Imaging of the Intestines
Introduction Imaging modalities The common radiologic modalities used to evaluate the intestines are the following: Preparation and orientation Prior to interpretation of any image, the physician should take certain preparatory steps. The same systematic approach should be followed every time: Determine the orientation of the image: Radiography (X-ray) Overview Exam technique General positioning: Positioning for […]
Imaging of the Liver and Biliary Tract
Introduction Imaging methods Preparation and orientation Prior to interpretation of any image, the physician should take certain preparatory steps. The same systematic approach should be followed every time. Ultrasonography Overview Exam technique Interpretation and evaluation Report includes: Normal findings CT Overview Exam technique Interpretation and evaluation Normal findings MRI Overview Exam technique Table: General principles […]
Liver Function Tests
Introduction Hepatobiliary anatomy Hepatobiliary physiology Table: Enzyme patterns in liver disease Liver disease ALT and AST ALP Bilirubin GGTP PT Acute liver damage (e.g., viral hepatitis) ↑↑↑ > 10 times normal level Usually ALT > AST Normal or ↑ Normal or ↑ ↑ Normal Chronic liver damage (e.g., fatty liver) ↑↑ Normal or ↑ Normal […]
Portal Hypertension
Etiology and Pathophysiology Etiology The etiologies of portal hypertension can be classified based on the location of increased resistance to blood flow through the liver. Prehepatic etiologies: Hepatic etiologies: Posthepatic etiologies: Pathophysiology Anatomy: Portal hypertension: Clinical Presentation Portal hypertension itself usually has no symptoms. Clinical manifestations arise as a result of the underlying etiology and/or […]
Intestinal Ischemia
Overview Definition Intestinal ischemia is a decrease in blood flow to the intestines resulting in hypoperfusion that may lead to bowel infarction. Mucosal sloughing occurs after approximately 3 hours of ischemia, and necrosis occurs after approximately 6–12 hours of ischemia. Types of intestinal ischemia Epidemiology For all types, intestinal ischemia primarily affects adults > 60 […]
Constipation
Overview Definition Constipation is a symptom generally defined as bowel movements < 3 times per week; stools are frequently difficult to pass. Epidemiology Classification Constipation can be classified as either primary or secondary, as well as by duration (acute or chronic). Etiology Primary constipation Primary constipation, also known as functional constipation, is when there are […]
Acute Abdomen
Overview Definition Acute abdomen is the constellation of signs and symptoms associated with severe abdominal pain and peritonitis that frequently requires emergency surgical intervention. Epidemiology Etiology Nonsurgical causes of acute abdomen: Surgical causes of acute abdomen: Anatomy Boundaries of the abdominal cavity External anatomy For descriptive purposes, the abdomen can be divided into 4 quadrants […]
Short Bowel Syndrome
Overview Definition Epidemiology Etiology Pathophysiology Physiology Consequences of bowel resection Several factors determine the degree of intestinal function loss after bowel resection: Phases of SBS Acute phase: Adaptation phase: Maintenance phase: Clinical Presentation and Diagnosis General clinical presentation Nutritional deficiencies Laboratory findings The following table summarizes possible laboratory findings in SBS that correlate with signs […]
Alcoholic Liver Disease
Overview Definition Alcoholic liver disease encompasses alcoholic steatosis (fatty liver, reversible), steatohepatitis (can be reversible), and cirrhosis (irreversible). All are secondary to alcohol use disorder. Epidemiology Etiology Pathophysiology Ethanol metabolism Histopathological changes Clinical Presentation Alcoholic steatosis (fatty liver) Alcoholic hepatitis Alcoholic cirrhosis Diagnosis and Severity Scores History Physical exam Laboratory studies Imaging Liver biopsy Disease […]
Diarrhea
Overview Definition Diarrhea is the passage of ≥ 3 watery or loose stools in 24 hours. Classification Diarrhea can be classified by the duration of symptoms: Additionally, diarrhea may be classified based on the underlying etiology and pathophysiology: Etiology Infectious diarrhea Inflammatory/invasive: Noninflammatory/noninvasive: Risk factors: Noninfectious diarrhea Secretory: Osmotic: Malabsorption: Inflammatory/exudative: Altered motility: Pathophysiology Infectious […]