Nephrotic and Nephritic Syndromes - Hausmann Flashcards
Contraindications for kidney biopsy
Coagulation defects (except nephrotic syndrome)
Aspirin/coumadin
Amyloidosis (do rectal or duodenal biopsy)
Multiple myeloma suspicion (do bone biopsy)
Check evidence base to see when in disease will show cause
What tests are done in the urine to determine kidney disease?
What are the indications of Acute Interstitial Nephritis (AIN)
WBC (Hansel Stain-shows acute interstitial nephritis)-can also indicate pyelonephritis (do a culture-if negative can be sterile pyuria)
Eosinophiluria (also suggestive of AIN)
Often allergic reaction from outside (antibiotics)
Classic Presentation: fever, rash on skin, normally no HTN. Sometimes can see activation of complement system (low C3 and C4)
May have different presentations, can have increased creatinine level from impaired clearance.
Treatment: prednisone for several weeks. Make sure this in the diagnosis (histology) before give steroids. Unless uncooperative psych patient or contraindications (in which case give steroids) do biopsy.
Hausmann’s characteristics of Acute Nephritic Syndrome
Macrohematuria
Cast is in the form of the tubule. In normal urine there may be a hyaline cast-physiologic with no cells inside- Tamm Hornfall proteins.
But if there are cells will be strapped in these casts
RBC casts caught inside the jelly: goes with hematuria
Edema in legs and around eyes
Pulmonary edema, CNS edema
Renal failure
Most common cause: PSGN
Can be combined with proteinuria (<500mg/day but some are worse)
No diagnosis without hematuria
Hematuria properties
RBC casts has to be from tubule, can’t be from bladder, ureter or urethra
BPH can cause hematura
Glomerular hematuria never causes a clot
Macrohematuria with clots is not a hematologic problem: either urologic or hematologic
Problem in coagulation system
Maybe proteinuria
Also PCKD (polycystic kidney disease), etc.
Essential Proteinuria
Most common dx where patient has nephrotic syndrome
Appears in children
Very high levels of protein
What are the 3 primary characteristics of nephrotic syndrome
Defined as >3g proteinuria
Low albumin levels
Normal creatinine
Focused Sclerosis
Secondary to obesity
Secondary to prolonged hyperfiltration
Lion after eats lamb has a high GFR
Obese patients that eat a lot have longstanding hyperfiltration
Heroin addicts and HIV patients can develop a similar disease
Also associated with urinary reflux early in life
If not corrected early can get FSGS, if corrected very early can be spared
Amyloidosis
Chronic bronchiectasis can later get nephrotic range proteinuria. Low BP from low albumin.
Patients with familial mediterranean fever (FMF): Treated by colchicine for life to prevent kidney disease
AA (amyloids) deposited on blood vessel walls-can cause severe bleeding, so do dx via rectal or urinary biopsy: less dangerous.
Relation albumin>globulin but if inverted suspect MM even if no bone pain, hypercalcemia and anemia. Need to make dx out of just one symptom and do bone biopsy instead of kidney biopsy.
Imerslund-Gräsbeck syndrome
Cubilin/megalin system is defective: it won’t correctly take up polypeptides in tubular fluid–>tubular proteinuria. Defect in cubilin/megalin mechanism. Also B12 deficiency.
Physiological reaction toward proteins and polypeptides is to reabsorb. System on apical side of proximal tubule: cubilin and megalin. Work together to grasp any polypeptide to endocytose into epithelial cell, metabolized and cleaved into AA. Reabsorbed and taken over by peritubular capillaries. Not just Na and Ca.
One of polypeptides dealt with in this way is insulin: filtered in the glomerulus and enters tubular fluid, uptaken by cubilin/megalin mechanism. 50% of insulin catabolism is done by the kidney.
Important because in chronic renal patients: t1/2 is increasing–>hypoglycemia if inject same amount of insulin.
Small amount of proteins in urine but electrophoresis of proteins shows no albumin because glomerulus is intact. Not taken up by proximal tubule and thus taken up by the urine.
Cubilin/megalin also work on small intestines. Take care of mechanism between intrinsic factor and vitB12. Reabsorbed in small intestines by these 2 proteins.
Families with a defect in these proteins will have severe vit B12 deficiency and pernicious anemia. Will need to inject B12 monthly.
Ask doctor-check for proteinuria
Pernicious anemia + proteinuria
Why do diabetic patients and glomerulopathy patients have better outcome with ACEi?
Because glomerular filtration of albumin and other proteins overwhelms the cubilin/megalin system and causes interstitial fibrosis.
ACEi reduces filtration and reduces uptake and stress of cubilin/megalin.
Also reduces effect of AngiI produced in tubular interstitium which causes fibrosis.
