GI Flashcards
What is gastroschisis?
Congenital malformation of the anterior abdominal wall causing extrusion of abdominal contents.
Not covered by peritoneum
What is derived from the foregut?
Midgut?
Hindgut?
Foregut - Pharynx to duodenum, liver, gallbladder, pancreas
Midgut - Duodenum to transverse colon
Hindgut - Distal transverse colon to rectum
What is an omphalocele?
Failure of intestines to return to body cavity after herniation into the umbilical cord. Covered by peritoneum
What causes intestinal atresia?
Duodenal atresia - failure to recanalize
Jejunal, ileal, colonic atresia - vascular accident in-utero
Vascular accident can cause apple peel syndrome where distal atrophic gut is wrapped around an artery.
When does midgut rotation occur?
6th week –> midgut herniates through umbilical ring
10th week –> abdominal cavity is large enough & midgut returns to it & rotates around SMA
Failure can cause malrotation of midgut or omphalocele
What are the possible types of tracheoesophageal abnormalities?
Which is most common?
Most common is EA with distal TEF
Others:
Pure EA
Pure TEF (H-type; fistula present but esophagus still patent)
What is seen with EA+TEF?
Drooling Choking with first feeding Cyanosis (laryngospasm to prevent reflux aspiration) Air in the stomach on CXR Failure to pass NG tube into stomach
What can result from malformation of the pancreas?
Annular pancreas - ventral pancreatic bud encircles 2nd part of duodenum & may cause narrowing. Due to failure of migration.
Pancreas divisum - Common; dorsal & ventral buds fail to fuse so that most pancreatic acini drain to minor sphincter. Predisposes to chronic pancreatitis.
From where does the spleen arise?
Arises from mesoderm but is supplied by foregut (celiac artery)
The other gut structures are all endodermal.
What are the retroperitoneal structures?
SAD PUCKER
Suprarenal glands Aorta & IVC Duodenum (2nd & 3rd parts) Pancreas (except tail) Ureters Colon (ascending & descending) Kidneys Esophagus (lower 2/3) Rectum (lower 2/3)
What is the falciform ligament?
Connects the liver to the anterior abdominal wall
Contains ligamentum teres (derivative of fetal umbilical vein)
What ligament contains the portal triad?
Hepatoduodenal ligament
Portal triad = hepatic artery, portal vein, common bile duct
What is the difference between an erosion and an ulcer?
Erosion = mucosa only
Ulcer = submucosa or deeper
What is the frequency of electrical rhythm along the GI tract?
Stomach = 3 waves/min
Duodenum = 12 waves/min
Ileum = 8 waves/min
What are the layers of the gut wall?
1) Mucosa (epithelium, lamina propria, muscularis mucosa)
2) Submucosa (includes Submucosal/Meissner’s plexus)
3) Muscularis externa (includes Myenteric/Auerbach’s plexus)
4) Serosa (intraperitoneal) or Adventitia (retroperitoneal)
What is the duodenum composed of histologically?
Villi & microvilli
Brunner’s glands (unique to duodenum; HCO3-)
Crypts of Lieberkuhn (throughout small & large intestine)
What is the histology of the ileum?
Peyer’s patches (unique to ileum)
Largest # of goblet cells in SI
Plicae circularis (along with jejunum)
Crypts of Lieberkuhn
What can result from failure of the vitelline (omphalomesenteric) duct to obliterate?
When should it obliterate?
Meckel diverticulum
Persistent vitelline duct
Vitelline cyst
Vitelline sinus
Should obliterate during the 7th week
What does an acid fast stain bind to?
Mycolic acid (TB, Nocardia)
What can cause papillary necrosis?
Sickle cell disease or trait
Analgesic use
Diabetes
Acute pyelonephritis
When is a child at risk for hemolytic disease of the newborn?
Anti-A or Anti-B Ig’s are formed early in life. If a mother is A or B, she will form IgM (cannot cross placenta). If she is O, she will form IgG (can cross placenta). Thus, even her first child is at risk.
