Midterm 1 Flashcards
Anatomic (surgical) pathologist vs. Clinical pathologist
Based on type of sample that they examine
Anatomic - diagnose based on examination of tissues
Clinical - tend to look at body fluids
Etiology
the underlying cause of the disease
Idiopathic
no known etiology
Morphology
the physical appearance of the disease
Gross morphology
the appearance to the eye
Natural history
how the disease progresses with time
Sequelea
complications associated with the disesase
Prevalence vs Incidence
Prevalence - total number of cases of that disease within a certain population
Incidence - the number of new cases of that disease within a particular time period (usually one year)
Mortality
the likelihood of death of an individual with that disease
Morbidity
the extent to which that disease affects the overall health of an individual
Syndrome
A disease characterized by the presence of a set of symptoms, signs, and/or lab features that are all related to a particular cause
What is the mnemonic for classification of disease?
VINDICATED Vascular Inflammatory Neoplastic Deficiency/degenerative Iatrogenic Congenital Autoimmunue/allergic Trauma Endocrine Drug Related
Iatrogenic
diseases that are due to results of treatment
Congenital
disease present from birth.
Parenchymal vs Stromal tissue
Parenchymal - performs function of tissue
Stromal - supportive function
What are the 4 types of tissues?
Connective - “connects” (hold in place, integrates) organs & systems *includes blood
Epithelial - covers or lines various body parts to protect the body and also is important for absorption, transportation, and secretion
Muscle - capable of contracting and generating tension in response to
stimulation; produces movement
Nervous - capable of sending and receiving impulses through
electrochemical signals; Controls movement etc.
Hypertrophy
increase in the size of tissue or organ due to increased size of the individual cells
Pathologic hypertrophy example
cardiac muscle cells enlarge in response to increased pressure in the systemic
circulation (hypertension)
Hyperplasia
an increase in the size of tissues or organ due to increase in number of cells
Pathologic hyperplasia example
endometrial hyperplasia is increased number of cells lining endometrial (uterus) cavity
Atrophy
decrease in size of tissue or organ due to a decrease in number and/or size of cells
Pathological atrophy example
muscle denervation causes atrophy of skeletal muscle supplied by that nerve
Metaplasia
a change of one cell type into another cell type
Metaplasia example
chronic smoking, simple columnar bronchial epithelium squamous epithelium
Dystrophic calcification
deposition of calcium in damaged tissue (eg. Atherosclerosis)
Metastatic calcification
deposition of calcium in normal tissue when there is hypercalcemia
Dysplasia
the presence of cells of an abnormal type within a tissue
What are the signs of necrosis in liver (liver damage/hepatitis)?
Liver contains enzymes that are released if cells are injured e.g. Aspartate aminotransferase (AST); Alanine aminotransferase (ALT)
What are the signs of necrosis in heart (heart damage/myocardial infarct)?
cardiac myocytes contain proteins that are released if cells are injured e.g. Troponin
Coagulative necrosis
– morphologic appearance of boiled meat (coagulated protein)
– most common form of necrosis; due to inactivation of hydrolytic enzymes
– solid internal organs (kidney, liver)
Liquefactive necrosis
– necrosis characterized by dissolution of tissue
– necrotic area is soft and filled with fluid (Brain infarct)
Caseous necrosis
– necrotic tissue with appearance of cheese
– form of coagulative necrosis with limited liquefaction; seen in TB
Fat necrosis
– necrosis of fat due to action of enzymes followed by formation of complexes with
calcium; white chalky areas form (especially around pancreas)
Fate of necrosis vs. Fate of apoptosis
Necrosis causes an inflammatory reaction, apoptosis does not
What are the 5 clinical signs of acute inflammation?
- heat - because of vasodilation
- redness - because of increased blood flow
- edema - inflammation causes vessels to become leaky and allow neutrophils etc to flow
- pain - due to bradykinins
- loss of function
What are the events in acute inflammation
• Change in size of caliber of blood vessels
- transient vasoconstriction
- vasodilation (heat, redness)
• Increased vascular permeability
- edema formation
• White blood cells enter site of injury
- kill organisms, mop up debris
What are the substances that mediate inflammation?
- Histamine
- Bradykinin
- Complement system
- Arachidonic acid (AA) derivatives
What is the source and role of histamine in inflammation?
- increases vessel permeability
* released by mast cells
What is the source and role of bradykinin in inflammation?
