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Flashcards in Renal: Pathology Deck (63):

  • Kidneys connected at the Lower Pole
  • Most common congenital Renal anomaly
  • Abnormally located in the Lower abdomen
  • Gets caught on the Inferior Mesenteric Artery root during Ascent from the Pelvis Abdomen

Horseshoe Kidney


  • Absent Kidney formation → Unilateral or Bilateral
  • Unilateral agenesishypertrophy of the existing Kidney and Hyperfiltration leads to increase risk of Renal failure later in life
  •  Bilateral agenesisOligohydramnios w/ Lung Hypoplasia, Flat Face, and Low ears and developmental defects of extremities (Potter Sequence) = incompatible w/ Life

Renal Agenesis


  • A condition in pregnancy characterized by a deficiency of amniotic fluid. It is the opposite of polyhydramnios
  • The breathing of the amniotic fluid helps stretches the babies lungs and helps to promote lung development – w/out the lungs fail to develop correctly



  • Noninherited, Congenital malformation of the Renal Parenchyma characterized by Cysts, and Abnormal tissue (e.g. cartilage)
  • Usually unilateral
  • Bilateral – MUST be distinguished from Inherited Polycystic Kidney disease

Dysplastic Kidney


  • Inherited defect – Bilateral enlarged Kidneys
  • Cysts in the Renal Cortex and Medulla
  • Autosomal Recessive - PKHD1 (6q21-p23)– form presents in infants as worsening Renal failure and Hypertension
    • Newborns present w/ Potter Sequence
      • Congenital Hepatic Fibrosis (Portal Hypertension)
      • Hepatic cysts – in the Liver and Kidney
  • Autosomal Dominant Young Adults as Hypertension due to increased Renin, Hematuria, and Worsening Renal Failure
    • Mutations APKD1 (16p13.3) or APKD2 (4q21) genes – cysts develop over time
    • A/w Berry aneurysm, Hepatic cysts, Mitral valve prolapse

Polycystic Kidney Disease (PKD)


  • Inherited disease causing Tubulointerstitial fibrosis and Progressive Renal Insufficiency w/ inability to concentrate urine
  • Autosomal dominant defect leading to Cysts in the Medullary collecting ducts
  • Parenchymal Fibrosis results in Shrunken Kidneys and woresening Renal Failure
  • Poor prognosis

Medullary Cystic Kidney Disease


  • Acute, Severe decrease in Renal Function (develops w/in Days) as measured by GFR (Normal 115 - 125 mL/min
  • Hallmark is Azotemia (↑ BUN and ↑ Creatinine [Cr], often w/ Oliguria (Urine < 500 mL/day) or Anuria (Urine < 100mL/day)), Polyuria (> 3 L/day)
    • Increase in nitrogenous waste production
  • Divided into PreRenal, PostRenal, and IntraRenal based on etiology

Acute Renal Failure (ARF)


  • Decreased Blood flow to Kidneys (e.g. cardiac failure) → common cause ARF
  • ↓ RBF → ↓ GFR – Azotemia and Oliguria - ↓ Urine production - Na+ / H2O and Urine retained
  • Reasbsorption of Fluid and BUN ensues (serum BUN:Cr ratio > 15); Tubular function remains intact (Fractional excretion of Na [ FENa] < 1% and Urine osmolality [osm] > 500 mOsm/kg – The Kidneys still have the ability to concentrate the Urine Urine Na < 10 (mEq/L) 

Prerenal Azotemia


  • Due to Obstruction of Urinary Tract downstream from the Kidney (e.g. Ureters)
  • ↓ GFR – Azotemia, and Oliguria
  • Early stage obstruction, increased Tubular pressure “forces” BUN into the blood - Urine Na+ < 20 mEq/L
    • (serum BUN:Cr ratio > 20); Tubular function remains intact
    • (FENa < 1% and Urine [osm] > 500 mOsm/kg – tubules still function
  • Long stage obstruction, Tubular damage ensues, resulting in decreased reabsorption of BUN
    • (serum BUN:Cr ratio > 15)
    • Decreased reabsorptoin of sodium (FENa > 4%) and Urine [osm] < 350 mOsm/kg, Urine Na > 40 mEq/L

