Pathology

Genetic And Pediatric Diseases Important Notes

1. Syndrome and their chromosomal abnormalities

2. Structural abnormalities of chromosomes include

• Translocation
• Deletions
• Inversion
• Ring chromosome
• Isochromosome

Genetic And Pediatric Diseases Short Essays

Question 1. Down’s syndrome
Answer:

• Down’s syndrome/trisomy 21/mongolism affects approximately 1 in 1000 births.
• It is the most common chromosomal disorder and is the commonest cause of mental retardation.

Down’s syndrome Etiology:

• Late maternal age
• Nondisjunction of chromosome 21 during an early stage of embryogenesis.

Down’s Syndrome Clinical Features:

• Epicanthal folds and flat facial profile,
• Slanting eyes produce a mango-loid appearance.
• Hands are short with a transverse single palmar crease.
• Abnormalities of ears, trunk, pelvis, and phalanges
• Cardiac malformations
• Congenital malformations are common and quite disabling
• Risk of developing acute leukemias, especially mega-karyotypic leukemia.
• Oral manifestations:
  • Deficient maxilla – class 111 relation,
  • Open mouth,
  • Large tongue,
  • Caries free teeth due to excess salivation.

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Genetic And Pediatric Diseases Short Questions And Answers

Question 1. Chromosome mutations
Answer:

• Mutation refers to permanent changes in the DNA. The genetic disorders arising from chromosomal aberrations are a consequence of numeric or structural abnormalities in the chromosomes.
• General features of chromosomal disorders and specific examples of diseases involving changes in the karyotype are as follows:
  • Chromosomal disorders resulting from mutations may be associated with absences/excess of chromosomes.
  • Absence-monosomy
  • Excess – trisomy.
• Generally, the loss of chromosomes produces more severe defects than the gain of chromosomes.
• Excess chromosomal material may result from a complete chromosome as in trisomy or a chromosome as in Rebortsonian translocation.
• Imbalances of sex chromosomes are tolerated much better than similar imbalances of autosomes.

Question 2. Inborn errors of metabolism
Answer:

• Storage diseases or inborn errors of metabolism are biochemically distinct groups of disorders occurring due to genetic defects in the metabolism of carbohydrates, lipids, and proteins resulting in intracellular accumulation of metabolites.
• Based on the biochemical composition, storage diseases are classified into distinct groups.

1. Glycogen storage disease: There is defective glucose metabolism resulting in excessive intracellular accumulation of glycogen.

Example:

• Von Gierke’s disease,
• Pompe’s disease,
• Mcardle’s disease etc.

2. Mucopolysacchari doses:

This results from a deficiency of specific lysosomal enzymes involved in the degradation of mucopolysaccharides/glycosaminoglycan- cans and is therefore, a form of lysosomal storage disease.

3. Other types:

• Sphingolipidoses/gangliosidoses – accumulation of gangliosides
• Gaucher’s disease – accumulation of glucose- offside.
• Niemann-pick diseases-accumulation of sphingomyelin.

Question 3. Erythroblastosis fetalis.
Answer:

Erythroblastosis fetal/Haemolytic disease of the newborn results from the passage of IgG antibodies from the maternal circulation across the placenta into the circulation of fetal red cells.

HDN can occur in 2 ways.

1. Incompatibility of ABO or Rh blood group system.

• Severest from may result in intrauterine death from hydrops fetal.

2. HDN due to ABO incompatibility.

• Occurs most frequently in infants born to group O mothers who possess anti-A /anti-B IgG antibodies.

