Urine Nephrology Now: A Primer for Students in Nephrology
This glossary provides definitions for essential nephrology terms for students beginning their clinical rotations. Understanding this vocabulary is fundamental to communicating effectively and comprehending complex renal concepts.
Condition characterized by increased acidity in the blood and body tissues (pH below 7.35). Renal acidosis occurs when kidneys fail to excrete sufficient acid or reabsorb sufficient bicarbonate.
Inflammatory condition of the kidney interstitium and tubules, typically caused by drug hypersensitivity, infection, or autoimmune disease, presenting with acute kidney injury, fever, rash, and eosinophilia.
Sudden decline in kidney function occurring over hours to days, characterized by rising serum creatinine, decreased urine output, or both. Common causes include prerenal, intrinsic, and postrenal factors.
Damage to tubular epithelial cells from ischemia or nephrotoxins, leading to acute kidney injury. Most common cause of intrinsic acute kidney injury.
Presence of albumin in urine, indicating glomerular damage. Microalbuminuria (30-300 mg/24h) may be the earliest sign of diabetic nephropathy.
Mineralocorticoid hormone produced by the adrenal cortex that regulates sodium reabsorption and potassium secretion in the distal nephron.
Condition characterized by decreased acidity in the blood and body tissues (pH above 7.45). Can be metabolic (increased bicarbonate) or respiratory (decreased carbon dioxide).
Hereditary disease characterized by progressive nephritis, hearing loss, and ocular abnormalities, caused by mutations in type IV collagen genes.
Disorder characterized by extracellular deposition of fibrillar protein in kidney tissue, leading to proteinuria and progressive kidney dysfunction.
Calculated value (Na⁺ - [Cl⁻ + HCO₃⁻]) that helps differentiate causes of metabolic acidosis. Normal range is 8-12 mEq/L.
Autoimmune disorder characterized by antibodies against glomerular basement membrane, causing rapidly progressive glomerulonephritis and often pulmonary hemorrhage (Goodpasture syndrome).
Also called vasopressin, regulates water reabsorption in collecting ducts, concentrating urine during states of dehydration.
Surgically created connection between an artery and vein, typically in the arm, used for hemodialysis access.
Synthetic tube connecting an artery to a vein, serving as hemodialysis access when native vessels are inadequate for AVF creation.
Most common inherited kidney disease, characterized by progressive development of fluid-filled cysts leading to kidney enlargement and declining function.
Elevation of nitrogenous waste products (BUN, creatinine) in the blood.
Inherited tubulopathy affecting the thick ascending limb of the loop of Henle, characterized by hypokalemia, metabolic alkalosis, and normal blood pressure.
Cup-shaped structure surrounding the glomerular capillary tuft, collects filtered fluid from the glomerulus.
Waste product of protein metabolism; elevated in kidney dysfunction. Normal range: 7-20 mg/dL.
Active form of vitamin D (1,25-dihydroxycholecalciferol) produced in the kidney, essential for calcium homeostasis.
Temporary vascular access device placed in a large vein (internal jugular, subclavian, or femoral) for hemodialysis when permanent access is unavailable.
Progressive, irreversible decline in kidney function classified into stages 1-5 based on estimated glomerular filtration rate (eGFR). Stage 5 is also known as end-stage renal disease (ESRD).
Volume of plasma completely cleared of a substance per unit time. Creatinine clearance approximates GFR.
Final portion of the nephron where fine regulation of water and electrolyte balance occurs under hormonal control.
Slow, continuous form of dialysis used in critically ill patients with hemodynamic instability.
Mechanism in the loop of Henle that concentrates urine by creating an osmotic gradient in the renal medulla.
Waste product of muscle metabolism used to estimate kidney function. Normal range: 0.7-1.3 mg/dL for men, 0.6-1.1 mg/dL for women.
Low molecular weight protein freely filtered by glomeruli; serum level serves as an alternative GFR marker less affected by muscle mass than creatinine.
Kidney disease resulting from diabetes mellitus, characterized by microalbuminuria progressing to overt proteinuria and declining GFR.
