metabolic disorders Flashcards
- Atrophy: definition, examples of atrophy
WHAT IS ATROPHY ?
Definition:
atrophy is a reduction in size and function of a cell, which causes an overall reduction in size and function of a tissue or organ
Differential diagnosis must be made with:
Hypoplasia- which is a congenital condition – the organ is smaller than normal at birth
aplasia or agenesis- which is also a congenital condition – the organ is missing at birth due to deffective embryogenesis
Etiopathogenesis: inactivity inanition ischemia compression neurogenic endocrinal autoimmune
Hypoplasia: micrognathism (or micrognathia ) (malformative syndromes)
Etiopathogenesis: inactivity malnutrition ischemia compression neurogenic causes endocrine factors autoimmune processes Types of atrophy according to etiology: 1. Atrophy by inactivity Occurs when an organ doesn’t function for a longer period of time or its function is not at full capacity Examples the limbs will display signs of muscular atrophy after prolonged immobilization (i.e. after severe bone fractures) in cases of mitral stenosis, the left ventricle receives less blood from the left atrium through the narrowed atrioventricular valve, causing in time a ventricular atrophy
Gum atrophy caused by loosing teeth
2. Atrophy by malnutrition
occurs when the tissues and cells do not receive their basic energetic needs, in other words their normal nutritional requirements
Examples:
the lack of minimal nutritional intake (food deprivation)
the lack of nutrient absorption (GIT diseases)
loss of nutritional substances (vomit, diarrhea, etc.)
Terminology used in case of atrophy by malnutrition:
Tissue-wasting
Cachexia: extreme weight loss in adult
Athrepsia (or athrepsy): extreme weight loss in infants
- Atrophy by ischemia
Appears in cases of progressive and partial ischemia, particularly caused by atherosclerosis;
the consequence is sclerous atrophy (cells in the vicinity of the partially obstructed blood vessel become smaller = atrophy, and the cells most distant from the blood vessel die and are replaced by connective tissue = sclerosis; the global process is described as scleroatrophy)
Examples:
in organs: kidneys, myocardium etc
at the level of the lower limbs
Partial ischemia due to atherosclerosis producing fibrosis of the gum witch affects the teeth health.
4. Atrophy by compression
Is a variant of atrophy by ischemia, but in this case it is produced by compression from the exterior on the blood vessel
5. Autoimmune atrophy
In immune responses against self-antigens (targeting the individuals’ own tissues or molecular structures), in which the targeted organs suffer atrophy
Examples:
Autoimmune gastritis in
pernicious anemia
- Hypertrophy: definition, examples of hypertrophy
WHAT IS HYPERTROPHY ?
WHAT IS HYPERTROPHY ?
Definition:
hypertrophy is the increase in size and function of an organ which implies the increase in size and function of each constituent cell
The cells become bigger, with a larger nucleus and with more structural components (mitochondria, endoplasmic reticulum etc.)
Hypertrophy appears in permanent cells, particularly in muscle cells, but it can also appear in stable cells.
Types of hypertrophy
1.Physiologic hypertrophy
During pregnancy, the uterine
muscle fibers increase in size,
under the influence of gestational
hormones
2.Adaptive hypertrophy
Effort hypertrophy
The skeletal muscle after prolonged,
repeated efforts (body-building)
Mandibular prognathism associated with acromegaly
b. Hormonal hypertrophy
• Excess of STH (can produce hypertrophy and hyperplasia), if it appears before puberty it produces gigantism, and if it appears after puberty it produces acromegaly (the extremities grow: the mandible, the nose, the short bones etc.)
- Hypeplasia: definition, examples of hipeplasia
Definition:
hyperplasia is the increase in size and function of an organ by the increase of the number of its constituent cells
Affects the labile cells, but can also appear in stable cells.
It may appeear simultaneously with hypertrophy
Hyperplasia and hypertrophy should be differentiated from hypergenesis, which involves the congenital overdevelopment of an organ
Hormonal overproduction:
TSH increase goiter
Hormone-directed hyperplasia in hormonally dependent syndrome
the endometrial glands and stroma undergo hyperplasia under the influence of estrogens
Lymphoid organs
during infections the lymph nodes present hyperplasia
Lymphoid hyperplasia, with germinal centers
Hyperplasia is a self-limited process, but some imbalances in its regulation may result in tumoral proliferation.
It is well established that many benign tumors and some malignant tumors have hyperplasic processes with superposed genetic defects.
- Metaplasia: definition, examples of epithelial metaplasia
Definition:
metaplasia is the replacement of a tissue with another type of tissue.
The metaplastic tissue is histologically normal, but its location is abnormal.
The young cells of a tissue proliferate and also change their type of differentiation
It does not occur in adult, mature or “differentiated” cells
Metaplasia is often reversible
Encapsulated pleomorphic adenoma (right) clearly demarcated from surrounding minor salivary glands.