Intracellular Accumulations Important Notes

1. Endogenous pigments

• It includes lipofuscin, melanin, and certain derivatives of hemoglobin
• Lipofuscin is a yellowish-brown intracellular lipid pigment
• Found in
  • Atrophied cells of old age so-called wear and tear pigment
  • Myocardial fibres
  • Hepatocytes
  • Leydig cells of the testes
  • Neurons of senile dementia

Intracellular Accumulations Long Essays

Question 1. Mention types of degeneration. Discuss pathogenesis and macroscopic appearance of fatty liver.
Answer:

Degeneration Types:

Fatty Liver Pathogenesis:

In fatty liver: Intracellular accumulation of triglycerides can occur due to defect at one/ more of the following 6 steps:

• Increased entry of fatty acids into the liver.
• Increased synthesis of fatty acids by the liver.
• Decreased conversion of fatty acids into ketone bodies resulting in increased esterification of fatty acids to triglycerides.
• Increased a-glycerophosphate causes increased esterification of fatty acids to triglycerides.
• Decreased synthesis of lipid acceptor protein resulting in decreased formation of lipoprotein from triglycerides.
• Block in the excretion of lipoprotein from the liver into plasma.

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Macroscopic Appearance of Fatty Liver:

1. Gross appearance

• Size- liver is enlarged
• Color-yellow
• Capsule- tense and glistening capsule
• Margins are rounded

2. Cut surface

• It bulges slightly
• Color varies from pale yellow to yellow
• The surface is greasy to the touch

Question 2. Define and classify degeneration. Discuss etiopathogenesis and pathology of fatty liver,
(or)
Mention types of degeneration. Discuss patho¬genesis and microscopic appearance of fatty liver
Answer:

Degeneration Definition:

• Degeneration is a process by which a tissue deteriorates, loses its functional activity, and may become con¬verted into or replaced by other kinds of tissue.

Fatty Liver:

• Fatty liver or steatosis is the intracellular accumulation of neutral fat within parenchymal cells
• It is common in the liver as it plays a central role in fat metabolism

Microscopic Appearance:

• The fatty liver shows numerous lipid vacuoles in the cytoplasm of hepatocytes
• It is seen as a clear area that may vary from minute droplets to an extension of the entire cytoplasm

1. Initially

• Vacuoles are small
• They are present around the nucleus
• Centrilobular hepatocytes are affected

2. Later

• Vacuoles enlarge
• They push the nucleus to the periphery of the cells
• Fat accumulation involves the entire lobule
• Occasionally adjacent cells containing fat may rupture producing fatty cysts
• Rarely, lymphogranuloma may appear consisting of a collection of microphones, lymphocytes, and multi-nucleate giant cells

Intracellular Accumulations Short Essays

Question 1. What is fatty liver? What are its causes?
Answer:

• Fatty change/steatosis is the intra-cellular accumula¬tion of neutral fat within parenchymal cells.
• It is especially common is the liver as it plays a central role in fat metabolism,
• It may occur in other non-fatty tissues like the heart, skeletal muscles, kidneys, and other organs.

Fatty Liver Types:

• Fatty change may be
  • Mild and reversible
  • Severe and irreversible resulting in cell death.

Etiology: Fatty change in the liver results from.

Question 2. Wear and tear pigment
Answer:

• Lipofuscin is known as wear and tear pigment.
• Lipofuscin/lipochrome is a yellowish-brown intra-cellular lipid pigment.
• It is a hemoprotein-derived pigment

Site of Appearance:

• In atrophied cells of old age and Lence known as wear and tear pigment.
• It is seen in myocardial fibers, hepatocytes, Leydig cells of the testis, and neurons in senile dementia.

Significance:

• Lipofuscin represents the collection of indigestible material in the lysosomes after intra-cellular lipid peroxi¬dation and is therefore an example of residual bodies.

Microscopy:

• By light microscopy, the pigment is coarse, golden brown granular, and often.’ accumulates in the central part of the cells around the nuclei.
• In heart muscle, change is associated with wasting of the muscle and is commonly refered to as brown atrophy.
• By electron microscopy, lipofuscin appears. J as integrally- ribosomal electron-dense granules in perinuclear location. Granules are composed of did-protein complexes.

