Necrosis

Necrosis describes a localized total death of any type of vital body tissue. Often, the tissue damage is not a concern as in most of the body, the majority of the body's functions can continue with a small fraction of the necessary tissue. However, if the dead tissue is extensive, it will soon overwhelm the ability of the immune system, liver, kidneys and heart to deal with the dead tissue and the chemicals released by it.
Body tissues die on a regular basis and are recognized by the immune system. Antibodies are created which break down the tissue further so it can be processed by the liver and disposed of in the digestive tract. This process releases potassium, which is disposed of through the kidneys. 
However, when tissue death is widespread, the body cannot cope with the additional dead tissue. The immune system may start attacking healthy tissue as well. The liver is often overwhelmed with the by-products and starts to fail. Potassium builds up in the body and starts to affect heart function, leading to a heart attack. 
The only way to treat necrosis properly is to remove as much of the dead tissue as possible. A riskier strategy is to slow down the absortion of the tissue by bypassing the blood vessels around the dead tissue (which is what House tried in Three Stories) This allows the healthy tissue to repair itself. Calcium should be given to the patient to reduce the potassium levels in the blood.