Page 1106 - TNFlipTest

P72 Pediatrics
Nephritic Syndrome
PHAROH
Proteinuria (<50 mg/kg/d) Hematuria
Azotemia
RBC casts
Oliguria
HTN
Nephrology Toronto Notes 2019 Nephritic Syndrome
Definition
• acuteorchronicsyndromeaffectingthekidney,characterizedbyglomerularinjuryandinflammation
• defined by hematuria (>5 RBCs per high-powered microscope field), presence of dysmorphic RBCs,
and RBC casts on urinalysis
• oftenaccompaniedbyatleastoneofproteinuria(<50mg/kg/d),edema,HTN,azotemia,andoliguria
Epidemiology
• highestincidenceinchildrenaged5-15yrold
Etiology
• humoralimmuneresponsetoavarietyofetiologicagents→immunoglobulindeposition→complement activation, leukocyte recruitment, release of growth factors/cytokines → glomerular inflammation and injury → porous podocytes → hematuria + RBC casts ± proteinuria
• HTNsecondarytofluidretentionandincreasedreninsecretionbyischemickidneys
Table 34. Major Causes of Nephritic Syndrome
Primary
(idiopathic)
Secondary
(systemic disease)
Decreased C3
Post-infectious GN (most common cause of acute GN in pediatrics)
Membranoproliferative
Type I (50-80%) Type II (>80%)
SLE
Bacterial endocarditis Abscess or shunt nephritis Cryoglobulinemia
Normal C3
IgA nephropathy
Idiopathic rapidly progressive GN Anti-GBM disease
HSP (very common) Polyarteritis nodosa Granulomatosis with polyangiitis Goodpasture’s syndrome
Clinical Presentation
• oftenasymptomatic;someoverlapinclinicalfindingsfornephriticandnephroticsyndrome
• grosshematuria,mild-moderateedema,oliguria,HTN
• signsandsymptomssuggestiveofunderlyingsystemiccauses(e.g.fever,arthralgias,rash,dyspnea,
pulmonary hemorrhage)
Investigations
• urine
■ dipstick (hematuria, 0 to 2+ proteinuria) and microscopy (>5 RBCs per high-powered microscope
field, acanthocytes, RBC casts)
■ first morning urine protein/creatinine ratio (<200 mg/mmol)
• bloodwork
■ CBC, electrolytes, Cr, BUN, albumin
■ impairedrenalfunction(↑CrandBUN)resultingin↑pHandelectrolyteabnormalities
(hyperkalemia, hyperphosphatemia, hypocalcemia)
■ mild anemia on CBC (secondary to hematuria)
■ hypoalbuminemia (secondary to proteinuria)
■ appropriate investigations to determine etiology: C3/C4 levels, serologic testing for recent
streptococcal infection (ASOT, anti-hyaluronidase, anti-streptokinase, anti-NAD, anti-DNAse B),
ANA, anti-DNA antibodies, ANCA, serum IgA levels, anti-GBM antibodies
• renalbiopsyshouldbeconsideredonlyinthepresenceofacuterenalfailure,noevidenceof
streptococcal infection, normal C3/C4
Management
• treatunderlyingcause • symptomatic
■ renal insufficiency: supportive (dialysis if necessary), proper hydration
■ HTN: salt and fluid restriction (but not at expense of renal function), ACEI or ARBs for chronic
persistent HTN (not acute cases because ACEI or ARBs may decrease GFR further)
■ edema: salt and fluid restriction, possibly diuretics (avoid if significant intravascular depletion)
• corticosteroidsifindicated:IgAnephropathy,lupusnephritis,etc.
Prognosis
• dependentonunderlyingetiology
• complicationsincludeHTN,heartfailure,pulmonaryedema,chronickidneyinjury(requiringrenal
transplant)