2. Basics of disease - terminology and classification

Question 1

What are the three definitions for disease from Stedman’s Medical Dictionary 27th ed’n?

Answer 1

1. An interruption, cessation or disorder of body function, system or organ
2. A morbid entity characterized usually by at least two of these criteria:
   
   1. recognized etiologic agent(s)
   2. identifiable group of signs and symptoms
   3. consistent anatomic alterations
3. Literally, dis-ease, opposite of ease when something is wrong with bodily function

Question 2

Define:

Organic Disease

Functional Disease

Answer 2

• Organic disease:
  
  • A disease in which there are anatomic or pathophysiologic changes in some bodily tissue or organ
  • Examples include: Irritable bowel syndrome (IBS) Chronic fatigue syndrome (CFS) Fibromyalgia
• Functional Disease:
  
  • Relating to a function
  • Not organic in origin; denoting a disorder with no known or detectable organic basis to explain the symptoms
  • Psychiatric illnesses are also largely considered functional since we cannot readily identify their underlying cause.

Question 3

Define:

• Disorder

Answer 3

Disorder: disturbance of function, structure or both, resulting from a genetic or embryonic failure in development OR from exogenous factors (eg poison, trauma, disease)

Question 4

Define:

Syndrome:

Answer 4

Syndrome: The aggregate of symptoms and signs associated with any morbid process, and constituting together the picture of disease

Question 5

Define Morbid

Answer 5

Diseased or pathologic

Question 6

Define Illness

Answer 6

• Can be: Synonym for disease
• Often refers specifically to the patients personal experience of their disease\

Question 7

Define:

• Symptom
• Asymptomatic
• Clinical

Answer 7

• Symptom
  
  • Manifestation of disease that patient experiences
• Asymptomatic
  
  • disease is present as evidenced by abnormal tests but without patient disability
• Clinical
  
  • Relating to bedside (direct care) of pt
    
    • Denoting findings or observations seen in the pt as opposed to laboratory findings

Question 8

Define:

• Systemic
• Etiology
• Diagnosis
• Prognosis

Answer 8

Define:

• Systemic
  
  • Affecting the entire body (vs localized)
• Etiology
  
  • The cause of a disease
• Diagnosis
  
  • The determination of the cause of the disease using history, clinical examination, and diagnostic modalities including labs and imaging
• Prognosis
  
  • The probable outcome or course of a disease

Question 9

What does -itis mean?

Answer 9

Refers to inflammation; ie a response to an agent that causes cell injury (physical, chemical, biological)

• Exudation of cells and fluids from the blood to the tissue leading to characteristic five cardinal signs of acute inflammation:
  
  • Dolor (pain)
  • Calor (heat)
  • Rubor (redness)
  • Tumor (swelling)
  • Functio laesa (loss of function)

Question 10

What are the characteristic five cardinal signs of acute inflammation?

Answer 10

• Exudation of cells and fluids from the blood to the tissue leading to characteristic five cardinal signs of acute inflammation:
  
  • Dolor (pain)
  • Calor (heat)
  • Rubor (redness)
  • Tumor (swelling)
  • Functio laesa (loss of function)

Question 11

What is an eponym and what is their current status in medicine?

Answer 11

Name [of disease/disorder] derived from (usually) a person

eg) Trisomy 21 preferred over Down Syndrome

Wegener’s granulomatosis renamed granulomatosis with polyangiitis

Question 12

Define:

• Specimen
• Analyzer
• Assay
• Biomarker

Answer 12

Define:

• Specimen
  
  • Sample (tissue, body fluid etc) obtained from patient for lab testing
    
    • eg biopsy
• Analyzer
  
  • An instrument (machine) that analyzes a specimen for an analyte
• Assay - used to measure the analyte
  
  • An analytic procedure to detect or measure something
  • Can have different assays to measure the same analyte
• Biomarker
  
  • A biologically derived something that can be objectively measured an which tells you something about a process or condition
    
    • ie indicates the presence or severity of disease
    • can be metabolic, genetic, molecular

Question 13

What are 9 (sometimes overlapping) ways diseases are classified?

Answer 13

1. Congenital and hereditary disease
   
   • trisomy 21, birth defects due to maternal infection
2. Inflammatory/immunological disease
   
   1. systemic lupus erythematosus, inflammatory bowel disease
3. Infectious disease
   
   1. Tuberculosis, measles, HIV
4. Degenerative disease (osteoarthritis, atherosclerosis, alzheimers)
5. Metabolic disease
6. Neoplastic disease (typically referencing cancer; lipoma, adenocarcinoma of colon
7. Environmental disease (heavy metal toxicity, tobacco, or alcohol-related disease
8. Iatrogenic - result of treatment for something else
   
   1. Medication side effect, inadvertent injury during surgery
9. Idiopathic: “no idea the cause”
   
   1. denoting a disease of unknown cause, appears to arise spontaneously
   2. Impedes curative treatment and development of targeted therapies for the disease
   3. in children, risk of recurrence in other child(ren) is unknown