1. Introduction: Chapter 1
Human Diseases
Introduction: Chapter 1

2. Definitions
Disease
Disorder or cessation of body functions, systems or organs having at least 2 of the following:
Recognized etiology
Identifiable group of symptoms and signs
Consistent anatomic alteration

3. Definitions Illness Syndrome
Condition of the patient experiencing the disease
Syndrome
Group of signs & symptoms associated with any disease that together constitute a picture of that disease

4. Definitions Symptom Sign Complaints of the patient Subjective
Abdominal pain, shortness of breath, etc.
Sign
Physical findings
Objective
Labored respirations, pallor, etc.

5. Disease Categories According to etiology (cause)
Infectious, traumatic, hereditary, etc
According to body system involved
Cardiac, respiratory, dermatologic, etc

6. Disease Categories Acute vs. chronic Multiple system vs. single system
Focal vs. diffuse
Organic vs. psychological
Age group (pediatric vs. geriatric)

7. How a diagnosis is made SOAP format S = subjective = symptoms
Patient complaints and observations
O = objective = signs
Physical exam, tests by examiner
A = assessment (suspected diagnosis)
Differential diagnoses
P = plan (further tests & treatment)

8. Etiology The cause of the disease Many diseases are multifactorial
More than one causal factor
Adult onset diabetes, addictions
Predisposing factors:
Condition making a person more susceptible to developing a disease
Hypertension, diabetes, colon polyps, etc

9. Hereditary Diseases Due to abnormalities of DNA or chromosomes
Not the same as congenital disease
Recognizable at birth
May affect any or multiple organ systems, various severities
May not be apparent at birth

10. Terminology: Genetics
Chromosome
23 pairs, counting 2 sex chromosomes
Homozygous
Heterozygous
Genotype
Phenotype
Mutation

11. Hereditary Diseases: Categories
Mendelian alterations
One gene involved
Chromosomal alterations
Part or all of a chromosome involved
Multiple genes involved
Multifactorial errors

12. Mendelian Disorders Mutation in a single gene Subcategories: Recessive
Dominant
Sex-linked
Autosomal

13. Mendelian Disorders Autosomal disorders
Two identical copies of a gene exist
Recessive disease
Will not manifest if there is at least one normal copy of the gene
Dominant disease
Will manifest if there is even one abnormal copy of the gene

14. Autosomal Disorders: Examples
Autosomal Recessive
Cystic fibrosis, Tay-Sachs disease, PKU, cretinism, sickle cell anemia
Autosomal Dominant
Diabetes insipidus, retinoblastoma

15. Other Mendelian Disorders
Sex-linked or X-linked
Hemophilia
Duchenne’s Muscular Dystrophy

16. Hereditary Diseases: Chromosomal
Abnormalities in chromosome number or chromosome structure
Mechanisms of these alterations:
Additions
Deletions
Translocations

17. Chromosomal Diseases: Examples
Trisomy 21 (Down Syndrome)
Klinefelter’s Syndrome (XXY)
Turner’s Syndrome (missing X)

18. Disease Category: Inflammatory
Inflammation
Cascade of numerous chemical reactions
Increase local WBC and edema
Acute or chronic
Response to many stimuli
Physical agents, toxins, infections, trauma, allergens, chemicals

19. Inflammatory Diseases
Signs and Symptoms
Edema
Erythema
Pain/tenderness
Warmth
Variable loss of function

20. Disease Category: Infectious
Infection:
Invasion and multiplication of pathogenic organisms in the body
Bacteria, viruses, rickettsiae, fungi, protozoa, parasites
Vs. non-pathogenic organisms
Overgrowth = pathological

21. Infectious Agents Bacteria (bacterium)
Single celled organism capable of reproduction, DNA, RNA, & protein synthesis.
Gram negative or gram positive in color
Cocci, bacilli, or spiral in shape
May be pathogenic or nonpathogenic

22. Infectious Agents Rickettsiae (rickettsia)
A genus of bacteria (Rickettsiales)
Obligate intracellular parasites
Arthropod vectors usually
Typhus, Rocky Mtn. Spotted Fever, etc

23. Infectious Agents Protozoa Unicellular animal-like microorganisms
Phylum Protista
Saprophytes often
Live on dead tissue
Fecal-oral route, food or water contaminated with cysts/spores, insect bite
Malaria, giardia, sleeping sickness

24. Infectious Agents Virus Smallest microorganisms
A nucleic acid inside a protein shell
Reproduces only after infecting host cell
Classified by
DNA vs. RNA
Reproductive method (retrovirus)
Mode of transmission (enterovirus)
Etc.

