Helicobacter pylori Gastritis

Slide 1 · Helicobacter pylori gastritis

Microbial colonization · chronic active inflammation · divergent clinical outcomes

Pathogenesis, morphology and clinicopathologic interpretation

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · Learning objectives

Explain how H. Pylori survives and persists within gastric mucus.

Relate antral versus extensive atrophic disease to acid output and complications.

Recognize the characteristic pattern of chronic active gastritis.

Select and interpret the major diagnostic modalities.

Slide 3 · A single infection can produce divergent disease

Persistent gastric colonization

Location and host response differ

Ulcer-predominant or atrophic phenotype

Different long-term complications

The anatomic pattern of inflammation helps predict acid secretion, morphology and risk.

Slide 4 · Evidence that the organism causes gastritis

H. Pylori cultured by Warren and Marshall

Marshall ingested a cultured preparation

Repeat biopsy showed colonization and gastritis

Recovery followed antibiotic treatment

An experimental challenge linked bacterial infection to gastric inflammation.

Slide 5 · The organism and its principal niche

Curved or spiral-shaped bacillus adapted to gastric mucus.

Resides predominantly in mucus overlying foveolar epithelial cells.

Bacterial survival depends on movement, pH protection and adherence.

Long-term colonization provokes chronic mucosal inflammation.

Slide 6 · Natural history begins with colonization

Acquisition usually in childhood

Acute infection often causes mild or no symptoms

Untreated infection frequently persists

Later detection during chronic gastritis or ulcer evaluation

Infection can precede clinical presentation by many years.

Slide 7 · The human reservoir and likely transmission

Humans are the primary carriers.

Fecal–oral transmission is considered the main route.

Persistent asymptomatic colonization facilitates transmission.

Acquisition is closely linked to the childhood environment.

Slide 8 · Why childhood living conditions matter

Crowded living conditions and limited sanitation

Greater opportunity for early-life exposure

Gastric colonization established

Persistence into adulthood without treatment

Environmental exposure helps explain cohort differences in infection prevalence.

Slide 9 · Risk associations reported in the United States

Lower income and household crowding.

Limited education and residence in rural settings.

Birth outside the United States and older age.

Differences between population groups may reflect social and historical exposures.

Slide 10 · Age-associated prevalence of H. Pylori in the US

US age group

Reported infection estimate

Interpretation

Before 10 years

Uncommon in high-resource countries

Improved childhood sanitation

18–30 years

About 10%

Lower prevalence in younger cohort

Older than 65 years

Up to 50%

Higher historical exposure

Slide 11 · Antral and corpus involvement are not equivalent

Body / fundus

Antrum

Schematic stomach regions

Antrum often most heavily colonized

Long-standing infection may extend into body and fundus

Slide 12 · Survival requires overcoming gastric acidity

Acidic gastric lumen

Mucus layer provides a protected niche

Organisms locate near epithelial surface

Sustained colonization and inflammation

H. Pylori survives in a locally modified microenvironment rather than freely multiplying in highly acidic lumen.

Slide 13 · Four bacterial virulence functions

Virulence attribute

Principal contribution

Flagella

Movement through viscous gastric mucus

Urease

Generation of ammonia and elevation of local pH

Adhesins

Adherence to surface foveolar epithelial cells

CagA and other effectors

Alteration of epithelial functions and injury responses

Slide 14 · Flagella support persistence in mucus

Viscous mucus impedes passive dispersal

Flagellar motility permits active movement

Bacteria avoid acidic microenvironments

Localization near epithelium is maintained

Motility is an adaptation to the structure and pH gradient of the gastric niche.

Slide 15 · Urease creates a buffered microenvironment

Endogenous gastric urea

Bacterial urease activity

Ammonia generation

Higher local pH and bacterial survival

Urease protects the bacterium locally; It does not make the entire gastric lumen alkaline.

Slide 16 · Why urease matters clinically

Urease is both a survival mechanism and a diagnostic target.

Local buffering enables persistence in gastric mucus.

Rapid urease testing uses gastric biopsy material.

Urea breath testing exploits the same bacterial enzymatic activity.

