The glomerulus is the filtering unit of the kidney. It is made up of a tuft of capillaries, whose walls can selectively filter wastes and electrolytes from the blood. Around each glomerulus is a containment sac (Bowman’s membrane) that has an exit into the renal tubule. Thus, the blood is filtered, the filtrate collecting as urine that flows out, ultimately, via urination.
Glomerular disease, a broad term for pathologic abnormalities in the glomeruli, can be inherited genetically or acquired. It can be diffuse, involving most of the glomeruli, or focal, involving <50% of them.
Causes of Glomerular Disease
- Hypovolemia and dehydration: Due to overuse of diuretics, decreased oral intake of fluids, or diarrhea.
- Hypotension: Due to heart failure, causing decreased kidney perfusion.
- Liver disease (portal hypertension).
- Intrinsic renal vascular disease: Including atherosclerosis and the effects of diabetes, affecting both large and small kidney blood vessels.
- Intrinsic glomerular disease: Affecting the glomeruli primarily, or secondarily from drug toxicity or systemic rheumatoid/autoimmune disease.
- Nephritis–red blood cell (RBC): Casts and albuminuria; can be both chronic and acute.
- Nephrosis–proteinuria: Can be both chronic and acute. Excretion of protein in the urine decreases the protein in the blood and can lead to edema or fluid collecting in the abdomen (ascites) or lung spaces (pleural effusion).
- Intrinsic tubular disease: The tubule, which with the glomerulus, makes up the nephron unit, can undergo acute tubular necrosis (ATN), usually due to drug toxicity, cardiac surgery, or severe sepsis; ATN causes significant kidney injury.
- Obstructive nephropathy: Obstruction anywhere in the urinary tract can cause stasis of urine above the obstruction, decreasing glomerular filtration. Stones, prostate surgery, metastatic cancer, or unrecognized surgical damage (suturing the ureter) can cause it.
Signs and Symptoms of Glomerular Disease
- Hematuria: blood in the urine
- Proteinuria: urinary excretion of protein
- Renal insufficiency
- Hypertension: acutely in a person with previously normal blood pressure
- Edema (swelling): bloating, or shortness of breath
- Hypercoagulation: resulting in thrombus formation with risk of thromboembolic events (pulmonary emboli)
- Fever, chills, night sweats
- Heart murmurs: chest pain from pericarditis
- Colitis, pancreatitis
- Peripheral neuropathy
- Arthritis, myalgia
- Infections (Staph, Strep, hepatitis, HIV, syphilis)