Dr. Brenna Katherine Yursik MD, MPH

Leukocyte Esterase Urine TestLeukocyte esterase (LE) is an esterase produced by white blood cells (WBCs) or leukocytes. A leukocyte esterase test is a urine test used to detect the presence of white blood cells and other health conditions associated with infection.Normally, leukocyte esterase...

What is creatine phosphokinase (CPK)?Creatine phosphokinase (CPK) is an enzyme, which is predominantly present in the heart, brain, and skeletal muscles. Converting creatine into phosphate is the main task of this enzyme. The cells of the body then quickly consume or burn this phosphate and use it...

What is lightheadedness?Lightheadedness or feeling faint may not always be a cause for concern. However, it may also indicate an underlying health problem and can increase the risk of falling and fall-related injuries. If you feel lightheaded, drink water or fluids containing electrolytes and take...

What is epistaxis?Epistaxis or commonly called a nosebleed is defined as a type of bleeding that occurs from the nostrils, the nasal cavity, or the nasopharynx. Nosebleeds are mostly caused by the rupture of blood vessels inside the nose. Bleeding may be spontaneous or caused by injuries or trauma....

What is Reye’s syndrome?Reye's syndrome is a rare but serious condition that can cause swelling of the liver and brain. Even though this condition can occur at any age, it is mostly reported to affect children and teenagers, especially those who are trying to recover from viral infections, such as...

Uncontrollable shivering is characterized by the rapid shifting between muscle relaxation and contraction. It is through these contractions that the body warms itself up when exposed to cold. Shivering is not always accompanied by fever. In some cases, shivering may occur before the onset of...