Renal Disease, Metabolic Disorders, and Body Fluids

Comprehensive vocabulary flashcards covering renal diseases, metabolic urine disorders, and clinical body fluid analysis based on lecture notes.

Acute Glomerulonephritis (AGN)

A glomerular disorder caused by immune complexes depositing on glomerular membranes $1\text{--}2\,\text{weeks}$ after a Streptococcus infection, leading to inflammation, hematuria, proteinuria, oliguria, and RBC casts.

Chronic Glomerulonephritis (CGN)

A progressive renal disorder resulting from persistent glomerular injury, characterized clinically by fatigue, anemia, hypertension, edema, oliguria, markedly decreased GFR, and broad casts.

Goodpasture's Syndrome

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

IgA Nephropathy

A glomerular condition characterized by deposition of IgA-containing immune complexes on the glomerular membrane, classically presenting with visible macroscopic hematuria following physical exercise or infection.

Nephrotic Syndrome

A renal disorder marked by severe disruption of the glomerular filtration membrane, leading to massive proteinuria, hypoproteinemia, edema, hyperlipidemia, and lipiduria with oval fat bodies and fatty casts.

Acute Tubular Necrosis (ATN)

The destruction and death of renal tubular epithelial cells caused by severe renal ischemia (e.g., shock, trauma, surgery) or nephrotoxins, characterized by noticeable renal tubular epithelial (RTE) cells and RTE casts in urine sediment.

Fanconi Syndrome

A generalized tubular dysfunction characterized by defective reabsorption in the proximal convoluted tubule (PCT), leading to urinary wasting of glucose, amino acids, phosphorus, sodium, potassium, bicarbonate, and water despite normal blood levels.

Nephrogenic Diabetes Insipidus

A condition in which renal tubules fail to respond properly to antidiuretic hormone (ADH), producing high volumes of pale-yellow urine with consistently low specific gravity.

Renal Glucosuria

An inherited autosomal-recessive defect involving absent or reduced-affinity tubular glucose transporters, resulting in glucosuria despite completely normal blood glucose concentrations.

Acute Pyelonephritis

An acute upper urinary tract infection usually caused by bacteria ascending from the lower urinary tract, presenting with urinary frequency, burning, lower-back pain, WBCs, and WBC casts in urine.

Chronic Pyelonephritis

A chronic upper urinary tract disorder caused by ongoing urinary obstruction or reflux, resulting in chronic inflammation, scarring, fibrosis of renal tissue, and progression toward end-stage renal disease.

Lower Urinary Tract Infection

Infection limited to the bladder (cystitis) or urethra (urethritis), presenting with dysuria, frequency, burning, pyuria, and bacteria, but characteristically lacking urinary casts.

Acute Interstitial Nephritis (AIN)

An allergic inflammatory reaction of the renal interstitium frequently caused by medications such as antibiotics, NSAIDs, or diuretics, presenting with hematuria, proteinuria, oliguria, rash, and increased urinary eosinophils.

Pre-Renal Acute Renal Failure

Acute renal impairment caused by decreased blood flow and hypoperfusion reaching the kidneys, such as from acute hemorrhage or severe shock.

Renal Acute Renal Failure

Acute renal failure resulting from direct acute disease, inflammation, or toxic injury localized within the kidney tissue itself, such as nephrotoxic acute tubular necrosis.

Post-Renal Acute Renal Failure

Acute renal failure triggered by mechanical obstruction to the outflow of urine downstream from the kidneys, such as urinary calculi or bladder tumors.

Isosthenuria

A state in advanced renal disease and ESRD where the urine specific gravity is fixed at approximately $1.010$, reflecting total loss of renal tubular concentrating and diluting capacity.

Renal Calculi

Solid aggregates of crystallized mineral and chemical compounds formed within the urinary tract, most commonly consisting of calcium oxalate.

Overflow Metabolic Disorder

A systemic metabolic dysfunction wherein an enzyme defect or organ malfunction causes an intermediate metabolite to accumulate in blood until it exceeds renal reabsorptive capacity, resulting in elevated levels in both blood and urine.