Postrenal Azotemia


  • Injury and Necrosis of Tubular Epithelial cells
  • Most common cause of Acute Renal Failure (ARF) (intrarenal azotemia) may have Oliguria and Azotemia
  • A/w Rhabdomyolysis and Crush injury
  • Necrosis cells plug Tubules; Obstruction decreases GFR
  • Muddy-brown, Granular, Casts are seen in the Urine
  • Dysfunctional Tubular Epithelium results in Decreased Reabsorption of BUN (serum BUN:Cr ratio < 15)
  • Decreased reabsorption of sodium (FENA > 2%)
  • Inability to concentrate Urine (Urine [osm] < 500 mOsm/kg)

Acute Tubular Necrosis


  • Decreased blood supply results in Necrosis of Tubules (decreased ATP leads to ischemia)
  • A/w rupture of the Basement membrane (Tubulorrhexis)
  • 1st: Often Preceded by Prerenal Azotemia
  • Proximal Tubule and Medullary segment of the Thick Ascending Limb are particularly Susceptible to Ischemic Damage

Ischemic Acute Tubular Necrosis


  • Toxic agents result in Necrosis of Tubules
  • Proximal tubule is particularly susceptible
  • 2nd: Causes include Aminoglycosides (most common), Heavy metals, Myoglobinuria (crush inj.), Ethylene glycol (a/w oxalate crystals in urine), Radiocontrast dye, Urate, Tumor lysis syndrome
  • Hydration and Allopurinol are used prior to initiation of Chemotherapy to Decrease risk of Urate-induced ATN
  • Dx: Oliguria (2-3 weeks before recovery, regen.) w/ 'Muddy' Brown Granular casts
  • Elevated BUN and Creatinine
  • Hyperkalemia w/ Metabolic acidosis – decreases excreating of organic acids – Anion gap
  • Tx: Reversible but requires Supportive Dialysis since Electrolyte imbalance – Fatal (Oliguric phase)

Nephrotoxic Acute Tubular Necrosis


  • Drug-induced Hypersensitivity involving the Interstitium and Tubules - acting as Haptens
  • Results in Acute Renal Failure (intrarenal azotemia)
  • Caused by NSAIDS, Penicillin, and Diuretics
  • Presents w/ Oliguria, Fever, and Rash days to weeks after starting a drug; Eosinophils and Azotemia may be seen in Urine
  • WBC casts
  • Resolves w/ cessation of drug
  • May progress to Renal papillary necrosis

Acute Interstitial Nephritis


  • Necrosis of Renal papillae 'sloughing'
  • Presents w/ Gross Hematuria and Flank Pain
  • Polyuria, Rust-colored urine, ARF, Sediment, Casts
  • CXR - Ring of calcification (neprocalcinosis)
  • Causes include:
    • Chronic Analgesic abuse (long term Phenacetin or Aspirin use) (Acetaminophen is a derivative)
    • Diabetes mellitus
    • Sickle cell traits or Disease
    • Severe Acute Pyelonephritis

Renal Papillary Necrosis


  • Glomerular disorders characterized by Proteinuria (> 3.5 g/day) resulting in:
    • Hypoalbuminemia – pitting edema
    • Hypogammaglobulinemia – increased risk of infection – protein in blood
    • Hypercoagulable state – due to loss of Antithrombin III – loss of anti-coagulant protein – breaking up of thrombi and prevention of thrombi anti-coagulet
    • Hyperlipidemia and Hypercholesterolemia – may result in Fatty Casts in urine – thin blood – Liver adds Fat to Thicken the blood