Adenoid cystic carcinoma showing characteristic cribriform pattern and uniform small basaloid cells. Types of metaplasia Epithelial metaplasia squamous epithelium glandular epithelium Mesenchymal metaplasia Mesothelial metaplasia Tumoral metaplasia A. Epithelial metaplasia Squamous metaplasia: in the bronchi (airways): the ciliated columnar pseudo-stratified epithelium is replaced with squamous epithelium. This process can be triggered by smoking, chronic bronchitis etc. The new type of epithelium has greater resistance to the aggressive agents, but it is the first step which makes possible the development of bronchial squamous carcinoma
Necrosis of salivary tissue and squamous metaplasia of ducts in necrotizing sialometaplasia.
A. Epithelial metaplasia
Glandular metaplasia:
The esophageal squamous epithelium may be replaced with glandular epithelium of gastric or intestinal type, in the lower third of the organ in case of gastro-esophageal reflux (Barrett esophagus): the metaplastic tissue is more resistant to the intermittent reflux of stomach acid, but this is the first step towards the occurrence of esophageal adenocarcinoma.
- Dentigerous cysts
lined by thin, nonkeratinizing squamous epithelium, often shows mucous cell metaplasia.
- Necrosis: definition, types of necrosis after their causes
Definition:
necrosis is the cellular death in a living organism, which determines an inflammatory reaction
TYPES OF NECROSIS:
I. The Coagulative necrosis
II The liquefactive necrosis
III.Traumatic fat necrosis (traumatic):
IV. Fibrinoid Necrosis V. The caseous necrosis VI. The gummatous necrosis VII. The gangrene gangrene is a particular type of necrosis and subsequent degradation of a tissue through an ischemic mechanism sometimes associated with a superposed bacterial infection. Most frequently it occurs at the limbs and in some internal organs.
Gangrene Types:
Dry gangrene:
• Definition: coagulative necrosis through an ischemic mechanism of tissues exposed directly to the air.
• Localization: at the lower limbs, hands, ear, nose (at the extremities of the body)
• Causes: slowly installed ischemia though arteriosclerosis, obliterating thrombangeitis, prolonged arterial spasm
Wet gangrene
• Definition: tissues with dry gangrene that becomes infected later (streptococci, staphylococci)
• Location: lower limbs, intestines, appendix, gall bladder, lungs, mouth, etc.
• Clinical signs: start randomly, not at the most distal sites from the obliterated vessel, the area is grey-black, swollen, imprecisely delimitated and rapidly extending to the neighboring tissues
• Noma (derived from the Greek “nomein” meaning “to devour”) is a devastating gangrenous disease which attacks children, quickly destroying their mouth, nose, and face, and which can prove fatal after just a few weeks. Noma, also known as cancrum oris, seems to start on the gum and extends outwards to the cheeks and lips. Without prompt treatment, mortality rates from this disease are as high as 70-90%, with most deaths attributed to complications such as pneumonia, diarrhea and septicemia.
Gaseous gangrene
• Etiology: Clostridium perfringens or other anaerobic germs that produce necrosis and fermentation releasing gases that dissect and disrupt the tissues and cause subcutaneous or internal vesicle formation.
• It may appear in open fractures, extensive traumas, large, crushed wounds, contaminated by dirt or other infected foreign bodies
• Clinically: a dark swollen area, with a putrid smell and crackle sensation at tissue palpation (due to the presence of gas bubbles in the tissue)
- Fibrosis: definition, types of fibrosis
Fibrosis is the microscopically term = proliferation of the connective tissue (fibroblasts and fibers)
Types of fibrosis:
1. According to its main elements:
collagen fibrosis: made of collagen fibers
fibroblast-collagen: made of cells (fibroblasts) and collagen fibers
vascular fibrosis: made of cells, fibers and many blood vessels
Types of fibrosis:
2. According to its etiology:
post-inflammatory (ex: chronic hepatitis)
dystrophic (ex : necrosis granulation tissue connective tissue)
tumoral (ex: connective stroma of a carcinoma, nodular fasciitis, fibromatoses)
Types of fibrosis:
3. According to its topography (place in the organ):
systematic fibrosis does not modify the structure of the organ
encapsulated fibrosis is the formation of a connective capsule around a pathological process (ex: around an abscess, a hematoma, etc.)
Types of fibrosis:
4. According to its characteristics:
atrophic fibrosis causes retraction of the area involved (ex: scleroatrophy of the gum)
the connective tissue proliferates excessively in cases of hypertrophic fibrosis (ex: hypertrophic scars, keloids = white, glassy, tough areas)
- Keratinous dystrophy and leukoplakia
Definition:
keratinous dystrophy is a metabolic disorder that affects the production of keratin by the squamous epithelia (which are normally present in a certain region or appear there through metaplastic processes).
e. a cornified layer: can suffer from :
hyperkeratosis: the thickening of the keratinous, normally anucleate stratum (when the keratin layers do not contain any nuclei between them, the situation is also called orthokeratosis)
parakeratosis: nuclear debris can be found between the thickened keratin layers (in accelerated keratinisation)
dyskeratosis: the presence of keratin in other places than normal (on the surface). It appears because of the premature keratinisation of the cells from the spinous layer, also called keratinocytes
Dyskeratosis can be :
1. benign: it appears in Molluscum contagiosum
2. malignant: it appears in “in situ” or invasive squamous cell carcinomas
B. Squamous, not keratinized epithelium (the squamous mucosa)
keratosis:
the appearance of keratin on the surface of a squamous mucosa (at a microscopic level; e.g.: in the larynx).
leukoplakia:
the appearance of some white spots (at a macroscopic level) on the squamous mucosa.
