Introduction
Vasculitis is a broad term used for diseases that affect the blood vessels of the body. Inflammation of the blood vessels is the characteristic hallmark of this disease. The blood vessels - arteries, veins, or capillaries - allow for a smooth flow of blood throughout the body. In a diseased patient, the inflamed vessels constrict the vessel diameter. This, in turn, interrupts the flow of blood in the affected region. The human body comprises an intricate network of varying sizes of blood vessels that supply blood to all the organ systems of the body. Vasculitis can potentially affect large, small, or both categories of blood vessels. The severity of vasculitis often depends on the stage of the disease, the organ system it acts on, and the health status of the patient. This article reviews how vasculitis impacts the renal system of the body and what steps need to be taken to manage the disease.
What Comprises the Renal System?
The renal system comprises the kidneys, the ureter, the urinary bladder, and the urethra. Each component of this system has its own special part to play in the making, storing, and passing of urine.
The kidneys are about the size of a potato. Present as a pair in the human body, these bean-shaped organs are located on either side of the spine, just below the ribcage. Although the urinary system is only involved in eliminating the urine from the body, the role of kidneys is not just limited to it. Kidneys also retain certain essential nutrients and fluids, regulate blood pressure, release hormones, and regulate red blood cell formation in the human body.
The ureters allow for passage of the waste fluid that is filtered out of the kidneys. This is the urine. The urine gets collected in a storage tank called the urinary bladder. The bladder capacity differs between the sexes, with about 500 ml in women and 700 ml in men. One feels the urge to urinate when the bladder is filled with about 200 to 350 ml of urine in it. The urethra is the outlet through which the urine is excreted out of the body.
How Does Vasculitis Impact the Kidneys?
Renal vasculitis is autoimmune in nature. The disease involves one's own immune system to attack the small blood vessels present in the glomeruli of the kidney. The glomerulus is the main filtering unit of the kidney that is responsible for filtering waste material and extra fluids in order to maintain a healthy fluid balance in the body. In renal vasculitis, the small network of blood vessels comprising the glomeruli are inflamed, often leading to bursting open or tearing of the vessels. This leads to spilling of the blood and proteins into the urine. When a large number of these glomeruli are affected, the function of the kidneys is disrupted and may even call for a hospital emergency.
How To Diagnose Renal Vasculitis?
The means by which a confirmed diagnosis of renal vasculitis is made include:
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Symptoms
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Blood Tests
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Urine Analysis
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Kidney Biopsy
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The symptoms of renal vasculitis do not really appear until the disease has reached its advanced stages. The generalized symptoms of vasculitis include tiredness, fatigue, and loss of appetite. The specific involvement of kidneys goes unnoticed as there is no symptom of pain or discomfort felt in the developing stage of the disease.
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Blood tests are performed to check the blood cell count, the creatinine levels, and the kidney function of the body. The kidney function is said to be normal when the glomerular filtration rate (GFR) is found to be 60 percent or above. Below 10 percent indicates the need for dialysis. The doctor specifically checks for the presence of ANCA (Anti-Neutrophil Cytoplasmic Antibodies) in the blood.
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Urine analysis is performed to check for the presence of blood cells and protein in the urine. High levels of blood and protein in urine indicate vasculitis of the glomeruli vessels or the presence of any other inflammatory disease of the kidneys. Brown tea-colored urine is usually a sign of blood leaking into the urine.
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A kidney biopsy is carried out to assess the severity of kidney damage and the prognosis of the treatment plan.
What Are the Types Of Renal Vasculitis?
Renal vasculitis is also referred to as ANCA Glomerulonephritis. The ANCA are antibodies that attack the blood vessels of the glomeruli of the kidney, causing inflammation. The three subtypes of renal vasculitis are:
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Granulomatosis with Polyangiitis (GPA or Wegener’s Disease): An uncommon condition characterized by inflamed blood vessels present in nose, ears, throat, sinuses, and kidney.
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Microscopic Polyangiitis (MPA): Typically affects smaller blood vessels. The cause of this disorder is not identified.
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Eosinophilic granulomatosis with Polyangiitis (EGPA or Churg-Strauss Disease): The inflammation of the blood vessels limit the flow of blood to organs and tissues.
All three of these types include the presence of ANCA antibodies that offer a major contribution in inflammation of the small blood vessels of the body.
What Is the Treatment Of Renal Vasculitis?
Once the diagnosis is confirmed, the treatment of renal vasculitis is carried out in two phases -
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Initial induction phase.
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Prolonged maintenance phase.
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The initial induction phase involved managing the disease symptoms with an aggressive approach. The primary goal of this phase is to lower the inflammatory responses of the immune system and prevent further kidney damage from occurring. The use of high-dose steroids and immunosuppressive drugs is prescribed by the doctor in this phase, which lasts for about three to six months.
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The induction phase is followed by a prolonged maintenance phase that mainly focuses on preventing the recurrence of the disease once remission is achieved. The dosage and frequency of drugs are reduced in this phase, and regular blood tests and urine analyses are ordered to check for any signs of renal relapse.
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A relapse case is also treated with the same approach as any case. One must keep a good check on one's blood profile and kidney function to prevent delayed diagnosis of a relapse.
What Is Dialysis and When Is It Needed?
According to data, about 20 percent of renal vasculitis patients suffer from end-stage renal disease (ESRD). The end-stage renal disease indicates that the kidneys are not equipped to carry out their functions optimally and require external assistance. Dialysis is the process that aids in 'cleaning' the blood of waste and excess fluid with the help of a hemodialysis machine. It can be carried out in the hospital or at home with an advised frequency of three times a week. Once kidney function is restored, one can step away from dialysis and monitor the renal functions via tests and laboratory analysis of the excreted urine.
Conclusion
A fair percentage of people with renal vasculitis show a good prognosis following treatment with medications and therapies. The majority of these patients can see improved results without requiring any dialysis. The most negative outcome is observed in patients who require immediate dialysis upon diagnosis. Kidney transplantation is also a preferred choice for many doctors if the patient is deemed fit enough to undergo organ transplantations. However, the recurrence of vasculitis in the transplanted kidney is also a possibility that needs to be looked out for.