Basics of Nephrotic Syndrome


  • Most common cause of Nephrotic syndrome in Children (idopathic) (80%)
  • Usually Idiopathic; may be a/w Hodkin lymphoma (cytokine-mediated damage)
  • Normal glomeruli on H&E stain; Lipid may be seen in Proximal tubule cells - "Lipoid nephrosis" - 'Foamy'
  • Effacement of Foot processes on electron microscopy
  • No immune complex deposits; negative immunofluorescence – not deposit mediated
  • Selective Proteinuria (Loss of Albumin, but not immunoglobulin)
  • Excellent response to Corticosteroids (knock out cytokine production) (damage is mediated by cytokines from T cells)
    • Hodgekins Lymphoma – overproduction of cytokines by Reed-Sternberg cells – Fever, Chills, Night sweats

Minimal Change Disease (MCD)


  • Most common cause of Nephrotic Syndrome in Hispanics and African Americans
  • Usually Idiopathic; may be a/w HIV, Heroin use, and Sickle cell disease, Massive obesity, INF treatment
  • Focal accumulation of Hyaline material (<50%) (some glomeruli) and Segmental Sclerosis (involving only part of the glomerulus) – sclerosis on H&E stain
  • Effacement of Foot processes on EM
  • No immune complex deposists; Negative IF
  • Poor response to steroids -> Cyclophosphamide and Cyclosporine -> Progresses to Chronic Renal Failure

Focal Segmental Glomerulosclerosis (FSGS)


  • Most common cause of Nephrotic syndrome in Caucasian Adults
  • Usually idiopathic; may be a/w Hepatitis B and C, Solid tumors, SLE, Rheumatoid arthritis, Syphilis, Schistosomiasis, Malaria, Leprosy, Phospholipase A2 receptor, Drugs (NSAIDs and Penicillamine)
  • GBM Thickening on H&E w/ 'Spike and dome'
  • Due to Immune Complex Deposition (granular IF; subepithelial deposits), and Nephrotic SLE
  • Poor response to Steroids progresses to Chronic Renal Failure

Diffuse Membranous Glomerulopathy


  • Thick Glomerular basement membrane on H&E, often w/ ‘TRAM-Track’ appearance - Hypercellular glomeruli
  • Immune Complex Deposition (granular IF)
  • Dividied into (2) Types based on Location of Deposits
    • Type ISubendothelial (HBV, HCV, Cryoglobulinemia) (Type III Hypersensitivity)
    • Type II – "dense deposit disease" – Intramembranous; a/w C3 Nephritic Factor (auto-Ab that Stabalizes C3 Convertase, leading to Overactivation of Complement, inflammation, and Low Levels of circulating C3), No IgG present
  • Poor response to Steroids; progresses to Chronic Renal Failure

Membranoproliferative Glomerulonephritis


  • High Serum glucose leads to Nonenzymatic glycosylation of the Vascular basement membrane resulting in Hyaline arteriolosclerosis (basement membrane becomes Leaky – leaking protein – Hyaline prolif.) -> mesangial expansion
  • Glomerular Efferent >> Glomerular Afferent in the Arteriole – leading to High Glomerular Filtration process
    • Hyperfiltration injury leads to Microalbuminuria
  • Eventually progresses to Nephrotic Syndrome
    • Characterized by Sclerosis of the Mesangium w/ formation of Kimmelstiel-Wilson nodules
  • ACE inhibitors slow progression of Hyperfiltration-induced damage

Diabetic Nephropathy


  • Kidney is the most commonly involved organ in Systemic Amyloidosis
  • Amyloid deposists in the Mesangium, resulting in Nephrotic Syndrome
  • Characterized by Apple-green Birefringence under Polarized light after straining w/ Congo red

Systemic Amyloidosis


  • Glomerular Inflammation and Bleeding -> Hematuria
  • Mild Proteinuria (< 3.5 g/day)
  • Oliguria (< 400 mL/day) and Azotemia (↑ BUN and Creatinine) – decrease in urine and increase in nitrogenous waste products w/in the blood
  • RAAS w/ Periorbital / Pitting Edema and Hypertension
  • RBC casts and Dysmorphic RBCs in urine
  • Biopsy reveals Hypercellular, Inflamed glomeruli
  • Immune-complex deposition activates complement; C5a attracts Neutrophils – which Mediate damage – Hypercellularity
  • C3 levels, anti-GBM titer, and ANCA titer

