Renal Disease, Metabolic Disorders, and Body Fluids

Vocabulary practice flashcards covering renal diseases, amino acid and porphyrin metabolic disorders, and body fluids (CSF, synovial, serous, and amniotic fluids) based on the lecture material.

Acute Glomerulonephritis (AGN)

An inflammatory glomerular disorder occurring $1\text{--}2\,\text{weeks}$ after a Streptococcus infection, caused by immune-complex deposition on the glomerular membrane and characterized by hematuria, proteinuria, oliguria, RBC casts, dysmorphic RBCs, and elevated anti-streptolysin O (ASO).

Chronic Glomerulonephritis (CGN)

A slowly progressive glomerular disorder presenting with worsening fatigue, anemia, hypertension, edema, oliguria, a markedly decreased GFR, and broad casts in urine.

Goodpasture's Syndrome

An autoimmune disorder involving autoantibodies directed against the glomerular basement membrane, often preceded by a viral respiratory illness and presenting with hemoptysis, dyspnea, proteinuria, hematuria, and RBC casts.

IgA Nephropathy

A glomerular disorder characterized by the deposition of IgA-containing immune complexes on the glomerular membrane and elevated serum IgA, typically presenting as macroscopic hematuria following infection or exercise.

Nephrotic Syndrome

A condition resulting from severe glomerular membrane damage that permits massive protein loss into urine, presenting with marked proteinuria, hypoproteinemia, peripheral edema, hyperlipidemia, lipiduria, oval fat bodies, and fatty/waxy casts.

Acute Tubular Necrosis (ATN)

Damage and destruction of renal tubular epithelial cells caused by severe ischemia (e.g., shock, trauma, surgery) or nephrotoxic agents (e.g., antibiotics, radiographic contrast media, heavy metals), characterized by prominent RTE cells and RTE casts.

Fanconi Syndrome

A generalized reabsorption failure in the proximal convoluted tubule (PCT) affecting glucose, amino acids, phosphorus, sodium, potassium, bicarbonate, and water, classically presenting with glucosuria in the presence of normal blood glucose.

Nephrogenic Diabetes Insipidus

A tubular defect in which renal tubules fail to respond properly to antidiuretic hormone (ADH), leading to the excretion of large volumes of pale-yellow urine with low specific gravity.

Renal Glucosuria

An inherited autosomal-recessive disorder characterized by a decreased number or reduced affinity of tubular glucose transporters, causing glucose excretion in urine despite normal serum glucose levels.

Acute Pyelonephritis

An upper urinary tract infection typically resulting from ascending bacterial migration (most commonly Escherichia coli), characterized by rapid onset, urinary burning, frequency, lower-back pain, and the presence of WBC casts in urine.

Acute Interstitial Nephritis (AIN)

An allergic inflammatory reaction of the renal interstitium, commonly induced by medications such as antibiotics, NSAIDs, or diuretics, manifesting as fever, skin rash, oliguria, hematuria, proteinuria, and urinary eosinophils without bacteria.

Isosthenuria

A clinical state seen in end-stage renal disease (ESRD) where the urine specific gravity remains fixed at approximately $1.010$, reflecting total loss of the kidney's capacity to concentrate or dilute urine.

Calcium Oxalate

The most frequently encountered chemical component of renal calculi (kidney stones).

Overflow Metabolic Disorder

A disorder in which a disrupted metabolic pathway causes a plasma substance to accumulate until it exceeds the tubular reabsorptive threshold, resulting in elevated concentrations in both blood and urine.

Renal Metabolic Disorder

A metabolic defect involving an impaired tubular reabsorption or transport mechanism, resulting in an abnormal accumulation of a substance in urine while blood levels remain normal.

Phenylketonuria (PKU)

An inherited metabolic disorder caused by a deficiency of phenylalanine hydroxylase, preventing the conversion of phenylalanine to tyrosine and leading to mental development delays, fair skin/hair, seizures, and a mousy urine odor.

Tyrosyluria

The excretion of increased concentrations of tyrosine and its metabolites in urine, which can lead to the formation of microscopic tyrosine and leucine crystals.

Melanuria

The urinary excretion of melanin or its precursor melanogen, commonly associated with malignant melanoma, which oxidizes upon exposure to air and darkens the urine to dark brown or black.

Alkaptonuria

An inborn error of metabolism caused by a deficiency of homogentisic acid oxidase, causing homogentisic acid accumulation in tissues, cartilage pigmentation, and urine that turns black under alkaline conditions.

Maple Syrup Urine Disease (MSUD)

An inborn metabolic disorder involving an enzyme deficiency that impairs the metabolism of the branched-chain amino acids leucine, isoleucine, and valine, resulting in keto-acid accumulation and a characteristic maple-syrup urine odor.

Isovaleric Acidemia

A branched-chain organic acidemia caused by deficient isovaleryl coenzyme A metabolism, recognizable by a distinct sweaty-feet odor in affected individuals.

Indicanuria

A condition caused by intestinal disorders that increase the bacterial conversion of tryptophan to indole, which is converted by the liver to indican and oxidizes to indigo blue upon exposure to air.

5-Hydroxyindoleacetic Acid (5-HIAA)

A degradation product of serotonin that is excreted in markedly elevated amounts in the urine of patients with malignant intestinal carcinoid disorders.

Porphyrias

A group of inherited or acquired metabolic disorders resulting from enzyme deficiencies or toxic inhibition along the heme synthesis pathway, causing accumulation of porphyrins and precursors that can turn urine a port-wine color upon air exposure.

Lesch–Nyhan Disease

An inherited disorder characterized by a complete deficiency of an enzyme in purine metabolism, leading to massive uric acid crystal formation, motor defects, intellectual disability, gout, and pediatric renal calculi.

Cerebrospinal Fluid (CSF)

A clear body fluid formed by selective filtration in the choroid plexuses that protects the central nervous system, regulates intracranial pressure, delivers nutrients to neural tissues, and removes metabolic waste.

Xanthochromia

A pink, orange, or yellow discoloration of cerebrospinal fluid supernatant commonly caused by red blood cell degradation products following a cerebral hemorrhage.

Monosodium Urate (MSU) Crystals

Needle-shaped crystals found inside or outside cells in synovial fluid under polarizing microscopy, characteristic of gout.

Calcium Pyrophosphate Dihydrate (CPPD) Crystals

Rhombic, square-shaped, or rod-like crystals frequently located in the vacuoles of neutrophils in synovial fluid, characteristic of pseudogout.

Transudate

A non-inflammatory serous fluid effusion resulting from systemic hemodynamic disruptions (e.g., congestive heart failure), characterized by a clear/pale-yellow appearance, total protein $\le 3\,\text{g/dL}$, specific gravity $< 1.015$, normal LDH, and glucose equal to serum.

Exudate

An inflammatory serous fluid effusion resulting from local mesothelial membrane damage, infection, or malignancy, characterized by a cloudy appearance, total protein $> 3\,\text{g/dL}$, specific gravity $> 1.015$, increased LDH, and elevated WBC counts.

Lecithin/Sphingomyelin (L/S) Ratio

A clinical laboratory assay performed on amniotic fluid to evaluate fetal pulmonary maturity.

Alpha-fetoprotein (AFP)

A diagnostic biochemical marker tested in amniotic fluid to screen for fetal neural tube defects.