Mothers must be inoculated (with the first birth) against Rh. Subsequent births are at risk.
What is the difference in mechanism between unfractionated heparin and LMW heparin?
Unfractionated heparin binds Xa & IIa equally
LMW heparin preferentially binds Xa
*Antithrombin is needed in both cases to form the ternary inactive complex (heparin, AT, Xa/IIa)
What is the function of human Placental Lactogen (hPL)?
Insulin resistance –> fetus gets more of the glucose
^Lipolysis, proteolysis –> energy for both mom & fetus
hPL levels rise throughout gestation to support a growing fetus
What can be seen as a side effect of massive amounts of blood transfusions?
If a patient gets an entire body content of blood (5L) in under 24h, citrate from the blood products (additive) can accumulate and chelate the blood calcium causing hypocalcemia.
Where do the nitrogen atoms in urea come from?
Free NH3 (alanine cycle) Aspartate (added into the urea cycle)
How id carbamoyl phosphate synthetase I regulated?
Rate-limiting enzyme in the urea cycle
It is activated by N-acetylglutamate
What physical exam findings are more specific for iron deficiency anemia?
Dysphagia Spoon nails (koilonychia)
What growth factors are responsible for angiogenesis?
FGF
VEGF
This is true both in granulation tissue & in tumorgenesis
What is the receptor for rabies virus in the body?
Nicotinic ACh receptor
What is the cellular receptor for CMV?
Cellular integrins
What is the cellular receptor for Rhinovirus?
ICAM1
What murmurs can be heard better with the patient leaning forward?
Aortic murmurs
It brings the valve close to the chest wall
What can cause Pure Red Cell Aplasia?
Thymoma (auto-Ab's) Lymphocytic leukemia (auto-Ab's) Parvovirus infection
PRCA is selective aplastic anemia seen with erythroblasts but sparing granulopoiesis & thrombopoiesis.
What are the effects of dobutamine?
Selective B1 agonist
Inotropy > Chronotropy
^Contractility
^Cardiac conduction velocity (proarrhythmic)
^Myocardial O2 consumption
What drains the lower limbs & male genitalia?
Testis –> para-aortic
Penis & cutaneous calf –> deep inguinal
Scrotum & rest of leg –> superficial inguinal
Where does HBV acquire its envelope?
Endoplasmic reticulum
How does HBV use its reverse transcriptase?
The viral mRNA transcript is packaged into a capsid & RT acts on it to produce circular DNA that is partially ds. This is the infective form of HBV.
What toxicity is seen with Vincristin/Vinblastine?
Neurotoxicity
They inhibit MT assembly & thus axonal transport in neurons.
What are the vegetations of bacterial endocarditis composed of?
Platelets
Fibrin
Bacteria
What causes bronchiolitis?
Bronchiolitis is viral
It is inflammation of the bronchioles (smallest air passageways).
What is the DDx for absent thymic shadow?
SCID
DiGeorge syndrome
What is the cause of Leukocyte Adhesion Deficiency 1 (LAD1)?
Absence of LFA-1 (CD18), an integrin required for leukocyte tight adhesion.
What is the cause of Leukocyte Adhesion Deficiency 2 (LAD2)?
Impaired formation of Sialyl-Lewis carbohydrate ligands on leukocytes, leading to impaired selectin binding.
It is a milder form of LAD than LAD1 & LAD3. No delayed separation of the umbilical cord.
What is seen with leukocyte adhesion deficiency 3 (LAD3)?
Delayed separation of the umbilical cord (Types 1 & 3)
Recurrent skin infections without pus formation
Bleeding complications
What is the blood supply to the lesser curvature of the stomach?
Greater curvature?
Lesser curvature:
Proximal - Left gastric
Distal - Right gastric
Greater curvature:
Proximal - Left gastroepiploic
Distal - Right gastroepiploic
What are the GI watershed zones?
Splenic flexure
Sigmoid colon/rectum
What are the sites of porto-systemic venous anastomoses?
