Lecture 1 Flashcards
What is disease?
Any disturbance of the structure or function of the body
How do we know we are sick?
Subjective manifestations of disease (symptoms related to lesions)
Secondary Prevention
Intervention after the disease has begun, but before it’s symptomatic
Example of Secondary Prevention
Screening measures (screening pregnant women for substance use)
Tertiary Prevention
Intervention after a disease or injury is established
Example of Tertiary Prevention
Treating an addiction, Treating Cancer
Syndemic Factors
2 or more concurrent factors exacerbate prognosis or burden of a disease
Syndemic Factors
2 or more concurrent factors exacerbate (worsen) the prognosis or burden of a disease
Examples of Syndemic Factors
Social, mental, environmental or economic factors (can promote or worsen a disease)
Epigenetics
How behaviours and environmental factors can change how a gene is expressed
What can amplify or repress gene expression to increase the risk or worsen disease?
Diet, physical activity, smoking, alcohol consumption, polluntants, mental stressors, depression, shift work, etc.
Symptoms and Signs
A physical or mental indicator of an illness or disease
Pathogenesis
The process of disease development
Etiology
The investigation for a cause of disease
Diagnosis
Determining the nature and cause of illness through the patient’s medical history, physical examination, differential diagnosis
Differential Diagnosis
Finding the difference between 2 or more conditions which share similar signs or symptoms
Differential Diagnosis
Finding the difference between 2 or more conditions which share similar signs or symptoms (could be done using lab tests or other diagnostic procedures)
Treatment types
Specific Treatment and Symptomatic Treatment
Specific Treatment
Treatment directed at the underlying cause of the disease (Potentially take away the illness)
Symptomatic Treatment
Alleviates symptoms but doesn’t influence the course of the disease (Improves patient’s quality of life but doesn’t take away the illness)
Elements of the history of current illness
Severity, time of onset, and characteristics of patient’s symptoms (aids with diagnosis + differential diagnosis)
Medical history
Details of the patients general health and previous illnesses to help provide a diagnosis on the current problem
Family health history
Health of patient’s parents and family members; diseases that run in the patient’s family
Social History
Patient’s occupation, habits, alcohol and tobacco consumption, general health, current problems (All these factors can have an effect on the patient’s health)
Review of symptoms
Other symptoms that are not found in the history of current illness suggesting other parts of the body are affected by disease
Physical examination
Examination of patient’s body with the emphasis on parts that are affected by illness, pain, etc.
Considerations for general diagnostic tests
Cost, Invasive vs. noninvasive, asking the appropriate questions, False-positive/false-negative ratio for test
Importance of using screening tests for detection of disease
Provides the ability to detect early asymptomatic diseases to start treatment early and minimize the likely-hood of late-stage organ damage
Importance of screening for genetic diseases
Screen carriers of genetic disease that are transmitted to the child as dominant or recessive trait. This provides the ability for the patient to make decisions regarding childbearing and pregnancy management
Traits for a suitable screening test
A relatively inexpensive, noninvasive test that does not yield a high number of false-positive or false-negative results
Invasive screening example
Biopsy and endoscopy
Invasive screening example
Biopsy and endoscopy (histological exams)
Noninvasive screening example
CT and X-ray
Sensitivity
Percentage of patients with the disease misclassified as not having the disease. (+false negatives)
Purpose of clinical laboratory tests
To determine concentration of substances that are frequently altered by disease in blood or urine (ex. D-dimer tests, pregnancy tests, Hemoglobin levels)
X-ray
Use of high-energy radiation waves at lower doses to produce images to help diagnose disease (penetrates through tissue depending on tissue density)
Radiopaque
Appears white on film; high-density tissues such as bone absorb most of the rays
Radiopaque tissues
Appears white on film; high-density tissues such as bone absorb most of the rays (X-ray and CT scan)
Radiolucent tissues
Appears dark on film; low-density tissues allow rays to pass through (X-Ray and CT scan)
Barium Sulfate
Intestinal tract
Radiopaque oil
Bronchogram
Intravenous dye
Intravenous pyelogram (x-ray exam of urinary tract)
Radiopaque tablets
Visualize gallstones
Arteriogram
Visualize blood flow; identify narrowing or obstruction
Cardiac catheterization
Blood flow through heart; detect abnormal communications between chambers
Computed tomography (CT) scan
Radiation detectors record amounts of X-rays or ionizing radiation absorbed by body and feed data into a computer that reconstructs the data into an image. Delivers higher doses of radiation then X-ray
Use for CT scans
Screen for cancer and detects abnormalities in internal organs that cannot be seen on an X-ray
Magnetic resonance imaging (MRI)
Computer-constructed images of body based on response of hydrogen protons in water molecules when placed in a strong magnetic field
(interaction between the hydrogen protons in water and the strong magnetic field create an image)
T1 MRI
High signal: Fat, melanin, blood, etc.
Low signal: Iron, water, air, bone, tumors, collagen, etc.
T2 MRI
High signal: Water, edema (excess fluid in body tissue causing swelling), fat, blood, tumors, etc.
Low signal: Air, bone, acute blood
MRI vs. CT (Advantages)
MRI doesn’t use ionizing radiation, it detects abnormalities in tissue surrounded by bone, See cancers better, overall more detailed image produced then a CT scan
Uses for MRI
Multiple sclerosis (MS), breast cancer detection
Positron-emission tomography (PET)
Measures metabolism of biochemical compounds that are labelled with positron-emitting isotopes to measure organ function (usually combined with CT scans and are coloured spots)
Disadvantages of PET
Very expensive, not widely available, requires facilities for incorporating the isotopes into biochemical compounds
Use of PET
Assess biochemical function in the brain, determine metabolic activities, changes in blood flow, distinguish benign from malignant tumour (+glucose uptake in malignant tumours)
Radioisotope (radionuclide) studies
Evaluate organ function by determining rate of uptake and excretion of substances labeled with a radioisotope
Radioisotope for Anemia
Vitamin B12
Radioisotope for Hyperthyroidism
Radioactive iodine
Radioisotope for Pulmonary blood flow (presence of blood clots)
Albumin
Radioisotope for Cancer spread/determine the presence of tumour deposits
Phosphorus
Types of Cytology and histology exams
Papanicolaou (Pap) smear and Biopsy
Papanicolaou (Pap) smear
Invasive; identifies abnormal cells in fluids or secretions to detect cervical or other cancers
Biopsy
Tissue samples that undergo a histological exam to determine abnormal structural and cellular patterns
Electrical Activity
Measure electrical impulses associated with body functions and activities (ECG, EEG, EMG)
ECG
Measures changes in electrical activity of the heart in various phases of the cardiac cycle (Can identify disturbances in heart rate, rhythm, and abnormal impules)
EEG
Measures electrical activity of brain
EMG
Measures electrical activity of skeletal muscle during contraction and at rest
Endoscopy
Interior examination of body using a flexible instrument with a lens and light source through an incision or opening. Surgery can be preformed though this method.
Bronchoscope
Examination of Trachea and major bronchi
Cystoscope
Examination of Bladder
Laparoscope
Examination of Abdomen
Ultrasound
Mapping echoes are produced by high-frequency sound waves transmitted into body (echos will reflect a change in tissue density which produces images)
Preventative treatment
A treatment used to prevent illness (ex. statins to reduce risk of cardiovascular incidents)
Lesion
Any structural abnormality or pathologic change
Gross examination
Study of a diseased organ with the naked eye
