4. Hemodynamic Disorders, Thromboembolic Disease, and Shock
5. Genetic Disorders
6. Diseases of the Immune System
7. Neoplasia
8. Infectious Diseases
9. Environmental and Nutritional Diseases
10. Diseases of Infancy and Childhood
11
Systemic Pathology: Diseases of Organ Systems
11. Blood vessels
12. The Heart
13. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus
14. Red Blood Cell and Bleeding Disorders
15. The Lung
16. Head and Neck
17. The Gastrointestinal Tract
18. Liver and Gallbladder
19. The Pancreas
20. The Kidney
21. The Lower Urinary Tract and Male Genital System
22. The Female Genital Tract
23. The Breast
24. The Endocrine System
25. The Skin
26. Bones, Joints, and Soft Tissue Tumors
27. Peripheral Nerves and Skeletal Muscles
28. The Central Nervous System
29. The Eye
30
Systemic Pathology: Diseases of Organ Systems
17. The Gastrointestinal Tract
CONGENITAL ABNORMALITIES
Atresia, Fistulae, and Duplications
Diaphragmatic Hernia, Omphalocele and Gastroschisis
Ectopia
Diverticulum
A true diverticulum is a blind outpouching of the alimentary tract that communicates with the lumen and includes all three layers of the bowel wall.
Meckel Diverticulum
Meckel diverticulum is the most common true diverticulum which occurs in the ileum as a result of failed involution of the vitelline duct, which connects the lumen of the developing gut to the yolk sac.
It is solitary and extends from the antimesenteric side of the bowel.
▢ Rule of 2s:
Occur in approximately 2% of the population
Are twice as common in males
Most often symptomatic by age 2
Generally present within 2 feet of the ileocecal valve
Are approximately 2 inches long
▢ Histology:
The mucosal lining is normal as the small intestine, but it may present
◉ Ectopic pancreatic tissue:
◉ Ectopic gastric tissue: It may secrete acid ->Cause Peptic ulceration of adjacent small intestinal mucosa -> Present with occult bleeding or abdominal pain -> Resembles Acute appendicitis or Obstruction.
Congenital diverticulum
They are less common and occur in other parts of the small intestine and ascending colon.
Acquired diverticulum
They lack muscularis entirely or have an attenuated muscualris propria.
The common site is Sigmoid colon.
Pyloric stenosis
Pyloric stenosis is the hyperplasia of the pyloric muscularis propria, which obstructs the gastric outflow tract. Edema and Inflammatory changes in the mucosa and submucosa may aggravate the narrowing.
Congenital hypertrophic pyloric stenosis
▢ Epidemiology:
❖ Gender: 3 to 4 times more common in male.
❖ Occurrence: Once in 300 to 900 live births.
❖ Genetic:
◉ Monozygotic twins: High rate of concordance, with a 200 fold increased risk if one twin is affected.
◉ Dizygotic twins and Siblings:
•
Increased only by 20-fold in one twin or sibling is affected.
•
These indicates complex multifactorial pattern of inheritance.
◉ Turner syndrome and Trisomy 18: Increased risk
❖ Drugs: Azithromycin or Erythromycin exposure, either orally or via mother's milk, in the first 2 weeks of life has been linked to increased disease incidence.
▢ Clinical symptoms:
Generally presents between the 3rd and 6th week of life as a
New onset regurgitation
Vomiting
Projectile
Nonbilious
After feeding
Frequent demands for re-feeding
▢ Physical examination:
Abdominal mass
Firm
Ovoid
1 to 2 cm
Abnormal left to right hyperperistalsis during feeding and immediately before vomiting.
▢ Treatment:
Surgical splitting of the muscularis (Myotomy)
Acquired pyloric stensis
▢ Causes:
Consequences of antral gastritis or peptic ulcers close to the pylorus.
Carcinomas of the distal stomach and pancreas -> Fibrosis and Malignant infiltration -> Narrow the pyloric channel
Hirschsprung disease also known as Congenital aganglionic megacolon is the congenital disease of distal intestine which lacks both Meissner submucosal and the Auerbach myenteric plexus resulting in absent peristalsis, functional obstruction and dilation proximal to the affected segment.
▢ Epidemiology:
❖ Occurrence: 1 of 5000 live births
❖ Gender: More common in male but longer aganglionic segments when present in female
❖ Association with other developmental abnormalities:
10% of cases occurs in children with Down syndrome
5% occurs in children with serious neurologic abnormalities.
▢ Pathogenesis:
▢ Morphology:
▢ Clinical features:
Failure to pass Meconium.
Obstruction or Constipation
Visible, ineffective peristalsis
Abdominal distension
Bilious vomiting
Passage of stool when only few cm of rectum is involved, may obscure the diagnosis
Enterocolitis
Fluid and electrolyte disturbances
Perforation
Peritonitis
▢ Treatment: Surgical resection of the aganglionic segment followed by anastomosis of the normal proximal colon to the rectum
