on 16-Aug-2017 (Wed)

Approximately 50% of these high-risk patients with acalculus cholecystitis will develop cholangitis, empyema, gangrene, or gallbladder perforation during their hospitalization. Supportive treatment with intravenous antibiotic coverage of anaerobic and gram-negative bacteria is required. Definitive therapy with cholecystectomy is preferred but may be contraindicated in severely ill patients

We follow the convention that an uppercase letter represents a random variable and a lowercase letter represents an outcome or specific value of the random variable. Thus X refers to the random variable, and x refers to an outcome of X. We subscript outcomes, as in x₁ and x₂, when we need to distinguish among different outcomes in a list of outcomes of a random variable.

For example, a discrete random variable X can take on a limited number of outcomes x₁, x₂, …, x_n (n possible outcomes), or a discrete random variable Y can take on an unlimited number of outcomes y₁, y₂, … (without end).1 Because we can count all the possible outcomes of X and Y (even if we go on forever in the case of Y), both X and Y satisfy the definition of a discrete random variable. By contrast, we cannot count the outcomes of a continuous random variable. We cannot describe the possible outcomes of a continuous random variable Z with a list z₁, z₂, … because the outcome (z₁ + z₂)/2, not in the list, would always be possible. Rate of return is an example of a continuous random variable.

In working with a random variable, we need to understand its possible outcomes. For example, a majority of the stocks traded on the New Zealand Stock Exchange are quoted in ticks of NZ$0.01. Quoted stock price is thus a discrete random variable with possible values NZ$0, NZ$0.01, NZ$0.02

In most practical cases, a probability distribution is only a mathematical idealization, or approximate model, of the relative frequencies of a random variable’s possible outcomes.

Low-risk gastric ulcers are clean-based or have a nonprotuberant pigmented spot and should be treated with oral PPI therapy, initiation of refeeding within 24 hours, and early hospital discharge.

Blood transfusion for upper GI bleeding should be performed in patients with (1) hemodynamic instability and ongoing bleeding or susceptibility to complications from oxygen deprivation (for example, ischemic heart disease) and (2) a hemoglobin level less than 7 g/dL (70 g/L) if hemodynamically stable with no active or massive bleeding

Patients with cirrhosis who meet the Milan criteria (up to three hepatocellular carcinomas tumors ≤3 cm or one tumor ≤5 cm) are best treated with liver transplantation and have excellent 5-year survival rates.

A diagnosis of hepatocellular carcinoma can be made in a patient with cirrhosis in the presence of lesions larger than 1 cm that enhance in the arterial phase and have washout of contrast in the venous phase

The vast majority of hepatocellular carcinomas in the context of cirrhosis can be diagnosed with radiologic criteria alone.

Sorafenib, a compound that targets growth signaling and angiogenesis, should be reserved for patients with Child-Turcotte-Pugh class A or B cirrhosis, good performance status, and vascular, lymphatic, or extrahepatic spread of the tumor.

Transarterial chemoembolization (TACE) should not be performed before referral to a transplant center. Ultimately, patients who are expected to be on the waiting list for longer than 6 months are recommended to receive locoregional therapy such as TACE to control the tumor while awaiting a transplant. However, TACE should only be performed after the liver transplant evaluation is completed.

Patients with a positive antibody to hepatitis C virus (HCV) but negative HCV RNA do not have HCV infection, and no further testing is required

Positive anti-HCV with negative HCV RNA indicates either false-positive anti-HCV or cleared infection, and positive anti-HCV with positive HCV RNA indicates active infection. Rarely, in instances of acute HCV infection or in an immunosuppressed patient, HCV RNA may be positive despite a negative anti-HCV

Because MYH-associated polyposis is an autosomal recessive disorder, both parents must be carriers of an MYH mutation in order for a child to inherit the syndrome.

Genetic testing is usually done at the age at which high-risk colorectal cancer screening would begin, which is 18 years in MAP and attenuated familial adenomatous polyposis and 12 to 15 years in classic FAP

Patients with variceal hemorrhage and cirrhosis are at high risk for infection and require antibiotic prophylaxis, regardless of the presence or absence of ascites

An oral fluoroquinolone such as norfloxacin or intravenous ciprofloxacin (when oral intake is not possible) are the acceptable choices. Intravenous ceftriaxone may be more effective for patients with Child-Turcotte-Pugh class B and C cirrhosis

A nonselective β-blocker is recommended as secondary prophylaxis after recovery from a variceal bleed, but it would not be warranted in the acute setting in this patient with hypotension

An upper endoscopy should be performed in this patient with presumed variceal hemorrhage within 12 hours, but only after she has been treated with standard pharmacotherapy (octreotide and antibiotics) and appropriately resuscitated to enable safe endoscopy. A blood pressure of 72/54 mm Hg is too low to be able to proceed immediately with a safe endoscopy

The most likely diagnosis is celiac disease. This patient has the combination of loose stools, unintentional weight loss, elevated liver chemistry test results, and iron deficiency anemia without an obvious source of blood loss. Minor elevations of serum aminotransferase levels are found in up to 50% of patients with celiac disease and may be the only presenting feature in approximately 9% of patients. Serum aspartate aminotransferase (AST) is usually less than 80 U/L, and alanine aminotransferase (ALT) is usually less than 130 U/L.