Portal–>Systemic:
Left gastric–>Esophageal
Paraumbilical–> Epigastric & lateral thoracic
Superior rectal–>Middle & inferior rectal
Together cause esophageal varices, caput medusae, & hemorrhoids
What are means of drug administration that bypass 1st pass metabolism?
IV
SubQ
Sublingual
Rectal suppository
What is the blood supply to/from the anus?
Above pectinate: Superior rectal (IMA)–>Superior rectal (portal)
Below pectinate: Inferior rectal (int. pudendal)–>Inf. rectal (IVC)
What is the lymphatic drainage of the anus?
Above pectinate line - deep nodes
Below pectinate line - superficial inguinal nodes
Where is the most common location of an anal fissure?
On the midline posterior wall of the anus, below the pectinate line
Presents with BRBPR & pain w/ defecation
What are the zones of a hepatic lobule?
Which are affected first by insults?
Zone 1 = periportal - affected 1st by viral hepatitis
Zone 2
Zone 3 = centrilobular - affected 1st by ischemia, EtOH, drugs
Just remember periportal is affected by (zone) 1 thing - viruses
What is the organization of the femoral region?
Going from lateral–>medial: NAVL
Nerve
Artery
Vein
Lymphatics
What is contained in the femoral sheath?
Femoral triangle?
Femoral sheath: Femoral artery, vein, & deep inguinal LN’s
(not the nerve)
Femoral triangle: Femoral nerve, artery, vein (not the femoral canal)
What are the types of diaphragmatic hernias?
Sliding hiatal hernia:
Most common
GE junction displaced upward
“Hourglass stomach”
Paraesophageal hernia:
Fundus protrudes into thorax next to esophagus
Both can cause GERD
What patient populations are the various abdominal hernias associated with?
Indirect - male infants (patent processus vaginalis)
Direct - older males (weakened abdominal wall)
Femoral - women
Where is an indirect hernia located?
What layers cover it?
Lateral to inferior epigastric artery. Goes through deep inguinal ring –> superficial inguinal ring –> scrotum
Covered by all 3 layers of spermatic fascia.
Where is a direct hernia located?
What layers cover it?
Medial to inferior epigastric artery.
Protrudes through Hasselbach’s triangle (through abd wall) –> superficial inguinal ring –> can extend into scrotum
Covered by external spermatic fascia only.
Where is a femoral hernia located?
Below inguinal ligament & lateral to pubic tubercle.
The leading cause of bowel incarceration (smaller hole)
More common in women.
What form the borders of Hasselbach’s triangle?
Rectus abdominus
Inguinal ligament
Inferior epigastric vessels
This is the site of a direct inguinal hernia.
Gastrin
Secreted by:
Effects:
Regulation:
Secreted by: G cells in gastric antrum
Effects: ^acid secretion, motility, growth of gastric mucosa
Regulation: ^ by amino acids, vagal stim, stomach distention, ^pH
Can be ^ with chronic PPI use. Phenylalanine & tryptophan are the strongest stimulators.
Cholecystokinin
Secreted by:
Effects:
Regulation:
Secreted by: I cells of duodenum/jejunum
Effects: ^pancreatic secretion, GB contraction, spincter of Oddi relaxation, decreases gastric emptying
Regulation: ^ by fatty acids & amino acids
Secretin
Secreted by:
Effects:
Regulation:
Secreted by: S cells in duodenum
Effects: ^pancreatic HCO3- secretion, ^bile secretion, inhibits gastric acid secretion
Regulation: ^by acid, ^by FA’s in duodenum
Somatostatin
Secreted by:
Effects:
Regulation:
Secreted by: D cells of pancreatic islets & GI mucosa
Effects: Inhibits secretion of gastric acid & pancreatic secretion, inhibits GB contraction, inhibits insulin & glucagon release
Regulation: ^ by acid, inhibited by vagal stimulation
Glucose-dependent insulinotropic peptide (GIP)
Secreted by:
Effects:
Regulation:
Secreted by: K cells of duodenum & jejunum
Effects: decreases gastric acid secretion, ^insulin release
Regulation: ^by fatty acids, amino acids, oral glucose
Vasoactive Intestinal Peptide (VIP)
Secreted by:
Effects:
Regulation:
Secreted by: Parasympathetic ganglia
Effects: ^intestinal water & electrolyte secretion, ^relaxation of smooth muscle & sphincters
Regulation: ^by vagal stimulation, decreased by adrenergics
What is seen with a VIPoma?
