Gastroenterology

Missed Concepts

• Food protein-induced allergic proctocolitis shows up at 1-4 weeks of age with blood and mucus streaked stools. Treat by eliminating dairy from the maternal diet. It is benign and self-limited.
• The shortest interval for repeat colonoscopy is for large adenomas (>2 cm) removed piecemeal. Second shortest interval is 1 year for > 10 adenomas.
• Initial evaluation for gastroparesis is EGD to evaluate for mechanical obstruction.

Esophageal Pathology

• H&P:
• Dx: Adenocarcinoma is more common in the distal 2/3 esophagus (smooth muscle), while squamous cell carcinoma is found in the upper 1/3 (skeletal muscle).
• Tx:

GERD

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PUD

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IBD

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IBS

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Diarrhea

• H&P:
• Dx: For chronic diarrhea, send stool microscopy, electrolytes, and fat content.
• Tx: For acute viral gastroenteritis. Diet recommendation is to resume normal eating without excessive sugars. For Giardia (chronic, oily, nonbloody, weight loss, bloating), treat with tinidazole.

Celiac Sprue

• H&P:
• Dx:
• Tx: Thyroid hormone replacement doses are higher in patients with Celiac disease due to levothyroxine malabsorption.

UGIB

• H&P:
• Dx: Nasopharyngeal laryngoscopy is preferred over EGD when there is a possible upper esophageal mass
• Tx:

LGIB

• H&P:
• Dx: Workup for hematochezia is colonoscopy if HDS, resuscitate, ± surgery/IR consult, EGD if HDUS. Angiodysplasias (e.g. AVMs) are associated with AS, vWD, and ESRD.
• Tx:

Pancreatitis

• H&P:
• Dx: 2 of 3 criteria—acute onset severe epigastric pain, elevation of lipase or amylase ≥ 3x ULN, characteristic findings on imaging. Thiazide diuretics and most loop diuretics are in important cause of drug-induced pancreatitis. Hypertriglyceridemia can also cause pancreatitis.
• Tx:

Approach to LFTs

GGT measurement helps differentiate if elevated alk phos is from liver (elevated) or bone (normal)

Cholestasis (ALK + TBili)	No Obstruction	Indirect bili: Hepatitis, Cirrhosis
		Direct bili: PBC, Drug-induced, Post-op, Sepsis
	Obstruction	PSC, Choledocholithiasis, Cholangiocarcinoma, Pancreatic cancer, Pancreatitis
Hepatocellular Injury (AST + ALT)	Viral	Hepatitis Virus (A-E), EBV, CMV, HSV, VZV
	Autoimmune/Genetic	Autoimmune, Wilson, Hemochromatosis, α1-antitrypsin deficiency
	Drugs/Toxins	EtOH, APAP

Gallstone Disease

• H&P: Female, Fat, Forty, Fair, Fertile
• Dx: Cholestatic pattern of elevated bilirubin and alk phos, Charcot triad for ascending cholangitis includes RUQ pain, fever, jaundice. When clinical suspicion for acute cholecystitis is high, but US is negative or inconclusive, get HIDA scan.
• Tx: For acute/ascending cholangitis, treat with ERCP within 24-48 hrs

Viral and Non-viral Hepatitis

• H&P:
• Dx: HBsAg, HBeAg, HBV DNA, and ALT are elevated during the early symptomatic phase of infection. In later stages anti-HBs, anti-HBe, and total anti-HBc are all elevated. In the window period, only IgM anti-HBc and anti-HBe will be elevated.
• Tx:

Cirrhosis and Ascites

• H&P:
• Dx: Calculate SAAG, if ≥ 1.1, think portal hypertension (from CHF, cirrhosis, EtOH hepatitis); if < 1.1, think cancer, pancreatitis, nephrotic syndrome.
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Acetaminophen Toxicity

• H&P:
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Heredity Hemochromatosis

• H&P: Males present young (30s), Females present late (60s); hyperpigmentation, arthritis, cardiomyopathy, diabetes
• Dx: Elevated AST and ALT; increased serum ferritin and transferrin saturation; HFE gene mutation
• Tx: Therapeutic phlebotomy

Wilson Disease

• H&P: Age < 35 with neuropsychiatric symptoms (depression, movement disorders) and hepatomegaly
• Dx: Elevated AST and ALT; liver biopsy, or genotyping (ATP7a gene)
• Tx: Lifelong chelation (penicillamine, trientine), high dose PO zinc, transplant

α1-Antitrypsin Disease

• H&P: Associated with emphysema in young non-smokers
• Dx: Elevated AST and ALT; serum AAT levels, genotyping
• Tx: Transplant, AAT augmentation

Autoimmune Hepatitis

• H&P: Young to middle-aged; F>M; painless hepatomegaly
• Dx: Elevated AST and ALT; ANA, anti smooth muscle, and LKMA antibodies are positive. Biopsy.
• Tx: Corticosteroids and azathioprine

PBC

• H&P: Intrahepatic bile duct destruction; Age 30-65; F>M; Fatigue and jaundice; pruritis and osteoporosis; associated with hypothyroid and arthritis
• Dx: Elevated ALK + bili; positive AMA; no bile duct dilation on imaging
• Tx: Ursodeoxycholic acid, cholestyramine, fat-soluble vitamins; transplant in rare cases

PSC

• H&P: Intra and extra hepatic bile duct fibrosis; Age 30-40; M>F; associated with IBD (UC>Crohn's); asymptomatic or presenting with fatigue, pruritic, RUQ pain
• Dx: Elevated ALK + bili; ANA, anti smooth muscle, and anti pANCA antibodies; bile duct dilation on imaging
• Tx: Ursodeoxycholic acid, cholestyramine, fat-soluble vitamins; transplant frequently required