DDX Kidney lecture Flashcards
Pain - LITRAAA
localization, intensity, type, radiation, aggravating – alleviating factors, accompanying signs
Pain - Sudden onset, cramping
Obstruction of the urinary tract
Pain - Blunt, unilateral
renal cyst infection/bleeding,
tumor,
renal infarct,
renal vein thrombosis,
with fever and UTI:
pyelonephritis,
abscess
Pain - Blunt, bilateral
interstitial nephritis,
renal edema,
glomerular diseases are usually not painful
Pain - Dysuria, pollakisuria
Lower UTI
Hematuria - Macroscopic
suggest urological origin (but may be seen in IgA nephropathy)
Hematuria - Microscopic
may be either urological or nephrological in origin
Hematuria - Urology causes
Renal/uroepithelial tumor, stone, UTI (eg. cystitis), renal cyst rupture, papillary necrosis
Hematuria - Nephrological causes
Glomerulonephritis,
Alport-syndrome,
thin basement membrane disease,
acute interstitial nephritis
Hematuria - Healthy person
Dipstick negative, sediment < 3-4 RBC/high power field
Hematuria - isomorphic RBCs
Urolological
Hematuria - dysmorphic RBCs
Nephrological
Proteinuria and albuminuria - „clinically significant” proteinuria:
> 500mg/day (>50mg/mmol creatinine)
Dipstick usually positive for proteins
Proteinuria and albuminuria - microalbuminuria
> 30mg/day (30 mg/mmol)
May suggest early diabetic nephropathy
Is associated with cardiovascular events
Proteinuria - „nephrotic” proteinuria
> 3-3.5g/day (0.3-0.35 g/mmol) that is accompanied with the nephrotic syndrome
Proteinuria - Spurious proteinuria (non renal)
inaccurate sampling,
blood in the urine,
colpitis
Proteinuria - Functional
temporary:
fever,
intense physical exercise,
venous congestion
Orthostatic proteinuria
Proteinuria - Glomerular: glomerulonephritis, glomerulopathy
Damaged glomerular tuft spills albumin and variable amount of globulins in the primary filtrate
(more severe damage more globulin)
Proteinuria - Tubular proteinuria
Damage to the proximal tubule leads to failure to reabsorb small molecular weight proteins
(eg. Fanconi syndrome, interstitial nephritis)
Proteinuria - „overflow” proteinuria
High amount of small molecular weight protein in the serum is being filtered and overflows reabsorption
(kappa/lambda light chains a.k.a. Bence-Jones proteinuria)
Urinary electrophoresis - Albumin spike
AL amyloidosis
Urinary electrophoresis - Gamma spike
Multiple myeloma (often w/ albumin spike)
Urinary electrophoresis - General increase
Nephrotic syndrome
Immunological tests - ANA (anti-nuclear antibody)
SLE, other systemic autoimmune disease
Immunological tests - ANCA (anti-neutrophil cytoplasmic antibody)
Small vessel vasculitis (pauci-immune crescentic GN)
Immunological tests - Anti-dsDNS antibody
SLE
Immunological tests - SS-A, SS-B antibody
Sjögrens’ syndrome, SLE
Immunological tests - Anti-GBM antibody
Goodpasture syndrome
Immunological tests - Anti-streptolysin antibody
Poststreptococcal glomerulonephritis
„Major” nephrology syndromes
- Nephritis
- Rapidly progressive glomerulonephritis (RPGN)
- Nephrosis
- Acute kidney injury
- Asymptomatic proteinuria and/or haematuria
- Chronic kidney disease
Nephritic syndrome hallmarks
- Hematuria
- Proteinuria
- Urinary casts (RBC)
- Hypertension
- Edema
- Oliguria
- Decreased GFR
Differential diagnosis hallmarks: Postinfectiosus glomerulonephritis
subacute endocarditis, abscess
Differential diagnosis hallmarks: Membranoproliferative glomerulonephritis
Lupus nephritis,
cryoglobulinemia,
monoclonal immunoglobulin deposition
„dens-deposit” disease,
C3 glomerulonephritis
Rapidly progressive glomerulonephritis syndrome (RPGN) - general overview
Rapid worsening of kidney function (weeks/months)
Nephritic urinary findings
• Glomerular hematuria, variable proteinuria
• Cellular (RBC) casts
Frequent systemic symptoms • vasculitis • Pulmonary (bleeding) • upper airway infection (usually occurs DURING an ongoing mucosal infection) • Arthritis • Fever • Neuropathy
RPGN Light microscope
Crescents with parietal cell proliferation
Glomerular necrosis
Differentiation of crescent glomerulonephritis with RPGN: 1. Linear immunglobulin deposition
- Anti-GBM antibodies
- Renal +/- pulmonary symptoms
- Goodpasture disease
Differentiation of crescent glomerulonephritis with RPGN: 2. Granular immunglobulin deposition
- These are immuncomplexes
* eg. lupus nephritis, IgA nephropathy
Differentiation of crescent glomerulonephritis with RPGN: 3. No immunglogulin deposition
„pauci-immune” = „hardly any” • These are ANCA vasculitides • Granulomatosis with polyangitis • Microscopic polyangitis • Eosinophil granulomatosis with polyangitis
Nephrotic syndrome overview
- Proteinuria (usually >3 g/day)
- Hypolbuminemia
- Edema
- Hyperlipoproteinemia
- Thromboembolic events
- GFR may be normal
Differential diagnosis of the nephrotic syndrome: Primary renal disease (no other organ involvement)
– Primary membranous glomerulopathy (usually anti-PLA2 receptor antibody positive)
– Minimal change nephropathy
– Primary focal segmental glomerulosclerosis
Differential diagnosis of the nephrotic syndrome: Renal manifestation of a systemic disease
– Diabetic nephropathy
– Amyloidosis
– Secondary FSGS (congenital podocytopathy, HIV, extreme obesity, glomerular loss for an unrelated reason)
– Secondary membranous glomerulopathy (lupus nephritis, malignancy, drugs, hepatitis B/C, syphilis, NSAIDs, TNF- inhibitors)
Indications for renal biopsy
- Nephrotic syndrome
- Nephritic syndrome
- RPGN
- Asymptomatic proteinuria in the 1-3g/day range (particulary if GFR declines or proteinuria increases)
- Acute kidney injury (intrinsic)
- If there is a suspicion that it is not caused by acute tubular necrosis
- Chronic kidney disease of unknown origin
- But not if on US small scarred kidneys
- Dysfunction of transplanted kidney
Contraindications to renal biopsy
- Uncooperative patient
- Single kidney
- Multiple renal cysts
- Renal neoplasm
- Acute pyelonephritis
- Uncontrolled bleeding diathesis
- Uncontrolled blood pressure (BP > 160/95 mmHg)
Asymptomatic urinary abnormality - Asymptomatic proteinuria (usually 0,5-2g/day)
Glomerular diseases eg.
- Early diabetic nephropathy
- secondary FSGS
- Hypertensive nephropathy
Asymptomatic urinary abnormality - Asymptomatic microhaematuria
Glomerular diseases eg.
- IgA nephropathy
- Alport syndrome
- Thin basement membrane abnormality