Slide 17 · Adhesins retain bacteria at the epithelial surface

Bacteria approach foveolar surface

Adhesion proteins mediate binding

Surface-associated colonization is stabilized

Persistent epithelial inflammatory stimulus

Slide 18 · CagA and VacA: Epithelial virulence effectors

CagA and vacuolating cytotoxin VacA.

Experimental studies associate these factors with altered epithelial functions.

Virulence-factor carriage varies among bacterial isolates.

Observed clinical correlations do not establish a single deterministic outcome.

Slide 19 · CagA modulates epithelial cell behavior

CagA-containing strain colonizes mucosa

CagA enters epithelial cytoplasm

Intracellular signaling is altered

Structural remodeling of the epithelial cell

Robbins cautions that the contribution to human clinical outcomes remains substantially correlative.

Slide 20 · Virulence does not equal inevitable cancer

Bacterial strain properties modify risk; They do not determine fate alone.

CagA is associated with more extensive mucosal injury in some populations.

Host cytokine responses and other defenses influence the phenotype.

Population-level associations do not establish an individual prognosis.

Slide 21 · CagA carriage differs across populations

Population group

Reported proportion

Interpretation

All H. pylori isolates

CagA pathogenicity island ~50%

Virulence varies across strains

High gastric-cancer-prevalence populations

~90% of isolates

Association, not individual causation

Slide 22 · Host cytokine balance shapes severity

Greater TNF or IL-1 expression

Reduced anti-inflammatory IL-10 expression

Stronger inflammatory response

Association with extensive gastritis and atrophy

Possible genetic polymorphism associations; These are not diagnostic tests.

Slide 23 · Disease severity emerges from three interacting domains

Bacterial adaptation and virulence

Mucosal defenses

Host genetic / immune response

Site and severity of chronic injury

The same microbe can produce a spectrum of anatomic and clinical patterns.

Slide 24 · Antral-predominant infection favors high acid output

Body / fundus

Antrum

Schematic stomach regions

Antral gastritis: Increased gastrin stimulation

Oxyntic body: Preserved or expanded acid-secreting mass

Slide 25 · Antral inflammation changes G-cell signaling

Antral-predominant gastritis

G-cell stimulation

Increased gastrin production

Greater stimulus to parietal cells

Inflammation in the antrum can alter acid physiology outside the antrum.

Slide 26 · Parietal cell expansion links gastrin to acid

Persistent gastrin stimulation

Expanded parietal-cell compartment

Normal to increased acid secretion

Greater propensity for peptic ulceration

Slide 27 · The ulcer-associated phenotype

Antral-predominant inflammation

Gastrin increases

Acid output rises

Gastric or duodenal peptic ulcer risk increases

Antral H. Pylori gastritis is a mechanism for ulcer risk, not itself an ulcer diagnosis.

Slide 28 · Long-standing infection can become extensive

Persistent mucosal inflammation

Involvement extends to corpus / fundus

Chronic gland injury

Atrophy and intestinal metaplasia may develop

Slide 29 · H. Pylori-associated atrophy is typically patchy

Atrophy reflects loss of native gastric glands.

Long-standing H. Pylori infection can damage corpus mucosa.

Atrophy is often patchy rather than uniformly distributed.

The process is not characterized by parietal-cell autoantibodies.

Slide 30 · Intestinal metaplasia follows chronic mucosal injury

Persistent inflammatory injury

Gland loss / atrophy

Intestinal-type epithelial replacement

Association with gastric adenocarcinoma risk

Metaplasia is a tissue adaptation and a marker of an altered carcinogenic milieu.

Slide 31 · Loss of parietal-cell mass alters acid physiology

Corpus gland atrophy

Parietal-cell mass decreases

Gastric acid secretion falls

Ulcer-promoting high-acid state is attenuated

Slide 32 · Gastrin rises despite reduced acid secretion

Atrophic H. Pylori gastritis can impair acid production.

Reduced acidity stimulates compensatory gastrin release.

Residual parietal cells usually preserve some acid secretion.

Hypergastrinemia is generally less marked than in autoimmune gastritis.

