Medical Mystery of the Week

      Because of the resurgence of COVID19 you are still practicing telemedicine. You are presented a case of a 77-year-old man who injured his thumb in a table saw accident at the age of 57. Ever since he has noted painful hypersensitivity in the thumb most marked with light stroking of the skin. Subjectively, the thumb feels cold although the actual temperature is normal. Pictures of the thumb and adjacent fingers are shown below.
      DIAGNOSIS: Complex regional pain syndrome (CRPS) a chronic pain condition with both  inflammatory and autonomic features. The syndrome occurs in ∼ 7% of persons with limb fractures, limb surgery, or limb injuries. Many cases resolve within the first year with a smaller subset progressing to a chronic form in which the inflammatory response ("warm complex regional pain  syndrome") is eventually superceded by autonomic nervous sytem abnormalities ("cold complex regional pain syndrome"). Management options include physical and occupational therapy, biphosphonates, calcitonin, subanesthetic intravenous ketamine, free radical scavengers, oral corticosteroids, and spinal cord stimulation. The presented case has early clubbing of the fingernails on the ipsilateral side of injury (see below).

Palmar surface of the thumb showing the table saw injury scar (left image). Picture of the injured finger thumbnail (right image). 

Pictures of several fingernails in the ipsilateral hand showing early clubbing. There are three principal signs of clubbing: 1. Angulation: the normal nail plate makes an angle of 20° or more dorsalward with the axis of the finger; diminution in the angle is evidence of clubbing; 2. Curvature of the nail: the normal nail is slightly curved whereas the clubbed nail is more convex (i.e., describes a curve with a very short radius); 3. Floating nail root: pressing on the portion of the nail plate covered with skin reveals a springing resilience.

BONUS QUESTIONS: True or false. 1. WHO statistics show that 78% of boys and 84% of girls aged 11-17 do not meet recommended levels of physical exercise. TRUE. 2. Physical exercise increases circulating levels of M1-polarized macrophages. FALSE. Exercise increases levels of M2-polarized (antiinflammatory) macrophages and decreases levels of M1-polarized (inflammatory) macrophages ; 3. Aerobic exercise can increase telomere length. TRUE. 4. Physical exercise exerts its beneficial effects in part by decreasing blood levels of IL-6. FALSE. During exercise IL-6 levels increase 100-fold or more. 5. Long-term aerobic exercise reduces blood monocyte production of IL-10 and increases their production of TNF-α. FALSE. The reverse is true - exercise decreases mononuclear cell production of proinflammatory cytokines (TNF-α, IL-1, IFN-γ) while increasing their production of antiinflammatory cytokines (IL-10, IL-4).