Pathophysiology integumentary

• Epidermis


  Outermost layer of the skin
• Dermis


  Middle layer of the skin
• Hypodermis (subcutaneous)


  Innermost layer of the skin
• Dermal appendages


  • Nails
  • Hair
  • Sebaceous glands
  • Eccrine and apocrine sweat glands
• Blood supply


  • Limited to the dermis
  • Papillary capillaries
• Macule


  Circumscribed flat area of skin different in color and texture from its surrounding tissue, <1 cm in size
• Patch


  A large macule, >1 cm
• Papule


  Small, solid, elevated lesion, <1 cm in diameter
• Plaque


  Elevation of skin, > 1 cm in diameter, often times silvery and scaly
• Pustule


  A visible accumulation of purulent fluid under skin, < 1 cm in diameter
• Vesicle


  A circumscribed elevation of the skin containing serous fluid, < 1 cm in diameter
• Nodule


  Solid mass of skin, observed as an elevation or can be palpated, > 1 cm in diameter, often extends into the dermis
• Bulla


  Circumscribed elevation containing fluid, >1 cm in diameter, extends only into the epidermis
• Wheal


  Elevated white or pink compressible papule or plaque, a red, axon-mediated flare often surrounds it
• Cyst


  Any closed cavity/sac containing fluid or semisolid material
• Pressure Ulcers


  Ischemic ulcers resulting from any unrelieved pressure on the skin, causing underlying tissue damage
• Causes of pressure ulcers

  • Pressure
  • Shearing forces
  • Friction
  • Moisture
• Stages of pressure ulcers

  • Stage 1: Non-blanchable erythema of intact skin
  • Stage 2: Partial-thickness skin loss involving epidermis or dermis
  • Stage 3: Full-thickness skin loss involving damage or loss of subcutaneous tissue
  • Stage 4: Full-thickness skin loss with exposure of muscle, bone, or supporting structures
  • Suspected deep tissue injury: Discolored (purple or maroon) intact skin or blood-filled blister
  • Unstageable: Full-thickness tissue loss with base of ulcer covered by slough or eschar, or both
• Preventive techniques for pressure ulcers


  • Frequent skin assessment
  • Repositioning every 2 HOURS
  • Pressure reduction, removal, and distribution
  • Elimination of moisture
  • Optimize nutrition and hydration
• Eczema (atopic dermatitis)


  Inflammatory process causes erythema of the skin, characterized by severe pruritus (itching), lesions with indistinct borders, epidermal changes, and when chronic, the skin becomes thickened, leathery, and hyperpigmented from recurrent irritation and scratching (lichenification)
• Contact dermatitis (allergic and irritant)

  Inflammatory process where CD4 and CD8 T lymphocytes are responsible, caused by allergic agents like antimicrobials, anesthetics, hair dyes, preservatives, latex, adhesives and from plants in the Rhus genus, or irritant agents like soaps, detergents, organic solvents
• Psoriasis


  Chronic, relapsing, proliferative, inflammatory skin disorder caused by complex interactions between macrophages, fibroblasts, dendritic cells, natural killer cells, T-helper, and regulatory T cells, showing evidence of dermal and epidermal thickening, with epidermal turnover going from 14 to 20 days to 3 to 4 days, resulting in erythematous plaques surrounded by thick silvery scales
• Psoriasis pathophysiology


  Activated T-cells release growth factors, causing keratinocytes and blood vessels to grow, creating papules, which attract neutrophils and monocytes that enter the papules and create inflammation
• Pityriasis rosea


  Benign, self-limiting inflammatory disorder caused by a virus, usually occurring during the winter months, with a herald patch (circular, demarcated, salmon-pink, 3- to 10-cm lesion) and secondary lesions developing within 14 to 21 days and extending over the trunk and upper part of the extremities
• Tinea infections


  Superficial fungal infections caused by dermatophytes that attack the dead cells, resulting in an inflammatory reaction
• Types of tinea infections

