Lecture 1: Introduction

Question 1

Pathology Definition

Answer 1

Pathology Definition: medical science that studies the nature of disease

Originated from the Greek words:
“pathos” means disease
“logos” means science
The science of disease!

• Divided into two specific areas:

1. Clinical Pathology (lab work)
2. Anatomic Pathology (dissection)

Question 2

Definition of Health

Answer 2

Definition of Health:

The World Health Organization (WHO) defines health as:
“a state of complete physical, mental, and social well being and not merely as the absence of disease”

Health: absence of disease, more like a continuum with wellness at one end (optimal level of function) and illness at the other end. Constantly changing throughout life on this scale.

Illness: deviation from healthy state, biological or psychological alteration that causes a malfunction in an organ or system in the body, a disturbance,

Question 3

6 areas of description of a disease

Answer 3

1. Pathogenesis: includes both etiology and pathophysiology:

a. Etiology-cause of the disease

b. Pathophysiology- what happens in your body with this disease

2. Epidemiology
3. Clinical findings
4. Diagnosis
5. Treatment
6. Prognosis

Question 4

1. Pathogenesis of disease

Answer 4

1. How the disease develops and its progression on both a cellular level and clinical presentation and the cause of the disease.

a. Pathophysiology of a disease:
what happens in the body from the disease processes

b. Etiology of a disease:
what is the cause of the disease

Question 5

2. Epidemiology of a disease:

Answer 5

The incidence, the distribution and the possible control of a disease.

Answers these questions:

Is the incidence increasing or decreasing?
Is it transmissible or contagious?
Are there risk factors for the disease?
Can it be prevented?
Is it more common in one geographic area?

• Example of Epidemiology of a disease:

Diabetes Type II:

Is the incidence increasing or decreasing? increasing
Is it transmissible or contagious? no
Are there risk factors for the disease? Yes, obesity, sedentary lifestyle
Can it be prevented? Yes, mostly
Is it more common in one geographic area? Yes, in western cultures

Question 6

3. Clinical Findings of a disease are called signs and symptoms

Answer 6

1. Sign: an objective finding observed or measured by the therapist

        eg/ fever (on a thermometer), cough (observed), a positive lab test

2. Symptom: a subjective finding reported by the patient, not observable by the therapist

        eg/ headache, back pain, depression or anxiety

Question 7

4. Diagnosis of a Disease:

Answer 7

A diagnosis of a disease based on clinical findings, lab tests, biopsy tests and imaging.

Question 8

5. Treatment of a Disease:

Answer 8

An intervention that eliminates the disease or eliminates the symptoms of a disease

Question 9

6. Prognosis of a Disease

Answer 9

A prediction of how the disease will progress.

how quickly
how severely
how deadly

Morbidity: how many people get it
Mortality: how many people die from it

Question 10

Disease Terminology

Answer 10

1. Idiopathic Disease: cause of disease is unknown

eg/ Autoimmune diseases, scoliosis, fibromyalgia

2. Iatrogenic Disease: cause of disease is from a medical intervention

eg/ Radiation therapy or chemotherapy may cause cancer, pharmaceuticals (drugs) have many side effects and affect other organs (liver and kidneys)

3. Nosocomial Disease: cause of the disease originated in a hospital

eg/ Ventilator associated pneumonia, Methicillin resistant Staphylococcus aureus (MRSa), clostridium difficile, urinary tract infections, tuberculosis

4. Prevalence: “the proportion of cases” or how many total cases of a disease are present in a population at risk at one time (how widespread the disease is). Often expressed in cases per 10,000 or 100,000 or in a percent. EXISTING CASES

eg/ prevalence of obesity in children aged 3-4 was 12.8% in 2001

5. Incidence: “the risk of contracting the disease” or the rate of new cases of a disease that are present in a population at risk over a given amount of time. Usually expressed in cases per 10,000 or 100,000
   per year. NEW CASES

eg/ incidence of strep throat annually is 16.9 per 100,000 people.

Question 11

Iatrogenic or Nosocomial diseases in Canada:

Answer 11

7.5 adverse events per 100 admissions in hospital so 7.5%
Medical errors account for 28,000 deaths annually, third leading cause of death in Canada (from the “Canadian Patient Safety Institute”)

Question 12

Disease states:

Answer 12

1. Acute: rapid onset, short duration, usually self limiting

eg/ dehydration, allergies, infection, accidents

2. Chronic: slow, insidious onset, longer duration, often causes permanent impairment

eg/ cancer, inflammation, diabetes

3. Latent: no clinical signs yet but disease is present, if infectious this is called the incubation period
4. Prodromal: evidence of illness, but tests are not definitive
5. Syndrome: a collection of signs and symptoms that occur together in a specific disease

Question 13

Pain

Answer 13

Evidence supports massage and touch as beneficial for symptomatic reduction of pain perception.

Pain is a complex, private, abstract experience that is difficult to explain or describe to others.