Macroscopically, leukoplakia can be :
flat: less important, it can disappear at the same time as the cause
verrucous: it can evolve into a carcinoma
hairy: it is in relation with the Epstein-Barr virus, HIV
Microscopically, leukoplakia can be:
hyperkeratosis, parakeratosis, dyskeratosis, and it can evolve into an “in situ” carcinoma, and then into an invasive carcinoma.
- Atheromatosis: definition, macro and micro aspects, complications
Definition:
the formation of atheromas on the internal walls of the arteries, through deposits of cholesterol
Atherosclerosis is the fibrosis of atheromas from atheromatosis
Etiopathogenesis (predisposing factors)
Hyperlipidemia
HTA
Diabetes
Smoking
Obesity
Stress
Macroscopic features: simple lesion: • spots, striations, patches, plaques complex lesion: • ulcer, thrombosis, connective organisation, calcification
Microscopic features:
accumulation of free cholesterol and xanthomatous cells inside the artery’s wall, under the intima
inflammatory cells in the intima (connective organization of the lesion), atrophy of the media
The complications of atherosclerosis:
a. Local:
towards the lumen: stenosis, thrombosis, hemorrhage inside the lesion (ballooning)
inside the wall: disruption (hemorrhage), aneurysm
b. Regional:
embolism (from the lesion or the thrombi formed in relation with the lesion)
partial ischemia (scleroatrophy) or total ischemia (infarction)
Morbid associations: atherosclerosis HTA Obesity DM Polyglobulia Cholesterol calculs, xanthelasma
- Melanin dystrophy: hypo- and hyper- melanosis
Hypermelanosis
A .General (diffused)
1. The Addison disease
• in CAG insufficiency, through: TB, autoimmune adrenalitis, etc
• An increased production of ACTH and MSH with generalized pigmentation of the skin and mucosal surfaces
2. Arsenic, silver poisonings (argyria)
3. Hemochromatosis
4. Late cutaneous porphyria
B. Localized:
1. Chloasma or the pregnancy mask (melasma) appears physiologically in some pregnant women. It is a pigmentation of the forehead and the cheekbones, the hyper pigmentation of the mammary areoles, the white abdominal line and the external genitalia.
2. Ephelis (freckles): brown, small spots, which intensify after exposure to sunlight
3. Solar lentigines (actinic lentigo): various brown spots on the skin exposed to sunlight, they usually appear in elderly people (also called senile lentigo)
4. Post-inflammatory hyper pigmentations: Systemic Lupus Erythemathosus (SLE), flat lichen, etc
5. Nevi: benign tumors of melanocytes
6. Malignant melanomas: malignant tumors of melanocytes
II. Hypomelanosis
A. General:
1. Albinism:
• AR
• tyrosinase defficiency
• clinically: white skin, white hair, red pupils (the melanin of the eye is missing, blood vessels can be seen)
• In evolution: actinic keratosis appears on the tegument, then basal or squamous cell carcinoma because of the absence of melanin’s protective effect against UV rays
B. Localized:
1. Vitiligo:
• It has autoimmune pathogenesis, with self antimelanocyte antibodies (they destroy melanocytes)
• They are associated with other autoimmune diseases: Hashimoto thyroiditis, Addison disease, etc
• clinically: well delimitated, not pigmented areas, with an irregular shape and a hyperemic or hyperpigmented margin, situated on periorificial skin of the face (mouth, eyes), on the chest , the dorsal side of the hand, on genitalia, at the site of previous inflammation, burns, trauma (the Koebner phenomenon)
2. Hypomelanosis in cutaneous inflammations: • leprosy • sarcoidosis 3. Hypomenalosis in dermatological diseases : • white pityriasis • psoriasis 4. Chemical hypomenalosis (toxic) : • retinoic acid • benzoyl peroxide
- Calculosis: general features and sialolithiasis
WHAT IS LITHIASIS ?
Definition:
lithiasis is the appearance of calculi in various areas of the body
Calculi are precipitate phases in a solution situated in an excretory tract
Pathogenesis:
the increase of crystalloids in a secretion (eg : salts in the urine, bilirubin in the bile)
the presence of a precipitation nucleus (i.e.: desquamated cells, microbes, foreign organisms)
Stasis of secretion which favors the infection of the increased amount of secretion
Localization: gall bladder, billiary ducts kidneys, ureters, bladder pancreas salivary glands lung Dimensions: big, medium, small (gravel) very small, mixed with secretion (billiary mud) Shape: round, faceted, coralliform, forked Number: unique or multiple Color and consistency: carbonates : white, breakable oxalates : grey, tough dark : yellow, breakable cholesterol : yellow, breakable billiary salts : green, breakable
Complications: colic : very big pain obstruction ulcerated epithelium with hemorrhage malignization
