Week 1 Flashcards
Define pathology
the study of disease
Define disease
very simply, a change in normal body function/structure that leads to abnormal function
Define sign
clinical sign that can be objectively observed or measured by a physician or nurse
Define symptom
subjective complaint described by the patient (ex. dizziness, nausea, chest pain)
Define etiology
study of the causes of disease
Define pathogenesis
mechanism of disease
-The sequence of cellular events that take place from the initial contact with the etiologic agent until the expression of disease
Define pathological and morphological manifestations
changes in structure and function of tissues, organs, and systems
Define prognosis
anticipated course of the disease and final outcome
Define epidemiology
the study of the distribution (pattern) and determinants (causes, risk factors) of health-related states, including disease
Define incidence
number of new cases arising in a population over a given time period
Define prevalence
total number of cases of the disease in a given population
What are the two main categories of divisions of Pathology at LHSC?
Anatomical pathology and clinical pathology
What are the subcategories of anatomical pathology?
- Surgical pathology
- Cytopathology
- Forensic pathology
- Molecular pathology
What are the subcategories of clinical pathology?
- Clinical chemistry
- Immunology
- Blood bank/hematology
- Microbiology
Describe surgical pathology
Large tissue specimens and their architecture under a microscope for diagnosis; typically removed surgically; steps include:
-Gross (macroscopic) examination of organs and tissues such as biopsies, e.g., skin, cervix, breast
-Histological (microscopic) examination
-Generation of a diagnostic pathology report that’s comprehensive to inform physicians and patients
Describe cytopathology
The examination of cells under the microscope in the absence of tissue architecture; several types of samples including:
1. Exfoliative
-Spontaneous (spontaneously produced by the patient) such as urine
-Mechanical such as cervical pap smear or bronchial brushings
2. Interventional
-Fine needle aspiration
a. Lymph node
b. Thyroid
Describe forensic pathology
Specializes in forensics and performs autopsies, including in criminally suspicious cases
Describe molecular pathology
A department on its own but also an adjunct for surgical and cytopathology
Describe clinical chemistry
i.Covers a bunch of different clinical and biochemical tests
ii.Clinical Chemistry Specimens: blood, urine, sputum, stool, other body fluids such as bone marrow
Describe hematology
Responsible for the blood products that are distributed in the hospital
Describe microbiology
looks at microorganisms, viruses, bacteria
What techniques are used in pathology?
-Gross examination – examine specimen with the naked eye
-Microscopic examination – light microscopy is used to look at cellular morphology
-Electron Microscopy (special technique) Looks at organelles within the cells
-Ancillary tests (special technique)
Describe ancillary tests
o Immunohistochemistry – selectively identifies proteins in cells to aid with diagnosis
o Special histochemical stains – highlight specific tissues (elastic tissue, collagen); pigment (iron, melanin); microorganisms
o Molecular pathology – the detection and/or analysis of nucleic acid molecules (DNA or RNA) to provide clinical information (Chromosomal analysis, DNA sequencing)
Type of tests:
* Constitutional Genetic Disorders
* Metabolic Disorders
* Hereditary Cancer Panels – genetic predisposition to developing cancer
* Solid tumour testing – treatment purposes
List the pathway of a specimen through pathology and laboratory medicine
- Gross examination – described in gross section of pathology report
- Then prepare sample for microscopic examination, steps:
- Tissue cut from specimen
- Placed in cassette
- Processed – any water content removed
- Tissue embedded in wax
- Cut on microtome
- Thin section
- Slide and Stained (hematoxylin and eosin stain – pink/purple stain)
Techniques in anatomical pathology include what?
gross examination, microscopic examination, ancillary tests
What can be tested by the laboratory?
Most fluids and cells contain biological components that have diagnostic applications
In the chemistry laboratory the most common specimens are?
blood and urine
For blood tests, the two main collection types used are?
finger prick, or venipuncture
To obtain accurate test results, it is important to do what?
collect the proper specimen type in the correct tub and follow the correct order of draw
Most laboratory errors occur in which phase of testing?
pre-analytical phase
-ensuring the laboratory receives a quality specimen is key to reporting of accurate test results to the clinical team
Why are laboratory tests requested (10 reasons)?
- Diagnosing a disease
- Screening for a disease
- Determine severity of an illness
o E.g., serum K needed for nerve transmission in heart and muscle contraction
o Normal range of serum K 3.5-5.0 mmol/L - Determine appropriate management
o E.g, prostate cancer – prostate specific antigen (PSA) is used to monitor patient for post-surgical recurrence of tumour - Monitor the progress of surgical recovery
- Therapeutic drug monitoring
- Identify drugs of abuse or poisonings
- Assessment of baseline or nutritional status
- Protection against legal repercussions
- Re-test to verify abnormal results
Define accuracy
describes the ability of data, measurements, or results to match the actual ‘true’ value
Define precision
is how close these data, measurements, or results are to each other, working as a measure of the spread of data from the average
What is often used to confirm (rule in) or exclude (rule out) a disease?
Laboratory tests
Define prevalence
defined as the percent of patients who have the disease that is being tested
_____ _____ and _____ are important for interpreting test results, they are calculated based on the decision threshold and can change if that moves.
Test sensitivity and specificity
Describe laboratory stewardship
Laboratory stewardship refers to the appropriate utilization of laboratory tests which encompasses correctly ordering, retrieving, and interpreting these tests
What is Choosing Wisely Canada?
A national organization that is dedicated to the reduction of testing and efficacious resource use
Why does unnecessary testing, procedures, and treatments occur?
-Fear of lawsuit
-Practice habits are difficult to change
-Patient requests without evidence or knowledge of risks/benefits
-Lack of time for shared decision making
up to what percent of tests, treatments, and procedures performed in Canada are potentially unnecessary?