WDHA syndrome:
Watery Diarrhea
Hypokalemia
Achlorhydria
Seen as a non-alpha/non-beta pancreatic cell tumor.
Motilin
Secreted by:
Effects:
Regulation:
Secreted by: Small intestine
Effects: Produces migrating motor complexes (MMC’s)
Regulation: ^during fasting state, stimulated by erythromycin
How is B12 absorbed?
Binds Haptocorrin (R-factor) in saliva –> binds intrinsic factor (parietal cells) –> absorbed in TERMINAL ILEUM
What is secreted by parietal cells of the stomach?
Chief cells?
Parietal cells - Gastric acid, intrinsic factor
Chief cells - Pepsinogen (activated to pepsin by acid)
How is salivation regulated?
Salivation is increased by both sympathetic & parasympathetic activity
How does vagal stimulation cause gastric acid secretion?
1) GRP synapse on G cells –> Gastrin in circulation –> ECL cells release histamine –> parietal cells respond
(most important mechanism)
2) GRP synapse on G cells –> Gastrin stimulates parietal cells
3) Direct ACh synapse on parietal cells
What type of pump is located on the gastric parietal cell membrane?
H+/K+ ATPase exchanger
What substances act on the parietal cell to modulate gastric acid secretion?
Stimulate:
ACh (M3)
Gastrin (Gq)
Histamine (H2)
Inhibit (Gi):
Prostaglandins
Somatostatin
What is responsible for the activation of trypsinogen?
Duodenal mucosa –> Enterokinase/Enteropeptidase –> Activated trypsin –> can cleave other trypsin molecules to activate
How does flow rate affect pancreatic secretion ionic composition?
Low flow rate –> ^Cl-
High flow rate –> ^HCO3-
What molecules are responsible for carbohydrate digestion & absorption in the GI tract?
Salivary/Pancreatic amylases –> oligosaccharides
Brush border oligosaccharide hydrolases –> monosaccharides
Transporters:
SGLT1 = Glucose & Galactose (Na+ dependent)
GLUT-5 = Fructose (facilitated diffusion)
Where in the GI tract is iron absorbed?
Duodenum
Absorbed as Fe2+
“Iron Fist Bro”
Where is Folate absorbed in the GI tract?
Duodenum
“Iron Fist Bro”
Where is B12 absorbed in the GI tract?
Terminal ileum along with bile acids (requires intrinsic factor)
“Iron Fist Bro”
What is the oxidation state of body iron?
Fe2+ absorbed
Fe3+ when bound to transferrin/ferritin
Fe2+ in heme
What is the rate-limiting step in bile acid synthesis?
Cholesterol 7-alpha-hydroxylase
What are the functions of bile?
1) Digestion/absorption of lipids & ADEK
2) Cholesterol excretion (body’s only means of doing so)
3) Antimicrobial activity (membrane disruption)
How is heme broken down within macrophages?
Heme –(Heme oxygenase)–> Biliverdin
–(Biliverdin reductase) –> Unconjugated bilirubin
How is bilirubin handled following its release from macrophages?
Transported to liver on albumin –(UDP glucuronosyltransferase)–> Conjugated bilirubin released in bile –(gut bacteria)–> Urobilinogen
Why is urine yellow?
Why is poop brown?
Urine - urobilin
Poop - stercobilin
What causes Behcet syndrome?
What is seen?
Immune complex vasculitis involving small blood vessels
Triad of:
Recurrent aphthous ulcers (canker sores)
Genital ulcers
Uveitis
What is the lymphatic drainage of the esophagus?
