younger, but equal in older; high in USMulitple hits; starts in situ (most in the head); highly invasive and elicits a strong desmoplastic reaction; malignant epithelial cells may secrete/contain mucinAsyptomatic until perineural invasion and pain; painless jaundice, ab pain, wgt loss, anorexia, migratory thrombophlebitis (Troussea sign), anemia, hyperglycemiaSurgical resection (Whipple procedure) is rarely curative; pallitative measures


Portal hypertension


pre-hepatic disease (partial occlusion in portal vein, i.e. hemolytic jaundice); intra-hepatic (cirrhosis, malignant metastases, and hemolytic jaundice); or post-hepatice disease (compression of IVC or obstructive jaundice)Resistance to blood flow through liverHemorrhages, hemorrhoids, and caput medusae


Hepatitis


Viral or bacterial liver infection; leads to erosion through dense liver capsule into abdominal cavity or across diaphragm; results in pleuritis or empyema


Biliary colic


blockage in duct; RUQ pain due to distension between waves of contraction in duct


Gallstones


made from bilirubin metabolites, cholesterol, or calcium slatsCan obstruct gall bladder causing bile retention and rupture resulting in peritonitis; can obstruct common bile duct or hepatopancreatic duct (bile is diverted into pancreatic duct); or when gallstones pass through sphincters, make them less competenct to assist in regulating flow of bile and pancreatic enzymes


Volvulus


Twisting of intestines around mesentery; leads to compression and strangulation of blood vessels within mesentery; ischemia and necrosis; most prevalent in large bowel (cecum and sigmoid)


Acute hepatitis


inflammation of the liver or short durationCell injury includes apoptosis and necrosisJaundice, fatigue, nausea, loss of appetite, increased ALT/AST and bilirubin (C+UC)if severe, decreased albumin, increased PT time, increased ammonia=urgent transplant


Chronic hepatitis


VIRAL mneumonic (viral, immunologi, Rx, alcoholic/NASH, library list of genetic diseases)inflammation of the liver for longer than 6 monthsIncreased or decreased AST, ALT, bilirubin, albumin, and PTBiopsy must be performedCan progress to cirrhosis


Cirrhosis


Viral hep C, alcohol abuse, steatohepatitis (diabetes, obesity, idiopathic), immune (AI, primary biliary cirrhosis, primary sclerosing cholagnitis), genetic (hemochromatosis, Wilson);15% are cryptogenicChronic liver disease with loss of normal architecture, widespread fibrosis, ndoular transformation of parenchyma, portal hypertension, bleeding tendency, hepatic encephalopathyDecreased synthetics; can lead to liver cell carcinoma


Ascites


hypoalbuminemia, sinusoidal HTN, percolation o fhepatic lymph (blocked), and splenic congestion all cause>500 mL is detectableIf RBCs, think tumor


Hepatic encephalopathy


Shunting of blood by liver results in inadequate detoxification of potentially toxic metabolits by liverConfusion, stupor, coma, increased blood ammonia (>50)


Hepatorenal syndrome


renal failure caused by liver failureOligouria, increased BUN and creatinine, concentrated urine, pt unresponsive to diuretic therapy; jaundice, ascites, urinary failure, neurologic, dyspnea, infections, coagulopathy, endocrine


Hereditary hemochromatosis


asymptomatic until 40-50; iron is stored preferentially in liver; involves liver, skin, heart, endocrine, and jointsPresent with liver disease (cirrhosis), increased iron saturation, increased risk of liver cancerGrossly and histologically, can see accumulations of ironLung problems due to elastase


Alpha1-antitrypsin deficiency


Protein is not allowed to move to from ER to GA for secretion, so A1-AT accumulates in hepatocytes; abnormally low serum levels of it; present with liver diseaseJaundice and symptoms of cholestasis, increased transaminase, hepatocellular carcinoma; lung disease and vasculitis


Subhepatic cecum


lack of descent of the cecum from RUQ to LUQCan be asymptomatic, but increased risk for obstructive event


Appendicitis


fecal blockage of the appendix's lumen leading to vascular congestion, ischemia, bacterial growth, infection, perforation of wall with pus released into abdominopelvic cavityInitial pain is dull in umbilical region (referred via lesser thoracic splanchnic to T10) but becomes sharp and localized due to direct irritation of escaping pus to parietal peritoneum of the wall


Diverticulosis


dvlpt of small blind pouch in colonic wall that become inflammed and can rupture; frequent in older population; no popcorn or nuts as these can cause rupture


Ulcerative colitis


Chronic inflammation and destruction of mucosal lining that manifests as chronic diarrhea and abdominal painNo skip lesions


Lymphangitis


Inflammation of lymph vessels


Lymphadenitis


inflammation of lymph nodes


GERD


15-20% caused by impaired basal tone of LES; rest due to transient LES relaxationChronic symptoms (ie heartburn with or without mucosal damage produced by abnormal reflux of gastric content in esophagus); increased risk of developing esophageal adenocarcinoma


Psoas abscess


due to close interaction with overlying fascia, might impinge on nerve roots causing pain when psoas is contracted; relieve when lifting supine patient legs toward their abdomen


Lateral femoral cutaneous nerve syndrome


compression (ie belt too tight) and endocrine (alcoholism and diabetes) causesMononeuropathy; present with pain, numbness, tingling, burning and itching in anterolateral thigh