Solution used in dialysis containing water, electrolytes, and buffers that helps remove waste products from blood through diffusion.
Measure of how effectively dialysis removes waste products, commonly assessed using Kt/V (urea clearance × time/volume of distribution) or urea reduction ratio.
Neurological disorder occurring during or after hemodialysis, characterized by headache, nausea, and in severe cases, seizures or coma, due to rapid osmotic shifts.
Segment of the nephron between the loop of Henle and collecting duct, site of fine-tuning of electrolyte balance.
Medication that increases urine production. Major classes include loop diuretics, thiazides, potassium-sparing diuretics, and osmotic diuretics.
Swelling caused by excess fluid in body tissues, common in nephrotic syndrome and heart failure.
Ions in body fluids (sodium, potassium, chloride, bicarbonate, calcium, phosphate, magnesium) regulated by the kidneys.
Advanced kidney failure (stage 5 CKD) requiring renal replacement therapy (dialysis or transplantation).
Hormone produced primarily by the kidneys that stimulates red blood cell production in bone marrow; reduced in CKD leading to anemia.
Mathematical estimate of kidney function based on serum creatinine, age, sex, and race. Normal is >90 mL/min/1.73m².
X-linked lysosomal storage disorder causing progressive kidney damage, characterized by proteinuria and declining GFR, often with extrarenal manifestations.
Generalized dysfunction of the proximal renal tubule resulting in aminoaciduria, glycosuria, phosphaturia, and bicarbonaturia.
Rare glomerular disease characterized by organized fibrillary deposits in the glomeruli, presenting with proteinuria, hematuria, and progressive renal insufficiency.
Pattern of glomerular injury characterized by sclerosis of portions (segmental) of some (focal) glomeruli, a common cause of nephrotic syndrome.
Percentage of filtered sodium excreted in urine; helps differentiate causes of acute kidney injury. FENa <1% suggests prerenal causes.
Inherited tubulopathy affecting the distal convoluted tubule, characterized by hypokalemia, metabolic alkalosis, hypomagnesemia, and hypocalciuria.
Volume of fluid filtered by glomeruli per unit time, the best measure of kidney function.
Inflammation of the glomeruli, often immune-mediated, leading to hematuria, proteinuria, and potentially reduced kidney function.
Network of capillaries surrounded by Bowman's capsule where blood filtration occurs.
Presence of blood in urine, either visible (gross) or detected only by microscopy (microscopic).
Disorder characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury, often following gastrointestinal infection with Shiga toxin-producing bacteria.
Procedure removing waste products and excess fluid from blood using a semipermeable membrane and dialysate solution.
U-shaped segment of the nephron between proximal and distal tubules, critical for concentrating urine.
Dilation of the renal pelvis and calyces due to obstruction of urine outflow, potentially leading to kidney damage if prolonged.
Elevated serum potassium (>5.0 mEq/L), potentially life-threatening condition causing cardiac arrhythmias.
Elevated serum sodium (>145 mEq/L) usually indicating water deficit.
Elevated serum phosphate levels, common in CKD due to decreased renal excretion.
Elevated blood pressure, both a cause and a consequence of kidney disease.
Low serum potassium (<3.5 mEq/L), often caused by diuretics or gastrointestinal losses.
Low serum sodium (<135 mEq/L), most commonly caused by excess water retention.
Most common primary glomerulonephritis worldwide, characterized by IgA deposits in the mesangium, presenting with hematuria and varying degrees of proteinuria.
Inflammation of kidney tissue between tubules, often medication-induced, causing acute kidney injury.
Specialized cells near the glomerulus that secrete renin in response to decreased renal perfusion.
Kidney Disease: Improving Global Outcomes – international clinical practice guidelines for kidney disease management.
Medications (e.g., furosemide) that inhibit sodium reabsorption in the thick ascending limb of the loop of Henle.
Kidney inflammation in systemic lupus erythematosus, classified into six histological classes with varying prognoses and treatment approaches.
Specialized cells in the distal tubule near the glomerulus involved in tubuloglomerular feedback.