Upper 1/3 - Cervical nodes
Middle 1/3 - Mediastinal or tracheobronchial nodes
Lower 1/3 - Celiac & gastric nodes
What are the 3 types of salivary gland tumors & their presentations?
Pleomorphic adenoma - painless mobile mass composed of cartilage & epithelium; recur frequently
Warthin’s tumor - benign cystic tumor with germinal centers
Mucoepidermoid carcinoma - painful mass with occasional facial nerve palsy; mucinous & squamous components
What is seen with achalasia?
^LES tone due to loss of Auerbach’s plexus (Chagas; idiopathic)
Dysphagia to solids AND liquids
“Bird’s beak” on barium swallow
^risk of esophageal SCC
What is seen on manometry of achalasia & CREST/Scleroderma?
Achalasia = high LES pressure
CREST/Scl = low LES pressure
Both cause esophageal dysmotility
What causes GERD?
How does GERD present?
Impaired LES tone –> GERD
Heartburn & regurgitation while lying down
Nocturnal cough & dyspnea
Adult-onset asthma
What is the venous drainage of the esophagus?
Upper 2/3 = Azygous (systemic)
Lower 1/3 = Left gastric (portal)
What can cause esophageal stricture?
Lye ingestion
GERD
What is seen on histology in Barrett’s esophagus?
Intestinal metaplasia:
Nonciliated columnar epithelium with goblet cells
What type of esophageal cancers are caused by smoking?
Alcohol?
Smoking - both
Alcohol - just squamous
What GI abnormalities are seen with Down’s syndrome?
Duodenal atresia
Hirschsprung’s disease
What causes Hirschsprung’s disease?
Failure of neural crest cell migration –> aganglionic colon (missing both Meissner’s & Auerbach’s plexuses) –> functional obstruction w/ proximal dilation
What is seen in Ogilvie’s syndrome?
aka Acute Colonic Pseudo-obstruction
Obstruction of the cecum & right hemicolon without an identifiable obstruction
What causes duodenal atresia?
What is seen?
Failure of recanalization of the small bowel
Associated w/ Down syndrome
Presents with:
Early bilious vomiting
“Double bubble” on x-ray
What is seen with ischemic colitis?
Pain after eating (like angina in the heart)
Commonly occur at the splenic flexure or sigmoid colon
What is the most common cause of small bowel obstruction?
Adhesion (commonly following surgery)
What histologic factors increase an adenomatous polyp’s chances of becoming malignant?
^Size
Villous histology
Dysplasia
What is the most common type of polyp in the colon?
Hyperplastic polyps
Are juvenile polyps premalignant?
Single polyp = no malignant potential
Juvenile polyposis syndrome = ^risk of adenocarcinoma
What is seen in Peutz-Jeghers syndrome?
Nonmalignant hamartomas throughout GI tract
Hyperpigmented mucous membranes
^risk of CRC, breast, & gynecological cancers
What mutation causes FAP?
APC gene on chromosome 5
When it is mutated, beta-catenin is free to act as a transcription factor –> ^proliferation and impaired cell adhesion
What are the variants of FAP?
What is seen?
Gardner’s syndrome –> FAP + fibromatosis & osteomas
Turcot’s syndrome –> FAP + malignant CNS tumors
What causes HNPCC?
What is seen?
Aut. dominant mutation in DNA mismatch repair
^risk of CRC, ovarian, & endometrial cancers
Right colon is affected
Strep bovis
CRC
Get a colonoscopy
What tumor marker is used for CRC?
CEA
Only used to monitor recurrence, not a good screening tool
What are the most common sites of a carcinoid tumor?
Appendix
Ileum
Rectum
It is the most common malignancy in the small intestine
What is seen with carcinoid syndrome?
Wheezing
Diarrhea
Flushing
R. sided carcinoid heart disease (valvular fibrosis –> murmur)
It is right sided only because lung contains MAO (like liver) which can metabolize 5-HT –> 5-HIAA so serotonin never hits LA/LV.
What can be used to confirm liver/bile duct disease when alkaline phosphatase is elevated?