- increases vessel permeability
- causes pain
- derived from a plasma protein
Transudate vs. exudate
Transudate - fluid pushed through the capillary due to high pressure within the capillary; protein poor fluid containing few cells that forms due to a disturbance in forces across vessels walls
Exudate - fluid that leaks around the cells of the capillaries caused by inflammation; protein rich fluid containing white blood cells
that forms due to inflammation
Role of complete blood count in inflammation
to count number of white blood cells (involved in diff responses); e.g. increased neutrophils if inflammation — don’t need to draw blood from the specific location, can draw blood from somewhere else
Role and results of examining C-reactive protein (CRP) in inflammation
test does not tell you what is cause, just tells you that there is inflammation
What is the complement system?
• group of plasma proteins that act to help kill bacteria • mediate inflammation • 3 methods of activation - classical pathway - alternate pathway - Lectin pathway
What are Arachidonic acid (AA) derivatives?
• AA is formed from phospholipids in cell wall
• AA is metabolized to form various substances including leukotrienes,
prostaglandins, prostacyclin and thromboxane each of which affects inflammation
What are the cellular components of inflammation?
- Neutrophil (PMN)
- Eosinophils
- Basophils/mast cells
- Macrophages
- Lymphocytes/ Plasma cells
What is the role of neutrophils in inflammation?
- first cells to enter site of injury (very mobile)
- able to kill bacteria and engulf material (phagocytosis)
- produce chemicals to attract other cells
- short lived
What is the role of eosinophils in inflammation?
- mobile, kill bacteria
- involved in allergic reactions, parasitic infections
- longer lived, present in chronic inflammation
What is the role of Basophils/Mast cells in inflammation?
- release histamine
* basophils when in blood, mast cells when in tissue
What is the role of macrophages in inflammation?
- major phagocytes, enter site 3-4 days after injury
* present in chronic inflammation
What is the role of Lymphocytes/Plasma cells in inflammation?
- immune function in chronic inflammation
* release antibodies
What is purulent inflammation (pus)?
Dead neutrophils; inflammatory exudate rich in PMNs usually due to bacterial infection
What types of inflammatory exudates are there?
- Serous inflammation
- Fibrinous inflammation
- Purulent inflammation (pus)
What is fibrinous inflammation?
• inflammation characterized by exudate rich in fibrin
What is serous inflammation?
• inflammation characterized by exudation of clear fluid with few cells
What is ulcerative inflammation?
Specific term used to describe acute inflammation:
• inflammation characterized by loss of an epithelial lining due to the inflammation (ulceration)
What is pseudomembranous inflammation?
Specific term used to describe acute inflammation:
• inflammation characterized by ulceration and a fibrinopurulent exudate that forms a
pseudomembrane over the ulcer
What are the outcomes of acute inflammation?
There are 4 possible outcomes to acute inflammation:
• Complete resolution - regeneration of cells and restoration of normal function with no residual deficit [ideal outcome]
• Abscess formation - wall off the inflammatory focus within capsule; localized collection of pus
• Healing by fibrosis and scar formation - replacement of usual tissue with fibrous tissue
• Progression to chronic inflammation
What is chronic inflammation cell exudate?
lymphocytes, plasma cells and macrophages
What is granulomatous inflammation (and granulomas)?
• a specialized form of chronic inflammation
characterized by the formation of granulomas
Granuloma - accumulation of chronic inflammatory cells (lymphocytes, macrophages)
arranged in discrete nodules or aggregates (+/- multi-nucleated giant cells)
What is an example of caseating granulomas?
Tuberculosis
What is an example of non-caseating granulomas?
Sarcoidosis
How do skin wounds heal?
by filling in the defect with granulation tissue and then replacing the
granulation tissue with stronger fibrous tissue; with time the wound contracts due to the contraction of myofibroblasts
Describe wound healing by first intention
- the name given to the healing that occurs after a surgical incision
- scab formation, PMN enter and scavenge debris
- formation of granulation tissue
- resorption of granulation tissue and replacement by fibrous scar
Describe wound healing by second intention
- gaping wound that is either not closed surgically or can not be closed surgically
- granulation tissue forms and is gradually replaced with fibrous tissue
- with time the wound contracts however the overlying tissue is never the same
When do you not want to close a wound?
- Infection
- Human bites
What is the distribution of causes for developmental malformations?
