Pathophysiological Concepts Chapter 41: Structure, Function, and Disorders of the Integument

Pressure Ulcers

• Moisture from incontinence or sweating increases skin fragility.
• Risk factors for pressure ulcers include:
  • Prolonged pressure and immobilization.
  • Infrequent position changes and exposure to moisture.
  • Malnutrition and dehydration.
  • History of pressure ulcers and aging-related thin skin.

Staging of Pressure Ulcers

• Stage 1: Nonblanchable erythema on intact skin.
• Stage 2: Partial-thickness skin loss; open sore.
• Stage 3: Full-thickness skin loss; crater-like appearance with visible fat.
• Stage 4: Extensive tissue loss; exposes muscle or bone.
• Unstageable: Full-thickness loss obscured by slough or eschar.
• Deep Tissue Pressure Injury: Nonblanchable deep red discoloration; may have blood-filled blisters.

Treatment Strategies by Stage

• Stage 1: Frequent repositioning; moisture management; ensure nutrition and oxygenation.
• Stage 2: Clean wound with saline; cover with moisture-retaining dressing.
• Stage 3: Cleansing and potentially involving a wound care nurse.
• Stage 4: Dressings, debridement, and negative pressure wound therapy (NPWT).

Prevention of Pressure Ulcers

• Regular skin assessments and repositioning.
• Use specialty beds and offloading boots.
• Maintain moisture balance and ensure proper nutrition.

Skin Lesions

• Features for describing skin lesions include size, type, shape, color, surface area, and distribution.
• Primary lesions: Macule, papule, vesicle, etc.
• Secondary lesions: Scale, scar, ulcer, etc.

Scarring

• Keloids: Rounded, elevated scars extending beyond the injury site.
• Hypertrophic scars: Elevated but do not exceed the original border.

Dermatitis (Eczema)

• Characterized by itchiness and lesions with indistinct borders.
• Types include:
  • Allergic contact: hypersensitivity response.
  • Irritant contact: similar to allergic but involves irritants.
  • Atopic: often with hay fever or asthma history.
  • Stasis: related to venous stasis in legs.
  • Seborrheic: chronic inflammation affecting scalp and other areas.

Papulosquamous Disorders

• Psoriasis: Chronic inflammatory disorder, thickening dermis and epidermis, fast turnover of skin.
• Acne rosacea: Inflammation leading to flushing and sensitivity.
• Lupus erythematosus: Autoimmune disease with skin and systemic effects.

Bacterial Infections

• Types include folliculitis, furuncles, carbuncles, cellulitis, erysipelas, and impetigo.

Cellulitis

• Infection of dermis and subcutaneous tissue, marked by warmth, redness, swelling, and pain.
• Treatment: antibiotics and pain management, differentiate from necrotizing fasciitis.

Vascular Disorder - Scleroderma

• Causes thickening and hardening of the skin; can be localized or systemic.

Benign Tumors

• Seborrheic keratosis, keratoacanthoma, actinic keratosis, and nevi (moles) are types of benign skin growths.

Skin Cancer

• BCC: Most common skin cancer, grows slowly, rarely metastasizes.
• SCC: Second most common, can be linked to sun exposure.
• Melanoma: Most serious, often linked to UV exposure and family history; evaluated using the ABCDE criteria.

Kaposi Sarcoma

• Vascular malignancy associated with immunodeficiency, characterized by purplish-brown lesions.

Burns

• Caused by thermal or non-thermal sources, affecting cutaneous and respiratory systems.
• Burn classification: first-degree (epidermis), second-degree (partial thickness), third-degree (full thickness), fourth-degree (deeper tissues).
• Total Body Surface Area (TBSA) can be estimated using the rule of nines.

Fluid & Water Losses in Burns

• Major burns (>20% TBSA) cause significant fluid loss leading to hypovolemic shock.
• Intravenous fluid resuscitation is vital for recovery.

Responses to Major Burn Injury

• Cardiovascular: Decreased cardiac contractility, risk of shock if untreated.
• Cellular: Disrupted sodium-potassium pump, leading to cellular edema.
• Metabolic: Hypermetabolic response can last up to 2 years post-injury.
• Immunological: Prolonged immunosuppression, increased infection risk.

Treatment of Burns

• Goals: wound debridement, closure, nutrition support, pain management, and infection monitoring.

Cold Injury

• Types include:
  • Frostnip: Mild skin pallor, reversible.
  • Chilblain: Painful, violaceous skin changes.
  • Frostbite: Freezing injury leading to ice crystal formation; classified by depth.