Diseases & conditions A-Z List
Diseases & Conditions A-Z List - «H»:
Hyperkalemic periodic paralysis
Hyperkalemic periodic paralysis is a disorder that involves occasional episodes of muscle weakness and, sometimes, higher than normal levels of potassium in the blood.
It is one of a group of genetic disorders that includes hypokalemic periodic paralysis and thyrotoxic periodic paralysis.
Hypermobile joints are joints that move beyond the normal range with little effort. Joints most commonly affected are the elbows, wrists, fingers, and knees.
Children generally tend to be more flexible than adults, but those with hypermobile joints can flexing and extend their joints...
Hyperparathyroidism is excessive production of parathyroid hormone (PTH) by the parathyroid glands.
The parathyroid glands are located in the neck, near or attached to the back side of the thyroid gland. They produce p...
Hyperplasia is increased cell production in a normal tissue or organ. Hyperplasia may be a sign of precancerous changes. This is called pathologic hyperplasia.
It can also be due to the growth of completely normal cells. This is called physiologic hyperplasia.
Hypersensitivity pneumonitis is inflammation of the lungs due to breathing in a foreign substance, usually certain types of dust, fungus, or molds.
Hypersensitivity pneumonitis usually occurs in those who work in places where there are high levels of organic dusts, fungus, or molds. For exam...
Hypersplenism is a condition in which the spleen is overactive.
Hypersplenism can be caused by:
Various connective tissue and inflammatory diseases
Low level of one or more types of blood cells
Hypertension is the term used to describe high blood pressure.
Blood pressure is a measurement of the force against the walls of your arteries as the heart pumps blood through the body.
Blood pressure readings are measured in millimeters of mercury (mmHg) and usually given as two numbers -- for exam...
Hypertensive heart disease
Hypertensive heart disease refers to heart problems that occur because of high blood pressure. These problems include:
Coronary artery disease
Thickening of the heart muscle
High blood pressure increases the pressure in...
Hypertensive retinopathy is damage to the back part of the eye (retina) caused by high blood pressure.
High blood pressure can cause damage to blood vessels in the eyes. The higher the blood pressure and the longer it has been high, the more severe the damage is likely to be.
Your health car...
Hyperthyroidism is a condition in which the thyroid gland makes too much thyroid hormone. The condition is often referred to as an "overactive thyroid."
The thyroid gland is an important organ of the endocrine system. It is located in the front of the neck just below the voice box. The gland...
Hypertrophic cardiomyopathy (HCM) is a condition in which the heart muscle becomes thick. The thickening makes it harder for blood to leave the heart, forcing the heart to work harder to pump blood.
Hypertrophic cardiomyopathy is often asymmetrical, meaning one part of the heart is thicker t...
Hyperventilation is rapid or deep breathing that can occur with anxiety or panic. It is also called overbreathing, and may leave you feeling breathless.
See also: Rapid shallow breathing
When you breathe, you inhale oxygen and exhale carbon dioxide. Excessive breathing leads to low ...
Hyperviscosity - newborn
Hyperviscosity of the newborn is the slowing and blockage of blood flow that results when there are too many red blood cells in an infant's blood.
Hyperviscosity can occur when the percentage of red blood cells (RBCs) in the infant's blood is greater than 65%. This may result from various co...
Hypervitaminosis A is having too much vitamin A in the body.
There are two types of vitamin A hypervitaminosis:
Acute -- caused by taking too much vitamin A over a short period of time
Chronic -- occurs when too much of the vitamin is present over a longer period
Chronic vitamin A toxicit...
Hypervitaminosis D is a condition that occurs after taking excessive doses of vitamin D.
An excess of vitamin D causes abnormally high levels of calcium in the blood, which can eventually severely damage the bones, soft tissues, and kidneys. It is almost always caused by forms of vitamin D t...