Pathology flashcards

What characterizes endoinfectious processes of the digestive system?

Disorders with inflammatory manifestations caused by a biological imbalance between the host and its gut microorganisms

What percentage of fecal solids is made up of bacteria?

Around 60%

How many different bacterial species typically inhabit the human gut?

Approximately 300–500 or more species

How does the number of microbial cells in the gut lumen compare to the body’s eukaryotic cells?

It is about ten times greater

What congenital anomalies can predispose to digestive‐system endoinfections?

Enterocyte membrane dysfunction, cellular or humoral immunity failure, and tract dysplasias such as megacolon, dolichosigma, and diverticula

What is congenital small intestinal atresia?

A birth defect in which a segment of the small intestine is completely blocked or missing

How is purulent inflammation defined?

Production of pus containing dead neutrophils, necrotic cells, and edema fluid

How do microorganisms trigger appendiceal inflammation?

Following epithelial damage from luminal obstruction, dyskinesia, coprostasis, coproliths or helminths, plus intravascular stasis and thrombosis

What is superficial (catarrhal) appendicitis?

Early inflammation limited to mucosa and submucosa with hyperemia, edema, increased mucus secretion, and neutrophil infiltration

What defines ulcerative appendicitis?

Destructive focal mucosal erosion forming small ulcers with neutrophils extending into the submucosa

What is ulcerative-phlegmonous (suppurative) appendicitis?

Ulcers extending through the muscularis into the wall, diffuse pus formation, and serosal fibrinous exudate

What characterizes abscedent appendicitis?

A walled‐off abscess within or around the appendix, with central necrosis and fibrous capsule formation

What occurs in gangrenous appendicitis?

Severe inflammation causes vascular compromise, full‐thickness wall necrosis (gray‐green to black), and high perforation risk

What is a microperforation complication of appendicitis?

Minute wall breaches allowing small leaks of bacteria or fluid into surrounding tissues

What is a macroperforation complication?

A larger rupture of the appendix wall with frank leakage of pus and bowel contents into the peritoneum

What is periappendicitis with localized fibrino‐purulent peritonitis?

Spread of inflammation from the appendix serosa to adjacent peritoneum, producing a focal zone of fibrin and pus

What defines diffuse purulent peritonitis?

Generalized peritoneal infection by pus after appendix rupture, leading to widespread exudate

How can appendicitis lead to intestinal adhesions and obstruction?

Inflammation and healing deposit fibrous bands between bowel loops that can tether or kink the intestine

What is purulent thrombophlebitis as an appendicitis complication?

Septic thrombosis of veins draining the appendix that spreads to portal branches, causing liver abscesses and sepsis

What is appendix empyema?

Accumulation of purulent exudate (pus) confined within the appendiceal lumen

What is hydrops of the appendix (muco‐hydrops)?

Noninfectious distension of the appendix by a clear, mucus‐like fluid due to luminal obstruction

What is an appendiceal mucocele?

Dilatation of the appendix from intraluminal accumulation of mucinous material, which may arise from mucosal hyperplasia or mucinous neoplasm

What is gastrointestinal candidiasis?

Fungal infection of mucosal surfaces (mouth, esophagus) by Candida albicans, especially in newborns or immunocompromised patients

Where does Candida albicans normally reside without causing disease?

On skin, in the mouth, GI tract, and vagina as a benign commensal

What protects healthy individuals from Candida overgrowth?

Intact normal bacterial flora and robust immune defenses

What is thrush?

A superficial Candida infection of the oral mucosa

What are complications of gastrointestinal candidiasis?

Ulceration leading to perforation, postinflammatory scarring and strictures, and systemic dissemination (generalisation)

What is a gastric ulcer?

An ulcer of the stomach mucosa (ulcus ventriculi).

What is a duodenal ulcer?

An ulcer of the duodenal mucosa (ulcus duodeni) with defects deeper than half the mucosal thickness.

What are erosions?

Mucosal defects that involve less than half of the mucosal thickness.

What are the main damaging forces in peptic ulcer pathogenesis?

Gastric acidity and peptic enzymes.

What are the normal mucosal defensive forces against ulceration?

Surface mucus secretion

What causes peptic ulcer disease to develop?

An increase in damaging forces and/or impairment of the mucosal defenses.

List common causes of peptic ulcers.

Helicobacter pylori infection

Where are peptic ulcers most commonly located?

In the gastric pylorus and the proximal duodenum.

What proportion of peptic ulcers are solitary?

About 80%.

Describe the typical shape and size of peptic ulcers.

Round or oval lesions, 0.5–3 cm in diameter.

How deep can peptic ulcers extend?

They can vary in depth and may penetrate through the wall to reach the pancreas or liver.

What complications can arise from peptic ulcers?

Bleeding

What defines a precancerous condition?

A lesion or state with increased cancer risk if left untreated.

Give examples of precancerous conditions in the GI tract.

Chronic inflammation with ulceration

What is chronic inflammation with ulceration?

Persistent immune-mediated mucosal injury causing ulcers that may bleed or scar.

What is leukoplakia?

A white, well-defined hyperkeratotic mucosal patch that cannot be scraped off and is often premalignant.

What are GI polyps?

Localized mucosal overgrowths—whether inflammatory, hyperplastic, or neoplastic—that protrude into the lumen and may harbor dysplasia.

