Appendicitis: Pathology review


00:00 / 00:00



Appendicitis: Pathology review


Peritoneum and peritoneal cavity



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


Appendicitis: Pathology review

USMLE® Step 1 questions

0 / 2 complete


USMLE® Step 1 style questions USMLE

of complete

A 32-year-old man is brought to the emergency department due to severe abdominal pain, fever, nausea, and vomiting. The patient states that the pain started near the umbilicus yesterday evening, but has since moved towards the lower right side. He also reports that the pain increased in severity overnight, rating it up to a 10 on a 10-point scale. However, he now feels that the pain has diminished slightly. He describes the pain as sharp and states that it was especially bad en route to the hospital when the ambulance drove over bumps in the road. The patient has no past medical history and consumes a vegan diet. His temperature is 39.3°C (102.7°F), pulse is 124/min, respirations are 24/min, and blood pressure is 86/60 mmHg. Abdominal examination shows tenderness over the right lower quadrant. The patient is noted to tighten his abdominal muscles to lessen the pain. Which of the following physical examination signs is most likely to be present in this patient?  


Content Reviewers

Yifan Xiao, MD


Sam Gillespie, BSc

Zachary Kevorkian, MSMI

Daniel Afloarei, MD

Salma Ladhani, MD

While in the Emergency Department, Bella, a 22-year-old woman, presents with abdominal pain that started 6 hours ago. The pain was initially located around the umbilical area but it has migrated to the right lower quadrant in the past few hours. The pain is sharp, like being stabbed with a knife and it gets worse with movement. A physical examination showed tenderness of the right lower quadrant with moderate guarding and a low-grade fever of 100.4°F.

Shortly after, Edward, who’s 11, presents with generalized abdominal pain with vomiting and diarrhea. On examination, he appears ill and has a temperature of 104°F. His abdomen is tense with generalized tenderness and guarding. No bowel sounds are present.

Blood tests were ordered in both cases, detecting an increased white blood cell count of 12,000 cells per microliter with 85 percent neutrophils. Now, both people have appendicitis.

Now the appendix is the little close-ended hollow tube that’s attached to the cecum of the large intestine, and sometimes it’s called the vermiform appendix, where vermiform means “worm-shaped.” Normally, the appendix can be found in a retrocecal location, as well as pre-ileal, post-ileal, pelvic and subcecal. Its function is actually unknown, though some theories suggest it might be a “safe-house” for the gut flora and that it plays a part in the lymphatic and immune system. Okay, so appendicitis usually occurs because something gets stuck and obstructs the appendix. That something could be a fecalith, which is a hardened lump of fecal matter, a piece of undigested material like gum or seeds, or even a clump of intestinal parasites like pinworms.


  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. "APPENDICITIS" Emergency Medicine Clinics of North America (1996)
  4. "Suspected Appendicitis" New England Journal of Medicine (2003)

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.