3. Differential diagnosis in nephrology Flashcards
What are the main renal symptoms?
Most renal diseases present insidiously without pain, frequently only with laboratory abnormalities.
What are some urological causes of hematuria?
- Renal/ uroepithelial tumor,
- stone,
- UTI ( eg.cystitis),
- renal cyst rupture,
- papillary necrosis.
What are some nephrological causes of hematuria?
- Glomerulonephritis (!!!)
- Alport -syndrome,
- thin basement membrane disease,
- acute interstitial nephritis.
How can microscopic urinary sediment examination help differentiate between urological and nephrological causes of hematuria?
Urological causes have similar RBCs (isomorphic), while nephrological causes have variable appearance of RBCs (dysmorphic)
What is the differential diagnosis for acute cholecystitis?
- Pancreatic tumor,
- pancreatitis,
- colon neoplasm,
- spleen infarct.
What is the normal protein excretion in urine per day?
Up to 200 mg/day (20 mg/mmol).
What is the main protein secreted in the loop of Henle?
Tamm-Horsfall protein (uromodulin).
What is the normal albuminuria per day?
<30mg/day (<3mg/mmol).
What is the normal protein/creatinine ratio in spot urine?
20 mg protein/mmol creatinine.
What is the normal albumin/mmol creatinine in spot urine?
3mg albumin/mmol creatinine (normoalbuminuria).
What is the corresponding amount of proteinuria for a spot urine protein/creatinine ratio of 100 mg/mmol?
1 g/day proteinuria.
What is the term for hematuria with normal RBC morphology?
Isomorphic hematuria.
What is the definition of “clinically significant” proteinuria?
> 500mg/day (>50mg/ mmol creatinine).
What is the treatment target for most glomerular diseases?
Less than 500mg/day.
What is the definition of albuminuria?
> 30mg/day (3 mg/mmol).
What does a urine dipstick detect mainly?
Albumin.
What is the range of “nephrotic” range proteinuria?
> 3-3.5g/day (0.3 -0.35 g/ mmol).
What is the differential diagnosis for proteinuria if it is >200mg/day or >20mg/mmol?
- Spurious proteinuria (non-renal),
- functional : fever, orthostatic
- glomerular : glomerulonephritis,
- tubular : tubulointerstitial disease,
- “overflow”
What is a “differential diagnosis” in nephrology?
It is the process of distinguishing between different diseases that have similar symptoms in the kidneys.
What are the frequently used immunological tests in the diagnosis of renal diseases?
ANA (anti-nuclear antibody) and ANCA (anti-neutrophil cytoplasmic antibody).
What is Fanconi syndrome?
It is a condition where there is damage to the proximal tubule in the kidneys, leading to a failure to reabsorb small molecular weight proteins.
What is Bence-Jones proteinuria?
It is a type of “overflow” proteinuria where there is a high amount of small molecular weight protein in the serum that overflows reabsorption, such as kappa/lambda light chains.
What is the significance of ANA (anti-nuclear antibody)?
It is associated with SLE and other systemic autoimmune diseases.
What is the significance of ANCA (anti-neutrophil cytoplasmic antibody)?
It is associated with small vessel vasculitis (pauci-immune crescentic GN).
What is the significance of anti-dsDNS antibody?
It is associated with SLE.
What is the significance of anti-GBM antibody?
It is associated with Goodpasture syndrome.
What is the significance of anti-streptolysin antibody?
It is associated with poststreptococcal glomerulonephritis.
What is the significance of complement 3 and 4 decrease?
It is associated with SLE and cryoglobulinemia.
What is the significance of phospholipase A2 receptor antibody?
It is associated with membranous nephropathy.
What are the defining characteristics of nephrotic syndrome?
- Proteinuria (usually > 3.5g/day),
- hypalbuminemia,
- edema,
- hyperlipoproteinemia,
- thromboembolic events,
- GFR may be normal.
What are the primary renal diseases that can cause nephrotic syndrome?
- Primary membranous glomerulopathy (usually anti-PLA2 receptor antibody positive),
- minimal change nephropathy,
- focal segmental glomerulosclerosis.
What are the systemic diseases that can cause renal manifestation of nephrotic syndrome?
- Diabetic nephropathy,
- amyloidosis,
- secondary FSGS (HIV, extreme obesity),
- secondary membranous glomerulopathy (lupus nephritis, mixed cryoglobulinemia).
What is the further differentiation process for nephrotic syndrome?
It involves immunoserology and kidney biopsy.
What are the possible causes of secondary membranous glomerulopathy?
Lupus nephritis, malignancy, drugs, hepatitis B/C, syphilis, NSAIs, TNF-inhibitors.
What are the possible causes of proliferative glomerulonephritis?
- Immune complex and/or complement disregulation mechanisms,
- poststreptococcalis glomerulonephritis,
- postinfectiosus glomerulonephritis,
- membranoproliferative glomerulonephritis.
What are the symptoms of nephritic syndrome?
- Hematuria
- Urinary casts
- Hypertension
- Edema
- Oliguria
- Decreased GFR
What are some symptoms of Rapidly Progressive Glomerulonephritis Syndrome (RPGN)?
- Rapid worsening of kidney function,
- nephritic urinary findings,
- frequent systemic symptoms such as vasculitis, pulmonary bleeding, arthritis, fever, and neuropathy.
What is the prognosis for untreated RPGN?
The prognosis for untreated RPGN is dismal.
What is the typical finding in light microscopy for RPGN?
Light microscopy usually shows crescents with parietal cell proliferation (extracapillary proliferation).
What are some contraindications to renal biopsy?
Uncooperative patient, single kidney, multiple renal cysts, renal neoplasm, acute pyelonephritis, uncontrolled bleeding diathesis, and uncontrolled blood pressure (BP > 160/95 mmHg).
What are the different patterns observed in immunofluorescent microscopy in the evaluation of a biopsy sample in nephrology?
Granular pattern, Linear pattern, Pauci-immune pattern.
What is an asymptomatic urinary abnormality in nephrology?
Non-nephrotic proteinuria and/or hematuria without nephritic syndrome, usually 0.5-2g/day
What are some causes of asymptomatic proteinuria?
- early diabetic nephropathy,
- secondary FSGS,
- hypertensive nephropathy
What are some causes of asymptomatic hematuria?
glomerular diseases such as
- IgA nephropathy
- Alport syndrome,
- thin-basement membrane abnormality
What are some signs and symptoms of chronic kidney disease?
- decreased GFR,
- usually small kidneys with echogenic parenchyma,
- variable urinary abnormalities,
- complications according to the stages of CKD such as hypertension, electrolyte-acid base alterations, anemia, and cardiovascular diseases.
What should be done in cases of slow progression of chronic kidney disease?
In cases of slow progression of chronic kidney disease, preparation for renal replacement therapy and prevention of complications should be done.
