Henoch-Schonlein Purpura (HSP)
Henoch-Schonlein Purpura is a kind of vasculitis (disease or "inflammation" of blood vessels). It usually starts with stomach pain (with or without diarrhea) and a "spotty" or "blotchy" "red" or purple-like, located mostly on the leg and backside. The inflammation of the blood vessels can also cause problems in the joints and other organs in the body, including the kidneys. Henoch and Schonlein are the names of the doctors who first described this disease and "purpura" is the name of the kind of skin rash. The inflammation of the blood vessels in the skin shows up as a rash. The kidneys have a lot of special blood vessels that are designed to "filter" (clean) your blood all the time. These filters are called "glomeruli" (Latin for filter). "Nephritis" is Greek for kidney disease, so glomerulonephritis is the name of disease (vasculitis) of the kidney filters. When HSP affects the kidneys, blood leaks from the filters (glomeruli) into the urine (hematuria). If the injury is more severe, protein leaks too (proteinuria).
HSP can be diagnosed and treated by your pediatrician or family doctor. If there are any questions about the degree that the kidneys are being affected, the doctor can get advice from a pediatric nephrologist (kidney specialist). In a few children, the kidney problem will be serious, so your (your child's) doctor will refer you to a pediatric nephrologist.
Urine tests, by showing there is blood in the urine, will let the doctor know if the kidneys are being affected by HSP. Also, since body waste products are filtered from the blood by the kidneys, the doctor can tell how well the kidneys are working by measuring these wastes in the blood to see how well the kidneys are working. The blood tests that are measured to show how well the kidneys are working are called creatinine and blood urea nitrogen (BUN). The doctor may need to check these tests more regularly until the HSP is gone to be sure the kidneys remain working normally. During this time the doctor also watches for high blood pressure and also for high amounts of protein in the urine. Sick kidneys often cause hypertension, (high blood pressure). If blood pressure is high you (your child) will need to take medicines to treat it. Keeping the blood pressure normal helps keep the kidneys and the rest of the body healthy. If the kidneys get well, the blood pressure will become normal again and the medicines can be stopped. If blood tests show the kidney function is being affected, or if there is hypertension or high amounts of protein in the urine, your doctor will refer you to a nephrologist.
Although there is no single medicine that is 100% effective in treating kidneys that are severely affected by HSP, the nephrologist has the knowledge and experience to know what medicines may be helpful. Since severe glomerulonephritis can cause loss of kidney function in some cases, treatment should be tried. About 2% of kids with severe glomerulonephritis from HSP lose kidney function permanently. You may hear about a test called a "kidney biopsy". This is a test where a tiny piece of kidney is taken from one of the kidneys (both kidneys will show the same problem) and looked at under a microscope. This is absolutely needed in all cases since the findings rarely help in deciding treatment, because the findings in the urine, the abnormal levels of creatinine in the blood and or the protein in the urine are enough to make the nephrologist want to treat the problem.