Renal System Flashcards
Acute Kidney Injury
(Pre-Renal)
Caused by decr renal perfusion;
BUN/creatinine ratio typically >20:1
Fractional excreti Na+ <1%
Urine osmolality >500 mOsm/kg
Microscopy Hyaline casts
Acute Kidney Injury
(Post-Renal)
Caused by urinary tract obstruction with normal nephron capacity. Etiologies include bilateral calculi, enlarged prostate, or a renal tumor in an individual with a sole functional kidney.
Bilateral Hydronephrosis is also seen.
Acute Kidney Injury
(Intra Renal)
Aka Acute Tubular Necrosis
Renal ischemia (eg, hemorrhage, sepsis) or nephrotoxins (eg, aminoglycosides, radiocontrast)
Can also present in setting of cardiac ischemia due likely episode of Hypotension.
BUN/Cr Typically ~10-15
Fractional excretion Na+ >2%
Urine Osm ~300 mOsm/kg
Microscopy Muddy brown casts
PSGN
(Post Streptococcal Glomerluonephritis)
Aka Proliferative glomerulonephritis/ Acute glomerulonephritis
After streptococcal inf i.e Strep Pyogenes (2 wks) can present as 1-3 wks of red urine after sore throat.
Periorbital Edema
Hypertension
Micro/Gross Hematuria
Type-3 Hypersenstivity reaction (Antigen-Antibody complex that form in blood and deposit in kidney)
child recovers well, poor prognosis in adults
LM: hypercellular enlarged glomeruli.
IF: Granular deposits of IgG, IgM, C3 on GBM & Mesangium (lumpy-bumpy).
EM: Subepithelial humps b/w podocytes and GBM
Increase Anti-streptolysin-O & Anti-DNase B-titers
Decrease complement protien C3
Fanconi syndrome
Polyuria, renal tubular acidosis type II, growth retardation, electrolyte imbalances, hypophosphatemic rickets
(multiple combined dysfunction of the PCT)
Impaired PCT reabsorbtion of AA, Glucose, PO4–, HCO3–.
Caused by consumption of expired Tetracyclines.
HUS (Hemolytic-uremic syndrome)
In children, Predominately caused by Shiga toxin–producing Escherichia coli (STEC) infection (serotype O157:H7)
- Thrombocytopenia
- Hemolytic Anemia
- Acute kidney Injury
- Bloody Diarrhea
ADPKD
( Autosomal dominant polycystic kidney disease )
Genetic mutation in polycystin ( PKD1 , PKD2 )
Multiple large cysts in kidneys due to structural abnormalities in renal tubules.
Inherited with complete penetrance & Variable expressivity.
Can present with:
Flank pain, Hematuria, HTN, Progressive CKD.
PSGN
most common in kids;
sub epithelial humps - IgG, C3, and C4 deposition;
lumpy bumpy on EM;
ASO antibodies
Membranous Proliferative Glomerulonephritis
tram-tracks on LM, basement splitting
Urge Incontinence
urgency leads to complete voiding,
detrusor spasticity leads to small bladder volume;
PVRV: 5-10mL
RTA Type-2
Inability of PCT to reabsorb bi-carb (HCO3–).
proximal RTA = bad carbonic anhydrase, lost all bicarb in urine
Focal Segmental Glomerulonephritis
Seen in
IV drug abusers, African Americans, Hispanics, and HIV patients
Overflow Incontinence
cannot completely empty bladder
PVRV: residual volume > 100ml
Minimal Change Disease
Most common nephrotic syndrome in kids
Fused foot processes on EM, no renal failure, loss of charge barrier
Membranous Glomerulonephritis
Most common nephrotic syndrome in adults
LM: BM spikes,
EM: sub epithelial spikes and domes
IF: granular/ linear
Stress Incontinence
weak pelvic floor muscles
urinating when coughing, laughing, etc.
estrogen effect;
PVRV = 50ml
RTA Type-1
Inability of DCT to secrete Proton (H+).
distal (DCT) RTA = H+/K+ exchange in collecting duct is broken,
high urine pH (low H+ in urine)
Barter Syndrome
@ ascending loop
JG cell hyperplasia with renin excess;
no increase in blood pressure;
defect in kidney’s ability to reabsorb potassium
–presents like chronic loop diuretic use–
SIADH
( Syndrome of Inappropriate Anti-Diuretic Harmone )
Too much ADH (Vasopressin)
ADH is produced by supraoptic nucleus of hypothalamus and stored in posterior pituitary.
ADH increases water reabsorption in medullary collecting duct.
↓Serum Osmolality , ↓Serum specific gravity
↓ serum Na (< 135)
↑ Urine osmolality , ↑ Urine specific gravity
Tx :
– Demeclocycline (tetracycline causes insenstivity to ADH).
– Conivaptan & Tolvaptan (ADH receptor antagonists).
Types of renal tubular acidosis (RTA)
- Type 1 (distal):
Reduced ability to secrete (H+) in distal tubule (ie, H+ retention). Autoimmune diseases (eg, lupus, Sjögren syndrome) and amphotericin B toxicity. - Type 2 (proximal):
Reduced ability to (reabsorb) (bicarbonate) in proximal tubule (ie, bicarbonate wasting). Carbonic anhydrase inhibitors, multiple myeloma, and Fanconi syndrome. - Type 4:
Reduced production and/or response to (aldosterone). Diabetes mellitus, ACE inhibitors, NSAIDs, and heparin.
4 most common causes of renal papillary necrosis.
