Glossary of Terms

ADAMTS13: a type of protein that occurs naturally in the body. It helps break up a different protein that can help produce clots. An ADAMTS13 test can identify patients with TTP because they have low levels of ADAMTS13.  aHUS patients have normal or only slightly reduced levels

anemia: a condition in which the body does not have enough healthy red blood cells

Atypical: something that is irregular; an unusual type

atypical Hemolytic Uremic Syndrome (aHUS): a disease of the blood that causes low red blood cell and platelet counts, kidney failure, and damage to other vital organs, such as the heart and brain

Blood urea nitrogen (BUN): a person’s BUN level serves as an indication of renal health. A BUN test is primarily used, along with the creatinine test, to evaluate kidney function in a wide range of circumstances

Complement system: a network of proteins and enzymes that interact with each other to protect the body against foreign substances, like bacteria and other invading organisms. aHUS is a disease in which the complement system has trouble figuring out who is “one of us” and who is “one of them”

Creatinine: a chemical excreted by the kidneys, which when measured, shows whether the kidneys are functioning properly. Along with the BUN test, Creatinine tests evaluate kidney function in a wide range of circumstances

Colon: the lower part of the large intestine

Dialysis: a treatment for kidney failure. Normally, the kidneys work to filter the blood and remove waste, excess salt, and water. Kidney failure, also called “end-stage renal disease,” occurs when the kidneys stop working completely. During hemodialysis, a machine takes over the job of the kidney by filtering the blood outside of the body and then returning the filtered blood back to the body

E Coli: bacteria that normally exist in the lower intestines of humans and other animals, which can cause illness

Edema: swelling of certain parts of the body due to the presence of abnormally large amounts of fluid

Enzyme: a protein that starts a chemical reaction within the body

Haptoglobin: a blood protein made by the liver that connects to a certain kind of hemoglobin in the blood

Hematocrit: a blood test that measures the percentage of the volume of whole blood that is made up of red blood cells. A blood test can tell how much hemoglobin you have in your blood

Hemoglobin: a protein in red blood cells that carries oxygen

Immune system: a complex group of cells, proteins, and other molecules that work together to identify foreign organisms and substances, such as bacteria; the main role of the system is to protect the body against these foreign organisms

Infusion: a process during which fluid is introduced into the body through a vein

Kidney:  the organ that serves as the body’s natural filter of the blood, removing wastes and diverting them to the bladder

Lactate Dehydrogenase (LDH): an enzyme found in almost all body tissues, which plays an important role in cellular respiration

Microangiopathy: a disease of very small blood vessels

Monoclonal antibodies: special proteins designed to target other very specific cells or proteins in the body

Mutation: a permanent change in genetic material, usually in a single gene

Nephrologist: a physician who has been trained in the diagnosis and management of kidney disease

Plasma: the pale yellow liquid part of whole blood, in which the red and white blood cells and various other elements are suspended

Plasma infusion: a process wherein donated healthy plasma is transfused into another body

Plasmapheresis (plasma exchange): a process of removing, treating, and returning plasma to the body

Platelet: small, irregularly shaped clear cell fragments which circulate in the blood and are responsible for helping our blood clot

Renal: pertaining to the kidneys

Schistocytes: a fragmented part of a red blood cell, typically irregularly shaped, jagged, and asymmetrical

Shiga-toxin: a poison produced by E Coli bacteria that causes severe diarrhea

Shiga-toxin–producing E Coli hemolytic uremic syndrome (STEC-HUS): a syndrome triggered by Shiga-toxin–producing E Coli. The disease is characterized by diarrhea that is often bloody and followed by acute renal failure

Stroke: damage to the brain. Strokes can happen when an artery in the brain becomes clogged or starts bleeding and cuts off the blood supply to that portion of the brain

Syndrome: a set of symptoms that occur together in a pattern

Systemic: spread throughout the body

Thrombotic: producing blood clots

Thrombocytopenia: decreased numbers of platelets

Thrombotic Microangiopathy (TMA): clotting and inflammation that damages small blood vessels throughout the body; this is a symptom or a result of diseases such as aHUS and TTP

Thrombotic Thrombocytopenic Purpura (TTP): a rare condition that causes blood clots to form in small blood vessels throughout the body, leading to widespread thrombotic microangiopathy

Uremia: signs and symptoms of kidney failure; signs and symptoms of uremia can include nausea, vomiting, metallic taste in the mouth, muscle pain, and swelling


Alexion. aHUS: A Patient’s Guide. Available online at:  Accessed on November 28, 2012.