Gamma-glutamyl transferase (GGT)
What can cause an elevation in serum amylase?
Lipase?
Amylase = Mumps, acute pancreatitis Lipase = acute pancreatitis
What viruses are associated with Reye’s syndrome?
VZV
Influenza B
Can be any viral infection that is treated with aspirin in a child.
What is seen histologically with alcoholic hepatitis?
Macrovesicular fatty change
Mallory bodies
(condensed cytoskeleton –> cytoplasmic eosinophilic inclusions)
What autoantibodies are seen with the liver diseases?
Autoimmune hepatitis = Anti-smooth muscle
PBC = Anti-Mitochondrial
PSC = p-ANCA’s
What GI abnormalities are seen with Down’s syndrome?
Duodenal atresia
Hirschsprung’s disease
What causes Hirschsprung’s disease?
Failure of neural crest cell migration –> aganglionic colon (missing both Meissner’s & Auerbach’s plexuses) –> functional obstruction w/ proximal dilation
What is seen in Ogilvie’s syndrome?
aka Acute Colonic Pseudo-obstruction
Obstruction of the cecum & right hemicolon without an identifiable obstruction
What causes duodenal atresia?
What is seen?
Failure of recanalization of the small bowel
Associated w/ Down syndrome
Presents with:
Early bilious vomiting
“Double bubble” on x-ray
What is seen with ischemic colitis?
Pain after eating (like angina in the heart)
Commonly occur at the splenic flexure or sigmoid colon
What is the most common cause of small bowel obstruction?
Adhesion (commonly following surgery)
What histologic factors increase an adenomatous polyp’s chances of becoming malignant?
^Size
Villous histology
Dysplasia
What is the most common type of polyp in the colon?
Hyperplastic polyps
Are juvenile polyps premalignant?
Single polyp = no malignant potential
Juvenile polyposis syndrome = ^risk of adenocarcinoma
What is seen in Peutz-Jeghers syndrome?
Nonmalignant hamartomas throughout GI tract
Hyperpigmented mucous membranes
^risk of CRC, breast, & gynecological cancers
What mutation causes FAP?
APC gene on chromosome 5
When it is mutated, beta-catenin is free to act as a transcription factor –> ^proliferation and impaired cell adhesion
What are the variants of FAP?
What is seen?
Gardner’s syndrome –> FAP + fibromatosis & osteomas
Turcot’s syndrome –> FAP + malignant CNS tumors
What causes HNPCC?
What is seen?
Aut. dominant mutation in DNA mismatch repair
^risk of CRC, ovarian, & endometrial cancers
Right colon is affected
Strep bovis
CRC
Get a colonoscopy
What tumor marker is used for CRC?
CEA
Only used to monitor recurrence, not a good screening tool
What are the most common sites of a carcinoid tumor?
Appendix
Ileum
Rectum
It is the most common malignancy in the small intestine
What is seen with carcinoid syndrome?
Wheezing
Diarrhea
Flushing
R. sided carcinoid heart disease (valvular fibrosis –> murmur)
It is right sided only because lung contains MAO (like liver) which can metabolize 5-HT –> 5-HIAA so serotonin never hits LA/LV.
What can be used to confirm liver/bile duct disease when alkaline phosphatase is elevated?
Gamma-glutamyl transferase (GGT)
What can cause an elevation in serum amylase?
Lipase?
Amylase = Mumps, acute pancreatitis Lipase = acute pancreatitis
What viruses are associated with Reye’s syndrome?
VZV
Influenza B
Can be any viral infection that is treated with aspirin in a child.
What is seen histologically with alcoholic hepatitis?
Macrovesicular fatty change
Mallory bodies
(condensed cytoskeleton –> cytoplasmic eosinophilic inclusions)
What autoantibodies are seen with the liver diseases?
Autoimmune hepatitis = Anti-smooth muscle
PBC = Anti-Mitochondrial
PSC = p-ANCA’s
How does gallstone ileus occur?
