Distinguish Type I and Type II decompression sickness by their main clinical features.

• A. Type I: musculoskeletal pain and skin/mottling; Type II: neurologic, inner ear, or pulmonary symptoms
• B. Type I: musculoskeletal pain; Type II: skin changes
• C. Type I: respiratory symptoms; Type II: chest pain
• D. Type I: ocular symptoms; Type II: neurologic symptoms

Answer: (A)

In decompression sickness, the main difference lies in which body systems are affected. Type I is characterized by musculoskeletal pain (the bends) and skin changes such as mottling or pruritus, which are usually milder and localized. Type II involves more serious, deeper systems—neurologic symptoms (like numbness, weakness, ataxia, confusion or seizures), inner ear issues (vertigo, hearing loss), and pulmonary symptoms (cough, chest tightness, dyspnea). This reflects a shift from surface or peripheral tissue involvement to central and respiratory system involvement, which is why Type II is considered the more concerning form.

The correct description aligns with identifying Type I as musculoskeletal pain with skin/mottling, and Type II as neurologic, inner ear, or pulmonary symptoms.