– none identified (75%) – genetic (20%) – chromosomal (2%) – infection (2%) – chemical (1%)
What are some non-lethal examples of defective growth control genes?
• cleft lip and palate
– multi-factorial inheritance
• achondroplastic dwarfism
– autosomal dominant inheritance
What are thalidomide and isotretinoin?
Chemical teratogens (morning sickness and primarily used to treat severe acne)
Examples of infectious teratogens
(TORCH)
• Toxoplasmosis (parasite)
– brain microcalcifications, hydrocephaly, skin lesions
• Other (syphilis, listeria, )
• Rubella (German measles virus) (Fig. 5-4)
– microcephaly, congenital heart disease, micropthalmia
– 1st trimester exposure, unimmunized mother
• Cytomegalovirus
– brain microcalcifications, hydrocephaly
– skin lesions
• Herpes simplex virus
Aneuploidy
General term for an abnormal number of chromosomes (loss/gain)
Monosomy
Loss of a chromosome
Autosomal monosomies = fatal
Y only (YO) is fatal X only (XO) is not fatal (Turner’s syndrome)
Trisomy
The presence of an extra copy of a chromosome
Autosomal trisomies are not necessarily fatal (e.g. 21, 13, 18)
Additional sex chromosomes are not fatal
Down’s syndrome
Trisomy 21
1/800 (most common chromosomal disorder)
True trisomy 21 in 95% of cases
- usually maternal chromosome, increased likelihood with age
Specific typical features
Significant morbidity, increased mortality
Turner’s syndrome
Monosomy X (XO) 1/3000 Female phenotype Specific features Infertile
Klinefelter’s syndrome
Trisomy X (XXY) 1/700 Typical features (Fig. 5-11) Male phenotype Infertile (atrophic testes)
P 11 WAGR
Structural chromosomal abnormality
(Wilma, Aniridia, Genintal malformation, Mental Retardation)
Loss in short arm of chromosome 11
q 13 Retinoblastoma
Loss in long arm of chromosome 13
Causes tumours in retina due to deletion of prevention gene
Some Down’s - Translocation
T 21/14
Extra copy of chromosome 21 due to translocation, not a complete extra chromosome
Single gene disorder
Disorder due to defect in particular gene
Demonstrate patterns of inheritance (Mendelian Patterns)
Exceptions to rules of Autosomal dominant disorders
Variable penetrance - % of individuals with gene who express it
Variable expressivity - degree of expression in individual with gene
Marfan’s syndrome
Autosomal dominant disorder
1/10 000
Defect in fibrillin gene (structural protein)
Characteristic phenotype (skeletal abnormalities - tall, thin, loose joints; cardiovascular abnormalities - aortic aneurysms, dissections, valves; ocular abnormalities - dislocation of lens, retinal detachment)
Life expectancy shortened
- Death usually to aortic dissection
Familial hypercholesterolemia
Autosomal dominant disorder
1/800
Defect in LDL Receptor gene
- insufficient cholesterol removal
Cholesterol deposits in tissue
- premature atherosclerosis, xanthomas in soft tissues and skin
Homozygous have higher LDL than heterozygotes
- develop ischemic heart disease before age 20
Cystic fibrosis
Autosomal recessive disorder 1/2500 Carrier rate = 1/25 Defect in chloride transport gene Thick exocrine secretions (obstruction of ducts and infections) Chloride sweat test to help diagnose
Lysosomal storage diseases
Autosomal recessive disease
Group of diseases due to defects in different enzymes
Different disease depending on which enzyme disease is defective
Accumulation of materials in lysosomes
E.g. Tay-Sachs, Gaucherie Disease
Tay-Sachs
Autosomal recessive - lysosomal storage disease
Defective hexosaminidase
Brain changes, eye changes, 3-5 year life expectancy
Gaucher disease
Autosomal recessive - lysosomal storage disease
Defective glucocerebrosidase
Enlarged spleen, anemia, normal life expectancy (type 1)
Phenylketonuria (PKU)
Autosomal recessive
Ashkanzi jews
Defective phenylalanine hydrogenase gene
Converts PheA—Tyr
Accumulation of PheA and decreased Tyr result in psychoneural changes
Prevention - heel prick to ID, PheA deficient diet
Hemophilia
X linked recessive disorder
Defect in genes coding coagulation proteins
Type A - Factor VIII gene
Type B - Factor IX gene
Bleeding - joint spaces and minor traumas
Secondary complications
Treatment - factor replacement
Muscular dystrophy
X-linked recessive disorder
Defective dystrophin protein - attachment of cytoskeleton, weakened cell structure esp. in skeletal muscle