30%
What are the five things physicians and patients should question (not send for testing)?
- Don’t perform population-based screening for 25-OH-Vitamin D deficiency.
- Don’t screen with Pap smears if under 21 years of age or over 69 years of age.
- Avoid routine preoperative laboratory testing for low-risk surgeries without a clinical indication.
- Avoid standing orders for repeat complete blood count (CBC) on inpatients who are clinically/laboratorily stable.
- Don’t send urine specimens for culture on asymptomatic patients including the elderly, diabetics, or as a follow up to confirm effective treatment.
What are the types of errors in pathology and laboratory medicine?
- Pre-analytical – everything involving specimen retrieval
- Analytical – diagnosis
- Post-analytical – reporting
What types of pre-analytical errors could occur?
Collection, Ordering, Specimen labeling, Specimen processing, Correct clinical information provided
What precautions should you take to avoid the pre-analytical error involving collection?
-Collection – specimen collected from the correct patient
oVerbal and ID band confirmation
o2 step verification
What precautions should you take to avoid the pre-analytical error involving ordering?
-Ordering – correct test ordered
oSample taken from correct location
oCorrect tube used (blood test)
oCorrectly input into ordering system
What precautions should you take to avoid the pre-analytical error involving specimen labeling?
-Specimen labeling – patient and specimen identification
oPatient identification on label of specimen
oSpecimen correctly identified on label
What precautions should you take to avoid the pre-analytical error involving specimen processing?
-Specimen processing
oInadequate sample (volume or size)
oLost specimen
oInadequate or incorrect fixative
What precautions should you take to avoid the pre-analytical error involving correct clinical information provided?
-Correct clinical information provided
oPertinent information provided to assist with diagnosis
List how disease is classified (based on cause)
-Host/Genetic Factors (ex. sickle cell disease)
-Environmental Factors (ex. traumatic head injury)
-Combination of Factors (ex. heart disease, diabetes, cancer)
Not all _____ diseases manifest at birth
inherited (genetic)
Not all _____ diseases are genetic
congenital
Define congenital anomalies
Structural or functional deficits that occur in utero and are present at birth; may or may not have a genetic cause
Define malformation
intrinsically abnormal development process (ex. polydactyly, Spina Bifida, Congenital heart disease)
Define disruption
Secondary destruction of an organ or body region that was normal in development, extrinsic disturbance
Define deformation
Secondary or extrinsic destruction of the normal development process (ex. localized or generalized compression of growing fetus by biomechanical forces)
Genetic or congenital factors are what?
-Alterations in genetic material
oSingle mutation in a DNA base pair (ex. Sickle cell disease)
oAdditions/Deletions/Rearrangements of whole chromosomes
Trisomy 21 (Down Syndrome)
Define teratogens
environmental factors causing abnormal development or congenital anomalies
List common teratogens
-Infectious agents (ex. rubella, cytomegalovirus, toxoplasma)
-Drugs (ex. alcohol, isoretinoin)
-Chemical/heavy metals (ex. mercury, lead)
-Ionizing radiation
-Maternal disease (ex. maternal diabetes, hypertension)
What types of environmental factors cause disease?
- physical agents (ex. mechanical trauma, temp.)
- chemical agents (ex. poisons)
- infections - bacteria, virus, etc.
- drugs - therapeutic, recreational
- allergens
Describe exogenous allergens
originating outside the body
Describe endogenous allergens
arising within the body itself, generally proteins
How can we classify disease (based on pathology)?
1.Injury – physical, chemical, or biological agent
2.Inflammation – common to many diseases
3.Infection – infectious organisms; local or systemic
4.Immunological reaction – excessive/overactive response by the immune system; hypersensitivity reaction
5.Neoplasia – autonomous proliferation of cells; benign or malignant tumours
6.Metabolic or Endocrine – disorders of enzymes, hormones, secretory products/proteins ex. diabetes
7.Nutritional – deficiency in proteins or calories; decreased absorption, transport, or utilization (celiac disease); specific vitamin or mineral deficiencies (scurvy); psychological factors (anorexia nervosa); excess calories (obesity)
8.Vascular – important cause of death; narrowing of blood vessels (ex. atherosclerosis, heart attack (MI), stroke)
9.Psychological factors – can cause and affect disease processes; mental illness can lead to worsening somatic disease; addiction
Define idiopathic
unknown etiology; currently no known cause
Define iatrogenic
disease or any adverse condition resulting from treatment by a healthcare professional
Describe adverse events
unintended injury or complication resulting in death, disability or prolonged hospital stay
(very important causes of morbidity and mortality)
Define morbidity
illness or impairment/disability caused by disease
-Something that impairs the well-being or normal functioning of a patient
Define mortality
something causing the death of patient (death from disease)
What are the top 5 reasons for hospital stays in Canada?
- Giving birth
- COPD and bronchitis
- Heart attack
- Heart failure
- Osteoarthritis of the knee
What are the top 5 causes of death in Canada (2019)?
1.Malignant Neoplasms (all cancers)
2.Heart disease
3.Accidents (unintentional injuries)
4.Cerebrovascular diseases (neurocognitive diseases)
5.Chronic lower respiratory diseases
_____ are more likely to be diagnosed with cancer
Males
_____ are more likely to survive cancer when compared to males
Females
Approx. 90% of cancer diagnoses occur among Canadians who are at least _____ years of age
50 years of age
Which type of cancer has the highest mortality in Canada?
Lung
Life expectancy has been steadily increasing in Canada; increase of about _____ in life expectancy since 1921.
25 years
What are some reasons for improved life expectancy?
Sanitation, medical care, public awareness of good nutrition and the health risks associated with smoking, community advocacy