It is the main symptom that causes a person to seek health care and often indicates tissue damage.

It is a tool that our bodies use to communicate to our brain that something is wrong and we must do something.

Management of pain is a major challenge.

Question 14

Pain - definitions

Answer 14

1. Allodynia: pain, generally on the skin in response to something that does not normally cause pain. Believed to be a hypersensitivity reaction.
2. Hyperalgesia: an increased pain response (pain being more painful than it should be) an enhanced sensitivity to pain
3. Paresthesia: unpleasant or painful feelings with no stimulus, usually in the peripheral, described as tingling, numbness, skin crawling or itching

Question 15

three common theories that explain pain:

Answer 15

1. Pain Gate Theory (now called the neuromatrix theory)
2. Specificity Theory of pain
3. Pattern Theory of pain

Question 16

Pain Gate Theory or Neuromatrix Theory of Pain:

Answer 16

This explains how pain is produced in the body and how it may be therapeutically managed.

Pain nerve impulses pass through “gates” at the dorsal horn of the spinal cord level to reach the lateral spinothalamic tracts that then ascend to the brain.

Two things happen next:

1. The gates block the pain nerve transmissions via large fibres in inhibitory neurons
2. The gates allow the pain to travel to the brain via pain fibres and Substance P.

When more large fibres are firing the patient experiences less pain!

Nonpainful input like massage or touch closes the “gates” at the dorsal horns of the spinal cord to painful input.

This prevents painful sensation from travelling to the central nervous system for integration and essentially blocks pain.

This explains why touch or massage being a non painful input can reduce sensations of pain.

Massage increases the large fibre activity which has an inhibitory effect on pain signals.

1. Gates open: pain travels to the brain, inhibitory interneurons are inactive, substance P is released.
2. Gates closed: pain is inhibited at the dorsal horn of the spinal cord by inhibitory interneurons that are active.

Pain is an output of the brain and is produced when the brain concludes that the body is in danger of damage and action is required.

Each individual’s sensation and reaction to pain is called the neuromatrix and is comprised of genetic neural programs, individual experiences and behaviours.

If the neuromatrix is strengthened, pain becomes chronic via nociceptors.

This means less input is required to produce pain: this is called sensitization.

Reducing pain, reduces stress.

Question 17

2. Specificity theory of pain:

Answer 17

Specific pain receptors called nociceptors transmit signals to the “pain centre” in the brain that then produces the sensation of pain.

Pain is an independent sensation with specialized sensory receptors (nociceptors) that respond to damage and connect to the brain.

Question 18

3. Pattern Theory of Pain:

Answer 18

The Pattern Theory of pain states, there are no specific pain receptors, just a difference in the patterns of existing peripheral sensory receptors.

They respond to touch, warmth and other stimuli all together to perceive pain.

The pain is produced when certain patterns of neural activity occur or reach high levels in the brain.

Question 19

Definition of Pain:

Answer 19

Physical suffering or discomfort caused by illness or injury.

Pain is what our patient says it is and it exists when the patient says it does.

Question 20

Definition of Stress:

Answer 20

Stress is defined as the body’s reaction to external or internal changes that require a response.

The reactions are physical, mental or emotional and chemical.

Our bodies release hormones (chemicals) to compensate for this stress and these hormones interfere with many normal body processes and may lead to disease.

These hormones are all produced in our adrenal glands (epinephrine, norepinephrine and cortisol).

Our immune system is also affected by stress by decreasing white blood cell (WBC) production.

These stresses could be:

1. social (from a change in a job or change in relationship)
2. psychological (from anxiety or fear)
3. physiologic (from anesthesia or pain)

Question 21

Effects of Stress Related Hormones:

Answer 21

1. Adrenaline (epinephrine) - produced in the adrenal glands

This hormone activates the arousal mechanisms in the body (fight or flight mechanisms)

2. Noradrenaline (norepinephrine) - produced in the adrenal glands

This hormone activates functions in the brain

Excessive amounts: patient is hyperactive with disturbed sleep

Insufficient amounts: patient is sluggish, drowsy and fatigued

3. Cortisol:

• This is another stress hormone produced by the adrenal glands during prolonged stress.
• Elevated levels indicate an elevated sympathetic response.
• This hormone is implicated in many stress related symptoms or diseases, such as suppressed immunity, sleep disturbances, inappropriate inflammatory responses and increases in levels of substance P; a substance that enhances pain.

Massage has been shown to reduce levels of cortisol and substance P.

Massage has a regulating effect on these hormones by stimulating or inhibiting the sympathetic nervous system.

This can wake things up in an initial reaction (sympathetic response) and then calm things down after at least 15 minutes of massage (parasympathetic response).

