N17 - Differential diagnostics of renal diseases Flashcards
(22 cards)
Differential diagnosis of lumbal pain
sudden onset, cramping
- obstruction of urinary tract (ie. stone, blood clot, papilla necrosis)
- usually unilateral, radiating downwards toward bladder, genitalia
blunt pain
- unilateral: renal cyst infection/bleeding, tumor, renal infarct, renal vein thrombosis
- with fever and UTI: pyelonephritis, abscess
- bilateral: interstitial nephritis, renal edema, glomerular diseases are usually not painful
dysuria, pollakisuria
- lower UTI
lumbal pain of extrarenal origin
- lumbar spine, muscles, neurological
- atypical: acute cholecystitis, pancreatic tumor, pancreatitis, colon neoplasm, spleen
What do hematuria labarotory findings look like in a healthy person?
- dipstick negative
- sediment <3-4 RBC/high power field (x400)
What does macroscopic hematuria suggest?
urological origin (exception: IgA nephropathy)
What does microscopic hematuria suggest?
urological or nephrological origin
What are the urological causes of hematuria?
- renal/uroepithelial tumor
- stone
- UTI (ie. cystitis)
- renal cyst rupture
- papillary necrosis
What are nephrological causes of hematuria?
- glomerulonephritis
- Alport-syndrome
- thin basement membrane disease
- acute interstitial nephritis
What does microscopic urinary sediment help differentiate?
- urological: similar RBCs (isomorphic)
- nephrological: variable appearance of RBCs (dysmorphic) (ie. acanthocytes - glomerular origin)
- RBC casts suggest glomerular origin
What are the laboratory findings for proteinuria and albuminuria?
urine dipstick
- positive = urine albumin conc. >500mg/L
- detects mainly albumin so can be false negative if the protein is not albumin (ie. light-chains)
“clinically significant” proteinuria
- >500mg/day (creatinine >50mg/mmol)
- Heralds poor renal prognosis
- treatment target is less than 500mg/day
albuminuria
- >30mg/day (3mg/mmol)
- may suggest early diabetic nephropathy
- >300mg/day corresponds to about 500mg/day proteinuria
“nephrotic” range proteinuria
- >3-3.5g/day (0.3-0.35g/mmol) accompanied with nephrotic syndrome
What can the urinary sediment indicate?
-
RBC:
- isomorphic: urological bleeding (cystitis, stone, tumor)
- dysmorphic: glomerular, interstitial disease - WBC: UTI, acute interstitial nephritis, glomerulonephritis
- tubular cells: acute tubular necrosis, glomerulonephritis, allograft rejection
- transitional (urothel): normal, UTI, malignancy
- squamous epithelial cell: normal
- RBC cast: glomerulonephritis
- WBC cast: pyelonephritis, glomerulonephritis, AIN
- brown granular cast: ATN
What are the major nephrology syndromes?
- nephrotic syndrome
- nephritic syndrome (RPGN)
- acute kidney injury
- asymptomatic proteinuria/hematuria
- chronic kidney disease
What are the clinical features of nephrotic syndrome?
- proteinuria (>3.5g/day)
- hyperalbuminemia
- edema
- hyperlipoproteinemia
- thromboembolic events
- GFR may be normal
immunoserology and kidney biopsy for further differentiation
What is the differential diagnosis for nephrotic syndrome?
primary renal disease
- primary membranous glomerulonephropathy (usually anti-PLA2 receptor antibody positive)
- minimal change nephropathy
- focal segmental glomerulosclerosis
renal manifestation of a systemic disease
- diabetic nephropathy
- amyloidosis
- secondary FSGS
- secondary membranous glomerulopathy
What is the differential diagnosis of nephritic syndrome?
- poststreptococcalis glomerulonephritis
- postinfectious glomerulonephritis (ie. subacute endocarditis, abscess)
- membranoproliferative glomerulonephritis
- membranoproliferative glomerulonephritis
renal biopsy, immune serology and electrophoresis for further morphologic/etiologic diagnosis
Diagnosis of RPGN
- RPGN = rapid progressive glomerulonephritis
- renal biopsy w/ immunofluorescein staining and serology for further differentiation
- light microscopy shows crescents with parietal cell proliferation
- further differentiation is based on immunofluorescence and immunoserology
How is crescent glomerulonephritis differentiated from RPGN?
1. linear immunoglobulin deposition
- anti-GBM antibodies
- renal +/- pulmonary symptoms
- good pasture disease
2. granular immunoglobulin deposition
- these are immunocomplexes
- ie. lupus nephritis IgA nephropathy
3. no immunoglobulin deposition
- these are ANCA vasculitides
- granulomatosis w/ polyangitis
- microscopic polyangitis
- eosinophil granulomatosis w/ polyangitis
What are the indications for renal biopsy?
- nephrotic syndrome
- nephritic syndrome
- RPGN
- asymptomatic proteinuria (1-3g/day range)
- acute kidney injury (intrinsic): if it is not caused by ATN
- chronic kidney disease of unknown origin: not on small, scarred kidneys
- dysfunction of transplanted kidney
What are the contraindications of renal biopsy?
- uncooperative patient
- single kidney
- multiple renal cysts
- acute pyelonephritis
- uncontrolled bleeding diathesis
- uncontrolled blood pressure (BP> 160/95mmHg)
How is renal biopsy conducted?
- under local anesthesia, ultrasound guided
- evaluated by light, immunofluorescent or electron microscopy
What glomerular diseases cause asymptomatic proteinuria?
- proteinuria = 0.5-2g/day
- early diabetic nephropathy
- secondary FSGS
- hypertensive nephropathy
What glomerular diseases cause asymptomatic microhematuria?
- IgA nephropathy
- alport syndrom
- thin basement membrane abnormality
What are the signs and symptoms of chronic kidney disease?
- decreased GFR, variable progression
- usually small kidneys with echogenic parenchyma
- variable urinary abnormalities
- complications according to the stages of CKD
Differential diagnosis and therapy for CKD
- usually no diagnostic problem
- original kidney disease may not be identified
- slow progression so prepare for renal replacement therapy
- prevent further complications
