Lecture Notes: Dermatology and Rheumatology Review

Introduction

• Presenter: Rahul, pediatric critical care fellow
• Focus: High-yield USMLE Step 1 concepts in dermatology and rheumatology
• Objective: Provide evidence-based test-taking strategies, active recall, and integrated learning
• Community: Global reach with participants from various countries

Key Areas Covered

Neuromuscular Junction Disorders

• Myasthenia Gravis
  • Autoantibodies to postsynaptic acetylcholine receptors
  • Symptoms worsen with activity
  • Associated with thymomas
  • Treatment: Acetylcholinesterase inhibitors
• Lambert-Eaton Syndrome
  • Autoantibodies to presynaptic voltage-gated calcium channels
  • Symptoms improve with activity
  • Associated with small cell lung cancer

Bullous Skin Diseases

• Bullous Pemphigoid
  • Autoantibodies to hemidesmosomes
  • Tense blisters, Nikolsky negative
  • Limited oral involvement
• Pemphigus Vulgaris
  • Autoantibodies to desmosomes
  • Flaccid blisters, Nikolsky positive
  • Oral involvement

Skin Cancers

• Basal Cell Carcinoma
  • Most common, affects upper lip
  • Nodular appearance with blood vessels
• Squamous Cell Carcinoma
  • Precursor: Actinic keratosis
  • Affects lower lip, associated with sun exposure
• Melanoma
  • BRAF mutation association
  • ABCDE mnemonic for identification

Rheumatoid Arthritis vs Osteoarthritis

• Rheumatoid Arthritis
  • Autoimmune, systemic inflammation
  • Affects MCP, PIP joints
  • Positive rheumatoid factor and anti-CCP antibodies
• Osteoarthritis
  • Degenerative, wear-and-tear
  • Affects DIP, PIP joints
  • Associated with osteophytes

Seronegative Spondyloarthropathies

• Psoriatic Arthritis: Pencil-in-cup deformity
• Ankylosing Spondylitis: Bamboo spine, HLA-B27
• Reactive Arthritis: Triad of conjunctivitis, urethritis, arthritis

Lupus (SLE)

• Manifestations: Malar rash, arthritis, serositis, renal involvement
• Antibodies: Anti-double-stranded DNA, anti-Smith
• Drug-Induced Lupus: Anti-histone antibodies

Test-Taking Strategies

• Emphasize process over right answers
• Focus on big-picture concepts and integration across subjects

Conclusion

• Encouragement to engage with materials actively
• Availability of additional resources such as test-taking strategy courses and pharmacology reviews

Note: This lecture was designed to integrate multiple topics across dermatology and rheumatology to aid with USMLE Step 1 preparation. Concepts were taught using active recall and integration strategies to ensure better retention and understanding.