Nephritic Syndrome


  • Nephritic syndrome w/ Group A β-hemolytic Streptococcal Infection of the skin (impetigo) or pharynx - 'Starry-sky' appearance - Type III Hyper.
  • W/ Nephritogenic strains – Carry M protein Virulence Factor - Serum chemistry -> Antitreptolysin-O and anti-DNAase B are elevated, ANCA and anti-GBM neg.
  • After Infection w/ Nonstreptococcal organisms as well
  • Presents 2 -3 weeks after infection as Hematuria (cola-colored urine), Oliguria, Hypertension, and Periorbital edema -> "Smokey-brown" or "Cola-colored" urine
  • Usually seen in Children but may occur in Adults
  • Hypercellular, inflamed Glomeruli on H&E
  • Mediated by immune complex deposition (Granular IF); Subepithelial ‘humps or lumpy-bumpy’ on EM
  • Tx: Children rearely (1%) profress to Renal Failure
    • Some Adults develop Rapidly Progressive Glomerulnephritis (RPGN) (wks – mths)

Poststreptococcal Glomerulonephritis (PSGN)

Acute Proliferative Glomerulonephritis


  • Malignant form of Nephritic syndrome that progresses to Renal Failure in Weeks to Months
  • Characterized by Crescents in Bowman space (of Glomeruli) on H&E stain
  • Crescents are comprised of Fibrin and Macrophages
  • Clinical picture and IF help resolve etiology
  • (3) Distinct Types:
    1. ​Goodpasture syndrome - Type II, ANCA-negative
    2. Poststrep GN, SLE, IgA neph. Henoch-Schonlein purpura - ANCA-negative - Type III
    3. Wegener granulo. or ideopathic - PR3-ANCA / c-ANCA - positive

Rapidly Progressive Glomerulonephritis


  • IgA immune complex deposition in Mesangium of Glomeruli
  • Most common nephropathy worldwide
  • Presents during Childhood as Episodic Gross or Microscopic Hematuria w/ RBC casts
  • Usually following Mucosal Infection – IgA production in increased during Infection, a/w Hnoch-Schonlein purp.
  • IgA immune complex deposition in the Mesangium is seen on IF – glomerular bleeding
    • Every episodic infection you get bleeding from the Kidney a/w Celiac disease
    • Slow progress to Renal failure

IgA Nephropathy (Berger Disease)


  • Hereditary Glomerular injury, defect in Type IV collagen
  • Most commonly X-linked --> Mostly males
  • Results in Thinning and Splitting of the Glomerular basement membrane 'Foamy' changes
  • Presents as Gross Hematuria (males) and Sensory Hearing Loss and Ocular distribution – damage to basement membrane (nerve deafness, lens dislocation, cataracts) -> Females are carriers (mild symptoms)
  • Presented w/in Family History
  • ANCA and anti-GGM both negative, C3 lvls normal

Alport Syndrome (Hereditary Nephritis)


  • Infection of Urethra, Bladder, or Kidney
  • Most commonly arises due to Ascending Infection, Increased Incidence in Females
  • Risk factors include Sexual Intercourse, Urinary stasis, and Catheters

Basics of Urinary Tract Infection


  • Infection / Inflammation of the Bladder
  • Presents as Dysuria, Urinary frequency, Urgency, and Suprapubic pain, Systemic signs (Fever) are usually absent - "Honeymoon cystitis", indwelling catheters
  • Lab:
    • Urinalysis – cloudy urine w/ > 10 WBC/high power field
    • Neg. Culture – UrethritisChlamydia trachomatis and Neisseria gonorrhoeare
    • Dipstick – Positive leukocyte esterase (due to Pyuria) and Nitrites (bacteria convert Nitates to Nitrites)
    • Culture – greater than 100,000 colony forming units (GOLD-Standard)
  • Etiology: E. coli (80%), Stapjylococcus saprophyticus (young sexually active women), Klebsiella pneumoniae, Proteus mirabilisAlkaline urine w/ Ammonia scent, Enteroccus faecalis, Adenovirus



