Renal and Urinary Tract Pathology - Part 1 Flashcards
Horseshoe Kidney - Location of Trapping
Inferior Mesenteric Artery
Unilateral Renal Agenesis - Results (2)
1) Hyperfiltration + Hypertrophy of remaining kidney
2) Increased Risk of Renal Failure
Bilateral Renal Agenesis - Pathophysiology + Results (2)
Path - Oligohydramnios (Low Amniotic Fluid from failure of fetus to urinate
Results
1) Not Compatible with LIfe
2) Potter Sequence
Potter Sequence Mnemonic
1) P - Pulmonary Hypoplasia
2) O - Oligohydramnios (Cause)
3) T - Twisted Face
4) T - Twisted Skin
5) E - Extremity Defects
6) R - Renal Agenesis
Dysplatic Kidney - Keys (3)
1) Non-inherited congenital malformation of the renal parenchyma
2) Characterized by cysts and abnormal tissue
3) Usually unilateral without enlargement (bilateral think polycystic kidney disease)
Polycystic Kidney Disease (PKD) - Autosomal Recessive - 3 Keys
1) Bilateral + Associated with Congenital Hepatic Fibrosis
2) Failure can mimic agenesis and lead to symptoms similar to Potter
3) Presents in infancy
Polycystic Kidney Disease (PKD) - Autosomal Dominant - 3 Keys
1) Bilateral + Associated with 3 “Cysts” - Kidney + Liver (Portal HTN) + Brain (Berry Aneurism)
2) Mutation in the APKD1 and APKD2 Gene
3) Presents in young adults
Medullary Cystic Kidney Disease - Keys (2)
1) Autosomal dominant defect in the medullary collecting ducts
2) Results in shrunken kidney
Types of Acute Renal Injury (3) + Alternative Name
1) Prerenal - Reduced Flow
2) Intrarenal - Renal Paranchyma
3) Postrenal - Obstruction
Azotemia (Accumulation of Nitrogenous Waste Products - BUN/Cr) + Oligouria (lack of urine)
Major Types of Intrarenal Azotemia (3)
1) Acute Tubular Necrosis (ATN)
2) Acute Interstital Nephritis (AIN)
3) Renal Papillary Necrosis
Pre-Renal Azotemia - Cause + Findings (5)
Cause - Reduced blood flow to the kidney
1) Oligouria
2) Decreased GFR
3) Elevated BUN/Cr (Azotemia)
4) BUN/Cr Ratio > 15 - Issue is no flow which triggers aldosterone release - Aldosterone release increases in H2O re-absorption and with in BUN - Cr is not reabsorbed so it is not impacted
5) Fractional Excretion of Na (FENa) > 1% indicated the tubule can still reabsorb Na
Post-Renal Azotemia - Cause + Findings (5)
Obstruction - Causes back pressure reducing GFR
1) Oligouria
2) Decreased GFR
3) Elevated BUN/Cr (Azotemia)
4) Changes in BUN/Cr Ratio (Early > 15 //// Late < 15)
5) Changes in FENa (Early < 1% ////// Late > 2%)
Post-Renal Azotemia - Early vs. Late Stage Findings - 2 Each
Early
1) BUN/Cr - Elevated ( > 15) - Increased tubular pressure “pushes” more BUN re-absorption
2) Functioning Tubule = FENa < 1%
Late
1) BUN/Cr - Reduced ( < 15) - Long term obstruction leads to tubular damage - which reduces the number of receptors for BUN re-absorption
2) Loss of Function = FENa > 2%
Acute Tubular Necrosis - Cause + Findings (6)
Cause - Necrosis of Tubular Epithelial Cells
1) Muddy Brown Granular Casts
2) Oliguria
3) Azotemia
4) Hyperkalemia (decreased renal excretion) + metabolic acidosis (decreased organic acid secretion) - Anion Gap
5) BUN/Cr Ratio < 15 (Loss of BUN Re-absorption)
6) FENa > 2% + Inability to Concentrate Urine (Osm < 500)
Acute Tubular Necrosis - Major Types (2)
1) Ischemia - Usually preceeded by pre-renal azotemia - Proximal Tubule + Thick Ascending Limb Hit Worst
2) Nephrotoxic - Toxic agents damage the proximal tubules
Acute Tubular Necrosis - Nephrotoxic Causes (5)
1) Aminoglycosides (most common - Gentamicin)
2) Heavy Metal (Lead)
3) Myoglobuinuria (Crush Injury)
