65-YEAR- OLD MAN PRESENTS FOR EVALUATION OF WEAKNESS - DIAGNOSIS?

A 65-year- old man presents for evaluation of weakness. He states that for the last 6 months he has noticed difficulty when he reaches for things above his head or when he stands up from a seated position. He has a 20-pack- year smoking history but quit 15 years ago. On physical examination, you find the skin changes shown in figure 1 and 2.

Which one of the following is mostly associated with this patient’s condition? 1) Malignancy 2) CNS involvement 3) ABCD 4) Electrolyte and metabolic disturbance What is your clinical suspicion on this case?

Answer:

The cutaneous manifestations seen in the images are characteristic of Dermatomyositis (DM). DM is an idiopathic inflammatory myopathy presenting with proximal skeletal muscle weakness. In this case, the patient is presenting shoulder weakness (can’t reach above his head) and his hips muscles (can’t stand up from a seated position). The skin changes in hands are the Gottron’s papules, a palpable erythematous rash on the extensor surfaces of the MCP and PIP joints. The skin changes of the back corresponds to sun-exposed poikiloderma (areas of hypo and hyperpigmentation, telangiectasias, and atrophy in sun-exposed areas) There is an association between inflammatory myopathy and cancer. This is a paraneoplastic process that remains incompletely understood. However, it is believed that there is an expression of common autoantigens between cancer tissue and muscle tissue resulting in immunologic damage. Patients with cancer have five- to seven-fold higher incidence of dermatomyositis than the general population. CNS and Peripheral nerve involvement, along with electrolyte disturbances are important to consider in any case of weakness. However, these are not commonly associated with the skin changes above.

(With thanks to Dr. Leyla Bojanini for preparing the case.)