Duchenne = severe, wasting starts early
Becker’s= less severe, later onset
Fragile X syndrome
X-linked, non-classic inheritance
A portion of the X chromosome is “fragile” - due to CGG triplet repeats, increased number with each generation, once reached a certain number of repeats get expression
Features - mental retardation, enlarged testes
May not follow Mendelian patterns - pre-mutation is individual who does not have critical number of repeats, increased expression in subsequent generations
Dysraphia
Multifactorial inheritance disorder
Incomplete fusion of midline structures, spectrum of abnormalities
E.g. anencephaly, spina bifida, meningocele - each relates to where in the neural tube it had failed to fuse
If one child affected, increased risk
Folate during pregnancy helps decrease risk
Anencephaly
Multifactorial inheritance - dysraphia
Complete absence of brain
Spina bifida
Multifactorial inheritance - dysraphia
Defect in vertebral bones
Meningocele
Multifactorial inheritance - dysraphia
Defect in vertebra, meninges
Diabetes Mellitus Type 2
Multifactorial inheritance disorder
Environmental and genetic components
Prenatal diagnosis techniques
Ultrasound = malformation ID
Chorionic villus sampling = biopsy of placental villus, fetal cell for analysis (chromosomal, molecular techniques)
Amniotic fluid
Maternal blood = triple screen
IUGR
Underweight baby - Birth weight less than 3200g
Causes of premature birth
Maternal - malnutrition, smoking, SA
Fetal - genetics
Placental - insufficiency
Neonatal respiratory distress syndrome
Acquired neonatal syndrome
Increasing shortness of breath, usually preterm
Pathophysiology - inadequate surfactant in lungs to decrease surface tension of alveoli, atelectacis (alveolar collapse), hyaline membranes form
Periventricular brain hemorrhage
Long term respiratory difficulties
Can assess levels of surfactant in amniotic fluid before birth
Treatment - corticosteroids before birth
Birth injury
Acquired neonatal syndrome Mechanical trauma during delivery Malposition, large baby Skull fracture Intracranial hemorrhage Etc
Sudden infant death syndrome
Acquired neonatal syndrome
Sudden, unexpected death
Not understood
Maternal factors - young, low SES, smoking, drug use
Infant factors - low birth weight, male, not first born, prone position
What are the cells of the immune system?
T lymphocytes
B lymphocytes
Plasma cells
Natural killer cell lymphocytes
Types of T lymphocytes
T helper cells = help B lymphocytes produce antibodies
T cytotoxic lymphocytes = mediate killing of viral infected or transformed cells
B lymphocytes
Immunoglobulin protein on surface (Ab)
One B lymphocyte and it’s clones produce one antibody
Plasma cells
Differentiated B lymphocyte that secretes AB into serum
Natural killer cell lymphocytes
Neither B nor T
React against viral infected cells
Kill tumour, foreign cells without prior exposure
Antigen presenting cell (APC)
Cell that engulfs Ag, processes that Ag and expresses Ag on cell surface to activate immune response
Major Histocompatibility Complex (MHC)
Group of proteins to which processed Ag is attached and then transferred to cell surface
IgA
Ab present in secretions, milk
Dimer
IgE
Ag present in tissue (located on surface of mast cells)
Mediate allergic response (Type I hypersensitivity reaction)
IgD
Ab present on surface of B cells
Involved in activation of lymphocyte response to an Ag
IgM
Ab present in blood
First antibody produces in response to Ag
Neutralize microorganisms, activate complement
IgG
Ab present in blood
Increased production on re-exposure to particular Ag
Opsonin
** GO OVER **
Hypersensitivity reactions
Classification based on mechanism of immune injury Type 1 = anaphylactic Type 2 = cytotoxic type Type 3 = immune complex Type 4 = cell mediated (delayed)
Type I hypersensitivity
Exaggerated immune response due to excessive release of
mast cell derived mediators (Hm)
Mediated by IgE
Increased vascular permeability, edema, cells (eosinophils)
Allergic rhinitis
Allergic rhinitis
• allergens [pollens (hay fever), cats, dust mites] • inhaling allergen results in symptoms • itchy nose, sneeze, watery eyes • treatment - antihistamines, other - desensitization shots