- Sickle cell disease/trait
- Chronic analgesic use (eg, NSAIDS)
- Diabetes mellitus
- Acute pyelonephritis
Lupus nephritis occurs primarily due to?
Deposition of DNA/anti-DNA immune complexes within the glomerulus (e.g., mesangium, subendothelial or subepithelial space).
Occupational exposures to rubber, plastic, and aromatic amines are risk factors for which cancer?
Urothelial bladder cancer
Extrarenal manifestations of autosomal dominant polycystic kidney disease.
- Liver: cysts
- Neurovascular: intracranial berry aneurysms
Poststreptococcal glomerulonephritis
Shows a (granular) pattern of immunofluorescence composed of IgG, IgM, & C3 deposits along the glomerular basement membrane and mesangium.
Bartter syndrome
Characterized by a reabsorption defect in the (thick ascending loop of Henle) (Na/K/2Cl transporter) and mimics chronic (loop) diuretic use (alkalosis, hypokalemia, hypercalciuria).
Gitelman syndrome
Characterized by a reabsorption defect in the (distal convoluted tubule) and mimics chronic (thiazide) diuretic use (alkalosis, hypokalemia, hypercalciuria).
Renal cell carcinoma is often associated with paraneoplastic syndromes involving ectopic production of the following hormones (PEAR mnemonic).
- Parathyroid hormone-related protein (hypercalcemia)
- Erythropoietin (erythrocytosis)
- Adrenocorticotropic hormone (Cushing syndrome)
- Renin (hypertension)
List 4 common symptoms of acute cystitis.
- Dysuria,
- Suprapubic pain,
- Urinary frequency,
- Urinary urgency.
Acute Interstitial Nephritis
White blood cell casts, sterile pyuria, and urine eosinophils
Causes of hypophosphatemia
- Internal redistribution
- Decreased intestinal absorption
- Increased urinary excretion
RBC cast is seen in:
Glomerulonephritis
Metabolic acidosis
- Decrease PH and decrease HCO3-
- Respiratory compensation ASAP (Decrease CO2) ,
- Metabolic compensation (Via kidney) takes 3-4 days
Respiratory Acidosis
- Decrease PH but Normal HCO3-
- Increase CO2
- Metabolic compensation 3-4 days
Mixed Metabolic & Respiratory acidosis
- Decrease PH , Decrease HCO3 & Increase CO2
- Rx: Ventilation
Urine Analysis Clues
- Drug induced hypersenstivity: Eosinophils (Most common cause - Cephalosporins)
- Glomerulonephritis: RBC cast
- Infection: WBC ‘s , Bacteria
- Uric acid (Gout): Crystals
- Multiple Myeloma: Protienuria (Bence-Jones), Kappa & Lambda Chains
- Myoglobinuria: Blood dipstick +ive but no RBC s
- Nephrotic Syndrome: Proteinuria > 3.5 g/day & Fat casts
PSGN
2 weeks post Strep infection
GBS
2 weeks after Campylobacter Jejuni infection
Nephritic Syndrome
- Oliguria
- Hematuria
- Edema (+1)
- HTN
Diagnosis:
- Look for Protienuria , Hematuria
- If GFR is decreased, Think autoimmune, check complement ANCA & Anti-GBM
- Renal biopsy most definitive
5 Nephritic Syndromes
- Post streptococcal glomerulonephritis (PSGN)
- Good Pasture Glomerulonephritis
- Rapidly progressive glomerulonephritis (RPGN)
- IgA Nephropathy
- Membranoproliferative Glomerulonephritis (MPGN), Can progress to Nephrotic syndroem
Nephrotic Syndrome
- Generalized Edema
- Foamy Urine
- Ascites
- Hypercoagulable state
Diagnosis:
- Protienuria > 3.5g/day
> Generalized Edema
> Hypoalbuminemia (Decrease Albumin)
> Hyperlipidemia (Increase Albumin)
- Most cases are result of Systemic disease i.e. DM, SLE, Amyloidosis
Most commons in Nephrotic Syndromes
- MCC in Children: Minimal Change Disease
- MCC in adults: Focal Segmental GN
- Fatty Casts
4 Nephrotic Syndormes
- Membranous GN
- Minimal change disease (MCC in children)
- Focal Segmental GN (MCC in adults)
- Nodular Glomerular Sclerosis
Small size kidney pathologies
Renal Artery Stenosis:
- Atherolsclerosis
- Fibromuscular Dysplasia
- Unilateral
- Abdominal Bruit
- Low Volume state
Large Sized kidneys Pathology
- Polycystic Kidney Disease
- Medullary Sponge Kidneys
- Medullary Cystic Kidneys
Pyelonerphritis
- WBC casts
- Causes: E.Coli , Proteus, Klebsiella, Entercoccus
Urine casts
- WBC casts: Nephritis
- RBC casts: Glomerulonephritis
- Eosinophil casts: Interstitial Nephritis
- Fat/ Fatty casts: Nephrotic Syndrome
- Waxy cast: Chronic Renal Failure
- Hyaline/ Epithelial cast: Normal finding
- Crescents: RPGN….. Good pasture or Wegner’s
Wilms Tumor
- Most common Primary Renal cancer in children
- Aniridia (No colour in eyes)
- Hemihypertrophy
Associations:
- Varicoele
- Scoliosis
Renal Cell Carcinoma
- 90% occur in superior pole of kidney
- Painless Hematuria & Flank mass
- Produces EPO
- Mets via Retroperitonium
- Favourite mets site: Lungs (Cannon ball mets)
- 20% cases have contralateral reoccurence
Risk factors:
- Smoking
- VHL
- Tuberous Sclerosis