Question 3. Hemosiderosis
Answer:

Hemosiderosis Definition:

• Excessive storage of hemosiderin is called he-mosiderosis

Hemosiderosis Causes:

• Increased breakdown of red cells
• Systemic overload of iron due to
  • Primary causes
    • Idiopathic
    • Hereditary
  • Secondary causes
    • Thalassaemia
    • Sideroblastic anemia
    • Alcoholic cirrhosis

Hemosiderosis Effects:

1. Localized hemosiderosis

• Black eye occurs due to bilirubin and biliverdin
• Brown induration in the lungs occurs due to small hemorrhages

2. Generalized hemosiderosis

• Parenchymatous deposition of hemosiderin in the liver, kidney, pancreas
• Reticuloendothelial deposition in the liver, spleen, and bone marrow

Intracellular Accumulations Short Question And Answers

Question 1. Melanin pigment
Answer:

• Melanin is an endogenous pigment
• Melanin is a brown-black, non-hemoglobin-derived pigment normally present in the hair, skin, choroid of the eye, meninges, and adrenal medulla.

Melanin pigment Synthesis:

• It is synthesized in the melanocytes and dendritic cells

Melanin pigment Storage:

• Stored in the form of cytoplasmic granules in the phagocytic cells called as melanophores.

Melanin pigment Disorders:

Various disorders of melanin pigmentation cause gen¬eralised and localized hyperpigmentation and hypopigmentation.

1. Generalised hyperpigmentation is seen during.

• Addison’s disease
• Chloasma
• Chronic arsenal poisoning.

2. Focal hyperpigmentation.

• Cafe-au-lait spots in Albright’s syndrome.
• Peutz-Jeghers syndrome.
• Melanosis coli.
• Melanotic tumors
• Dermatopathiclymphadentis.

3. Generalised hypopigmentation.

• Albinism

4. Localised hypopigmentation.

• Leukodema
• Vitiligo
• Acquire focal hypopigmentation.

Question 2. Exogenous pigment
Answer:

Exogenous pigments are the pigments introduced into the body from outside such as by inhalation, ingestion, or inoculation.

Inhaled pigments:

• The most commonly inhaled substances are carbon/coal, dust, silica/stone dust, iron oxide, asbestos, and various other organic substances.
• These substances may cause occupational lung disease called pneumoconiosis.
• Extensive deposition of particulate material over many years provides low-grade inflammation, fibrosis, and impaired respiratory function.

Ingested pigments:

• Chronic ingestion of certain metals may produce pigmentation. E^/Argyria, chronic lead poisoning, melanosis coli.

Injected pigments:

• Examples of injected pigments are prolonged use of ointments containing mercury, dirt left accidentally in a wound, and tattooing by pricking the skin with dyes.
• In it pigment is taken by the macrophages and lies permanently in the connective tissue

Question 3. Fatty degeneration/ fatty change
Answer:

• Fatty degeneration or fatty change is the intracellular accumulation of neutral fat within parenchymal cells
• It occurs in the cytosol and represents an absolute increase in the intracellular lipids

Fatty change Types:

• Depending upon the cause and amount of accumulation, fatty change can be

1. Mild and reversible
2. Severe and irreversible- Causing cell death

Question 4. Causes of Ketonuria.
Answer:

• Metabolic abnormalities – diabetes, renal glycosuria
• Dietary conditions – starvation, fasting, prolonged vomiting, anorexia
• Hyperthyroidism, fever, pregnancy, lactation

Question 5. Ketone bodies.
Answer:

• Ketone bodies are water-soluble molecules – acetone, acetoacetate, and beta-hydroxybutyrate
• They are produced by the liver from fatty acids during low food intake, starvation, prolonged intense exercise, alcoholism or untreated diabetes mellitus
• Ketone bodies are readily picked up by the extrahepatic tissues and converted into acetyl CoA which enters the citric acid cycle
• It is oxidized in mitochondria for energy

Morphology Of Cell Injury Important Notes

1. Types of necrosis

2. Types of degeneration

• Cloudy swelling – a most common type
• Hydropic
• Hyaline
• Mucoid degeneration

3. Morphological forms of cell injury

• Reversible
  • Cellular Swelling
  • Fatty change
  • Hyaline change
  • Mucoid change
• Irreversible
  • Apoptosis
  • Autolysis
  • Necrosis

4. Apoptosis

• Apoptosis is physiological or programmed cell death
• It eliminates cells that are genetically altered or injured beyond repair without eliciting a severe host reaction
• It prevents the development of epithelial dysplasia by programmed cell death
• It is usually single-cell death and undergoes coagulative necrosis.

