Infection, Inflammation and Effects of Stress

• Pathogens’ ability to cause severe disease: virulence

Stages of Infection

• Initial exposure to first symptoms: incubation
• Pathogen multiplication and symptoms: prodromal (cough, sore throat)
• Fast pathogen replication and severe symptoms: invasion (fever, chills)
• Healing or death: convalescence

Inflammation Signs and Symptoms

• Acute/local inflammation: redness (erythema), swelling, warmth, pain, tenderness, loss of function
• Systemic inflammation: fever, chills, diaphoresis/sweat, elevated WBC

Bacterial Infections

• Pathophysiology: endotoxins lead to inflammation, treated with antibiotics
• Bacteremia: bacteria in the blood
• Septicemia: fever, chills, sweat lead to DIC and shock

Viral Infections

• Viruses need a host and antibiotics are of no use

Effects of Stress

• Sympathetic nervous system activation (fight or flight) causes high BP, high HR (tachycardia), and high glucose levels
• Long-term effects: cardiovascular disease, atherosclerosis, obesity, metabolic syndrome, decreased bone density, and shortened telomeres

Hypersensitivity Reactions

• Type I: IgE mediated, fast response (minutes), allergic reactions (asthma, allergic rhinitis)
• Type II: IgG, IgM mediated, intermediate response, antibodies attack body cells directly (rheumatic heart disease, autoimmune hemolytic anemia)
• Type III: IgG, IgM mediated, intermediate response, complex accumulation and destruction (rheumatoid arthritis, poststreptococcal glomerulonephritis)
• Type IV: T helper cells (Th1) mediated, late response (48-72 hours), cell-mediated cytotoxicity (transplant rejection, contact dermatitis)

Lab Values Importance

• WBC (White Blood Cells):
  • Normal range: 5,000-10,000/mcL
  • High (>10,000): leukocytosis (infection)
  • Low (<5,000): leukopenia (radiation/chemo, immunodeficiencies, bone marrow suppression)
  • Neutrophils increase with infection; normal ANC: 3,000-7,000
• Erythrocytes (RBCs) (Red Blood Cells):
  • Normal range: 4-6 million/mcL
  • High: polycythemia vera
  • Low: anemia
• Platelets (PLT):
  • Normal range: 150,000-400,000/mcL
  • High (>400,000): thrombocytosis (clotting leads to DVT)
  • Low (<150,000): thrombocytopenia (anti-coagulation, bleeding, causes may include DIC, HIT, ITP, medications)
• Hemoglobin: Normal range 12-18 g/dL
• Hematocrit: Normal range 37-50%, approximately 3x hemoglobin value

Complete Blood Count (CBC)

• WBC: Normal range 5,000-10,000/mcL
• RBC: Normal range 4.5-5.5 million/mcL
• Hemoglobin: Normal range 12-18 g/dL
• Hematocrit: Normal range 37-50%
• Platelet: Normal range 150,000-400,000/mcL

Conditions

• Idiopathic Thrombocytopenic Purpura (ITP): Autoimmune, IgG against platelets, symptoms include hemorrhage, bruising, petechiae, purpura
• Immunodeficiency: Increased risk for infection and cancer due to weakened immunity, prevent with handwashing
• Spleen function: Filters blood and removes damaged RBCs
• Cancer: Inflammation causes DNA mutation and loss of apoptosis, leading to uncontrolled growth
• Leukemia: Cancer of bone marrow affecting blood cells, exhibits low WBC (leukopenia), platelets (thrombocytopenia), RBC (anemia), fever from infection, weight loss, bleeding, pallor, fatigue, chemotherapy
• Lymphoma: Cancer of the lymphatic system
  • Hodgkin Lymphoma: Manifests as fever, weight loss, night sweats, painless swollen lymph nodes, diagnostic marker is Reed-Sternberg cells
  • Non-Hodgkin Lymphoma: Group of symptoms
• Benign Neoplasms/Cancers: Non-cancerous, well-differentiated, no metastasis, slow growth, encapsulated, harmful if in brain, vessels, nerves
• Malignant Neoplasms/Cancers: Cancerous, multi-colored, not well differentiated, no capsule, rapid growth, metastasizes
• DIC (Disseminated Intravascular Coagulation): Clotting and bleeding at the same time due to sepsis, infection, shock, symptoms include pallor, bleeding, bruising and hematoma, treated by addressing the cause with antibiotics or fluids
• HIV/AIDS: CD4 count <200, immunodeficiency increases cancer/infection incidence
• Cancer Risk Factors: Smoking, sun exposure, diet, alcohol, obesity, genetics
• **Cancer Warning Signs:**Unexplained weight loss, bleeding, fatigue; new growths or moles; changes in bowel or bladder habits, non-healing sores and infections.
• Lifestyle changes for cancer prevention exercise, no smoking, improve diet, limit alcohol, sunscreen, screenings
• Angiogenesis: Tumor related, growth of blood vessels to get nutrients
• Pernicious Anemia: Lacking intrinsic factor leads to B12 deficiency, treat with lifelong B12 injections
• Sickle Cell Anemia: Abnormal hemoglobin, abnormal RBC shape.
  • Symptoms: paresthesia/neuro changes, sore cracked tongue
  • Vaso-occlusive crisis: clumping of sickle cells leads to vessel occlusion leading to pain, ischemia
• Polycythemia Vera: High RBC, platelets/thrombocytosis, WBC/leukocytosis increases blood viscosity leading to clot risk
• Iron Deficiency Anemia: Most common anemia, symptoms: koilonychia, fatigue, SOB, pallor and weakness, caused by low hemoglobin from poor diet, bleeding or menstruation