Slide 33 · Two H. Pylori gastritis phenotypes

Antral-predominant

Antrum is main inflammatory site

Parietal-cell mass is preserved or increased

Acid output normal or increased

Peptic ulcer predisposition

Extended atrophic

Body / fundus also involved

Patchy parietal-cell loss

Acid output reduced

Intestinal metaplasia and cancer association

Slide 34 · Why ulcer and carcinoma associations diverge

High-acid branch

Predominantly antral H. Pylori gastritis

Gastrin stimulation and increased acid output

Greater duodenal ulcer propensity

Atrophic branch

Inflammation extends to corpus / fundus

Parietal-cell atrophy and lower acid output

Metaplasia with adenocarcinoma association

Slide 35 · Typical endoscopic appearance of infected antrum

Antral mucosa is commonly erythematous.

Surface may appear coarse or nodular.

Gross appearance is suggestive, not organism-specific.

Histology or organism-targeted testing supplies etiologic evidence.

Slide 36 · Intense inflammation may mimic neoplasia

Severe inflammatory infiltrates can thicken gastric rugal folds.

The resulting endoscopic appearance may resemble early cancer.

Appearance alone cannot establish either inflammatory or malignant etiology.

Histopathologic sampling resolves the morphologic differential.

Slide 37 · Why antral sampling often detects infection

Body / fundus

Antrum

Schematic stomach regions

Antrum: Preferred site

Body / fundus: May harbor organisms in extensive disease

Slide 38 · Organisms localize in superficial mucus

Superficial mucus / organisms

Foveolar epithelium

Superficial lamina propria

Mucosal surface niche

Bacteria overlie surface and neck epithelium.

Colonization can be dense near foveolar surfaces.

Deep lamina propria is not the principal reservoir.

Original schematic; Not a photomicrograph

Slide 39 · Bacterial distribution may be irregular

Heavily colonized foci may adjoin sparsely colonized areas.

Organisms are not evenly distributed across all gastric fragments.

Negative appearance at one level does not establish universal absence.

Site, sampling and organism-specific stains affect detection.

Slide 40 · The principal histologic pattern is chronic active gastritis

Chronicity: Plasma cells and lymphocytes in the lamina propria.

Activity: Neutrophils infiltrate epithelium or glandular lumens.

Additional clue: Mucosal lymphoid aggregates, sometimes germinal centers.

Identification of bacteria strengthens etiologic attribution.

Slide 41 · Superficial plasma-cell infiltrates are prominent

Superficial mucus / organisms

Foveolar epithelium

Superficial lamina propria

Chronic inflammation

Plasma cells can form superficial clusters or sheets.

Inflammation is often pronounced beneath epithelium.

Pattern accompanies the organism-rich surface.

Original schematic; Not a photomicrograph

Slide 42 · Lymphocytes and macrophages accompany plasma cells

The lamina propria infiltrate is mixed rather than purely neutrophilic.

Increased lymphocytes and macrophages accompany plasma cells.

A chronic immune response develops during persistent colonization.

These features are interpreted together with neutrophilic activity.

Slide 43 · Neutrophils establish active epithelial injury

Superficial mucus / organisms

Foveolar epithelium

Superficial lamina propria

Neutrophils

Neutrophilic activity

Neutrophils migrate across the basement membrane.

They infiltrate foveolar and glandular epithelium.

Their presence marks active mucosal inflammation.

Original schematic; Not a photomicrograph

Slide 44 · How a gastric pit abscess forms

Neutrophils recruited into lamina propria

Neutrophils traverse gland / pit epithelium

Cells accumulate in pit lumen

Pit abscess on histologic section

“Pit abscess” refers to luminal inflammatory-cell accumulation; It is not a gross abscess cavity.

Slide 45 · Histologic tools for organism detection

Stain / method

What it shows

Diagnostic contribution

Routine H&E

Sometimes visible curved organisms

Also assesses inflammatory architecture

Warthin–Starry silver

Dark organisms along superficial mucus

Histochemical enhancement

Immunohistochemistry

Organism-targeted staining

Often facilitates identification

Slide 46 · A silver stain does not substitute for morphology

Warthin–Starry highlights bacteria; H&E establishes tissue response.

Spiral organisms can be found within the surface mucus layer.

Interpret bacterial staining alongside epithelial and stromal changes.

Organism stains are interpreted with H&E tissue architecture.

Slide 47 · Immunostaining improves organism recognition

The source identifies organism-directed immunostains among preferred detection methods.

They can help when organisms are inconspicuous on routine H&E.

A positive stain must be localized to biologically plausible surface organisms.

Interpret results with sample quality and distribution in mind.

Slide 48 · Lymphoid follicles signal organized mucosal immunity

Superficial mucus / organisms

Foveolar epithelium

Superficial lamina propria

Induced mucosal MALT

Lymphoid aggregates may include germinal centers.

Plasma cells are abundant in adjacent lamina propria.

Acquired lymphoid tissue forms in the infected mucosa.

Original schematic; Not a photomicrograph

Slide 49 · From chronic infection to MALT lymphoma risk

Persistent H. Pylori-driven immune stimulation

Acquired gastric mucosal lymphoid tissue

Potential lymphoid neoplastic transformation

Increased gastric MALT lymphoma risk

Lymphoid aggregates are common reactive findings; They are not synonymous with lymphoma.

Slide 50 · Integrated morphology checklist

Compartment

Recognizable change

Mucus / surface

Curved organisms, often irregularly distributed

Superficial lamina propria

Prominent plasma-cell-rich chronic inflammation

Foveolar epithelium / pits

Intraepithelial neutrophils and pit abscesses

Lymphoid compartment

Aggregates, sometimes with germinal centers

Slide 51 · The biopsy diagnosis integrates several findings

A surface-associated organism plus chronic active inflammation strongly supports H. Pylori gastritis.

Lymphoid follicles add supportive context but are not obligatory.

Intensity and topography of inflammation vary between biopsies.

The tissue pattern also guides assessment of atrophy and metaplasia.

Slide 52 · Topography helps separate two major gastritides

H. Pylori-associated

Frequently antral-predominant

May extend to body in advanced disease

Often patchy atrophy

Autoimmune atrophic

Predominantly body / corpus

Antrum often spared

Glandular atrophy of oxyntic mucosa

Slide 53 · Different acid–gastrin signatures

H. Pylori-associated

Acid normal, increased or modestly reduced

Gastrin normal to increased

Residual acid secretion can persist

Autoimmune atrophic

Markedly impaired acid secretion

Gastrin often markedly increased

Parietal-cell destruction is central

Slide 54 · Immune and serologic distinctions

H. Pylori-associated

Bacterial colonization drives inflammation

Anti–H. Pylori antibodies may be detected

Parietal-cell autoantibodies not characteristic

Autoimmune atrophic

Parietal-cell and intrinsic-factor autoimmunity

H⁺/K⁺-ATPase antibodies may be present

Intrinsic-factor loss causes B₁₂ deficiency

Slide 55 · Contrasting clinical associations

H. pylori gastritis

Autoimmune atrophic gastritis

Peptic ulcer disease

Pernicious anemia

Gastric adenocarcinoma association

Gastric adenocarcinoma association

MALT lymphoma risk

Neuroendocrine cell hyperplasia / carcinoid association

Slide 56 · Clinical symptoms may be absent or nonspecific

Acute infection is often unnoticed or causes mild symptoms.

Patients may first be assessed during chronic gastritis or ulcer evaluation.

The chronic histologic lesion can exist without prominent symptoms.

Clinical history alone cannot prove ongoing bacterial colonization.

Slide 57 · Linking chronic gastritis to peptic ulceration

Antral-predominant colonization

G-cell stimulation and increased acid output

Heightened peptic injury susceptibility

Gastric or duodenal ulcer may develop

Slide 58 · Linking atrophic gastritis to neoplastic risk

Extensive chronic inflammation

Gland loss / intestinal metaplasia

Altered mucosal biology

Increased gastric adenocarcinoma risk

This slide summarizes an association/pathway; It does not imply inevitable malignant transformation.

Slide 59 · Major diagnostic test classes

Specimen / setting

Methods named by Robbins

Gastric biopsy

Histology, immunostains / histochemical stains

Gastric biopsy

Rapid urease test, bacterial culture, PCR

Noninvasive

Urea breath test, fecal detection

Blood

Serologic anti–H. pylori antibodies

Slide 60 · Histology answers both etiologic and tissue questions

Demonstrates the inflammatory pattern and organism localization.

