Week 5 Powerpoint Chapter 46

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Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Chapter 46 Disorders of Skin Integrity and Function

Transcript of Week 5 Powerpoint Chapter 46

Page 1: Week 5 Powerpoint Chapter 46

Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins

Chapter 46

Disorders of Skin Integrity and Function

Page 2: Week 5 Powerpoint Chapter 46

Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins

Skin Infections• Superficial fungal infections

– Examples: Ringworm, athlete’s foot

– Attack the keratinized (dead) cells

– Inflammatory reaction to toxins causes most signs and symptoms

• Deep fungal infections

– Examples: Candidiasis, sporotrichosis

– Attack living tissue

– May attack other organs

Page 3: Week 5 Powerpoint Chapter 46

Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins

Bacterial Skin Infections

• Impetigo

– May lead to post-streptococcal hypersensitivity reactions

– These can cause glomerulonephritis

• Remember “acute post infectious glomerulonephritis”?

Page 4: Week 5 Powerpoint Chapter 46

Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins

Viral Skin Infections

• Verrucae (warts)

– Benign neoplasms (papillomas)

• Herpes simplex (cold sores)

• Herpes zoster (shingles)

– Herpes invades dorsal root ganglia

– Caused when chickenpox herpesvirus is reactivated

– Travels out nerve to skin and causes a new inflammation

Page 5: Week 5 Powerpoint Chapter 46

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Question

Which of the following microbes cause warts?

a. Fungus

b. Virus

c. Bacteria

d. Any of the above may cause warts.

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Answer

b. Virus

Warts are caused by viruses; they’re benign neoplasms (abnormal tissue growths).

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Acne

• Disorder of sebaceous glands

• Related to:

– Hormonal stimulation of sebaceous glands

– Increased number of sebaceous cells

– Increased sebum production

– Inflammatory response to bacteria in sebum

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Allergic and Hypersensitivity Dermatoses

• Type I allergies

– Atopic eczema

• Chronic inflammatory

• Pruritic

– Urticaria (hives)

• Edematous wheals

• Can be acute or chronic

• Many causes, known and unknown

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Type I AllergiesType I allergies are mediated by IgE

Consider these questions:

• What cells must be involved in this process?

– On the first exposure to the allergen?

– On repeated exposure?

– When the allergen binds to IgE?

• What inflammatory mediators are involved? How?

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Question

Which chemical mediator is released by mast cells as part of the inflammatory response?

a. Histamine

b. Leukotriene

c. Cytokine

d. All of the above

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Answer

a. Histamine

Histamine (stored in mast cells) is one of the first substances to be released during the inflammatory response. Histamine release results in bronchoconstriction, mucosal edema, and increased mucus production.

Page 12: Week 5 Powerpoint Chapter 46

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Drug-Induced Skin Eruptions

• Erythema multiforme

– Occurs after herpes simplex; self-limiting

• Stevens-Johnson syndrome

– Skin detaches from body surface; <10% of body affected

• Toxic epidermal necrolysis

– >30% of epidermis detaches

– 30%–35% mortality rate

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Papulosquamous Dermatoses

• Psoriasis

• Pityriasis rosea

• Lichen planus

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PsoriasisActivated

T cells

growth factors

keratinocytes and blood

vessels grow

create papules

attract neutrophils

and monocytes

enter the

papules

create inflammation

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Burns

• First-degree: outer layers of epidermis

• Second-degree: epidermis and dermis

– Partial-thickness: only part of dermis

– Full-thickness: entire dermis

• Third-degree full-thickness

– Extends into subcutaneous tissue

– May damage muscle, bone, blood vessels

Page 16: Week 5 Powerpoint Chapter 46

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Scenario

Mr. D was boiling water and the pot tipped over on him…

• He has painful, bright pink, blistering burns over most of his left arm and chest

Question

• How would you categorize this burn?

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Complications of Burns

• Burn shock

• Respiratory system dysfunction

• Hypermetabolic response

• Renal insufficiency

• Gastric ulceration

• Sepsis

• Constriction of areas under circumferential burns

• Systemic infection

Page 18: Week 5 Powerpoint Chapter 46

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Question

Treatment for third-degree burn patients includes all but which of the following?

a. Fluid replacement

b. Removal of dead tissue/eschar

c. Antibiotics

d. Aloe

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Answer

d. Aloe

Patients suffering from third-degree (full thickness) burns lose fluid through the skin and are prone to infection. They must receive fluid replacement and antibiotics to fight or prevent infection. Dead tissue (eschar) must be removed daily (debridement) in order to prevent infection. Because third-degree burns destroy the epidermis, the application of topical aloe would serve no purpose.

Page 20: Week 5 Powerpoint Chapter 46

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Pressure Sores

External pressure

obstructs blood flow

ischemia to skin

tissue damage

Shear

bends blood vesselsFriction

damages dermis/

epidermis interface

Page 21: Week 5 Powerpoint Chapter 46

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Ultraviolet radiation

hits melanocytes

melanin oxidized - TAN

some UV reaches lower skin layers

immune cells

damagedinflammatory

mediators released

DNA damage

sunburn

more melanin produced - delayed

tanning

Sunburn – everything you didn’t want to

knonw

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Sun Exposure

• Sun exposure increases the risk of skin cancer

• Cumulative sun exposure increases risk of:

– Basal cell carcinoma

– Squamous cell carcinoma

• Severe sun exposure with blistering increases risk of:

– Malignant melanoma

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Malignant Melanoma

• Cancers arising from melanocytes

• Asymmetry

• Border irregularity

• Color variegation

• Diameter >0.6 cm

• Evolving change over time

Page 24: Week 5 Powerpoint Chapter 46

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Types of Melanomas• 70% are superficial spreading

– Raised edges; grow horizontally and vertically

– Ulcerate and bleed

• 15%–30% are nodular

– Dome-shaped, blue-black

• 4%–10% are lentigo maligna

– Slow growing, flat

• 2%–4% acral lentiginous

– On palms, soles, nail beds, mucous membranes

Page 25: Week 5 Powerpoint Chapter 46

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Question

Which type of skin cancer is associated with the worst prognosis?

a. Basal cell

b. Squamous cell

c. Malignant melanoma

d. Ependymal cell

Page 26: Week 5 Powerpoint Chapter 46

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Answer

c. Malignant melanoma

Malignant melanoma begins in the melanocytes, and possesses all of the characteristic features associated with cancer (asymmetry, irregular border, many colors, and a diameter >0.6 cm) as defined by the American Cancer Society.

Basal cell cancer has the best prognosis, and squamous cell cancer has a good prognosis as long as it is detected early.

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Skin Disorders of the Elderly

• Actinic (solar) damage

– Keratoses: premalignant lesions

– Lentigines: liver spots

• Vascular lesions

– Angiomas

– Telangiectases

– Venous lakes

Page 28: Week 5 Powerpoint Chapter 46

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Can you believe it?

• This is the final slide from the final chapter in the book.

• It’s been an interesting journey through the body and the disease and injury processes that can occur.

• Thank you for joining us as we explored Human Pathophysiology