25. Infectious Agents Fungi (fungus) Yeast, mold, or mushroom
Belongs to the kingdom Fungi
Candidiasis, Valley Fever, aspergillosis

26. Disease Category: Trauma
Physical, chemical, radiation injury
Usually physical mechanism
Effects of external force applied to the body
Categories:
Blunt or penetrating
According to body part affected
Physical, chemical, radiation

27. Trauma May cause shock Shock Hypoperfusion state
Classical signs and symptoms
Tachycardia
Hypotension
Pallor
Altered mental status/consciousness

28. Head Trauma Skull fractures Cerebral contusions Concussion
Often “protective”, less force transmitted to brain
Categories: open, closed, basilar
Cerebral contusions
Contusion of brain
Concussion
Alteration in function of brain without visible damage to brain

29. Head Trauma Intracranial hemorrhages Intracerebral- inoperable
Subarachnoid-nuchal rigidity
Epidural-lucid period
Subdural-most common ICB

30. Chest Trauma Rib fractures Pneumothorax Hemothorax
flail
Pneumothorax
“collapsed lung”, abnormal air collection in between the pleura
Hemothorax
Injury to heart, esophagus, lungs, major vessels

31. Abdominopelvic Trauma
Blunt
Liver and spleen most commonly injured
Penetrating
Small intestine most commonly injured
Major considerations:
Hemorrhage and infection (spillage of GI contents and nonpathogenic bacteria)

32. Spinal Trauma
Cervical spine trauma commonly associated with head trauma
Typical signs and symptoms:
Paresis or paralysis below injury level
Loss/alteration in sensation below injury level
Some autonomic (ANS) loss also

33. Extremity Trauma
May be fractures, dislocations, soft tissue or skin injury
May be associated with major disability
May be associated with nerve or blood vessel disruption

34. Environmental Diseases
Conditions caused by the effects of various components of the environment
Heat or cold
Radiation
Chemicals
Bariatric (atmospheric pressure)
Electrical injury
Animals, insects, marine life
Submersion or drowning

35. Environmental Diseases
Heat-related diseases
Prickly heat-rash, blockage of sweat pores
Heat edema
Heat syncope
Heat cramps
Heat tetany
Heat exhaustion-temp nl to 104
Heat stroke- temp over 105, altered mental status

36. Environmental Diseases
Cold-related diseases
Hypothermia-temp less than 95 degrees
Chilblains-damp, nonfreezing exposure
Trench foot-nonfreezing, water exposure
Frostbite-freezing, ice crystals in tissues
Frostnip-superficial injury, no ice crystals

37. Bariatric Diseases Low Pressure High Pressure Altitude diseases
Hypoxia, pulmonary HTN, Acute Mountain Sickness, HAPE, HACE
High Pressure
Air embolism, nitrogen narcosis
Decompression sickness
Nitrogen bubbles in blood & tissues
The “bends” = musculoskeletal form

38. Electrical Injuries Electric shock
May be due to natural (lightning strike) or man-made sources
Major effects:
Internal and external burns
Cardiac dysrhythmias
Local injuries/path of electrical current

39. Toxicology/Poisoning
Purposeful exposure
Suicide attempts
industrial exposure
Accidental exposure
Childhood ingestions
Theraputic medication errors
Occupational/industrial exposure

40. Toxicology Bimodal peaks of overdoses according to age
Toddler age group
adolescence
Supportive care usually the key to treatment and survival
Antidotes are rare.