  • Tinea capitis (scalp)
  • Tinea manus (hand)
  • Tinea pedis (foot, athlete's foot)
  • Tinea corporis (ringworm)
  • Tinea cruris (groin, jock itch)
  • Tinea unguium (nails) or onychomycosis
• Cellulitis


  Infection of the dermis and subcutaneous tissue
• Impetigo


  Superficial infection of the skin caused by Staphylococcus or Streptococci, highly contagious, with honey-colored crust with a moist erythematous base
• Human papillomavirus (HPV)


  Causes common warts, plantar warts, and condylomata acuminata (anogenital warts)
• Herpes simplex virus (HSV)


  HSV-1 associated with oral infections or infection of the cornea, mouth, and orolabial, with inflamed and painful vesicles, while genital infections are more commonly caused by HSV-2
• Herpes zoster (shingles) and Varicella (Chicken pox)

  Caused by the same virus - varicella-zoster
• Skin infections: fungal, bacterial and viral

  • Cellulitis: Infection of the dermis and subcutaneous tissue
  • Impetigo: Superficial infection of the skin, caused by Staphyococcus or Streptococci, highly contagious, with honey-colored crust and moist erythematous base
• Skin infections: fungal, bacterial and viral

  • Human papillomavirus (HPV): Common warts, usually on fingers, plantar warts on pressure points on bottom of feet, condylomata acuminata (anogenital warts, sexually transmitted)
• Skin infections: fungal, bacterial and viral

  • Herpes simplex virus (HSV-1 and HSV-2): Associated with oral infections or infection of the cornea, mouth, and orolabial, inflamed and painful vesicles
  • Herpes zoster (shingles) and Varicella (Chicken pox): Caused by the same virus - varicella-zoster virus (VZV), primary infection followed years later by activation of the virus to cause herpes zoster (shingles), virus remains latent in trigeminal and dorsal root ganglia
• Skin conditions


  • Warts
  • Varicella
  • Impetigo
  • Herpes simplex
• Benign Tumors


  • Actinic keratosis: Premalignant lesion composed of aberrant proliferations of epidermal keratinocytes
  • Nevi (moles or birthmarks): Benign pigmented or non-pigmented lesions
• Skin Cancer


  • Basal cell carcinoma: Most common cancer in the world, red macule or papule and may develop a depressed center, grows slowly, often ulcerates, develop crusts, and is firm to the touch, metastasis is rare
  • Squamous cell carcinoma: Usually in sun exposed areas, second most common human cancer, in situ or invasive, may occur as a result of actinic keratosis (premalignant lesion)
  • Malignant melanoma: Malignant tumor of the skin originating from melanocytes, most serious skin cancer, ABCDE approach to evaluate (Asymmetry, irregular Borders, variation in Color, Diameter ≥6 mm or different from other moles, Elevation or Evolution)
• Sun exposure


  • Increases the risk of skin cancer
  • Cumulative sun exposure increases the risk of basal cell carcinoma and squamous cell carcinoma
  • Severe sun exposure with blistering increases the risk of malignant melanoma
• Burns


  • First degree: Superficial, epidermis only, local pain and erythema, blanches with pressure, no blisters, heal in 3-6 days with no scarring
  • Superficial partial thickness: Epidermis and some dermis, blisters and heals in 10-21 days
  • Deep partial thickness: Epidermis and deeper dermis, blisters, heals in 2-6 weeks, usually without scars, wet or waxy dry, most painful
  • Full thickness: Epidermis, dermis, and underlying subcutaneous tissue, wound dry and leathery as eschar develops, without blisters, painless, escharotomies performed to release pressure and prevent compartment syndrome
  • Fourth degree: Full-thickness and deeper tissue, epidermis, dermis, and underlying subcutaneous tissue, tendons, muscle, and bone
• Escharotomy


  To prevent compartment syndrome