أسئلة الـ 11 باثو PPPM (قبل التعديل)

Bilharziasis

• It is an infective parasitic granuloma.
• Five species are known, the most important of which are S. Haematobium, S. Mansoni, and S. Japonicum.
• S. Haematobium and S. Mansoni are both present in Egypt.
• Hematuria is associated with the urogenital system.
• Melena is associated with the digestive system.
• The definitive host is man
• The intermediate host is a snail.
• The infective stage is cercaria, which emerges from the snail after 1 month and survives in water for 48 hours.
• Male carriers female
• Adult female deposits eggs.

Bilharzial Reaction

• Acute allergic dermatitis (type I immediate hypersensitivity reaction) can occur with cercaria.
• Swimmer's itch will be lost after 2 days.

Worms

• Living worms typically cause little to no reaction.
• Living worms feed on RBCs and release Bilharzial Pigment (Acid hematin)
• The pigment is removed by cells of the reticulo-endothelial system "RES" (Liver & spleen), leading to hyperplasia of RES and hepatosplenomegaly (HSM).
• Dead worms cause a severe allergic reaction with inflammatory cells (Macrophages, Eosinophils, Neutrophils “MEN”).

Ova

• Key feature is Bilharzial granuloma
• Can cause type IV hypersensitivity reaction
• Components include bilharzial ova (living & dead), chronic inflammatory cells (lymphocytes, plasma cells, & macrophages), eosinophils, foreign body giant cells, and outer granulation tissue which heals by fibrosis.

Bilharzial Lesions in Hollow Organs (Intestine & Urinary Bladder)

• Early lesions present as hyperemia and congestion of the mucosa due to immediate allergic reaction.
• Late lesions include polyp formation, common in the intestine, with a large number of sessile or pedunculated and branching polyps.
• Sandy patches are due to heavy ova deposition.
  • N/E presents as circumscribed, raised patch, with a rough and dirty yellow appearance (like wet sand), giving a gritty sensation when sectioned with a knife.
  • M/E shows calcified ova with minimal or no bilharzial reaction.
  • Fibrosis occurs in the surrounding tissue.
  • The overlying mucosa becomes atrophied, potentially leading to ulceration.
• Ulcers can be caused by the passage of ova, the tip or twisting of a polyp, secondary bacterial infection, allergic necrosis, or occurring over a sandy patch.
• Characteristics of NE include being single or multiple in number, small rounded or large irregular in size and shape, with a superficial or deep location, irregular margin, sharp edge, granular floor, and an indurated base due to fibrosis.
• Closed Fibrotic Lesion occurs due to ova deposition in deep submucosal vessels, healing by fibrosis, which stops the ova deposition in the submucosa and mucosa, with no ova passing in urine or stool (closed lesion).
• The ova deposition occurs in the muscle, subserosa and peritoneal layers, causing fibrosis in these sites. The bladder becomes fibrosed and small, leading to a contracted bladder with decreased capacity. The peritoneum exhibits a large peri-colic mass, and the intestinal lumen becomes narrowed.

Epithelial changes (UB only)

• Hyperplasia
• Epithelial metaplasia (glandular and squamous) can become precancerous.

Lesions in Solid Organs

• Hepatic Bilharziasis involves liver fibrosis without cirrhosis (pipe stem fibrosis of portal tracts), leading to portal hypertension.
• Bilharziasis of the Spleen, also known as "Egyptian Splenomegaly," is a syndrome characterized by intestinal Bilharziasis, hepatic fibrosis, splenomegaly, pancytopenia, and fever.
• Rectal biopsy in bilharziasis helps in the detection of bilharzial ova and granuloma.
• Cystoscopic biopsy in bilharziasis aids in the:
  • Detection of bilharzial ova and granuloma.
  • Diagnosis of precancerous lesions (glandular and squamous metaplasia). -Diagnosis of carcinoma (squamous cell carcinoma).

Viral Infections

• Herpes Simplex Virus (HSV)
  • HSV-1 and HSV-2 replicate in the skin and mucous membranes at the site of virus entry, such as the oropharynx or genitals, where they produce infectious virions, which spread to sensory neurons and innervate primary sites.
  • HSV-1 is a notable cause of corneal blindness in the United States.
  • The biopsy should be taken from the margin/edge of the ulcer rather than from its base.
  • Typical histologic findings only present at the edge of the ulcer
  • Infected squamous epithelial cells exhibit 3 Ms: molding of nuclear contours, margination of chromatin to the periphery of nuclei, and multinucleation.
  • Intranuclear inclusions (Cowdry type A) present as acidophilic inclusions with a surrounding clear halo.
  • HSV immunohistochemical (IHC) stain is required for diagnosis in equivocal cases.
• Cytomegalovirus (CMV)
  • Transmitted through blood and other bodily fluids such as sexual contact; blood products from transfusion or transplantation; and close contact with saliva and urine from infected individuals (specifically children).
  • Can latently infect monocytes and bone marrow progenitors, with potential reactivation when cellular immunity is depressed.
  • Infects endothelial cells, stromal fibroblasts, or epithelial cells.
  • A tissue biopsy should be taken from areas of ulceration or erosion.
  • Cytologic enlargement occurs with both intranuclear and intracytoplasmic basophilic or amphophilic inclusions.
  • CMV IHC or in situ hybridization can aid in detecting viropathic inclusions.

Actinomycosis

• Rare
• A suppurative granulomatous infectious disease.
• Generally caused by a group of anaerobic, gram-positive, filamentous bacteria
• Normal flora in the oral cavity, gastrointestinal tract, and female genital tract (treatable via antibiotics).
• The causative agent is Actinomyces Israelli.
• Clinically manifests as abscess formation or sinus drainage, resulting in sulfur granules.
• Mucosal damage with a defective mucosal barrier leads to infiltration of preexisting microorganisms, causing inflammation, granulation, fibrosis, and abscess. Sites:
  • Cervicofacial (post dental infection) is the most common site
  • Can occur on the skin (post-traumatic injury), in the pelvis (post intrauterine device placement), in the abdomen (post-ruptured appendix or bowel perforation), and the lung (smokers with poor dental hygiene, aspiration of infective material).
• Typically presents as a firm, swollen region on the skin with multiple draining abscesses and fistula tracts, with pus draining yellow sulfur granules.
• Microscopic examination reveals:
  • Bacterial colonies (sulfur granules) at the center of the inflammatory reaction, composed of basophilic radiating filaments.
  • Lymphocytes neutrophils, giant cells, and fibroblasts.
  • Asteroid bodies: pink rim at the periphery of the colony, due to immunoglobulin and cell debris, accruing around fungi, bacteria, and parasites.

Fungal Infection (Candidiasis)

• Candida albicans is the most prevalent fungal pathogen in humans.
• Normally resides in the skin, mouth, GI tract, and vagina (benign commensals).
• Seldom causes disease in healthy people.
• Diabetics and burn patients are particularly susceptible to superficial candidiasis can appear as yeast, pseudohyphae, and, less commonly, true hyphae.
• Fungal elements are normally located within squamous, fibrinopurulent, or necrotic exudate
• Pseudohyphae, important for diagnostics, appear as a chain of budding yeast joined and-to-end at constrictions, while true hyphae are defined by their septae.
• Identified through routine hematoxylin and eosin (H&E) stains, and with Gomori-methenamine-silver “GMS”, and periodic acid-Schiff “PAS” special stains.