Pattern of glomerular injury characterized by mesangial cell proliferation and thickening of the capillary walls, associated with various underlying conditions.
Common cause of nephrotic syndrome in adults, characterized by uniform thickening of the glomerular basement membrane due to subepithelial immune deposits.
Specialized cells in the glomerulus that provide structural support and have phagocytic and contractile properties.
Low blood pH due to decreased bicarbonate, common in advanced kidney disease.
Small amounts of albumin in urine (30-300 mg/24h), early marker of kidney damage.
Most common cause of nephrotic syndrome in children, characterized by normal-appearing glomeruli on light microscopy but foot process effacement on electron microscopy.
Surgical removal of a kidney, either partial or complete.
Clinical presentation with hematuria, proteinuria, hypertension, and reduced GFR, typically caused by glomerulonephritis.
Functional unit of the kidney consisting of the glomerulus and tubular system.
Hardening of renal vessels and parenchyma due to hypertension or aging, causing progressive loss of kidney function.
Catheter placed directly into the kidney to drain urine when normal outflow is obstructed.
Clinical syndrome characterized by heavy proteinuria (>3.5g/24h), hypoalbuminemia, edema, and hyperlipidemia.
Kidney damage caused by medications, toxins, or other substances.
Reduced urine output (<400 mL/24h in adults), often seen in acute kidney injury.
Regulates calcium and phosphate homeostasis; levels increase in CKD as compensatory mechanism for hypocalcemia and hyperphosphatemia.
Dialysis modality using the peritoneum as a semipermeable membrane for diffusion of waste products.
Specialized epithelial cell in the glomerulus forming filtration slits, critical for preventing protein leakage.
Hereditary disorder characterized by development of multiple cysts in the kidneys.
Immune-mediated glomerulonephritis following streptococcal infection, typically presenting with hematuria, proteinuria, and hypertension.
Principal intracellular cation; serum levels (normal 3.5-5.0 mEq/L) tightly regulated by the kidneys.
Abnormal amount of protein in urine (>150 mg/24h), marker of kidney damage.
First portion of the renal tubule, responsible for reabsorbing approximately 65% of filtered sodium, water, and other substances.
Bacterial infection of the kidney and renal pelvis, causing flank pain, fever, and pyuria.
Severe form of glomerulonephritis characterized by rapid loss of kidney function over days to weeks, with crescent formation on kidney biopsy.
Narrowing of the renal artery, potentially causing renovascular hypertension and ischemic nephropathy.
Procedure to obtain kidney tissue for diagnostic evaluation.
Bone disease resulting from chronic kidney disease, characterized by altered calcium, phosphorus, and vitamin D metabolism.
Treatments that partially replace kidney function, including hemodialysis, peritoneal dialysis, and kidney transplantation.
Group of disorders characterized by inability of the renal tubules to maintain normal acid-base balance.
Hormone system regulating blood pressure, sodium balance, and fluid volume.
Breakdown of muscle tissue releasing myoglobin into circulation, potentially causing acute kidney injury through tubular toxicity and obstruction.
Excessive parathyroid hormone production in response to hypocalcemia, common in CKD.
Principal extracellular cation responsible for maintaining extracellular fluid volume.
Benign condition characterized by thinning of the glomerular basement membrane, presenting with persistent microscopic hematuria.
Nitrogenous waste product of protein metabolism; serum concentration (in BUN) rises in kidney dysfunction.
Measure of dialysis adequacy calculated as percentage reduction in blood urea during hemodialysis. Target is typically >65%.
Clinical syndrome of advanced kidney failure characterized by elevated nitrogenous waste products and associated symptoms.
Examination of urine for physical, chemical, and microscopic properties, essential in kidney disease evaluation.
Cylindrical structures formed in renal tubules, visible on microscopic urinalysis; different types indicate various kidney pathologies.
Infection involving any part of the urinary system, commonly caused by bacteria.
Various methods used to access the bloodstream for hemodialysis, including AVF, AVG, and central venous catheters.
Abnormal retrograde flow of urine from bladder to ureters and kidneys, predisposing to recurrent UTIs and potential kidney damage.