Renal Metabolic Disorder

A metabolic abnormality caused by an intrinsic defect in renal tubular transport or carrier mechanisms, characterized by excessive urinary excretion of a substance alongside normal blood concentrations.

Phenylketonuria (PKU)

An inborn error of metabolism caused by a deficiency of phenylalanine hydroxylase, preventing conversion of phenylalanine to tyrosine and producing a characteristic mousy urine odor.

Tyrosyluria

The excretion of excess tyrosine and its metabolites in urine due to premature neonatal liver immaturity, severe acquired liver disease, or inborn enzymatic deficiencies, potentially showing microscopic tyrosine and leucine crystals.

Melanuria

The excretion of melanin metabolites in urine, often secondary to malignant melanoma, where colorless melanogen oxidizes upon air exposure to produce a dark brown or black appearance.

Alkaptonuria

An inherited metabolic disease caused by a deficiency of homogentisic acid oxidase, leading to accumulation and excretion of homogentisic acid that turns urine black when exposed to alkaline conditions.

Maple Syrup Urine Disease (MSUD)

An inherited disorder of branched-chain amino acid metabolism affecting leucine, isoleucine, and valine, resulting in keto-acid accumulation in blood and urine and producing a distinct maple-syrup odor.

Isovaleric Acidemia

An organic acid disorder caused by deficient isovaleryl coenzyme A metabolism, which leads to metabolic acidosis, vomiting, and a characteristic sweaty-feet odor.

Indicanuria

An abnormal urinary excretion of indican resulting from intestinal disorders that increase conversion of tryptophan to indole, which converts to colorless indican and oxidizes to indigo blue upon air exposure.

5-Hydroxyindoleacetic Acid (5-HIAA)

A urinary breakdown metabolite of serotonin that is markedly elevated in patients with malignant intestinal carcinoid disorders overproducing serotonin.

Porphyrias

A group of inherited or acquired metabolic disorders resulting from disruption of the heme biosynthetic pathway, causing accumulation of porphyrins or precursors that may impart a port-wine color to urine upon exposure to air.

Mucopolysaccharidoses

A group of inherited conditions (including Hurler, Hunter, and Sanfilippo syndromes) characterized by deficient breakdown and abnormal accumulation of glycosaminoglycans in connective tissue and urine.

Lesch–Nyhan Disease

An inherited enzymatic disorder characterized by hyperuricemia, motor deficits, intellectual disability, self-mutilation, and massive excretion of uric acid crystals in pediatric urine.

Cerebrospinal Fluid (CSF)

A clear fluid produced by the choroid plexuses through selective filtration that flows in the subarachnoid space to protect, cushion, nourish, and regulate intracranial pressure across the central nervous system.

Blood-Brain Barrier

A protective anatomical and physiological barrier formed by tightly joined endothelial cells lining brain capillaries, restricting the passage of large molecules, chemicals, many antibodies, and systemic medications into neural tissue.

Xanthochromia

Pink, orange, or yellow discoloration of cerebrospinal fluid supernatant following centrifugation, most commonly indicative of RBC breakdown products resulting from subarachnoid or cerebral hemorrhage.

Pellicle

A fine, web-like fibrin clot that forms in refrigerated CSF specimens, characteristically associated with tuberculous meningitis.

Oligoclonal Bands

Discrete bands seen upon protein electrophoresis of CSF that reflect local intrathecal immunoglobulin production, classically associated with multiple sclerosis.

Monosodium Urate (MSU) Crystals

Needle-shaped crystals found intracellularly and extracellularly in synovial fluid during polarizing microscopic evaluation, diagnostic of gout.

Calcium Pyrophosphate Dihydrate (CPPD) Crystals

Rhombic, square-shaped, or short rod crystals found within synovial fluid and neutrophil vacuoles under polarizing microscopy, diagnostic of pseudogout.

Serous Effusion

A pathologic accumulation of fluid between the parietal and visceral membranes within a body cavity (pleural, pericardial, or peritoneal spaces).

Transudate

A non-inflammatory serous fluid accumulation resulting from systemic hemodynamic disruptions (e.g., congestive heart failure), characterized by total protein $\le 3\,\text{g/dL}$, specific gravity $< 1.015$, and normal LDH.

