Dr. Karen H Nelson M.D.

The liver primarily produces cholesterol. Each day, it makes 1,000 mg of cholesterol. The cells lining the small intestine can also produce cholesterol. If the level of cholesterol in the body is low, it may mean that the body is producing low amounts of cholesterol and is going to shut down. In...

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...

Hematuria is the phenomenon in which traces of blood appear in the urine. It presents a unique problem because it is not a disease in itself. It is not infectious, nor is it capable of threatening a life. It is merely a warning sign that something is wrong inside the body. Though frightening in...

IntroductionA dry cough is a type of cough that does not accompany the production of mucus or phlegm. Most cases of dry cough are caused by certain allergic reactions from allergens, such as pollutants, dust, or toxins. The body usually tries to expel these irritants by coughing it out. In some...

Why are my tonsils swollen?The human body is a marvelous creation--a true work of art. It has the infrastructure to keep itself safe from harmful bacteria and viruses, and it has the ability to heal itself. One of these infrastructures is the tonsils. These are lymph nodes located at the back of the...

The ABO (A, B, AB, or O) blood group system is used to classify different types of antibodies in the plasma and antigens in the red blood cells (RBCs). The ABO blood group and RhD antigen determine the type of blood that is a perfect match for blood transfusions. The four ABO blood groups are: ...