Patients with celiac disease can also have coexisting liver disease such as autoimmune hepatitis, primary sclerosing cholangitis, or primary biliary cirrhosis

Improvements in liver chemistry studies that are related to celiac disease occur when such patients are treated with a gluten-free diet.

PBC is diagnosed by serum alkaline phosphatase levels greater than 1.5 times the upper limit of normal and typically normal serum total bilirubin levels

Up to 20% of patients with symptomatic gallbladder stones will have a common bile duct stone.

Acute pancreatitis could be a complication of a common bile duct stone, but the pain would not be intermittent and it would result in an elevated serum amylase level

Metoclopramide is the only drug approved by the FDA for the treatment of gastroparesis; however, metoclopramide is associated with side effects such as hyperprolactinemia, galactorrhea, and tardive dyskinesia that require discontinuation of the drug.

The initial treatment of diabetic gastroparesis should include a dietary management plan consisting of frequent small-volume meals that are low in fat and soluble fiber. Equally important is tight glycemic control

The risks of neurologic side effects of metoclopromide are increased with chronic therapy (greater than 3 months) and with use in the elderly and in women

N-acetylcysteine has been shown in a randomized controlled trial to improve transplant-free survival in non–acetaminophen-related acute liver failure in patients with grade I or II hepatic encephalopathy

absence of previous liver disease accompanied by new-onset hepatic encephalopathy and coagulopathy, usually in the presence of jaundice

The cause of ALF is most likely amoxicillin-clavulanate, which is the most common cause of drug-induced liver injury.

Intravenous acyclovir would be an appropriate treatment for herpes hepatitis. Herpes hepatitis classically presents with serum aminotransferase values in the multiple thousands and a disproportionately low serum bilirubin leve

Oral pentoxifylline is a second-line treatment for alcoholic hepatitis

The classic presentation of eosinophilic esophagitis is a young man with solid-food dysphagia that requires endoscopy for removal

eosonophilic esophagitis EoE is the result of eosinophil cell infiltration of the esophageal squamous mucosa. The incidence of EoE is thought to be increasing, and it seems to parallel the increasing incidence of allergic disease and asthma

GERD must be excluded because it can also cause esophageal eosinophilic infiltration. This can be done with a therapeutic trial of a proton pump inhibitor (PPI) for 8 weeks.

Endoscopy often reveals characteristic findings of esonophilic esophagitis EoE such as rings, longitudinal furrows, and sometimes strictures. Medical therapy consists of swallowed aerosolized topical glucocorticoids (fluticasone or budesonide).

Barrett esophagus (BE) is the result of chronic acid reflux, but it is usually not associated with dysphagia, especially in a young person. The diagnosis of BE is suggested by endoscopic findings of salmon-colored mucosa at the gastroesophageal junction compared with the normal pearl-colored squamous mucosa and is confirmed histologically by the presence of specialized intestinal metaplasia with acid-mucin–containing goblet cells

Diffuse esophageal spasm is usually characterized by dysphagia or chest pain but not food impaction. Manometry shows intermittent, high- amplitude, simultaneous, nonperistaltic contractions in response to swallowing. Findings of a “corkscrew esophagus” (caused by multiple simultaneous contractions) on barium swallow are typical of diffuse esophageal spasm.

Upper endoscopy is recommended for surveillance of duodenal cancer every 1 to 5 years in all patients with familial adenomatous polyposis.

A phenotypic variant of FAP called Gardner syndrome is associated with extraintestinal manifestations of FAP, which include congenital hypertrophy of the retinal pigment epithelium (CHRPE). CHRPE may be an indication of underlying FAP, but it has no attendant health risks for patients with FAP and does not require ongoing surveillance if detected

The most appropriate management is serial monitoring of liver enzymes. This patient has acute hepatitis B without evidence of marked liver dysfunction (such as markedly increased INR or hepatic encephalopathy). Typical clinical symptoms include malaise, fatigue, nausea, and right upper quadrant discomfort. Jaundice and cholestasis can develop 1 to 2 weeks after the onset of symptoms. Acute hepatitis B infection will resolve (defined as clearance of hepatitis B surface antigen within 6 months) in 90% of adult patients. Serial monitoring of liver enzymes and markers of liver synthetic function is the most appropriate management strategy