Non-alcoholic fatty liver disease


00:00 / 00:00



Non-alcoholic fatty liver disease

Gastrointestinal system

Peritoneum and peritoneal cavity disorders



Upper gastrointestinal tract disorders

Cleft lip and palate

Congenital diaphragmatic hernia

Esophageal web

Tracheoesophageal fistula

Pyloric stenosis



Oral candidiasis

Ludwig angina

Aphthous ulcers

Temporomandibular joint dysfunction

Dental abscess

Gingivitis and periodontitis

Dental caries disease

Oral cancer

Warthin tumor

Barrett esophagus


Plummer-Vinson syndrome

Mallory-Weiss syndrome

Boerhaave syndrome

Gastroesophageal reflux disease (GERD)

Zenker diverticulum

Diffuse esophageal spasm

Esophageal cancer

Eosinophilic esophagitis (NORD)


Gastric dumping syndrome

Peptic ulcer


Cyclic vomiting syndrome


Gastric cancer

Lower gastrointestinal tract disorders


Imperforate anus


Meckel diverticulum

Intestinal atresia

Hirschsprung disease

Intestinal malrotation

Necrotizing enterocolitis


Tropical sprue

Small bowel bacterial overgrowth syndrome

Celiac disease

Short bowel syndrome (NORD)

