Goodpasture’s syndrome (also known as Goodpasture’s disease and anti-glomerular basement antibody disease) is a rare disease that can affect the lungs and kidneys. It is an autoimmune disease, a condition in which the body's own defense system reacts against some part of the body itself. When the immune system is working normally, it creates cells called antibodies to fight off germs. No one knows why, in Goodpasture syndrome, the immune system makes antibodies that end up attacking the lungs and kidneys. A combination of factors has been implicated, and among these is the presence of an inherited component.
Signs and symptoms
Goodpasture’s syndrome can cause people to cough up blood or feel a burning sensation when urinating. But its first signs may be vague, such as fatigue, nausea, difficulty breathing, or skin pallor. These signs are followed by kidney involvement, represented first by small amounts of blood in the urine, protein in the urine, and other clinical and laboratory findings.
Other patients present with both lung and kidney disease; however, some patients present with one of these diseases alone. The first lung symptoms usually develop days to months before kidney damage is evident.
Lung disease
Lung symptoms may present as nothing more serious than a dry cough and minor breathlessness; and such mild symptoms may last for many years before more severe ones develop. At its most serious, however, lung damage may cause severe impairment of oxygenation so that intensive care is required. Deterioration between the two extremes may occur very rapidly, often at the same time as rapid deterioration occurs in the kidney. The patient often does not seek medical attention until he or she begins coughing up blood (hemoptysis). The patient may be anemic due to loss of blood through lung hemorrhaging over a long period. In Goodpasture’s syndrome, unlike many other conditions that cause similar symptoms, lung hemorrhaging most often occurs in smokers and those with damage from lung infection or exposure to fumes.
Kidney disease
The kidney portion of the disease mostly affects the glomeruli causing a form of nephritis. It is usually not detected until a rapid advance of the disease occurs and kidney function can be completely lost in a matter of days. Nephritic Syndrome in this disease will develop to another nephritic condition known as rapidly progressive (Crescentic) glomerulonephritis, or RPGN. Blood spills into the urine causing hematuria, the volume of urine output decreases and urea and other products usually excreted by the kidney are retained and build up in the blood. This is acute renal failure. Renal failure does not cause symptoms until more than 80% of kidney function has been lost. Symptoms include loss of appetite and malaise at first and then, when the damage is more advanced, breathlessness, high blood pressure and edema (swelling caused by fluid retention). The kidney involvement usually presents as nephritic syndrome, i.e. hematuria, a reduced glomerular filtration rate, and high blood pressure. This is in contrast to nephrotic syndrome, a rarer outcome of Goodpasture's, characterized by an abnormally large amount of protein in the urine (proteinuria), coupled with severe edema.
Pathophysiology
As with many autoimmune conditions, the precise cause of Goodpasture’s Syndrome is not yet known. It is believed to be a type II hypersensitivity reaction to Goodpasture’s antigens on the basement membrane of the glomerulus of the kidneys and the pulmonary alveolus, specifically the non-collagenous domain of the alpha-3 chain of Type IV collagen. The immune system wrongly recognizes these motifs as foreign and produces antibodies (IgG) toward them, eliciting an immune response. On an immunology stain Goodpasture's Syndrome usually presents with a linear staining pattern.
Renal failure is ultimately due to damage caused to the Glomerular Basement Membrane by immune system cells attacking in response to these antibodies. As the basement membrane is damaged, the ability of the kidneys to excrete waste and reabsorb nutrients is compromised.
Treatment
Goodpasture syndrome is treated with immunosuppressive drugs given by mouth to keep the immune system from making antibodies. Corticosteroids may be given intravenously to control bleeding in the lungs. A process called plasmapheresis (PLAZ-ma-fer-REE-sis) may be helpful and necessary to filter the harmful antibodies from the blood; this is usually done in combination with the steroid treatment.
Unfortunately, none of these treatments can reverse permanent kidney damage and for patients who have suffered from the syndrome, renal transplant may be needed once the disease has subsided.
Prognosis
In the 1970s, Goodpasture’s syndrome was most often fatal, but due to advances in diagnosis and treatment, deaths are less common now. Death from lung hemorrhage may occur before the diagnosis has been made, or in the initial stages of treatment before it has been properly controlled. With treatment, however, the patient can usually recover completely from lung damage. Kidneys, on the other hand, are less able to repair themselves and patients with kidney damage must often resort to a life on dialysis or kidney transplantation. Even with the best management there is still significant mortality from renal failure, particularly if the patient is otherwise in poor health. In addition, the immunosuppressive treatment many patients are treated with increases their risk of infection with a number of serious or fatal secondary diseases.