  • Infection of the Kidney - Cortex
  • Usually due to Ascending infection – increased Risk w/ Vesicoureteral reflux
  • Fever, Flank pain, WBC casts, and Leukocytosis, in addition to symptoms of Cystitis - 'striated parenchymal enhancement'
  • Most commonly: Tx: ABX
    • E. coli (90%)
    • Enterococcus faecalis (species)
    • Klebsiella species

Acute Pyelonephritis


  • Interstitial fibrosis / scarring and Atrophy of Tubules due to Multiple bouts of Acute Pyelonephritis
  • Vesicourecteral reflux (VUR) (Children) or Obstruction (Benign prostati hypertrophy BPH or Cervical carcinoma) - due to predisposition to infections
  • Leads to Cortical scarring w/ Blunted calyces
    • Low-grade Fever, Flank pain, Nausea / Vomiting, Failure to thrive, HTN, Renal insufficiency, Protenuria
    • Atrophic tubules containing Eosinophilic proteinaceous material resemble Thyroid follicles (‘Thyroidization’ of the Kidney, waxy casts may be seen in Urine)

Chronic Pyelonephritis


  • Precipitation of a Urinary solute as a Stone
  • Risk factors include High concentration of Solute in the Urinary filtrate and Low Urine Volume
  • Presents as a Colicky Pain w/ Hematuria and Unilateral Flank Tenderness
  • Stone is usually passed w/in Hours; if not, Surgical Intervention may be required



  • Radiopaque Stone type, Adults, Colorless Octahedron
  • Calcium Absorption of the gut > Excretion in the Urine or Primary Renal defect of Calcium re-absorption
  • Most common cause is Idiopathic Hypercalciuria, 2nd Hyperparathyroidism, Vit. D intoxication, Sarcoidosis; Hypercalcemia and its related causes must be excluded
  • Can also form from Ethylene glycol (antifreeze)
  • a/w Crohn disease – small bowel damage – increased abs. Oxolate – binds Ca2+ - stone
  • Tx: Hydrochlorothiazide (calcium-sparing diuretic)

Calcium Oxalate stones (↓ pH)
Calcium Phosphate stones (↑ pH)


  • 2nd most common Stone type
  • RadioopaqueRectangular prism, like 'Coffin-lids'
  • Most common cause is Infection w/ Urea-positive organisms (Proteus vulgaris, Staphylococci, Klebsiella, and Psuedomonas, but NOT E. coli); Alkaline urine leads to formation of stone + ABX
  • Results in Staghorn calculi cast (kidney stone) in Renal Calyces – act as a Nidus for Urinary tract infections
  • Tx: Surgical removal of stone (size) and Eradication of Pathogen, Carbonic anhydrase inhibitors (Acetazolamide)

Ammonium Magnesium Phosphate (AMP stone) (↑ pH)



  • Third most common stone (5%)
  • Radiolucent on CXR
  • Yellow or Red-brown, Diamond or Rhombus
  • Hot, Arid climates, Low urine volume, Acidic Urine pH
  • Most common stone seen in pts. w/ Gout
  • Hyperuricemia (in Leukemia or Myeloproliferative disorders) increases risk
  • Tx: Hydration and Alkalinization of Urine (potassium bicarbonate); Allopurinol is also administered in pts. w/ Gout

Uric acid (↓ pH)


  • Rare cause of Nephrolithiasis; most commonly see in Children
  • A/w Cystinuria (a genetic defect of tubules that results in decreased reabsorption of Cysteine, Ornithine, Lysine, Arginine), more likely in Acidic Urine pH
  • Fairly opaque w/ Ground-glass appearance CXR
  • Sodium nitroprusside test
  • Flat, Yellow, Hexagonal
  • May form Staghorn calculi
  • Tx: Hydration and Alkalinization of Urine

Cystine Stones (↓ pH)


