Dr. Stephen Todd Callahan MD, MPH

What is cholecystitis?Cholecystitis is the inflammation of the gallbladder, which is a pear-shaped organ situated under the liver. The gallbladder serves as the storage organ for bile until it is needed for the digestion of fatty foods in the duodenum or the first segment of the small...

Fibromyalgia has classic symptoms of widespread muscle pain and extreme fatigue. A combination of exercise, managing stress, medication, and a healthy lifestyle might ease your symptoms, but there is no cure and the causes are unknown. ...

Gout is primarily caused by uric acid, a natural by-product of the body’s digestive system. Uric acid is created during the breakdown of food in the digestive system, and it is supposed to be excreted thereafter. Due to various reasons, however, this uric acid isn’t properly removed from the...

Parkinson’s disease is a chronic, progressive movement disorder that affects the nervous system. It is characterized by gradual death and breakdown of nerve cells in the brain resulting in the decreased production of a chemical messenger called dopamine. Reduced dopamine levels cause abnormal...

What is melatonin?Melatonin is a hormone, which is naturally found in the body. This hormone is produced by the pineal gland and plays a role in regulating the circadian rhythm or sleep-wake cycle, fetal development, and fertility. Synthetic melatonin is also available in the form of nutritional...

There exist many symptoms that make the mononucleosis disease similar to other diseases, which makes it very difficult to distinguish it from other infections. Doctors administer treatment of the patient by giving him or her a physical test. This annual test checks out the patient's medical history....