#9 – Myocarditis

This 54-year-old man had a 5 year history of amyotrophic lateral sclerosis (ALS). He had been in relatively good condition until the past year, during which he had developed multiple episodes of pneumonia and required nursing home care. He was receiving an experimental protocol agent for ALS at the time of his death. The heart grossly showed no abnormalities.

There is widespread microscopic infiltration of the myocardium by inflammatory cells, an intermixture of neutrophils and lymphocytes. The inflammation is seen within the interstitial connective tissue and also surrounding myocytes, which are undergoing degeneration (appearing fragmented and partly eroded). Note, that in distinction to acute myocardial infarction, the nuclei of myocytes are intact and coagulative necrosis has not occurred.

• myocyte breakdown
• inflammation in the interstitium
• neutrophils and lymphocytes specifically
• inflammation around degenerating myocytes

Myocarditis is defined as inflammation with damage to cardiac myocytes due to a variety of injurious agents, including viruses and drugs.  In your slide, demonstrate to your instructor / select a field for annotation which concisely encompasses inflammation and damage to cardiac myocytes.  Also select a field to demonstrate to your instructor / for annotation which shows inflammation, and label the type(s) of inflammatory cells present.