Assesses active injury, lymphoid aggregates and glandular atrophy.

Can identify intestinal metaplasia when present.

Sampling must account for irregular bacterial distribution.

Slide 61 · Urea breath testing interrogates urease activity

Patient undergoes urea-based breath test

Bacterial urease acts on test substrate

Breath signal reflects urease metabolism

Noninvasive evidence of H. Pylori activity

Slide 62 · Fecal tests detect bacterial material

The stool specimen offers a noninvasive route to organism detection.

Fecal bacterial detection is one noninvasive test class.

The approach does not require gastric endoscopic sampling.

The result should be interpreted in the clinical testing context.

Slide 63 · Serologic testing detects a host response

Anti–H. Pylori antibody testing measures immune recognition.

The blood test does not require endoscopic sampling.

The measured target is a host antibody, not directly visualized bacteria.

Serology and direct organism-detection approaches answer different questions.

Slide 64 · Rapid urease testing uses biopsy material

Endoscopic gastric tissue collected

Sample introduced into urease assay

Bacterial urease causes assay signal

Biopsy-based evidence supporting infection

Slide 65 · Culture and molecular detection

Bacterial culture

Attempts recovery of viable gastric organisms

Growth requires successful bacterial culture conditions

Requires a gastric biopsy sample

PCR for H. Pylori DNA

Uses molecular detection of bacterial DNA

Alternative biopsy-based approach

Targets microbial nucleic acid rather than morphology

Slide 66 · A practical diagnostic synthesis

Clinical suspicion / gastric lesion

Choose biopsy or noninvasive modality

Seek organism / urease evidence

Interpret alongside tissue injury and phenotype

Testing is selected by clinical context; The sequence shown is conceptual rather than a guideline.

Slide 67 · Eradication addresses the causal infection

Antibiotics directed at the bacterium

Proton pump inhibitor co-therapy

Bacterial eradication

Clinical improvement often follows

Specific regimens, duration and resistance guidance were not supplied in the source; None are asserted here.

Slide 68 · Relapse and reinfection are distinct possibilities

Symptoms or infection may recur after incomplete eradication.

Reinfection can also occur after successful treatment.

Reinfection is particularly relevant in highly endemic settings.

Persistent gastric disease requires appropriate clinical reassessment.

Slide 69 · Case 1 — high-acid clinical phenotype

A patient with chronic H. Pylori antral gastritis develops a duodenal ulcer. Corpus parietal-cell function is preserved, with increased acid secretion.

Which causal sequence connects the antral lesion to ulcer risk?

Slide 70 · Case 1 — mechanistic interpretation

Antral inflammation

Stimulation of gastrin production

Parietal-cell and acid output increase

Duodenal ulcer susceptibility

Slide 71 · Case 2 — the atrophic phenotype

Gastric biopsies show long-standing inflammation extending beyond the antrum, patchy gland loss and intestinal metaplasia.

Which physiologic shift and long-term complication are associated with this pattern?

Slide 72 · Case 2 — mechanistic interpretation

Corpus involvement

Parietal-cell atrophy

Lower acid output

Increased gastric adenocarcinoma association

Compensatory gastrin may rise, but usually less than in autoimmune atrophic gastritis.

Slide 73 · Case 3 — pattern recognition in a biopsy

Antral biopsy shows a superficial plasma-cell-rich infiltrate, neutrophils within glandular epithelium and follicles with germinal centers.

What etiologic diagnosis should be considered, and where should organisms be sought?

Slide 74 · Case 3 — histologic interpretation

Chronic active mucosal inflammation

Induced lymphoid follicles

Inspect overlying surface mucus

Search for H. Pylori with H&E or targeted stains

Slide 75 · Integrated diagnostic–pathogenetic summary

The distribution of chronic active gastritis is the key organizing principle.

Antrum → gastrin and high acid → peptic ulcer tendency.

Extensive atrophic disease → low acid and metaplasia → cancer association.

Superficial organisms, neutrophils, plasma cells and follicles unite the histology.

Urease, organism detection and biopsy morphology provide complementary evidence.