Amoebiasis pathophysiology

Amoebiasis Microchapters
Home
Patient Information
Overview
Historical Perspective
Classification
Pathophysiology
Causes
Differentiating Amoebiasis from other Diseases
Epidemiology and Demographics
Risk Factors
Natural History, Complications and Prognosis
Diagnosis
History and Symptoms
Physical Examination
Laboratory Findings
Imaging
Treatment
Medical Therapy
Surgery
Prevention
Cost-Effectiveness of Therapy
Future or Investigational Therapies
Case Studies
Case #1
Amoebiasis pathophysiology On the Web
Most recent articles
cited articles
Review articles
CME Programs
Powerpoint slides
Images
American Roentgen Ray Society Images of Amoebiasis pathophysiology All Images X-rays Echo & Ultrasound CT Images MRI
Ongoing Trials at Clinical Trials.gov
US National Guidelines Clearinghouse
NICE Guidance
FDA on Amoebiasis pathophysiology
CDC onAmoebiasis pathophysiology
Amoebiasis pathophysiology in the news
Blogs on Amoebiasis pathophysiology
to Hospitals Treating Amoebiasis
Risk calculators and risk factors for Amoebiasis pathophysiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Yazan Daaboul, M.D.; Serge Korjian M.D.

Pathophysiology

Transmission

• E. histolytica cyst is usually transmitted by the fecal-oral route through contaminated drinking water or food)
• E. histolytica cyst may also be transmitted indirectly through direct contact with infected individuals.

Pathogenesis

• Following transmission, E. histolytica trophozoites inhabit in the large intestine of the human host.
• In the large intestine, the trophozoite invades the intestinal mucosa into the blood stream. Simultaneously, they form resistant cysts that are then excreted in human stools.
• Once in the bloodstream, the trophozoite migrates into the portal circulation and develops amebic liver abscess.

Invasion of Intestinal Mucosa

• E. histolytica trophozoites secrete proteases, which induce the release of mucin from goblet cells, resulting in glandular hyperplasia.
• E. histolytica is

Gross Pathology

On gross pathology, the following findings may be present in patients with amebiasis:

• Wavy surface epithelium (results from focal release of mucin and spasm of the muscular layer)
• Nodular and/or irregular ulcers in the cecum (most common), sigmoid colon, and rectum. Early ulcers are usually in the interglandular epithelium.

• Nodular: small (sub-centrimetric), rounded, elevated lesions with necrotic center and edematous rim
• Irregular: large (1-5 cm), shallow with broad elevated margins

Note: the mucosal folds may occasionally hide small colonic ulcers (false-negative results)

Microscopic Pathology

• On microscopic pathology, amebiasis is characterized by a flask ulcer (deep, microhemorrhagic ulceration involving the submucosa), which is a characteristic of advanced disease.
• Additional findings may be present in patients with amebiasis:

• Interglandular ulceration
• Hyperemia
• Thickened mucosa
• Reactive glandular hyperplasia
• Stromal edema
• Infiltration of neutrophils, eosinophils, and macrophages
• Lymphoid aggregates
• Detection of amebas on surface exudate
• Tissue necrosis, usually fibrinoid (advanced lesion)
• Formation of granulation tissue (advanced lesion)

Gallery

• 

  Invasive extraintestinal amebiasis. Adapted from Public Health Image Library (PHIL).

• 

  Amebic abscess of liver. Adapted from Public Health Image Library (PHIL).

• 

  Intestinal ulcers due to amebiasis. Adapted from Public Health Image Library (PHIL).

• 

  Intestinal ulcers due to amebiasis. Adapted from Public Health Image Library (PHIL).

• 

  Intestinal amebiasis. Adapted from Public Health Image Library (PHIL).

• 

  Amebic abscess in liver. Adapted from Public Health Image Library (PHIL).

• 

  Amebic abscess in liver. Adapted from Public Health Image Library (PHIL).

• 

  Amebiasis in intestine. Adapted from Public Health Image Library (PHIL).

References

Template:WikiDoc Sources