Exudate

An inflammatory serous effusion caused by direct damage, infection, or malignancy of the cavity membrane, characterized by total protein $> 3\,\text{g/dL}$, specific gravity $> 1.015$, and increased LDH.

Mesothelial Cells

The specialized simple squamous lining cells of serous membranes that appear as large cells or clusters with abundant blue-gray cytoplasm in serous cavity aspirates.

Lecithin/Sphingomyelin (L/S) Ratio

A biochemical ratio measured in amniotic fluid used clinically to evaluate fetal pulmonary surfactant production and lung maturity.

Alpha-Fetoprotein (AFP)

A protein quantified in amniotic fluid used primarily as a screening biomarker for fetal open neural tube defects.

Three Major Categories of Renal Disease

Glomerular, tubular, and interstitial disease; the lecture also covers renal failure and renal calculi.

Broad Causes of Glomerular Disorders

Immunologic causes and non-immunologic causes.

Immunologic Causes of Glomerular Disorders

Immune-complex deposition, increased serum immunoglobulin deposition, and immune-system mediators.

Non-Immunologic Causes of Glomerular Disorders

Chemicals and toxins, disruption of the membrane, amyloid deposition, and membrane thickening.

Four Highlighted Glomerular Disorders

Glomerulonephritis, Goodpasture’s syndrome, IgA nephropathy, and nephrotic syndrome.

Acute Glomerulonephritis (AGN) Precursor

AGN commonly occurs $1\text{--}2$ weeks after a Streptococcus infection.

Mechanism of Kidney Injury in AGN

Immune complexes deposit on the glomerular membranes, causing inflammation and impaired filtration.

Clinical Symptoms of AGN

Fever, edema around the eyes, fatigue, nausea, and hypertension.

Urinalysis Findings in Acute Glomerulonephritis

Hematuria, proteinuria, oliguria, RBC casts, dysmorphic RBCs, hyaline and granular casts, and WBCs.

Blood and Urine Culture Pattern in AGN

Blood and urine cultures are negative; anti-streptolysin O (ASO) titer is elevated.

Negative Urine Cultures in Post-Streptococcal AGN

The kidney injury is caused by post-infectious immune complexes rather than by bacteria actively growing in the urine.

Prognosis of AGN in Children vs. Adults

Children often recover spontaneously; adults may progress to chronic glomerulonephritis.

Chronic Glomerulonephritis (CGN) Presentation

Fatigue, anemia, hypertension, edema, and oliguria that gradually worsen.

Urinalysis Findings in Chronic Glomerulonephritis

Hematuria, proteinuria, glycosuria from tubular dysfunction, and many types of casts, including broad casts.

Glomerular Filtration Rate in CGN

GFR becomes markedly decreased.

Goodpasture’s Syndrome

An autoimmune disorder involving the formation of antibodies against the glomerular basement membrane.

Respiratory Manifestations of Goodpasture’s Syndrome

May follow viral respiratory disease and can cause dyspnea and hemoptysis.

Urinalysis Findings in Goodpasture’s Syndrome

Proteinuria, hematuria, and RBC casts.

Progression of Goodpasture’s Syndrome

Progression to chronic glomerulonephritis and end-stage renal disease (ESRD) is common.

Etiology of IgA Nephropathy

Immune complexes containing IgA deposit on the glomerular membrane; serum IgA levels are increased.

Characteristic Presentation of IgA Nephropathy

Macroscopic (visible) hematuria after exercise or an infection.

Progression of IgA Nephropathy

May gradually progress to chronic glomerulonephritis and end-stage renal disease (ESRD).

Nephrotic Syndrome

Renal condition where damage to the glomerular membrane allows large amounts of protein to pass into urine.

Mechanism of Edema in Nephrotic Syndrome

Loss of protein lowers blood protein levels, reducing the force that keeps fluid in blood vessels; fluid moves into tissues and causes edema.

Lipid Changes in Nephrotic Syndrome

Hyperlipidemia in blood and lipiduria in urine.