Morphology Of Cell Injury Long Essays

Question 1. Classify necrosis. Discuss its nuclear changes.
Answer:

Necrosis Classification:

Necrosis is classified into the following types:

1. Coagulative necrosis

• Caused by irreversible focal injury

2. Liquefaction necrosis

• Occurs due to ischaemic injury and bacterial or fungal infections

3. Caseous necrosis

• Found in the center of foci of tuberculous infections

4. Fat necrosis

• Occurs at two anatomically different locations

5. Fibrinoid necrosis

• Deposition of fibrin-like material occurs

Nuclear Changes In Necrosis:

1. Pyknosis

• It is a condensation of nuclear chromatin

2. Karyolysis

• Undergo dissolution

3. Karyorrhexis

• Fragmentation

Question 2. Define necrosis. Classify and discuss different types of necrosis.
(or)
Define necrosis. Discuss etiopathogenesis and morphology of various types of necrosis.
Answer:

Definition:

Necrosis is defined as a localized area of death of tissue followed by degradation of tissue by hydrolytic enzymes liberated from dead cells, it is invariably accompanied by an inflammatory reaction

Necrosis Types:

There are five types of necrosis

1. Coagulative necrosis

• Causes:
  • Ischaemia
  • Bacterial infection
  • Chemical agents like mercuric chloride
• Pathogenesis
  • Irreversible cell injury
  • Results in sudden cessation of blood flow

2. Liquefaction necrosis

• Causes:
  • Ischaemia
  • Bacterial infections
• Pathogenesis
  • Bacterial and fungal infections produce hydro-lytic enzymes
  • This causes the degradation of tissue

3. Caseous necrosis

• Occurs in the center of foci of Tuberculous infections

4. Fat necrosis

• Occurs at two anatomically different locations
• Types
  • Acute pancreatic necrosis
  • Traumatic fat necrosis

5. Fibrinoid necrosis

• Deposition of fibrin-like material occurs

Morphology of types of Necrosis:

Question 3. Define and classify gangrene. Write the differences between dry and wet gangrene
Answer:

Definition:

• Gangrene is a form of necrosis of tissue with superadded putrefaction

Gangrene Classification:

• Gangrene is classified into two main types

1. Dry gangrene
2. Wet gangrene

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Difference Between Dry and Wet Gangrene:

Question 4. Write about wet gangrene.
Answer:

Wet Gangrene:

Wet gangrene usually occurs in moist tissues and organs

Site Involved:

• Mouth
• Bowel
• Lung
• Cervix
• Vulva

Wet Gangrene Cause:

• Venous blockage

Wet Gangrene Pathogenesis:

• The affected part is filled with blood
• It favors the rapid growth of Putrefaction bacteria
• Formation of toxic products by bacteria
• Absorption of toxic products
• Causes septicemia
• Finally causes death

Wet Gangrene Features:

1. Gross features

• The affected part appears soft, swollen, putrid, rotten, and dark
• Part is stained dark

2. Microscopic features

• Coagulative necrosis is seen
• There is ulceration of the mucosa and intense inflammatory infiltration
• Lumen shows mucus and blood
• There is no line of demarcation present.