  • End-stage Kidney Failure – may result from Glomerular, Tubular, Inflammatory, or Vascular insults
  • Most common causes are Diabetes mellitus, HTN, and Glomerular disease (GFR < 60 mL/min)
  • Uremia, Azotemia, Nausea, Anorexia, Pericarditis, Platelet dysfunction, Encephalopathy w/ Asterixis, Deposition of Urea crystals in skin
  • Salt and Water retention w/ resultant Hypertension
  • Hyperkalemia w/ Metabolic acidosis – cannot get rid of organic acids
  • Anemia due to decreased Erythropoietin production by Renal Peritubular Interstitial cells
  • Hypocalcemia due to decreased 1-alpha-hydroxylation of Vit. D by Proximal Renal tubule cells and Hyperphosphatemia – cannot excrete PO4 bind to Ca2+ - low [Ca2+]
  • Renal Osteodystrophy – due to secondary Hyperparathyroidism osteomalacia and osteoporosis
  • Tx: Dialysis or Renal Transplant w/ cysts in shrunken end-stage Kidneys on dialysis

Chronic Renal Failure


  • Hamartoma comprised of (3) components
    • Blood vessels
    • Smooth muscle
    • Adipose tissue
  • Increased frequency in Tuberous sclerosis



  • Malignant epithelial tumor from Proximal tubules
  • Classic Triad (3) Hematuria (most common), Palpable mass, and Flank pain, Polygonal clear cells
  • Fever, Weight loss,  or Paraneoplastic syndrome (EPO – reactive polycythemic??, Renin – HTN, PTHrP – Hyper Ca2+, ACTH – Coshney’s symptom??)
  • A/w Left-sided Variocele – left spermatic vein involvement, Men - 50 - 70 years-old
  • Yellow-Mass w/ clear cytoplasm
  • Loss of VHL (3p) tumor supressor gene – increased IGF-1 (promotes growth) – increase HIF transcription factor – increases VEGF and PDGF
  • Sporadic – adult makes (60 y.o.) single tumor in Upper pole of Kidney
  • Hereditary tumors – young adults, Bilateral tumor, Von Hippel-Lindau disease (VHL gene)

Renal cell Carcinoma


  • Malignant Kidney tumor comprised of Blastemal (immature kidney mesenchyme), Primitive Embryonic Glomeruli and Tubules, and Stromal cells
  • Common in Children, avg. 2 - 4 y.o.
  • Large, Unilateral Flank mass w/ Hematuria and Hypertension (Renin secretion)
  • (3) Sporadic (90%) tumors w/ syndromic tumors
  1. WAGR syndromeWilms tumor, Aniridia, Genital abnormalities, and Mental and Motor Retardation a/w deletion of WT1 tumor suppressor gene (11p13)
  2. Denys-Drash syndrome – Wilms tumor, progressive Renal (glomerular) disease, and male Pseudohermaphroditism, a/w mutation of WT1
  3. Beckwith-Wiedemann syndrome – Wilms tumor, neonatal hypoglycemia, muscular hemihypertrophy, and organomegaly (including tongue); a/w WT2 gene cluster (11p15.5 ) particularly IFG-2

Wilms Tumor


  • Maliginant tumor; Urothelial lining of Renal pelvis, Ureter, Bladder, or Urethra
  • Most common type of Lower Urinary tract cancer (Bladder) (No casts)
  • Pee SAAC-N - Phenacetin, Smoking, Aniline/Azo dyes Long - term Cyclophosphamide and Naphthylamine
  • Older adults; w/ Painless Hematuria
  • (2) Pathways
  1. Flat – High-grade tumor then Invades, a/w early P53 mutation
  2. Papillary – low-grade papillary tumor then High-grade then Invades, NOT a/w P53 mut.
  • Multifocal and Recur (‘Field defect’ = entire endothelium has been exposed to carcinogen exp.)

Urothelial (Transitional cell) Carcinoma


  • Maliginant tumor, Squamous cells, usually w/in Bladder
  • In background of Squamous metaplasia (normal bladder does not have squamous epithelium)
  • 'Warty' or Ulcerated lesions
  • Chronic cystitis (older woman), Schistosoma hematobium infection (Middle Eastern and Egyptian males), and Long-standing Nephrolithiasis (chronic infection / Cystitis in young males)

Squamous Cell Carcinoma


  • Maliginant proliferation of Glands, usually involving the Bladder
  • Arises from a Urachal Remnant (@ the Dome of the Bladder)
    • Urachus is a duct that connect the Bladder into the Yolk sac – remnant becomes Adenocarcinoma
  • Cystitis glandularis (columnar metaplasia)
  • Exstrophy (congenital failure to form the Caudal portion of the Anterior abdominal wall and Bladder walls)



Diseases associated w/ Red Blood Cell casts?