Musculoskeletal Conditions

• Bone Cells:
  • Bone producing: osteoblasts
  • Bone cells: osteocytes
  • Bone breaking: osteoclasts
• Fractures and Infection Risk:
  • Simple (Closed) Fracture: low infection risk, skin intact
  • Compound (Open) Fracture: high infection risk, skin broken, bacteria enter
• Fracture Types:
  • Comminuted: shattered
  • Greenstick: broken on one side
  • Transverse: straight across
  • Oblique: diagonal
  • Spiral: twisting force
  • Compression: crushed
  • Stress/fatigue: hairline, tiny
  • Pathologic: weakening of bone
  • Occult: hidden, suspected
• Fracture Signs/Symptoms: Pain, tenderness, swelling, decreased mobility, numbness due to nerve trauma, muscle spasms, unaligned
• Dislocation: Total dislocation of bones within joints
• Compartment Syndrome: High pressure in muscle compartment, compromising vascular supply
  • Symptoms: pallor, pain, paresthesia, pulselessness, paralysis, pressure
  • Pulselessness -> pallor -> pressure -> pain -> paresthesia (numbness) -> paralysis
  • Risks: casts too tight, crush injuries lead to rhabdomyolysis
• Osteoporosis: Low bone mineralization, osteoclasts break down quicker than osteoblasts
  • Caused by: vitamin D deficiency, inactivity, steroids and menopause
  • Higher Fracture risk
  • Treat with weight-bearing exercises
• Gout: Overproduction of uric acid causes build up in joints.
  • Symptoms: pain, redness, swelling, tophi and renal stones
  • Triggered by: alcohol, aged cheeses, organ meats, and shellfish
  • Occurs more in males
• Rhabdomyolysis: Rapid breakdown of muscle tissue leaks myoglobin into bloodstream lead to kidney damage.
  • Caused by: crush injuries, overworking muscles, bedrest, dehydration and seizures
  • Elevated Creatine Kinase (CK)
  • Dark urine, muscle soreness/weakness
  • Treat by addressing the causes and providing fluids
• Fibromyalgia: Autoimmune, chronic pain makes diagnosis hard. - Symptoms: neuropathic pain, fatigue, tender points, and anxiety/depression
• Osteomyelitis: Bone infection results often from bacteria, open fractures and surgeries
  • Symptoms: low grade fever, lymphadenopathy, pain, swelling and fatigue
• Osteomalacia/Rickets: Inadequate bone mineralization
  • Caused by: Vitamin D deficiency
  • Symptoms: bone malformation, pain, fractures, and vertebral collapse
• Rheumatoid Arthritis (RA): Autoimmune inflammation of synovial fluid in joints - Genetic, affects women more - Symptoms: bilateral stiffness, tenderness, pain that improves w/ use, deviated joints
• Osteoarthritis (OA): Loss/damage of cartilage, bone-on-bone - Symptoms: unilateral pain with movement that improves with rest, Bouchard's and Heberden's nodes - Caused by: aging, wear/tear, increased weight, trauma
• Osteosarcoma: Bone cancer, also caused by aging and radiation
• Pressure Ulcers: Pressure over bony prominence
  • Caused by: bedrest, immobility, moisture, and friction
  • Pressure Ulcer Stages
    • Stage 1: non-blanchable redness, intact skin
    • Stage 2: epidermis and/or dermis, skin open, red or pink wound bed
    • Stage 3: full thickness skin loss, with fat present, no bone or muscle present
    • Stage 4: full thickness down to bone or muscle exposed
    • Unstageable: wound covered by slough or eschar, can't see wound bed
    • Deep Tissue Injury: discoloration (purple)
    • Prevention: Q2 turns, keep them dry, avoid friction, skin assessment

Burns

• First Degree: Epidermis, sunburn-like, redness, dry, painful
• Second Degree: Epidermis and dermis, red, moist/blisters, swelling, very painful
• Third Degree: Epidermis, Dermis, some subq, painless, white, shiny, looks charred
• Fourth Degree: All layers down to the bone, exposed muscle, bone
• Shock (due to burns): "Reduction in volume of perfusing blood" and destruction of vessels causes: decreased LOC, pale skin, hypotension, tachycardia, coolness to the touch
• Treatment (Burns): Aggressive IV Fluids, Nutrition, Infection Prevention and Wound Management
• Basal Cell Carcinoma: slow growing, ulcer/crusty looking
• Squamous Cell Carcinoma: raised pearl with defined boarders
• Melanoma: asymmetrical, uneven/irregular borders; different colors, large diameter
• Metastasis: Cancer Spreads
• Scleroderma: Thickening of the skin, hard, hypopigmented, taut
• Cellulitis: Infection of the dermis and subq, warm, pain, erythema, edema, marked redness, spreads rapidly
• Candidiasis: Opportunistic fungal infection, dark/moist environments (mouth, vagina, skin, GI), caused by antibiotics, warm climate, pregnancy, diabetes, weakened immunity
• Herpes:
  • HSV1: Oral
  • HSV2: Genital
  • Singular painful inflamed vesicles

Varicella-Zoster Virus (VZV)

• Chicken Pox/Shingles- reactivated when immune system is weak
• Painful fluid-filled vesicles around a dermatome, usually only appearing on one side of body
• Hair Loss
  • Alopecia: Generic Hair Loss
  • Hirsutism: male pattern hair growth on females
  • Androgenic: related to androgen levels to male pattern of baldness
  • Female pattern alopecia: thinning of hair
• Lupus (SLE) : autoimmune, systemic, butterfly rash on face; triggers include: trauma, viral, pregnancy, and autoimmune
• Stevens-Johnsons/Toxic Epidermal Necrosis: Peeling skin (like a red burn), an immune cell mediated hypersensitivity reaction to certain drugs.