Morphology Of Cell Injury Short Essays

Question 1. Types of necrosis with examples
Answer:

Types of Necrosis:

Question 2. Dry gangrene
Answer:

Gangrene:

• Gangrene is a form of necrosis of tissue with super-added putrefaction

Dry Gangrene:

• It is a form of gangrene occurring due to Ischaemia

Dry Gangrene Causes:

• Ischaemia
• Atherosclerosis
• Buerger’s disease
• Raynaud’s disease
• Trauma
• Ergot poisoning

Dry Gangrene Features:

• Begins in the distal part of a limb
• Occurs in one of the toes which is farthest from the blood supply
• Here bacteria fail to grow in the necrosed tissue
• Gangrene spreads slowly upwards until it reaches an area with a good blood supply
• The line of demarcation is seen between the gangrenous part and the viable part

Dry Gangrene Gross Appearance:

• The affected part is dry, shrunken, and dark black
• It appears black due to the liberation of hemoglobin from hemolysed red blood cells which is acted upon by hydrogen disulfide produced by bacteria
• The line of demarcation is seen

Dry Gangrene Microscopic Appearance:

• Necrosis with smudging of the tissue is seen
• The line of demarcation contains inflammatory granulation tissue

Question 3. What is dystrophic calcification? Give two examples.
Answer:

Dystrophic calcification is the deposition of calcium salts in dead and degenerated tissues with normal calcium metabolism and normal serum calcium levels

Dystrophic Types:

1. Calcification in dead tissue: Examples

• Caseous necrosis in tuberculosis
• Liquefaction necrosis in chronic abscess
• Fat necrosis
• Gamma Gandy bodies in chronic venous congestion
• Infarcts
• Thrombi in veins
• Haematomas in bones
• Dead parasites
• Calcification in breast cancer
• Congenital toxoplasmosis

2. Calcification in degenerated tissues

• Stroma of tumors
• Atheromas
• Dense old scars
• Cysts
• Calcinosis cutis
• Senile degeneration

Dystrophic Pathogenesis:

1. Initiation

• Precipitates of calcium and phosphate begin to accumulate both intracellularly and extracellularly

2. Propagation

• Mineral deposits propagate to form mineral crystals

Question 4. Differences between Necrosis and Apoptosis.
Answer:

Morphology Of Cell Injury Short Question And Answers

Question 1. Irreversible cell injury
Answer:

• Cell injury is defined as a variety of stresses a cell en-. counters as a result of changes in its internal and external environment
• When such an injury is severe and persistent, cell death occurs
• Such an injury is called irreversible cell injury

Irreversible cell injury Features:

• The inability of the cell to reverse mitochondrial dysfunction
• Disturbance in cell membrane functions
• Reduction in ATP
• Continued depletion of proteins
• Reduced intracellular pH
• Leakage of lysosomal enzymes

Question 2. Etiology of cell injury
Answer:

Cell injury occurs due to the following causes:

1. Genetic causes

2. Acquired causes

• Hypoxia and ischemia
• Physical agents
• Chemical agents
• Microbial agents
• Nutritional derangements
• Immunologic agents
• Aging
• Iatrogenic factors
• Idiopathic

Question 3. Free radical injury
Answer:

• The free radical injury occurs in situations like ionizing radiation
• Oxygen free radicals are produced within the mitochondrial matrix
• They are:
  • Superoxide
  • Hydrogen peroxide
  • Hydroxyl radical

Free radical injury Effects:

• Lipid peroxidation
• Oxidation of proteins
• DNA damage
• Cytoskeletal damage

Question 4. Reversible cell injury
Answer:

• Cell injury is defined as a variety of stresses a cell encounters as a result of changes in its internal and external environment
• When the stress is mild to moderate, the injured cell may recover, it is called reversible cell injury

Question 5. Hyaline calcification
Answer:

• It describes the glassy, homogeneous, eosinophilic appearance of a material
• It is associated with pathological conditions that may be intracellular or extracellular

Question 6. Dystrophic and metastatic calcification.
Answer:

Question 7. Apoptosis
Answer:

Apoptosis is a form of coordinated and internally programmed cell death that has significance in a variety of physiologic and pathological conditions

1. Apoptosis in biological processes

• Organized cell destruction during the development of the embryo
• Physiologic involution of cells in hormone-dependent tissues
• Normal cell destruction

2. Pathologic process

• Cell death in tumors
• Cell death by cytotoxic T cells
• Cell death in viral infections
• Pathologic atrophy of organs