Merck Manual

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Some Complications of Cancer

Some Complications of Cancer



Fluid accumulates in the bag like structure surrounding the heart (pericardium, or pericardial sac). This fluid puts pressure on the heart and interferes with its ability to pump blood. Fluid can accumulate when a cancer invades the pericardium and irritates it.

Fluid accumulates in the bag like structure around the lungs (pleural sac), causing shortness of breath.

Superior vena cava syndrome

Cancer partially or completely blocks the vein (superior vena cava) that drains blood from the upper part of the body into the heart. Blockage of the superior vena cava causes the veins in the upper part of the chest and neck to swell, resulting in swelling of the face, neck, and upper part of the chest.

Cancer compresses the spinal cord or the spinal cord nerves, resulting in pain and loss of function (such as urinary or fecal incontinence). The longer the compression of the spinal cord or spinal cord nerves persists, the less likely normal nerve function will return when the compression is relieved.

Brain dysfunction

The brain functions abnormally as a result of a cancer growing within it, either as a primary brain cancer or more commonly as a metastasis from a cancer elsewhere in the body. Many different symptoms can occur, including confusion, drowsiness, agitation, headaches, abnormal vision, abnormal sensations, weakness, nausea, vomiting, and seizures.


Bleeding may result from invasion and death of normal tissues and blood vessels or from the growth of abnormal, fragile blood vessels within a tumor.