Fistula must be present between GB & duodenum –> obstruction of small bowel by gallstones
What chemical mediates the damage seen in alcoholic hepatitis?
Acetaldehyde
What is seen on LFT’s with alcoholic hepatitis?
AST > ALT
This is because AST is within mitochondria and EtOH is a mitochondrial poison. This differentiates alcoholic hepatitis from viral hepatitis & NASH.
How does Reye’s syndrome present?
Hypoglycemia N/V Elevated liver enzymes Hepatomegaly Coma, death
How does phototherapy help in neonatal hyperbilirubinemia?
Does not conjugate it, just makes it water soluble so it can be excreted in the urine
What cell type mediates cirrhosis?
Stellate (Ito) cells
They are located in the space of Disse & normally function to store Vitamin A. When activated, they mediate the fibrosis seen in cirrhosis.
What can lead to cirrhosis?
Alcoholic cirrhosis HBV & HCV Wilson's disease Hemochromatosis Alpha-1 Antitrypsin deficiency Aflatoxin (Aspergillus)
What genetic disease has a high rate of HCC?
Hereditary tyrosinemia
What paraneoplastic syndrome is seen with HCC?
Polycythemia
What are the risk factors for hepatic adenoma?
OCP’s
Anabolic steroids
Can rupture during pregnancy. Often regress spontaneously.
What cell marker can be used for angiosarcoma?
CD31 (endothelial cell marker)
What is seen in Bud-Chiari syndrome?
Absence of JVD Hepatomegaly Ascites Abdominal pain Visible abdominal/back veins
What are the causes of Bud-Chiari syndrome?
Polycythemia vera
Hypercoagulable state
Pregnancy
HCC
What is seen histologically in the liver with A1AT deficiency?
Cirrhosis
PAS+ globules
What bilirubin levels will present as jaundice?
> 2.5 mg/dL
What are the causes of unconjugated bilirubinemia?
Hemolytic anemia
Neonatal jaundice
Gilbert syndrome
Crigler-Najjar syndrome
What are the causes of conjugated hyperbilirubinemia?
Biliary tract obstruction:
Gallstones
Pancreatic/Liver cancer
Echinococcus granulosus
Biliary tract disease:
PBC
PSC
Excretion defect:
Rotor syndrome
Dubin-Johnson syndrome
What causes a mixed (direct & indirect) hyperbilirubinemia?
Hepatitis
Cirrhosis
What causes Gilbert’s syndrome?
What is seen?
Mild deficiency in UDP-glucuronyl transferase
Mild unconjugated bilirubinemia
Triggered by fasting or stress
What causes Crigler-Najjar syndrome?
What is seen?
Absent UDP-glucuronyl transferase
Presents in neonatal life –> death within a few years
Jaundice
Kernicterus (bili deposition in brain)
Unconjugated bilirubinemia
Tx: Plasmapheresis & phototherapy
What causes Rotor’s syndrome?
What is seen?
Defective hepatocyte excretion of bilirubin
A benign condition
Conjugated hyperbilirubinemia
Dubin-Johnson = slightly more severe form with grossly black liver
What is seen with Wilson’s disease?
Decreased ceruloplasmin Cirrhosis Kayser-Fleisher rings Hemolytic anemia Basal ganglia degeneration Asterixis Dementia
What causes Wilson’s disease?
How is it treated?
AR defect in ATP7B gene (chrom 13) –> copper cannot be excreted into bile by hepatocytes
Tx: Penicillamine
What is seen in Hemochromatosis?
Diabetes Bronze color to skin Cirrhosis CHF (dilated or restrictive) Testicular atrophy ^risk of HCC
What causes hemochromatosis?
Primary hemochromatosis:
HFE mutation –> transferrin-Fe complex not taken up into intestinal epithelial cells –> no feedback inhibition –> excessive Fe absorption –> deposition in tissues
Secondary: Chronic transfusions (beta-thalassemia, etc.)
Tx: Phlebotomy, deferasirox, deferoxamine
How does biliary tract disease present?
