Renal Syndromes Flashcards
When a patient presents with gross or microscopic hematuria, what else should you be checking?
serum creatinine urine protein dysmorphic RBCs urinary casts sx of systemic disease
If a patient presents with hematuria in the setting of normal renal function, no proteinuria, no urinary casts, and no
symptoms, what are the next steps?
Repeat urinalysis (UA) to see if hematuria is persistent
If a patient presents with persistent hematuria in the setting of normal renal function, no proteinuria, no urinary casts, and no
symptoms, what is the next step?
If persistent, pursue urological work-up (imaging of kidneys/ureters/bladder +/-cystoscopy to rule out
urological cause of bleeding)
If a patient presents with abnormal renal function, dysmorphic RBCs, proteinuria, casts, and/or symptoms of systemic
disease, what is the next step?
further renal work-up is indicated to look for glomerular cause of hematuria
If patient presents with significant degree of proteinuria and/or if seen alongside hematuria, urinary casts, or abnormal renal
function, what is the next step? What is one special lab result you should get in this process?
immediate renal work-up is indicated
This includes quantification of the proteinuria using a urinary albumin/creatinine ratio
What are some common causes of transient proteinuria?
exercise, fever, or infection
When a patient presents with a combination of hematuria and proteinuria, what renal syndrome should you be looking for?
glomerular disease
What helps classify a patient with nephritic v. nephrotic syndrome?
Degree of proteinuria and other lab/clinical findings help classify whether the patient has a nephritic or
nephrotic syndrome
What is an important step in diagnosis and management of a possible glomerular disease?
renal biopsy
What do RBC casts indicate?
glomerular hematuria and nephritic syndrome
what do lipid/fatty casts or oval fat bodies indicate?
nephrotic syndrome
What is the maltese cross sign when looking at urine under polarized light?
oval fat bodies which indicate nephrotic syndrome
How is renal biopsy usually done?
ultrasound guided with 2-5 cores extracted
How is tissue from a renal biopsy examined?
light microscopy
immunofluorescence
electron microscopy
What does light microscopy look for in a renal biopsY?
ook for cell proliferation, glomerular basement membrane abnormalities, and to identify worrisome lesions such as crescents or necrosis
What does immunofluorescence look for in a renal biopsy>
Ig or complement staining
What does electron microscopy look for in a renal biopsy?
immune complex deposition, mainly
Proteinuria >3 g/day o Hypoalbuminemia o Hyperlipidemia o Lipiduria o Edema
This constellation of findings indicate what syndrome?
nephrotic syndrome
What are the primary and secondary causes of nephrotic syndrome?
Primary kidney disease or systemic disease
What are examples of primary kidney disease leading to nephrotic syndrome?
Membranous nephropathy, Focal segmental glomerulosclerosis, Minimal change disease
What are secondary kidney disease that can cause nephrotic syndrome?
diabetic nephropathy or amyloidosis
What effect does nephrotic syndrome have on coagulability of blood?
Hypercoagulability due to many factors including the relative loss of more anti-coagulant than pro-
coagulant proteins in the urine
What happens to vitamin D levels in nephrotic syndrome?
Low levels due to loss of vitamin D binding protein in urine
What is the most common cause of nephrotic syndrome in Caucasian adults?
membranous nephropathy
What is the clinical presentation of membranous nephropathy?
swelling of extremities over days to weeks
What kind of nephrotic syndrome is Often associated with other systemic conditions such as solid tumor cancers, medication exposure (NSAIDs, Gold), infections (ex/ Hepatitis B or C), or autoimmune disease (ex/ SLE)
membranous nephropathy
Thick glomerular basement membranes on light microscopy
“Spikes” and “holes” can be seen on Jones (silver stain)
Granular IgG staining on immunofluorescence microscopy
Sub-epithelial immune-complex deposits on electron microscopy
Staining for phospholipase A2 receptor (PLA2R) may be positive
These kidney biopsy findings would point to what condition?
membranous nephropathy as the cause of nephrotic syndrome
What would lab values be in membranous nephropathy?
o Urine will show significant proteinuria (>3g/d but can be as much as 10-20 g/d)
o Can have hematuria but less common
o Oval fat bodies, lipid/fatty casts can be seen in urine sediment (maltese cross on polarized light) o Serum creatinine may be normal or elevated
o Dyslipidemia
What are the primary treatment methods in membranous nephropathy with low degrees of proteinuria?
o Lower degrees of proteinuria, focus is on RAAS blockade, salt restriction, and diuresis
For higher levels of proteinuria in membranous nephropathy, what are the treatments?
For higher levels of proteinuria, immunosuppressive therapy is used to modulate the immune system
Cyclophosphamide or Calcineurin inhibitors + steroids Rituximab may also be effective
What kind of nephrotic syndrome is common in AA and linked to APOL1 mutations?
Focal Segmental glomerulosclerosis (FSGS)
Is FSGS usually primary or sednoary?
usually primary
Although more uncommon, what are some causes of secondary FSGS?
Can be secondary to other conditions such infection (HIV), medication (Heroin, Interferon, Lithium, Pamidronate),
Genetic mutation, Reduced renal mass or hyperfiltration injury (genitourinary reflux, congenital malformations,
sickle cell disease, obesity)
What is the clinical presentation of FSGS?
o Edema if often present but may be absent, especially in secondary forms
o HTN is common
What are the lab findings for FSGS?
o Renal function may be abnormal (elevated creatinine in ~1/3)
o Proteinuria may be sub-nephrotic range in secondary forms
o Hematuria may be present
In a kidney biopsy, you see: - 1 or more lesions of segmental sclerosis on light microscopy
- Scant or non-specific staining of IgM, C3, or C1q seen on immunofluorescence
- Podocyte foot process effacement (focal or diffuse) on electron microscopy
What type of renal syndrome is this?
nephrotic syndrome caused by FSGS
What is the first step in treating FSGS?
treating the secondary causes (HIV, obesity)