In the case of hematochezia, the blood may coat the stool, be mixed in with the stool, or even be passed by itself without any stool at all. Potential causes of black colored stools include: acidified blood (blood from higher in the digestive tract)
The most common symptoms of a meniscus tear are: 1  Knee pain. 2  Swelling of the knee. 3  Tenderness when pressing on the meniscus.  Popping or clicking within the 1  knee. Limited motion of the knee joint.
A burning sensation in the knees is a symptom of several conditions, including arthritis and peripheral artery disease, a condition that occurs when the arteries become narrowed, according to Healthgrades. Burning sensations can also indicate peripheral neuropathy, a condition caused by nerve damage in the legs.