4) Ethylene Glycol (Oxalate Crystals)
5) Tumor Lysis Syndrome (Leukemia treatment massive cell death + increase in uric acid)
Acute Interstitial Nephritis - Pathophysiology
Inflammation of Renal Connective Tissue - Hypersensitivity Reaction with Eosinophils
Acute Interstitial Nephritis - Causes (3) + Findings (4)
Causes
1) NSAIDs
2) Penicllin
3) Diuretics
Findings
1) Eosinophils
2) Oliguria
3) Fever
4) Rash
Renal Papillary Necrosis - Presentating S/Sx (2) + Causes (4)
S/Sx
1) Gross Hematuria
2) Flank Pain
Causes
1) Sickle Cell Trait
2) Diabetes
3) Chronic Analgesic Abuse
4) Severe Acute Pyelonephritis
Nephrotic Syndrome - Basic Findings (5)
1) Proteinuria ( > 3.5g/day)
2) Hypoalbuminemia (Pitting Edema)
3) Hyperlipidemia (Fatty Casts in Liver)
4) Hypogammaglobulinemia - (Loss of Ig) - Increased risk for Infection
5) Hypercoaguable (Loss of Antithrombin III)
Nephritic Syndrome - Basic Findings (5)
1) RBCs (Dysmorphic) and RBC Casts in Urine (Hematuria
2) Low Urine Volume (Oliguria)
3) Only Mild Proteinuria
4) Salt Retention + HTN
5) Hypercellular Glomerulus (Inflammation) with swelling into the Bowman’s Space on H&E
Major Classes of Nephrotic Syndromes (6)
1) Minimal Change
2) Focal Segmental Glomerulosclerosis (FSGS)
3) Memranous Nephropathy
4) Membranoproliferative Glomerulonephritis
5) Diabetes Meleitus
6) Systemic Amyloidosis
Minimal Change Disease - Cause + Key Findings (5)
Cause - Effacement of podocyte foot processes by cytokine storms (T-Cell Based)
Findings
1) Effacement on EM with normal H&E
2) Excellent Response to Steroids
3) Selective Alubmin proteinuria
4) No immune complex deposits (or IF)
5) Most common in children + Hodgkin’s
Focal Segmental Glomerulosclerosis (FSGS) - Cause + Findings (4)
Cause - segmental sclerosis of glomerular filtration units with effacement of foot processes (collagen deposits)
Findings
1) Focal Segmental Sclerosis on H&E
2) EM Effacement of Podocytes
3) No immune complex deposits (or IF)
4) Non-response to steroids
Focal Segmental Glomerulosclerosis (FSGS) - Key Populations (4)
1) African + Hispanic Adults
2) HIV
3) Heroin Use
4) Sickle Cell
Membranous Nephropathy - Cause + Findings (4)
1) Subepithelial (podocyte) deposits of immune complex with a spike and dome appearance on EM
Findings
1) Spike and Dome on EM - podocytes deposits new BM over-top the immune deposits
2) Thick Basement membrane on H&E
3) Poor response to steroids
4) Immune complex deposition that lights up on IF
Membranous Nephropathy - Key Populations (5)
1) Caucasian Males
2) Hepatitis B/C
3) SLE
4) Tumors
5) Drugs (NSAIDs + Penicillin)
Three Locations of Immune Deposition in Nephrotic Syndromes
1) Sub-Epithelial (Podocyte) - Membranous Nephropathy
2) Sub-Endothelial - Membranoproliferative Type I
3) Basement Membrane - Membranoproliferative Type II
Membranoproliferative Glomerulonephritis - Cause + Types
Nephitic/Nephrotic Syndrome - Immune Complex Deposition
Type I - Subendothelial deposit
Type II - Dense Deposit Disease - BM Deposits due to C3 Convertase - Change in C3 Convertase prevents it from being turned off –> Overactivation of compliment (low circulating C3)
Membranoproliferative Glomerulonephritis - Findings (4)
1) Tram Track Appearance on H&E due to the mesangeal cells spliting the BM
2) Immune Complex Deposition with IF Granules
3) Type II - Low Circulating C3
4) Poor Steroid Response
Diabetes Induced Nephrotic Syndrome - Pathophysiology
High Serum Glucose - Non-Enzymatic Gycosylation of vascular BM - Efferent more affected than afferent - Leads to high GFR and Pressure leading to injury and albumin leak
