H

Heartburn
Pronounced – HART-burn
A painful, burning feeling in the chest. Heartburn is caused by stomach acid flowing back into the esophagus. Changing the diet and other habits can help to prevent heartburn. Heartburn may be a symptom of Gastroesophageal Reflux Disease (GERD).

Helicobacter pylori (H. pylori)
Pronounced – HELL-uh-koh-BAK-tur py-LOH-ree
A spiral shaped bacterium found in the stomach. H. pylori damages stomach and duodenal tissue, causing ulcers. Previously called Campylobacter pylori.

Hemochromatosis
A condition in which too much iron builds up in the body over time. Without treatment, this extra iron can damage the organs, mainly the liver, heart, and pancreas, and cause organ failure. Hemochromatosis is one of the most common genetic diseases in the United States. But iron overload also can happen due to other diseases or from years of taking too much iron or from repeated blood transfusions or dialysis for kidney disease. The most common treatment to remove extra iron is to remove some blood.

Hemoglobin
The oxygen carrying pigment and predominant protein in the red blood cells. Hemoglobin forms an unstable, reversible bond with oxygen. In its oxygenated state it is called oxyhemoglobin and is bright red. In the reduced state it is called deoxyhemoglobin and is purple blue.

Hemorrhoid
Pronounced – HEM-royd
Swollen blood vessels in and around the anus and lower rectum. Continual straining to have a bowel movement causes them to stretch and swell. They cause itching, pain, and sometimes bleeding.

Hepatitis
Pronounced – heh-puh-TY-tis
A group of diseases in which the liver becomes enlarged and inflamed, causing fever, nausea, vomiting, abdominal pain, and dark urine. Hepatitis sometimes causes permanent damage. Viral hepatitis means that a person has liver inflammation due to a virus. Viral infection of the liver makes the liver swell up and stop working well. Hepatitis may be caused by viruses or by medicines or alcohol. Hepatitis has the following forms: Autoimmune Hepatitis, Hepatitis A, Hepatitis B, Hepatitis C, Hepatitis D – Delta Agent, and Hepatitis E.

Hernia
Pronounced – HUR-nee-uh
Hernia: The part of an internal organ that pushes through an opening in the organ’s wall. Most hernias occur in the abdominal area.

Hiatal Hernia (Hiatus Hernia)
Pronounced – hy-AY-tul HUR-nee-uh
A small opening in the diaphragm that allows the upper part of the stomach to move up into the chest. Causes heartburn from stomach acid flowing back up through the opening.

Hirschsprung Disease
Pronounced – HURSH-sprung
Hirschsprung disease, or HD, is a disease of the large intestine. HD usually occurs in children. It causes constipation, which means that bowel movements are difficult. Some children with HD can’t have bowel movements at all. The stool creates a blockage in the intestine.

Human Leukocyte Antigen (HLA)
Antigens, tolerated by the body, that correspond to genes that govern immune responses. Also known as major histocompatibility complex.

Hydrochloric Acid (HCl)
Pronounced – hy-droh-KLOR-ik ASS-id
An acid made in the stomach. Hydrochloric acid works with pepsin and other enzymes to break down proteins.

Hydrogen Peroxide
A chemical used in bleaches, dyes, cleansers, antiseptics, and disinfectants. In a concentrated form, it is toxic and irritating to tissues.

Hyperbilirubinemia
Pronounced – HY-pur-bil-ee-roo-buh-NEE-mee-uh
Hyperbilirubinemia is too much bilirubin in the blood. Symptoms include jaundice. This condition occurs when the liver does not work normally.

Hypercalcemia
Pronounced – HY-per-kal-SEE-mee-uh
Abnormally high amount of calcium in the blood.

Hyperthyroidism (overactive thyroid)
Pronounced – HY-per-THY-ROY-dih-zum
When too much thyroid hormone is made, it is called overactive thyroid or hyperthyroidism. Symptoms include weight loss, chest pain, cramps, diarrhea, and nervousness.

Hypopharynx
The hypopharynx is the bottom part of the pharynx and is the part of the throat that connects to the esophagus.

Hypothyroidism (underactive thyroid)
Pronounced – HY-poh-THY-ROY-dih-zum
When not enough thyroid hormone is made, it is called underactive thyroid or hypothyroidism. Symptoms include weight gain, constipation, dry skin, and sensitivity to the cold.