41. Drowning
Hypoxemia caused by obstruction of airway by laryngospasm and fluid while patient is submerged.
Fresh vs. salt vs. chlorinated water
Often associated with hypothermia.
Other complications, e.g. aspiration pneumonia
Higher survival rates in children.
Association with diving accidents.
Spinal trauma and other injuries

42. Bites and Stings Most commonly fatal sting in US: Black Widow Spider
Hymenoptera (bee sting)
Allergic etiology
Black Widow Spider
Local muscle cramping generalizes
Abdominal findings, severe pain
HTN in 10-30%, some with coma, shock, & respiratory failure

43. Bites and Stings Brown Recluse Spider
Local effects: erythema, blisters, spreading necrosis
Varies with amount of envenomation

44. Asphyxiation Cessation of oxygenation Also carbon dioxide accumulation
Variable etiologies
Drowning
Airway obstruction
Hypoventilation
Toxic inhalational injuries

45. Burns Categorized by depth Percentage of TBA (total body surface area)
Rule of Nines (modified for pediatrics)
Prognosis
Varies with depth and TBSA involved

46. Immune-Related Diseases
Basic categories of immune diseases
Immune deficiency
Deficient protection against invading organisms
May be iatrogenic
Allergy/anaphylaxis
Activation of inflammatory/histamine reactions
Autoimmunity
Immune system reacts against the patient as if he/she is an invading organism

47. Immune System Concepts Review
Congenital or acquired
Humoral
Immunoglobulins (Ig’s)
Circulating proteins, rapid response
Cellular
T-cells, B cells & others
Tissue response mostly
Often delayed (takes days)

48. Immune System Review Vocabulary Phagocytosis Antibody Antigen
Macrophages
anaphylaxis

49. Allergic Symptoms Skin Respiratory Life-threatening Urticaria, wheals
Erythema, pruritis
Respiratory
Airway edema, obstruction, stridor
Wheezing, asthma, dyspnea
Life-threatening
Anaphylactic shock

50. Autoimmune Diseases Can affect any body system
Often affect multiple systems
Often unpredictable course
Exacerbating and remitting
Examples:
Ulcerative colitis, primary biliary cirrhosis, hemolytic anemia, ITP, Hashimoto’s thyroiditis, etc

51. Immunodeficiency Diseases
Involve impaired resistance to infection
Often have recurrent or opportunistic infections
Examples:
AIDS, Hodgkin’s lymphoma

52. Nutritional Diseases Deficiencies of some elements of diet
Vitamins, protein, minerals, etc
Excesses of some elements of diet
Same as above
Malnutrition
Obesity

53. Malnutrition Condition in which body is not getting enough nutrients
Varies from mild to life-threatening
Variety of etiologies:
Improper quality & quantity of food
Malabsorption, anorexia, loss of taste or smell senses, drug-food interactions
Increased metabolism or need for fuel (certain disease states e.g. trauma, burns, cancers)

54. Types of Malnutrition Kwashiorkor Marasmus Starvation
Protein-calorie malnutrition, poor protein intake compared to calories, S/S: protuberant abdomen
Marasmus
Severe malnutrition in children, mostly calorie deficiency, first year of life, disease or parasitic infestation = usual cause
Starvation
Lack of all/most nutrients needed to preserve life

55. Vitamin Deficiency Scurvy = vitamin C deficiency
Fatigue, weakness, aches, gum bleeding
Rickets = Vitamin D deficiency
Bone pain & weakening, deformities
Beriberi = thiamin (B1) deficiency
Diets with polished rice
Nerve & cardiac damage, lassitude, anorexia

56. Obesity Accumulation of excess fat rather than excess weight alone
BMI (body mass index) over 30
Measure of weight relative to height
Over 50% adults and 20% children in US are overweight, 33% are obese
2nd leading cause of preventable death in US (tobacco is #1)

57. Other categories: Idiopathic Iatrogenic Of unknown etiology
Caused by medical treatment

58. Vitamin Deficiency Pellegra = niacin (vit B3) deficiency
Also protein deficiency (tryptophan is an essential AA)
Diet often relies on corn
The Four D’s
Diarrhea
Dermatitis
Dementia
death