What Conditions Can Cause Symptoms of Dark Yellow Urine With a Thick, Cloudy Substance?

A dark yellow coloration of urine can be caused by many factors, while cloudy urine is often a sign of urinary tract infection, reports MedlinePlus. Causes of dark yellow discoloration range from side effects of certain medications to over-consumption of B vitamins.

The most common cause of a cloudy or milky appearance in urine is a urinary tract infection, explains MedlinePlus. These infections are usually bacterial in nature and may also result in urine with a strong and unpleasant smell. Less commonly, the presence of crystals, fat, mucus or blood cells in the urine may give it a milky appearance.

Dark yellow urine is one of the side effects of many laxative drugs, some antibiotics and blood thinners, such as warfarin and rifampin, according to MedlinePlus. The antibiotics used to treat many urinary tract infections often have this side effect, so dark yellow and cloudy urine is likely to occur in patients undergoing treatment for such infections. Carotene and B vitamins excreted in the urine can also give it a dark yellow color. Urine that is a dark brown rather than yellow may indicate a liver problem due to cirrhosis of the liver or hepatitis infection, but in most cases urine discolored due to liver problems is clear rather than cloudy or milky.