Thank you to Vhaibhav for presenting a really interesting case of a patient with progressive proximal muscle weakness and tenderness to palpation found to have a significantly elevated CK, who subsequently developed white out of the left lung. We discussed several teaching points outlined below. While it is unclear if there is an endobronchial lesion, let’s review some of the paraneoplastic processes that could occur.
DDx for Lung White Out:
White Out of Lung:
- Trachea deviated to side of white out => Collapsed Lung (Lung tissue compressed pulling over the trachea and right heart border)
- Trachea deviated to side opposite of white out => Something Filling Chest Cavity (Blood, Fluid, Pus)
Paraneoplastic Syndromes Affecting Muscles:
|Category||Disease Name||Antibody||Associated Cancer||Clinical|
|Neuromuscular||Myasthenia Gravis||AChR Antibody
|Thymic hyperplasia (more rarely SCLC, thyroid CA, breast CA, Hodgkin lymphoma)||Often with ocular symptoms, weakness of eyelids or extraocular muscles (ptosis, diplopia), fluctuating skeletal muscle weakness|
|Lambert-Eaton Myasthenic Syndrome (LEMS)||Antibody against voltage-gated calcium channels||SCLC||Often starting with hip girdle weakness. Less dramatically shoulder girdle weakness, progress in caudocranial direction, assoc with decreased/absent reflexes|
|Inflammatory Myopathies||Dermatomyositis and polymyositis||Myositis-specific antibodies (i.e. myositis panel)||CA of breast, lung, ovary, stomach, NHL||Proximal skeletal muscle weakness, Gottron’s papules (among many other signs/symptoms)|
|Peripheral Nerve Hyperexcitability||Paraneoplastic Neueromyotonia||Anti-LGI1||Thymoma, SCLC, Hodgkin lymphoma||Muscle stiffness caused by continuous muscle fiber activity, muscle cramps, twitching, spasm, stiffness, carpopedal spasm|
|Necrotizing Myopathy||Acute Necrotizing Myopathy||Anti-SRP, Anti-HMGCR||Tumors of lung, breast, GI tract||Symmetric, painful, predominantly proximal weakness leading to severe disability over 1-2 months|
Song Credit: SWV – “Weak” – https://youtu.be/976b8TPPFJU
- Darnell RB & Posner, JB (2003). Paraneoplastic syndromes involving the nervous system. NEJM 349:153-1554.
- Paraneoplastic Syndromes of Muscles: