Renal - Miscellaneous Flashcards
What are the general symptoms of glomerulonephritis?
Hematuria, proteinuria, decreased GFR, HTN
What are the general symptoms of nephrotic syndrome?
Hypoalbuminemia, edema, hyperlipidemia, fatty casts, proteinuria >3.5g/24hr
What are the general symptoms of nephritic syndrome?
Hematuria, azotemia, HTN, oliguria, subnephrotic range proteinuria
Normal GFR = ?
> 90 mL/min
Normal urine output = ?
1500 mL/24 hr
Normal urine protein = ?
<150 mg/24 hr
Normal FeNa = ?
1%
Normal FeUrea = ?
35%
Normal specific gravity = ?
1.003-1.030
Normal urine pH = ?
5-8
Normal # of RBC on microscopy = ?
0-2/hpf
Normal # of WBC on microscopy = ?
0-5/hpf
Oliguria = ?
<500 mL/24 hr
Polyuria = ?
> 3000 mL/24 hr
Anuria = ?
0 mL/24 hr
Dysmorphic RBCs indicate an issue with…
Glomeruli
RBC casts indicate ___.
Glomerulonephritis
WBC casts indicate ___.
Pyelonephritis
Epithelial (muddy brown) casts indicate ___.
Acute tubular necrosis
Fatty casts indicate ___.
Nephrotic syndrome
Granular casts indicate ___.
CKD (or non-specific)
Hyaline casts indicate ___.
Dehydration, exercise, diuertics
Waxy casts indicate ___.
Advanced kidney disease
GFR = ?
([U] x V)/[P]
Cockcroft Gault equation - GFR = ?
((140 - age) x weight (kig) x 0.85 if female)/(72 x serum creatinine)
FeNa = ?
(UNa/PNa)/(UCr/PCr) x 100
What is a normal FF?
20%
What is the normal RPF?
625 mL/min
What is a normal urine Na?
20 mEq/L
Compare the urine Na+ in a pre-renal and renal issue.
Pre-renal: <20 mmol/L
Renal: >20 mmol/L
Compare the FeNa and FeUrea in a pre-renal and renal issue.
Pre-renal: <1%
Renal: >1%
Compare the urine specific gravity in a pre-renal and renal issue.
Pre-renal: >1.015
Renal: ~1.010
Compare the urine osmolality in a pre-renal and renal issue.
Pre-renal: >350 mmol/kg
Renal: <350 mmol/kg
Compare the casts seen in a pre-renal, renal, and post-renal issue.
Pre-renal: hyaline
Renal: Granular
Post-renal: hyaline
Compare the U/P creatinine ratio in a pre-renal and renal issue.
Pre-renal: >40
Renal: <20
Compare the serum BUN/Cr ratio in a pre-renal and renal issue.
Pre-renal: >20:1
Renal: <10:1
What are the symptoms of nephritic syndrome?
Acute onset of hematuria (dysmorphic RBC, RBC casts), oliguria, azotemia, HTN, edema, mild proteinuria
What are the four types of nephritic syndrome?
- Post-infectious GN
- Ig-A nephropathy
- Hereditary nephritis
- Rapidly progressive GN
What is systemic IgA nephropathy?
HSP
What are the symptoms of nephrotic syndrome?
Massive proteinuria (>3.5 g), hypoalbuminemia, generalized edema, hyperlipidemia, lipiduria
What are the three types of primary nephrotic syndrome?
- Membranous nephropathy
- Minimal change disease
- FSGS
What are the two types of nephrotic syndrome with hematuria?
- Membranoproliferative glomerulnephritis
2. Dense deposit disease
If pH <5, think ___.
Metabolic acidosis
If pH >5.3 in the presence of metabolic acidosis, think ___.
Distal RTA
If pH >8, think ___.
Presence of urea-splitting organisms
A specific gravity of 1.001 is very ___ and a specific gravity of 1.030 is very ___.
Dilute; concentrated
What does a specific gravity of 1.010 indicate?
Urine is neither concentrated nor dilute
If there is an acute decline in renal function and specific gravity is > 1.020, think ___.
Pre-renal issue (urine can still be concentrated)
If there is an acute decline in renal function and specific gravity is ~1.010, think ___.
Renal issue (urine can no longer be concentrated)
If there is hyponatremia, normally expect a ___ specific gravity. If there is hypernatremia, normally expect a ___ specific gravity.
Low; high
If specific gravity is > 1.010 in the setting of hyponatremia, think ____.
ADH secretion is occurring (urine is being concentrated)
If specific gravity is <1.010 in the setting of hypernatremia, think ___.
Diabetes inspidius (urine is being diluted)
If there is elevated blood glucose and glycosuria, think ___.
Diabetes mellitus
If there is normal blood glucose and glycosuria, think ___.
Proximal tubule dysfunction
If there is ketoacidosis and ketonuria, think ___.
Diabetic or alcoholic ketoacidosis
If there is no ketaocidosis and ketonuria, think ___.
Starvation, ketogenic diet, isopropyl alcohol ingestion
If there is bilirubin in the urine, think ___.
Hepatobiliary disease
If there is bilirubin in the urine without urobilinogen, think ___.
Biliary obstruction
If there is urobilinogen in the urine, think ___.
Liver disease
If there is leukocyte esterase or nitrites in the urine, think ___.
UTI
Compare the presentations of of the 4 types of nephritic syndrome.
- Acute post-infectious GN: Hematuria, edema, HTN, renal failure within 1-4 weeks of a throat/skin infection (presentation less clear in adults)
- IgA nephropathy: recurrent, often painless hematuria within 1-2 days of an upper respiratory, GI, or urinary infection, proteinuria
- Hereditary nephritis: isolated hematuria, nephritis, no infection, hearing issues and ocular issues
- Rapidly progressive GN: rapidly progressive loss of renal function, nephritic syndrome
Type I - gross hematuria, oliguria, hemoptysis
Type II - gross hematuria, oliguria
Type III - gross hematuria, oliguria, hemoptysis/SOB
Compare the epidemiology of the 4 types of nephritic syndrome.
- Acute post-infectious GN: children 6-10 y/o (rare in adults)
- IgA nephropathy: most common glomerular disease, children and adults
- Hereditary nephritis: 5-20 y/o males (age of presentation)
- Rapidly progressive GN:
Type I - young men
Type II - older children/young adults
Type III - older adults
Compare the etiology/pathogenesis of the 4 types of nephritic syndrome.
- Acute post-infectious GN: formation of Ag/IgG IC in circulation, deposition of IC in capillary wall, complement activation, influx of neutrophils, damage and endocapillary proliferation + in-situ IC formation
- IgA nephropathy: infection causes massive IgA production, IgA/Complement IC formation, deposition in mesangium, alternative complement pathway activated
- Hereditary nephritis: error in collagen type IV synthesis (affects GBM, cochlea, lens)
- Rapidly progressive GN:
Type I - anti-glomerular basement membrane Ab
Type II - IC formation, necrosis and breaks in glomerular BM
Type III - ANCA (Ab to neutrophilic granules)
Compare the histology, IF, and EM images of the 4 types of nephritic syndrome.
- Acute post-infectious GN: Histology - capillary obliteration, endocapillary proliferation, PMN influx; EM - humps; IF: IgG + Ag/Complement
- IgA nephropathy: Histology - mesangial proliferation, EM - electron dense deposits; IF - IgA + complement/auto-Ab
- Hereditary nephritis - Histology - normal; EM - basket weave (lamina densa splitting); IF - negative
- Rapidly progressive glomerulonephritis - All types - Histology: crescents
Type I: IF - linear IgG, EM - none
Type II: IF - granular deposits (Ig + complement), EM - electron dense deposits
Type III: IF - pauci immune, EM - pauci immune
What other lab tests are important in acute post-infectious GN?
- ASO titer increases
- Complement decreases
- Coca-cola, tea-colored urine
What other lab tests are important in IgA nephropathy?
- No decrease in complement
Describe the IgA nephropathy with extra-renal symptoms (systemic IgA).
Henoch Schonlein Purpura
Mainly seen in 3-8 y/o
IC deposits in kidney (hematuria), skin (purpuric skin lesions), GI (abdominal pain and GI bleeding), and joints (arthralgia)
Which nephritic syndromes do not involve immune complexes?
Hereditary nephritis
Type I and III rapidly progressive GN
What is Goodpasture disease?
Type I rapidly progressive GN + alveolar basement membrane involvement
What is the antigen attacked in Goodpasture disease?
NC1 (non-collagenous protein)
What triad is commonly affected in GPA? What type of ANCA and antigen are involved?
Ear/nose throat
Lungs
Kidney
c-ANCA, PR3
Compare the presentations of of the 3 types of nephrotic syndrome.
All three: nephrotic syndrome
- Membranous nephropathy: edema, thrombosis (loss of AT-III), infection
- Minimal change disease: edema
- FSGS: hematuria, reduced GFR, HTN
Compare the epidemiology of the 3 types of nephrotic syndrome.
- Membranous nephropathy: 30-60 y/o, second most common nephrotic syndrome
- Minimal change disease: 2-6 y/o, most common nephrotic syndrome in children, adults (10%)
- FSGS: adults (most common nephrotic syndrome) and children
Compare the etiology/pathogenesis of the 3 types of nephrotic syndrome.
- Membranous nephropathy: autoimmune response against renal Ags, IC formation, podocyte injury, NO inflammatory response, often associated with cancer
- Minimal change disease: reversible podocyte injury
- FSGS: irreverisble podoctye injury, leads to sclerosis and lumen obliteration
Compare the histology, IF, and EM images of the 3 types of nephrotic syndrome.
- Membranous nephropathy: Histology - normal; EM - subepithelial electron dense deposits, IF - granular deposits (IgG and C3); silver stain - spike and dome pattern (basement membrane positive - black)
- Minimal change disease: Histology - normal; EM - effacement/fusion of podocyte foot processes; IF - none
- FSGS: Histology - segemental sclerosis; EM - effacement of podocytes in all glomeruli; IF - none.
What are the two renal antigens targeted in membranous nephropathy?
PLA2R, THSD7A
What other lab tests are important in membranous nephropathy?
- Ab testing for PLA2R, THSD7A
2. No drop in complement
If you have membranous nephropathy, you must rule out ___.
Cancer
Discuss steroid treatment of minimal change disease and FSGS.
Minimal change disease responds to steroids. FSGS initially responds to steroids but may become resistant.
What are the three common etiologies of FSGS?
- Primary (idiopathic)
- Adaptive (response to nephron loss)
- APOL1 (risk alleles)
What are the three uncommon etiologies of FSGS?
- Genetic
- Medication-associated
- Virus-associated
Compare the etiology/pathogenesis of the 2 nephrotic/nephritic syndromes.
- MPGN: IC formation with classical complement activation
2. DDD: sustained activation of the alternative complement pathway (non-antibody mediated)
Compare the histology, IF, and EM images of the 2 types of nephrotic/nephritic syndrome.
- MPGN: Histology - lobular tufts; EM - electron dense deposits and tram tracks; IF - IgG + complement; silver stain - tram tracks
- DDD: Histology - none mentioned; EM - dense deposits in lamina densa; IF - C3 (no Ig)
What are the two major control points affecting the complement pathway in DDD?
- C3NeF is an autoantibody against C3 convertase - it stabilizes the enzyme and prevents its degradation
- H factor normally degrades C3 convertase; mutations/autoantibodies diminish its ability to do so
What is an important drug treatment for DDD?
Eculizumab
What are three systemic kidney issues and how are they categorized (nephrotic/nephritic)?
Nephrotic: diabetic nephropathy, amyloidosis
Nephritic: lupus nephritis (can be nephrotic 10% of the time)
What are the symptoms of diabetic nephropathy?
- Proteinuria
- Progressive decrease in GFR
- HTN
What important histologic finding is seen in diabetic nephropathy?
KW nodules (thickening of GBM, increased mesangial matrix)
Discuss the clinical presentation of TMAs.
- Microangiopathic hemolytic anemia
- Thrombocytopenia and thrombi in microcirculation
- Renal failure
- Diarrhea (HUS only)
Discuss the lab tests for TMA.
- Thrombi and endothelial injury in histology
- Thrombocytopenia
- Schistocytes on blood smear
- ADAMTS13 mutation
What are the two major categories of tubulointerstitial diseases?
- Tubulointerstitial nephritis
2. Acute tubular injury/necrosis
What are the primary types of tubulointerstitial nephritis?
Infectious: pyelonephritis (acute, chronic, papillary necrosis, viral, xanthogranulomatous)
Non-infectious:
1. Acute drug-induced (particularly NSAIDs, aristolcholic acid)
2. Metabolic (urate and oxalate nephropathies)
3. Neoplasm (multiple myeloma - uric acid, hypercalcemia, light chain casts)
What are the two major causes of acute tubular injury/necrosis?
Ischemia and toxins
Compare acute and chronic pyelonephritis on histology.
Acute: patchy interstitial suppurative inflammation (PMNs)
Chronic: lymphocytes, fibrosis, sclerosis, dilated tubules
What are the 4 broad causes of pre-renal AKI?
- Absolute decrease in ECV
- Relative decrease in ECV
- Low ECV + impaired renal autoregulation
- Vasoconstriction and occlusion
What causes an absolute decrease in ECV?
Vomiting, diarrhea, hemorrhage
What causes a relative decrease in ECV?
HF, cirrhosis
What causes low ECV + impaired renal autoregulation?
NSAIDs, ACEI/ARB
What causes vasoconstriction and occlusion?
Hypercalcemia, chemo, renal artery stenosis
What are some exogenous toxins that can cause acute tubular necrosis?
Antibiotics, chemotherapy, contrast, mannitol
What are some endogenous toxins that can cause acute tubular necrosis?
Myoglobin (rhabdo), uric acid (tumor lysis), light chains (myeloma), hemoglobin (hemolysis)
What is the classic triad of symptoms seen in acute interstitial nephritis?
Fever, rash, eosinophilia
What are the clinical features of contrast nephropathy?
- Increase in serum creatinine 2-3 days after contrast administration
- Non-oliguric
- Pre-renal urine indices, high specific gravity
- ATN eventually