Pathophysiology Psoriasis Psoriatic Arthritis Cellulitis.

Pathophysiology

PsoriasisPsoriatic Arthritis

Cellulitis

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PSORIATIC ARTHRITIS

An inflammatory arthritis that occurs in a patient with psoriasis.

Harrison’s Internal Medicine 17th edition

A form of arthritis that occurs in patients with psoriasis with the hallmarks of an "inflammatory" arthritis, including joint pain, erythema, and swelling, often

with prominent stiffness. Mease, P., Menter, A. (2005) , Psoriatic Arthritis: Understanding Its Pathophysiology and Improving Its

Diagnosis and Management. Retrieved from: http://cme.medscape.com/viewarticle/509053

Clinical Features

• Unique to Psoriatic Arthritis:– DIP joint involvement– Nail changes – Dactylitis – Enthesitis– Spondylitis Lytic and periarticular new bone

formation x-ray features – Iritis or Uveatis

Mease, P., Menter, A. (2005) , Psoriatic Arthritis: Understanding Its Pathophysiology and Improving Its Diagnosis and Management. Retrieved from: http://cme.medscape.com/viewarticle/509053

Clinical Features

• Patterns of Arthropathy1. Arthritis of DIP joints2. Asymmetric oligoarthritis3. Symmetric polyarthritis4. Axial involvement5. Arthritis Mutilans

Psoriatic Arthritis

Distal Interphalangeal joint arthritis

• Occurs in 15 % of cases• Nail changes also seen

Harrison’s Internal Medicine 17th edition

Psoriatic Arthritis

• Asymmetric Oligoarthritis• Involves the knee or any large joint

with a few small joints in the fingers and toes– Metarsophalangeal– Proximal interphalengeal– Distal interphalengeal

• Dactylis– Sausage shaped digits due to inflammation of

the flexor tendons and synovium and pitting edema of the distal extremities may be observed

Harrison’s Internal Medicine 17th edition

Psoriatic Arthritis

Symmetric polyarthritis• Affects the Hands, wrists, knees,

and feet symmetrically– Proximal interphalangeal joints– Metacarpophalangeal joints

• Peripheral joints are less tender compared to RA

Harrison’s Internal Medicine 17th edition

Psoriatic Arthritis

Axial Arthropathy • Spine and sacroiliac

joints

Harrison’s Internal Medicine 17th edition

Psoriatic Arthritis

Arthritis mutilans• Widespread shortening or

telescoping of digits due to osteolysis of the phalanges and metacarpals

• coexisting with ankylosis and contractures in other digits

• opera-glass deformity or pencil-in-cup radiographic findings

• Fever

Harrison’s Internal Medicine 17th edition

Nail Changes

• Pitting• Horizontal ridging• Onycholysis• Discoloration of nail

margins• Dystrophic

hyperkeratosisOnycholysis

Nail pitting

OnychodystrophyHarrison’s Internal Medicine 17th edition

Dactylitis

Involvement of the distal and proximal interphalangeal joints, together with tendon

sheath involvement, may give the digit a sausage shape

Harrison’s Internal Medicine 17th edition

Enthesitis

Inflammation at the sites of ligamentous and tendinous insertions

Emedicine Retrieved from: http://emedicine.medscape.com/article/1108557-overview

Risk Factors:•Immunocompromised due to meds•Auspitz sign – break in skin integrity

Psoriasis

Cellulitis

Indigenous flora colonizing the skin

Staphylococcus aureusStreptococcus

pyogenesExogenous bacteria

Indigenous flora colonizing the skin

Staphylococcus aureusStreptococcus

pyogenesExogenous bacteria

Harrison’s Principles of Internal Medicine 17th ed.

Cellulitis• At the involved site

– Localized pain– Erythema – Swelling– Warmth– Borders are not sharply

demarcated

• Fever and chills• Malaise

Harrison’s Principles of Internal Medicine 17th ed.