Question 22

Our body responds to stress in many general systemic ways

Answer 22

1. Increased heart rate
2. Contraction of the spleen
3. Release of glucose
4. Redirection of blood supply
5. Respiratory system changes
6. Decrease in blood clotting time
7. Dilation of pupils

Common Stress Responses in the body caused by fluctuations in the autonomic nervous system resulting in changes in hormones or chemical levels.

Common Stress Responses in the body caused by fluctuations in the autonomic nervous system resulting in changes in hormones or chemical levels.

irritability, hyperexcitation, depression intermittent anxiety

migraine and tension headaches
pounding heart

easily startled

premenstrual tension or absent menses
dry throat and mouth

high pitched nervous laughter

pain in neck or lower back
impulsive behaviour and emotional instability

stuttering or other speech difficulties loss of, or excessive appetite
overpowering urge to cry, run or hide grinding of teeth

increased use of drugs (tobacco, caffeine, OH)
inability to concentrate insomnia

nightmares
weakness or dizziness inability to sit still or physically relax neurotic behaviour
fatigue sweating

psychosis
tension and extreme alertness frequent need to urinate

proneness to accidents
trembling and nervous tics diarrhea, indigestion, queasiness, vomiting

Question 23

Stress Terminology:

Answer 23

Hypostress: characterized by boredom and restlessness, no stress

Eustress: moderate or normal stress interpreted as being beneficial

Hyperstress: extreme stress when overwhelmed by responsibility, may contribute to
health problems if long term

Distress: a state of severe anxiety or strain

Question 24

Types of Pain

Answer 24

1. Acute:

symptom of a disease condition that is usually temporary, acts as a warning signal (can activate the sympathetic nervous system-fight or flight), sudden onset, easily localized.

The patient can describe the pain and it often subsides with treatment.

eg/ open wound

2. Subacute:

somewhere between acute and chronic, (often is a flare up of a chronic condition).

3. Chronic:

has no purpose like acute pain, very common today, this pain persists or recurs usually lasting longer than 6 months.

Has an obscure onset and the nature of the pain can change over time. The pain is diffuse and poorly localized.

Other descriptive types of pain: nociceptive, intractable, somatic, systemic, radicular, functional, psychogenic, referred, neurogenic, radiating and phantom.

Question 25

Types of Pain

Answer 25

1. Nociceptive Pain:

Occurs when actual or threatened tissue damage occurs, a protective response

Due to activation of nociceptors, specialized pain receptors

Described as usually localized, achy, throbbing, dull, deep or pulling

Starts as acute pain and lessens with time and healing

A normal and appropriate function of the nervous system

2. Neurogenic or Neuropathic Pain:

Generated or sustained by the nervous system
An inappropriate response to damage by misreading sensory inputs

Results from nerve damage or malfunction of the nervous system

Involves problems of signals from the nerves

Always chronic and may escalate with time

Pain is described as burning, shooting, tingling and radiating

Secondary symptoms include depression (chronic pain), sleep disturbances, fatigue and decreased mental and physical functions

Common in neurodegenerative, metabolic and autoimmune diseases

Two types:

a. Central neuropathic pain - from central nervous system (eg/ a stroke)

b. Peripheral neuropathic pain - related to injury or disease in the periphery (eg/ compressed peripheral nerve)

3. Mixed Pain:

Combination of neuropathic pain and nociceptive pain.

4. Intractable Pain:

Pain that is excruciating and constant.

Can not be controlled by standard medical care like pharmaceuticals or nerve blocks.

Considered incurable.

5. Somatic Pain:

arises from the stimulation of receptors in the skin or from receptors (nociceptors) in skeletal muscles, joints, tendons and fascia.

This pain is sharp, throbbing, aching, burning and well localized.

There are two specific types:

a. Superficial somatic pain: from cutaneous or superficial structures, along myelinated “A” delta fast nerve fibres, very fast transmission: “the express highway”.

b. Deep somatic pain: from deep structures like periosteum, muscles, tendons, joints and blood vessels, along unmyelinated “C” slow nerve fibres, very slow transmission: “the dirt road”.

Referred Pain Patterns: Somatic

Dermatomes

6. Visceral Pain:

Arises from stimulation of receptors in the viscera or internal organs, usually from ischemia, or strong GI contractions or from the smooth muscles in those organs.

Pain is referred, poorly localized and it is often vague and diffuse.

Referred Pain:

• The cerebral cortex (brain) is able to locate the origin of pain based on past experiences and it accurately projects the pain in the stimulated area.

It can be somatic or visceral.

• The area to which the pain is referred and the visceral organ that is stimulated receive their nerves from the same section of the spinal cord.

Because of this the brain may misinterpret the sources.

Eg/ pain of a heart attack is felt in the skin over the heart as well as down the left arm.

When pain is referred, it is because the source is derived from the same embryonic segment as the site of pain, we call these segments dermatomes.

7. Systemic Pain (muscle pain):

Pain felt all over your body, often related to a systemic infection, a medication side effect or an underlying illness.

Eg/ muscle aches associated with influenza infection or “the flu”.