Case-study. A 25 years old male with past medical history of alcohol abuse was admitted to the ED with complains of severe lower back and bilateral legs pain. He had been running twelve miles every day for two weeks using 3 lbs weights attached to each leg and 2 lbs weights attached to each arm preparing for the marathon. The other complaint was a dark color urine for two days.
What is the cause of his symptoms. Explain the mechanism.

The lower back pain and bilateral leg pain is due to over and intense physical activity which causes stretching of ligaments and muscles resulting in back and leg pain. Such pain can be managed by limited or by reducing physical activity.  The dark color of urine is due to the presence of bile (bilirubin) in the urine. Here the patient has a past medical history of alcohol abuse. Excessive alcohol intake enhances gut permeability resulting in enhanced absorption of bacterial endotoxins. Excessive endotoxins in the liver cause damage of the kupffer cells in the liver, resulting in the release of bilirubin in the blood which ultimately passes through kidneys into the urine.

Explanation:

the cell theory states that all living things including animals, as well as plants, are made of cells.