Pruritis Jaundice Dark urine Light stools HSM
What is seen hisologically with PBC & PSC?
PBC: lymphocytes & granulomas
PSC: “Onion skin” bile duct fibrosis
Beading seen on ERCP
What type of gallstones are radiolucent/radiopaque?
Cholesterol stones = usually radiolucent
Pigment stone = usually radiopaque
What are the risk factors for cholesterol gallstones?
Obesity Age Estrogens Multiparity Crohn's disease Cystic fibrosis Clofibrate Rapid weight loss Native American heritage
How is cholelithiasis diagnosed?
Ultrasound HIDA scan (radionucleotide biliary scan)
What can cause acute pancreatitis?
GET SMASHED: Gallstones Ethanol Trauma Steroids Mumps Autoimmunity Scorpion sting Hypercalcemia/Hypertriglyceridemia ECRP Drugs
also bleeds from gastroduodenal artery (posterior duodenal ulcer)
What can result from acute pancreatitis?
DIC ARDS Hypocalcemia (fat necrosis) Hemorrhage Infection Pseudocyst formation (which can still rupture --> hemorrhage)
What causes chronic pancreatitis?
Basically repeated bouts of acute pancreatitis:
- Alcohol abuse (adults)
- Cystic fibrosis (kids)
- Idiopathic
Amylase & lipase not as high as in acute pancreatitis. Can lead to pancreatic insufficiency.
What tumor marker is used for pancreatic adenocarcinoma?
CA-19-9
10 letters in “pancreatic”
From where does pancreatic adenocarcinoma arise?
Pancreatic ducts
What are the risk factors for pancreatic adenocarcinoma?
Smoking
Chronic pancreatitis
Age
Jewish & Black descent
How does pancreatic adenocarcinoma present?
Abdominal pain radiating to the back
Weight loss
Trousseau’s sign - migratory thrombophlebitis
Obstructive jaundice (tumor in head of pancreas; most common)
Tx: Whipple procedue, chemo, radiation
What are the H2 blockers?
What is their use?
Toxicities?
Cimetidine, Ranitidine, Famotidine, Nizatidine
Take them before you DINE –> impairs gastric acid secretion
Used for PUD, gastritis, GERD
Toxicities:
Cimetidine - CYP450 inhibitor, antiandrogen, HA, ^creatinine
What are the PPI’s?
What are their uses?
Toxicities?
Omeprazole, Lansoprazole, Pantoprazole, Dexlansoprazole
Irreversibly bind H+/K+ ATPase in parietal cells
Used for PUD, GERD, ZES
Toxicities: C. diff infection Pneumonia Hip fractures Hypomagnesemia w/ long term use
What is Misoprostol?
What is it used for?
PGE1 analog –> ^gastric mucous barrier & less acid production
Uses:
Prevent NSAID-induced ulcers
Keep PDA open
Induction of labor
Contraindicated in women of childbearing age (abortifacient)
What is Sulfasalazine?
What are its uses?
Toxicities?
Sulfapyridine (abx) + 5-aminosalicylic acis (anti-inflammatory)
Activates by colonic bacteria
Used for Crohn’s & UC
Toxicities:
Reversible oligospermia
What is Ondansetron?
What are its uses?
5-HT3 antagonist –> powerful central antiemetic
Used to control postop & chemo-induced vomiting
What is Metaclopramide
What are its uses?
Toxicities?
D2 receptor antagonist –> ^LES tone & gut motility (except colon)
Used for postop & diabetic gastroparesis; also antiemetic
Toxicities:
Parkinsonism
Interaction with digoxin & diabetic agents
What is the lymphatic drainage of the colon?
Para-aortic
The sigmoid colon drains to the inferior mesenteric
What are the appropriate ages for Tanner development?
Females: II = 11 III = 12 IV = 13 V = 14
Males: II = 12 III = 13 IV = 14 V = 15
What is precocious puberty?
Puberty beginning before age 8 in girls or 9 in boys.
Aneurysm of what cerebral artery can lead to a blown pupil?
PCA