Lactose intolerance

Whipple's disease

Protein losing enteropathy

Microscopic colitis

Crohn disease

Ulcerative colitis

Bowel obstruction

Intestinal adhesions


Gallstone ileus

Abdominal hernias

Femoral hernia

Inguinal hernia

Small bowel ischemia and infarction

Ischemic colitis

Familial adenomatous polyposis

Peutz-Jeghers syndrome

Gardner syndrome

Juvenile polyposis syndrome

Colorectal polyps

Colorectal cancer

Carcinoid syndrome

Irritable bowel syndrome


Diverticulosis and diverticulitis


Anal fissure

Anal fistula


Rectal prolapse

Liver, gallbladder and pancreas disorders

Crigler-Najjar syndrome

Biliary atresia

Gilbert's syndrome

Dubin-Johnson syndrome

Rotor syndrome



Portal hypertension

Hepatic encephalopathy


Wilson disease

Budd-Chiari syndrome

Non-alcoholic fatty liver disease

Cholestatic liver disease

Hepatocellular adenoma

Autoimmune hepatitis

Alcohol-induced liver disease

Alpha 1-antitrypsin deficiency

Primary biliary cirrhosis

Primary sclerosing cholangitis


Neonatal hepatitis

Reye syndrome

Benign liver tumors

Hepatocellular carcinoma


Biliary colic

Acute cholecystitis

Ascending cholangitis

Chronic cholecystitis

Gallstone ileus

Gallbladder cancer


Acute pancreatitis

Pancreatic pseudocyst

Chronic pancreatitis

Pancreatic cancer

Pancreatic neuroendocrine neoplasms

Zollinger-Ellison syndrome

Gastrointestinal system pathology review

Congenital gastrointestinal disorders: Pathology review

Esophageal disorders: Pathology review

GERD, peptic ulcers, gastritis, and stomach cancer: Pathology review

Inflammatory bowel disease: Pathology review

Malabsorption syndromes: Pathology review

Diverticular disease: Pathology review

Appendicitis: Pathology review

Gastrointestinal bleeding: Pathology review

Colorectal polyps and cancer: Pathology review

Neuroendocrine tumors of the gastrointestinal system: Pathology review

Pancreatitis: Pathology review

Gallbladder disorders: Pathology review

Jaundice: Pathology review

Viral hepatitis: Pathology review

Cirrhosis: Pathology review


Non-alcoholic fatty liver disease


0 / 10 complete

USMLE® Step 1 questions

0 / 1 complete

High Yield Notes

27 pages


Non-alcoholic fatty liver disease

of complete


USMLE® Step 1 style questions USMLE

of complete

A 52-year-old man is brought to the emergency department after being found unconscious on the sidewalk. He is arousable to sternal rub. The patient’s family is contacted, and his next of kin reports that the patient is currently undomiciled. Past medical history is notable for hypertension. The patient has been drinking a pint of vodka daily for the last 12 years, but does not consume tobacco or illicit substances. Temperature is 37.0°C (98.6°F), pulse is 92/min, respirations are 13/min, and blood pressure is 156/95 mmHg. Physical examination reveals jaundice, palmar erythema, and pungent breath. The lungs are clear to auscultation. The abdomen is soft and mildly tender to palpation; there is shifting dullness to percussion. The liver is not palpable. Which of the following is most likely to be present if a biopsy of the patient’s liver is performed?

External Links


Content Reviewers

Rishi Desai, MD, MPH


Vincent Waldman, PhD

Tanner Marshall, MS

Nonalcoholic fatty liver disease is actually a spectrum of disease, going from least to most severe—steatosis, steatohepatitis, fibrosis, and finally cirrhosis.

Nonalcoholic fatty liver disease results from fat deposition in the liver, which is unrelated to alcohol or viral causes.

Typically, it affects individuals with metabolic syndrome, which includes a combination of three of the following five diagnoses: obesity, hypertension, diabetes, hypertriglyceridemia, and hyperlipidemia.

Given how common metabolic syndrome has become, it’s not surprising that the rate of nonalcoholic fatty liver disease has also increased dramatically.

It’s a massive problem growing in lock-step with expanding waistlines, affecting about three quarters of all obese individuals, including many children.

Although the exact mechanism of nonalcoholic fatty liver disease isn’t clear, insulin resistance seems to play an important role.

Over time, insulin receptors on various tissues including the liver become less responsive to insulin, and as a result the liver goes into a mode where it increases fat storage and decreases fatty acid oxidation.

That means decreased secretion of lipids into the bloodstream, in the form of lipoproteins, and increased synthesis and uptake of free fatty acids from the blood, a process called steatosis.

Steatosis causes fat droplets to form within hepatocytes, some of which become large enough to cause the hepatocytes to swell up with fat and push the nuclei to the edge of the cell.

You can see this on a histopathology slide of the liver.

All of these white circles are large deposits of fat.

Zooming out and looking at the liver, you see widespread steatosis which makes the liver appear large, soft, yellow, and greasy.

Over time, that fat in the hepatocytes is vulnerable to degradation.

Unsaturated fatty acids, or fatty acids that have at least one double bond in their carbon chain, have hydrogen atoms that are especially vulnerable to initiators such as the reactive oxygen species like the hydroxyl radical that have an unpaired electron.


Non-alcoholic fatty liver disease (NAFLD) is a condition in which excess fat is deposited in the liver, leading to inflammation and scarring. NAFLD is a common liver disorder that affects people who do not drink alcohol excessively. NAFLD commonly affects people with metabolic syndrome, which includes a combination of three of the following five diagnoses: obesity, hypertension, diabetes, hypertriglyceridemia, and hyperlipidemia.

Symptoms of NAFLD may be subtle or absent in the early stages of the disease. In advanced stages, symptoms may include fatigue, abdominal pain, and jaundice. NAFLD can progress to a more serious condition called non-alcoholic steatohepatitis (NASH), which can lead to liver scarring and cirrhosis. Treatment for NAFLD may involve lifestyle changes such as weight loss, regular exercise, and a healthy diet to help reduce fat in the liver and improve insulin resistance.


  1. "Robbins Basic Pathology" Elsevier (2017)
  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
  4. "CURRENT Medical Diagnosis and Treatment 2020" McGraw Hill Professional (2019)
  5. "The Role of Intestinal Bacteria Overgrowth in Obesity-Related Nonalcoholic Fatty Liver Disease" Nutrients (2014)
  6. "Non-alcoholic fatty liver disease" BMJ (2014)

Copyright © 2023 Elsevier, except certain content provided by third parties

Cookies are used by this site.

USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.