  • Glomerulonephritis
    • IgA nephropathy
    • Poststreptococcal glomerulonephritis
  • Goodpasture syndrome (rapidly progressive glomneph.)
  • Malignant HTN
  • Vasculitis
  • Renal ischemia


What diseases are a/w White Blood Cell casts?

  • Acute Pyelonephritis
  • Interstitial nephritis
    • Tubulointerstitial inflammation
  • Lupus Nephritis
  • Transplant rejection
  • WBCs in Urine indicate UTI


What diseases are a/w
Granular 'Muddy-brown' casts?

  • Acute Tubular Necrosis (ATN)
  • Chronic Renal failure
  • Nephrotic Syndrome
    • Fatty casts are also seen in Nephrotic syndrome


What diseases are a/w Epithelial cell casts?

  • Acute tubular necrosis (ATN)
  • Ethylene glycol toxicity
  • Heavy-metal poisoning
  • Acute rejection of Transplant graft


What diseases are a/w Hyaline casts?

  • Often seen in Normal Urine
  • Concentrated urine samples
  • Pyelonephritis


  • Deposition of Fibrous, Insoluble proteins in β-pleated configuration deposits in the Kidney
  • 'Light-chain deposition disease'
  • Proteinuria, Severe-Edema, Renal insufficiency, also a/w secondary diseases (Multiple Myeloma, TB, RA, etc.)
  • Congo red stain -> Apple-green birefringence = amyloidosis
  • Tx: Melphalan and Prednisone

Renal Amyloidosis


  • A/w both Nephrotic and/or Nephritic syndromes
  • Weight gain, High BP, Darker 'foamy' urine, Swelling around the eyes, legs, ankles, or fingers
  • A/w 5 classes of involvement

Lupus Nephritis

  • Class I - No evidence of disease
  • Class II - Mesangial involvement
  • Class III - Focal proliferative nephritis
  • Class IV - Diffuse proliferative nephritis (most common type in SLE)
  • Class V - Membranous nephritis, characterized by extreme edema and protein loss


  • antibodies against proteins in Globular Basement Membrane (anti-GBM)
  • Can be seen in Lung and Kidnes due to cross-reactivity of antigens (eg. α3 chain of collagen type IV) common to both alveolar and GBM
  • Type II Hypersensitivity
  • Hematuia, Proteinuria, and Rapidly Progressive Glomerulonephritis (RPGN), Hymoptysis, Dyspnea
  • Serum anti-GBM Ab, ANCA typically neg. C3 is normal
  • RBC casts and mile proteinuria, Linear ribbon-like IgG

Goodpasture syndrome


  • Focal / Segmental Necrotizing vasculitis and Necrotizing granulomas in Upper and Lower respiratory tract (Lungs) w/ occasional Crescent Formation
  • Nonspecific symptoms, Fever, Arthralgias, Lethargy, Malaise, Chronic sinusitis, Hemoptysis, and Hematuria
  • Nephritic symptoms and mild Proteinuria
  • Cytoplasmic staining ANCA (c-ANCA) - positive
  • NO IgG or anti-GBM, and Complement are normal
  • Tx: Corticosteroids and Cyclophosphamide w/ Dialysis and Renal Transplantation

Wegener Granulomatosis


  • Develops as a result of 'patchyInfarction of the Cortices of the Kidney secondary to Ischemia -> can progress to Acute Renal Failure (ARF) - Bilateral
  • A/w Abruptio placentae, Eclampsisa / Preeclampsia, Septic shock, Hemolytic-uremic syndrome (in children)
  • Sepsis, Disseminated Intravacular Coagulation (DIC), Obstetric complications, Anuria, evidence of ARF, Flank pain, and FEVER

Diffuse Cortical Necrosis


Nephritic Syndrome Diseases?

