Nephritic/Nephrotic Syndrome…in a Rush

Which one involves blood? Protein?? Beckoning back to the Step 1 days of yonder, let’s dive into the a little bit of renal anatomy and disease.

Basics

• Nephrons
  • The renal functional units (workhorse of the kidneys)
  • Composed of
    • Glomerulus
      • made up of afferent and efferent arterioles
      • Filters blood into the tubules
    • Tubules
      • Converts filtrate into urine

Nephrotic Syndrome

• Glomerular disorder characterized by proteinuria
  • >3.5 g/day
• Diagnosis
  • UA, CMP, CBC. lipid and autoimmune panel
  • CXR if concerned for associated effusion
• Types
  • Minimal Change Disease
    • Account for 90% of cases of nephrotic syndrome in children under the age of 10 years
    • Diffuse effacement of the epithelial cell foot processes leading to proteinuria causing edema and intravascular depletion
      • Due to decreased oncotic pressure
      • Loss all the “good” proteins in your body
        • Hypovolemic shock
        • Hypertension
        • Thromboembolic events
          • DVT and renal vein thrombosis
          • Due to decreased levels of antithrombin III and plasminogen
    • Clinical presentation
      • Edema (classically periorbital edema)
      • Malaise, fatigue, weight gain
      • Growth failure
    • Usually successfully treated with steroids    
    • May progress to FSGS
  • Focal Segmental Glomerulosclerosis
    • Segmental sclerosis and hyalinosis
    • Can be idiopathic or genetic
      • Other causes: HIV infection, morbid obesity, reflux nephropathy
    • More common in African Americans and age <10 years old
    • Primary FSGS has inconsistent response to steroids
    • May progress to chronic renal disease
  • Membranous nephropathy
    • Deposition of immune complexes in the GBM
    • More common in Caucasians
    • 1/3 of patients achieve remission
    • 40% go on to develop ESRD
  • Amyloidosis
    • Kidney is most common organ involved in systemic amyloidosis
  • Diabetic glomerulonephropathy
    • Nonenzymatic glycosylation of the GBM and afferent arterioles
      • Allows proteins to leak through
    • Most common cause of chronic renal disease in the US

Nephritic Syndrome

• Glomerular disorder characterized by glomerular inflammation and bleeding
• Limited proteinuria (<3.5g/day)
• salt retention, periorbital edema, hypertension
• RBC casts and dysmorphic RBCs on UA
• NephrItic = Inflammatory
  • Types
    • IgA nephropathy (Berger’s disease)
      • Most common cause of glomerulonephritis
      • More common in young Asian males
      • autoimmune
      • Begins DAYS after onset of URI
        • IgA is what lines the mucous membranes and intestines, acute illness leads to proliferation
        • Look for history of coca cola colored urine following URI symptoms
    • Membranoproliferative Glomerulonephritis
    • Henoch-Sconlein Purpura
      • IgA vasculitis
      • classic tetrad: palpable purpura, abdominal pain, arthritis/arthralgias, renal disease
      • treatment with steroids is controversial
      • treatment focus is on hydration, rest, and analgesics
    • Post-Streptococcal glomerulonephritis
      • Begins weeks after strep infection
      • usually occurs in kids, but can happen in adults
      • get ASO titer
      • Not prevented by antibiotics (unlike Rheumatic fever associated with strep)
      • HTN treated with furosemide
    • Rapidly Progressive glomerulonephritis
      • progresses to renal failure in weeks to months
      • Vasculitides such as Wegner’s, Henoch-Schonlein
      • Goodpasture’s Syndrome
        • Hematuria and pulmonary hemorrhage
        • Hydrocarbon exposure and smoking can flare up disease
      • Churg-Strauss (Eosinophilic Granulomatosis with Polyangiitis)
        • association with asthma
      • Wegner’s disease (Granulomatosis with polyangiitis)
        • Wet
          • Pulmonary hemorrhage
        • ESRD
        • Granuloma
      • Microscopic Polyangiitis
• Management
  • ABCs
    • Some of these patients can present with devastating pulmonary hemorrhage and respiratory distress
  • Loop diuretics and nitrates for pulmonary edema
  • IV fluids if concern for hypovolemia, even if swelling present
  • Loop or thiazide diuretics for HTN
  • consider steroids
    • mainstay of treatment for nephrotic syndrome, but response depends on the underlying cause
  • mild disease may consider discharge with outpatient nephrology follow up

Thanks to Dr. Dissanayake for her amazing lecture, linked below!!