What is atrophic gastritis?

Thinning of the gastric mucosa with loss of glands and parietal cells, resulting in decreased acid and intrinsic factor production.

What is Barrett’s esophagus?

Replacement of normal squamous epithelium in the distal esophagus by intestinal-type columnar epithelium due to chronic acid reflux.

What is intraepithelial dysplasia (carcinoma in situ)?

Full-thickness epithelial atypia without invasion past the basement membrane—the final premalignant stage.

What are the hallmarks of cancerous tumors?

Abnormally large, partly autonomous masses with genetic changes, continuous growth after carcinogen removal, and parasitic consumption of host resources.

What GI tract complications can lead to death?

Lumen obstruction

Congenital small intestinal atresia with enlargement, purulent inflammation and necrosis

Epithelium is intact and no inflammatory cells intraepithelial

Inflammation started due to large coprolith → ischemia, epithelium disclamation and inflammation in deep layers of appendix

Enterobiosis vermicularis penetrate through mucosa into deep layers → cause inflammation

Hyperaemic vessels

Purulent exudate on surface of appendix + inflammation

Discoloration of appendix and purulent exudate around and inside appendix.

No muscular or submucosal layer is visible → only necrosis

Adenomas – tubular structure of neoplasm

Tubular papillary carcinoma

Tubular and papillary structures formed from neoplastic epithelial cells from GI tract

Explain all three pictures

Cyanate ring carcinoma

Ø  Formed of neoplastic cells from GI tract.

Ø  Alcion blue in the middle where we see mucus inside cells.

Ø  Immunohistochemical reaction (right) – positive for cytokeratin’s → shows that they are carcinoma epithelial origin.

Ø  Whitish region near coronary artery – metastasis:

1.     Caused obstruction of BV → infarction.

Ø  Congenital outpouching in the small intestine.

1.     Usually located in the ileum, that results from a failure of the omphalomesenteric duct (also known as the vitelline duct) to fully close during foetal development.

Mucosa is red, ulcerated due to UC

Ulcerative colitis

1.     Architecture of mucous gland is distorted, branched, deformed.

2.     Infiltration of leukocytes.

3.     Centre with ulceration.

Pseudomembranous colitis:

Damaged mucosa covered with exudate with greenish colour.

Pseudomembranous colitis:

1.    Green – rest of mucous glands.

2. Other regions with necrotic debris due to inflammation and exudate

What is Meckel’s diverticulum?

A congenital outpouching of the small intestine, usually in the ileum, resulting from failure of the omphalomesenteric (vitelline) duct to close during fetal development.

What is tonsillitis?

Inflammation of the tonsils and pharynx, often viral in origin with possible secondary bacterial infection (e.g., Streptococcus, Staphylococcus).

What factors predispose to tonsillitis?

Common cold, immune system failure, vitamin deficiency, and other underlying diseases.

How is tonsillitis classified by clinical course?

As acute or chronic.

How is tonsillitis classified by exudate type?

Serous, fibrinous, purulent, or necrotizing.

What are complications of tonsillitis?

Peritonsillar abscess, retropharyngeal abscess, purulent otitis media, phlegmon, thrombophlebitis, sepsis, and scarring.

What is enteritis?

Inflammation of the small intestine leading to impaired nutrient absorption, malnutrition, and diarrhea with water and salt loss.

How is enteritis classified by location?

Duodenitis, jejunitis, or ileitis.

How is enteritis classified by course?

Acute or chronic.

How is enteritis classified by etiology?

Infectious, toxic, immune‐mediated, or nutritional.

What are the morphological types of acute enteritis?

Catarrhal, fibrinous, purulent, and ulcerative‐necrotizing.

What are the histologic features of chronic enteritis?

Loss of epithelial brush border, cell vacuolation and death, and lamina propria infiltration by lymphocytes, plasma cells, and eosinophils.

What complications can result from enteritis?

Bleeding, perforation, dehydration, and—if chronic—cachexia, hypoproteinemia, anemia, and vitamin deficiencies.

What is typhlitis (caecitis)?

A necrotizing inflammatory condition of the caecum that can extend into the ascending colon or terminal ileum.

What are other segment‐specific colitis terms?

Transversitis (transverse colon), sigmoiditis (sigmoid colon), proctitis (rectum), proctosigmoiditis (rectum + sigmoid), pancolitis (entire colon), enterocolitis (small + large intestine), and gastroenterocolitis (stomach + small + large intestine).

How do the causes and complications of colitis compare to enteritis?

They mirror enteritis in etiology, pathogenesis, morphology, and complications such as bleeding, perforation, and systemic effects.

What is ulcerative colitis?

A chronic idiopathic inflammatory bowel disease beginning in the rectum, progressing proximally, with a relapsing (undulating) course and diffuse mucosal and submucosal inflammation.

Which layers of the bowel are affected in ulcerative colitis?

The mucosa and submucosa.

What factors may trigger ulcerative colitis?

Commensal gut bacteria, dietary and environmental factors, primary immunological defects, mucus secretion disorders, genetic predisposition, psychological stress, or combinations.

What are complications of ulcerative colitis?

Cachexia, anemia, sepsis, secondary amyloidosis, toxic megacolon, pseudopolyps, and intraepithelial neoplasia progressing to carcinoma.