  • Acute poststreptococcal glomerulonephritis
  • Rapidly progressive glomerulonephritis
  • IgA glomerulonephropathy (Berger disease)
  • Alport Syndrome


Diseases that are both Nephritic and Nephrotic?

  • Diffuse proliferative glomerulonephritis
  • Membranoproliferative glomerunephrtis


Disease of Nephrotic Syndrome?

  • Focal segmental glomerulsclerosis
  • Membranous nephropathy
  • Minimal Change Disease
  • Amyloidosis
  • Diabetic glomerulonephropathy


Consequences of Renal Failure?

    • Metabolic Acidosis
    • Dyslipidemia (esp. ↑ Triglycerides)
    • Hyperkalemia
    • Uremia - marked by Azotemia
    • Na+/H2O retention
    • Growth retardation and developmental delay
    • Erythropoietin Failure (anemia)
    • Renal osteodystrophy


  • Defect in ability of α intercalated cells to secrete H+
  • New HCO3- is not generated -> Metabolic Acidosis
  • A/w Hypokalemia -> ↑ Risk for Ca-PO4 Kidney Stones due to ↑  Urine pH and ↑ Bone turnover
  • Causes: Amphotericin B toxicity, Analgesis nephropathy, Multiple myeloma (light chains), and Congential anomalies (Obstruction) of the Urinary tract

Type I - Renal Tubular Acidosis

(Distal Tubule, pH > 5.5)


  • Defect in Proximal Tublue HCO3- reabsorption
  • Results in ↑ excretion of  HCO3- in Urine and subsequent Metabolic Acidosis
  • Urine is acidificed by α intercalated cells in Collecting Tubule
  • A/w Hypokalemia, ↑ Risk of Hypophosphatemic Rickets -> Fixed acid lost in Urine
  • Causes: Fanconi Syndrome (Wilson disease), Chemicals toxic to Proximal tubule (Lead, Aminoglycosides), and Carbonic Anhydrase Inhibitors 

Type II - Renal Tubular Acidosis

(Proximal, pH < 5.5)


  • ​​Hypoaldosteronism
  • Aldosterone resistance  or K+ - sparing diuretics
  • Results in HyperKalemia -> impairs Ammoniagenesis in the Proximal Tublue
    -> ↓ Buffering capacity  
    -> ↓ H+ excretion into Urine

Type IV - Renal Tubular Acidosis

(HyperKalemic, pH < 5.5)


  • Reabsorptive defect in PCT
  • A/w ↑ Excretion of nearly all Amino acids, Glucose, HCO3-, and PO43-
  • May result in Metaboic Acidosis (Proximal Renal Tubular Acidosis) -> HyperKalemia
  • Causes: Hereditary defects (Wilson disease), Ischemia, and Nephrotoxins / drugs
  • The Kidneys put out FABulous Glittering Liquid

Fanconi Syndrome

  • FABulous Glittering Liquid
  • FAnconi syndrome in the 1st defect of PCT
  • Bartter syndrome is next (Thick ascending loop of Henle)
  • Gitelman syndrome is after Bartter (DCT)
  • Liddle syndrome is last (Collecting tubule)


  • Reabsorptive defect in Thick Ascending Loop of Henle
  • Autosomal recessive
  • Affects Na+ / K+ / 2Cl- Cotransporter
  • Results in HypoKalemia and Metabolic Alkalosis w/ HyperCalciuria

Bartter Syndrome


  • Reabsorptive defect of NaCl in DCT
  • Autosomal recessive
  • Less severe than Bartter syndrome
  • Leads to HypoKalemia and Metabolic alkalosis, but w/out HyperCalcuria

Gitelman Syndrome


  • ↑ Na+ reabsorption in Distal and Colecting tubules
    (↑ activity of Epithelial Na+ channel)
  • Autosomal dominant
  • Results in HTN, HypoKalemia, Metabolic alkalosis,
    ↓ Aldosterone
  • Tx: Amiloride

Liddle Syndrome