Urinalysis Findings in Nephrotic Syndrome

Marked proteinuria, fat droplets, oval fat bodies, renal tubular epithelial (RTE) cells, fatty and waxy casts, and sometimes hematuria.

Acute Tubular Necrosis (ATN)

Damage and death of renal tubular cells, commonly due to ischemia or nephrotoxic substances.

Ischemic Acute Tubular Necrosis

Tubular damage caused by a severe decrease in renal blood flow, such as with shock, trauma, or surgery.

Nephrotoxic Acute Tubular Necrosis

ATN caused by drugs (antibiotics, anesthetics, X-ray contrast media, chemotherapy) or toxins (heavy metals, organic solvents, poisons).

Management Approach for ATN

Remove the underlying cause and manage symptoms.

Urinalysis Findings in ATN

Noticeable RTE cells and RTE casts; hyaline, granular, waxy, and broad casts may also occur.

Fanconi Syndrome

A generalized failure of reabsorption in the proximal convoluted tubule (PCT).

Reabsorption Deficits in Fanconi Syndrome

Failure to reabsorb glucose, amino acids, phosphorus, sodium, potassium, bicarbonate, and water.

Urinalysis Pattern in Fanconi Syndrome

Glucosuria despite normal blood glucose, along with mild proteinuria.

Nephrogenic Diabetes Insipidus

Condition in which the renal tubules fail to respond properly to antidiuretic hormone (ADH).

Urine Findings in Nephrogenic Diabetes Insipidus

Low specific gravity, pale-yellow urine, and possible false-negative chemical test results because the urine is dilute.

Renal Glucosuria vs. Fanconi Syndrome

Renal glucosuria affects glucose reabsorption specifically; Fanconi syndrome is a generalized proximal-tubule reabsorption failure.

Cause of Renal Glucosuria

An inherited autosomal-recessive defect involving fewer glucose transporters in renal tubules or transporters with reduced affinity for glucose.

Key Laboratory Finding in Renal Glucosuria

Glucose is present in urine even though blood glucose is normal.

Most Common Renal Disease

Urinary tract infection (UTI).

Female Predisposition to UTIs

Females have shorter urethras, hormones influence bacterial adherence to mucosa, and prostate fluid has antibacterial action in men.

Causative Organisms of UTIs

Typically caused by gram-negative rods; Escherichia coli (E. coli) is the most common.

Clinical Features of UTI

Dysuria and lower abdominal pain; increased WBCs and bacteria in urine.

Casts in Urinary Tract Infection

Casts indicate upper urinary tract involvement; they are not expected in a lower UTI.

Pathogenesis of Acute Pyelonephritis

Most commonly by ascending movement of bacteria from the lower urinary tract; bacteria may also descend through the bloodstream.

Conditions Promoting Acute Pyelonephritis

Problems emptying the bladder, obstruction such as calculi, pregnancy, and reflux of urine from the bladder into the ureters.

Symptoms and Urinalysis in Acute Pyelonephritis

Rapid onset, urinary frequency, burning, and lower-back pain; urine contains WBCs and WBC casts.

Chronic Pyelonephritis

Chronic obstruction and reflux nephropathies causing persistent inflammation, scarring, and fibrosis of renal tissue.

Urinalysis Progression in Chronic Pyelonephritis

Early findings resemble acute pyelonephritis; later there may be granular, waxy, and broad casts, increased protein, hematuria, and decreased concentrating ability.

Severe Outcome of Chronic Pyelonephritis

Patients may develop end-stage renal disease (ESRD).

Lower Urinary Tract Infections

Infections confined to the lower urinary tract: cystitis (bladder infection) and urethritis (urethral infection).

Symptoms of Lower UTI

Urinary frequency and burning.

Urinalysis Findings in Lower UTI

Many WBCs and bacteria, increased urine pH, mild proteinuria, and hematuria; casts are absent.

Acute Interstitial Nephritis (AIN)

An allergic reaction that causes inflammation of the renal interstitium, often due to medications.

Medications Listed as Causing AIN

Antibiotics, NSAIDs, and diuretics.

Symptoms of Acute Interstitial Nephritis

Fever, skin rash, oliguria, and edema.