Diabetes Induced Nephrotic Syndrome - Key Finding + Key Treatment
1) Kimmelstiel Wilson Nodules - Mesangium sclerosis of “white” areas on the glomerulus on H&E - Patho-neumonic
2) Treat with ACE Inhibitors - slow progression of the damage + also hit AII which reduces efferent constriction
Systemic Amyloidosis Induced Nephrotic Syndrome - Pathophysiology + Key Finding
Amyloid deposits in the mesangium resulting in apple green birefringence under polarized light with Congo Red Stain
Basic Findings of Nephritic Syndrome
1) RBCs (Dysmorphic) and RBC Casts in Urine (Hematuria
2) Low Urine Volume (Oliguria)
3) Only Mild Proteinuria
4) Salt Retention + HTN
5) Hypercellular Glomerulus (Inflammation) with swelling into the Bowman’s Space on H&E
Major Nephritic Syndromes (5)
1) Post-Strep Glomerulonephritis
2) Rapidly Progressing Glomerulonephritis
3) IgA Nephropathy
4) Alport Syndrome
5) Membranoproliferative Glomerulonephritis
Post-Streptococcal Glomerulonephritis (PSGN) - Cause + Findings (6)
Cause - 2-3 Weeks after Group A B-Hemolytic Streptococcal Infection - with M-Protein Virulence Factor
Findings
1) Hematuria (Cola-Colored Urine)
2) Oliguria
3) HTN
4) Periorbital Edema
5) Hypercellular inflamed glomeruli on H&E
6) Sub-epithelial humps on EM due to complement mediated immune comple
Rapidly Progressing Glomerulonephritis (RPGN) - Pathophysiology + Key Findings
Class of diseases - rapidly progressing complement mediated nephritis
Key Findings
1) Crescent shapes in the Bowman’s made of macrophages and fibrin
2) IF Patterns unique to each major cause
Linear Immune Fluorescence in RPGN - Disease
Goodpasture Syndrome
Granular Immune Fluorescence in RPGN - Disease (2)
1) Post-Strep GN with Progression
2) Diffuse Proliferative GN
Negative Immune Fluorescence in RPGN - Disease (3) + Alternative Name
Pauci-Immune
1) Wegener Granulomatosis - cANCA
2) Microscopic Polyangiitis
3) Churg-Strauss - pANCA
Goodpasture Syndrome - IF Pattern + Key Points (3)
Linear (Anti-BM Collagen Antibody) IF
Key Points
1) Usually with hemoptysis + hematuria
2) Young Males
3) Different from Wegner’s in that it doesn’t have sinus issues
Diffuse Proliferative GN - IF Pattern + Key Points (2)
Granular Pattern (Like Post-Strep GN)
Key Points
1) Antigen-Antibody deposit (sub-endothelial)
2) Common in SLE
Wegener’s Granulomatosis - IF Pattern + Key Points (2)
Negative IF with Positive c-ANCA
Key Points
1) Accompanying Lung Disease + Nasopharynx Disease
2) Different from Goodpasture in that it has nasopharyxn involvement
Churg-Strauss - IF Pattern + Key Points (2)
Negative IF with Positive p-ANCA
Key Points
1) Triad - Granulomatous Inflammation + Eosinophilia + Asthma
2) Triad is key difference vs. Microscopic polyangiitis
Microscopic Polyangitis - IF Pattern + Key Points (2)
Negative IF with Positive p-ANCA
Key Points
1) Missing triad is key difference vs. Churg-Strauss
IgA Nephropathy - Cause + Key Findings (3)
Nephritic Syndrome - IgA Immune complex deposition in the mesangium of glomeruli
Findings
1) Presents during childhood with hematuria
2) Usually follows mucosal infection (e.g. gastroenteritis - IgA produced to fight mucosal infection)
3) Slow progression to renal failure
Alport Syndrome - Cause + Key Findings (5)
Nephritic Syndrome - X-Linked Defect in Type IV Collagen
Findings
1) X-Linked
2) Thinning and Splitting of Glomerular BM
3) Isolated Hematuria
4) Hearing Loss + Ocular Disturbance (Affects Membranes)
