Nephrotic and Nephritic Syndromes

Nephrotic and Nephritic Syndromes

Nephrotic and Nephritic Syndromes

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Syndrome Overview - Defining the Duo

FeatureNephrOtic SyndromeNephrItic Syndrome
Primary DefectPodocyte damage, ↑ permeabilityGlomerular Inflammation
ProteinuriaMassive: $ > \textbf{3.5g/24h}## Syndrome Overview - Defining the Duo
                   | Mild-moderate: $ < \textbf{3.5g/24h}## Syndrome Overview - Defining the Duo

                 |

| Hematuria | Often absent/microscopic | Gross/microscopic; RBC casts | | Edema | Severe, generalized (hypOalbuminemia) | Mild, periorbital (Na⁺/water retention) | | Hypertension | Less common, may be late | Common, often abrupt (Increased BP) | | Renal Function | Often preserved initially | Often Impaired (↑ creatinine, oliguria) | | Key Features | HypOalbuminemia, hyperlipidemia, lipiduria | Immune complex deposition | | Mnemonic | 📌 PrOteinuria, HypOalbuminemia, Oedema, Hyperlipidemia | 📌 Inflammation, Immune complexes, Increased BP, Impaired renal fn. |> ⭐ Oval fat bodies (Maltese cross appearance under polarized light) are characteristic of nephrotic syndrome.

Nephrotic Syndrome - Leaky Filters Galore

Pathophysiology: Podocyte injury, loss of GBM negative charge → ↑ protein permeability.

Cardinal Features:

  • Proteinuria: $ > \textbf{3.5 g/24h}$ (or $ > \textbf{50 mg/kg/day}$ children).
  • Hypoalbuminemia: Serum albumin $ < \textbf{3 g/dL}$.
  • Generalized Edema: Anasarca, often periorbital.
  • Hyperlipidemia & Lipiduria: Oval fat bodies, fatty casts.

📌 NAPHROTIC Mnemonic: Na+ retention, Albuminuria, Proteinuria ($ > \textbf{3.5g/day}$), Hyperlipidemia, Renal vein thrombosis, Orbital edema, Thromboembolism, Infection, Coagulability.

Common Causes:

  • Primary Glomerular Diseases:
    DiseaseKey Biopsy Finding
    MCDPodocyte effacement (EM)
    FSGSSegmental sclerosis (LM)
    Membranous Neph.Thick GBM, subepithelial spikes (EM/IF)
  • Secondary Causes:
    • Diabetes Mellitus (most common in adults)
    • Amyloidosis
    • SLE (Class V)

EM of podocyte effacement and deposits

⭐ Minimal Change Disease is the most common cause of nephrotic syndrome in children and shows diffuse effacement of podocyte foot processes on electron microscopy.

Nephritic Syndrome - Inflamed & Angry Gloms

Pathophysiology: Glomerular inflammation & immune complex deposition → glomerular injury, ↓GFR.

  • Cardinal Features (📌 PHARAOH):

    • Proteinuria (mild-moderate, <3.5 g/day)
    • Hematuria (cola-colored urine, RBC casts present)
    • Azotemia (↑BUN, ↑Creatinine)
    • RBC casts (confirms glomerular hematuria)
    • Anti-Strep titres (↑ in PSGN, e.g., ASO >200 IU/mL)
    • Oliguria (<400 mL/day)
    • Hypertension (HTN)
  • Common Causes:

    • Primary Glomerulonephritis (GN):
      CauseKey Biopsy Finding
      IgA NephropathyMesangial IgA deposits
      PSGNDiffuse hypercellularity, subepithelial "humps"
      RPGNCrescents in Bowman's space
    • Secondary: SLE, Henoch-Schönlein Purpura (HSP), Vasculitis (e.g., GPA, MPA).

Post-streptococcal glomerulonephritis pathology

⭐ PSGN: 1-3 wks (pharyngitis) or 2-6 wks (impetigo) post-infection; features subepithelial 'humps' (EM), low C3.

⭐ IgA Nephropathy is the most common glomerulonephritis worldwide and often presents with episodic macroscopic hematuria concurrent with mucosal infections.

DiseaseSyndromeLMIFEMKey Notes
MCDNephroticNormalNegativeFoot process effacementChildren; steroid-responsive
FSGSNephroticSegmental sclerosisOften negativeFoot process effacementHIV, heroin; variable response
Membranous Neph.NephroticThick GBM, spikesGranular IgG, C3Subepithelial depositsIdiopathic, HBV, SLE; "spike & dome"
Diabetic Neph.NephroticK-W nodulesNegativeThick GBMDM; ESRD risk
IgA NephropathyNephriticMesangial prolif.Mesangial IgAMesangial depositsBerger's; URI-hematuria
PSGNNephriticDiffuse prolif., humpsGranular IgG, C3Subepithelial "humps"Post-strep; good prognosis (kids)
RPGN (Crescentic)NephriticCrescentsVariable: Linear IgG (Goodpasture's), Pauci-immune (ANCA), Granular (Immune complex)GBM breaks (Goodpasture's)Rapid renal failure; urgent Rx

High‑Yield Points - ⚡ Biggest Takeaways

  • Nephrotic Syndrome is defined by massive proteinuria (>3.5 g/day), hypoalbuminemia, edema, and hyperlipidemia.
  • Minimal Change Disease: commonest nephrotic in children; effacement of podocyte foot processes on EM.
  • Nephritic Syndrome presents with hematuria (RBC casts), oliguria, hypertension, and azotemia.
  • Post-Streptococcal Glomerulonephritis (PSGN): classic nephritic, ↑ASO titers, low C3, subepithelial "humps".
  • IgA Nephropathy (Berger's Disease): most common primary glomerulonephritis; recurrent hematuria often after URI.

Practice Questions: Nephrotic and Nephritic Syndromes

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An 8-year-old child presents with hematuria 5 days after a throat infection. What is the most likely diagnosis?

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Flashcards: Nephrotic and Nephritic Syndromes

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Acute interstitial nephritis is associated with _____-uria and pyruria (classically eosinophils)

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Acute interstitial nephritis is associated with _____-uria and pyruria (classically eosinophils)

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