🩺 Nephrology Reference: Screening, Diagnostics & Treatment

Based on Nelson's Textbook of Pediatrics, 22nd Edition (Chapters 557–573) | Quick clinical guide by disease category

πŸ“– Chapter 557: Introduction to Glomerular Diseases

πŸ” Screening Tests
  • Urinalysis (dipstick + microscopy) for hematuria/proteinuria
  • Blood pressure measurement (annual in well-child visits)
  • Serum creatinine and eGFR (if risk factors: prematurity, FHx kidney disease)
πŸ”¬ Diagnostic Tests
  • Renal biopsy (light microscopy, immunofluorescence, EM)
  • Serum complement (C3, C4) – helps distinguish postinfectious GN (low C3) vs IgA (normal)
  • Anti-GBM antibodies, ANA, ANCA, anti-dsDNA
  • Quantitative proteinuria (uPr/Cr, 24h urine)
πŸ’Š Most Accurate Treatment Principles
  • Disease-specific immunosuppression (steroids, cyclophosphamide, MMF, rituximab)
  • ACEi/ARB for proteinuria & hypertension to slow CKD progression
  • Blood pressure control (<50th percentile on ABPM in proteinuric CKD)
Reference: Nelson 22e, Ch 557.1–557.2

πŸ“– Chapter 558: Clinical Evaluation of Hematuria

πŸ” Screening
  • Urine dipstick (peroxidase reaction) + microscopic confirmation
  • Repeat urinalysis on first morning void
  • Family history (Alport, thin GBM, PKD, IgA nephropathy)
πŸ”¬ Diagnostic Tests
  • Urine microscopy: RBC casts/dysmorphic RBCs β†’ glomerular; normal RBCs β†’ lower tract
  • Serum C3, C4, creatinine, ASO, anti-DNase B, ANA, ANCA
  • Renal/bladder ultrasound (structural lesions, stones, hydronephrosis)
  • Spot urine Ca/Cr for hypercalciuria
  • Sickle cell screen (Black patients)
πŸ’Š Treatment
  • Treat underlying cause (antibiotics for UTI, hydration for hypercalciuria, immunosuppression for GN)
  • Referral to nephrology if persistent proteinuria, hypertension, reduced GFR
  • Thiazide diuretics for symptomatic hypercalciuria
Reference: Nelson 22e, Ch 558, Table 558.2, Fig 558.1

πŸ“– Chapter 559: Isolated Glomerular Diseases

πŸ” Screening
  • Urinalysis for hematuria (especially post-URI gross hematuria β†’ think IgA)
  • Family history: hearing loss, CKD (Alport, thin GBM)
  • Blood pressure, serum creatinine, C3 (low in poststreptococcal, normal in IgA)
πŸ”¬ Diagnostic Tests
  • Renal biopsy with immunofluorescence (IgA deposits; linear IgG in anti-GBM)
  • ASO/anti-DNase B + low C3 (poststreptococcal GN)
  • Genetic testing: COL4A5 (Alport), COL4A3/A4 (thin GBM & AR Alport)
  • Skin biopsy (absent Ξ±5 chain in X-linked Alport)
  • Audiometry (Alport sensorineural hearing loss)
πŸ’Š Most Accurate Treatment
  • IgA nephropathy: BP control, ACEi/ARB; steroids if persistent proteinuria; sparsentan (adults)
  • Alport: ACEi/ARB to slow progression; kidney transplant for ESKD
  • Poststreptococcal GN: supportive (diuretics, BP control); antibiotics for carrier state
  • MPGN: prolonged alternate-day steroids; eculizumab for C3GN/atypical HUS
  • RPGN (crescentic): steroids + cyclophosphamide Β± plasmapheresis
Reference: Nelson 22e, Ch 559.1–559.7, Table 559.1

πŸ“– Chapter 560: Multisystem Disease + Hematuria

πŸ” Screening
  • Urinalysis in all children with SLE, HSP, or HUS
  • Annual BP, creatinine, uPr/Cr in SLE
  • Stool culture & Shiga toxin (suspected STEC-HUS)
πŸ”¬ Diagnostic Tests
  • SLE: ANA, anti-dsDNA, low C3/C4; renal biopsy (WHO/ISN class)
  • HSP/IgA vasculitis: clinical tetrad; biopsy shows IgA deposits
  • Goodpasture: anti-GBM antibodies, linear IgG on biopsy
  • HUS: peripheral smear (schistocytes), LDH, low platelets, renal function; complement genetics for atypical HUS
πŸ’Š Most Accurate Treatment
  • Lupus nephritis: MMF or cyclophosphamide + steroids + hydroxychloroquine; ACEi/ARB
  • HSP nephritis: supportive; severe crescents β†’ steroids + cyclophosphamide/MMF
  • Goodpasture: plasmapheresis + steroids + cyclophosphamide
  • Typical STEC-HUS: supportive (avoid antibiotics, transfusions as needed)
  • Atypical HUS: eculizumab (anti-C5)
Reference: Nelson 22e, Ch 560.1–560.5

πŸ“– Chapter 561: Tubulointerstitial Disease

πŸ” Screening
  • Urinalysis (WBC casts, low-grade proteinuria, eosinophils)
  • Serum creatinine, BUN, electrolytes
  • History of drug exposure (NSAIDs, penicillins, PPIs)
πŸ”¬ Diagnostic Tests
  • Renal biopsy (lymphocytic infiltration, interstitial edema)
  • Urine eosinophils (not sensitive/specific)
  • Genetic testing (NPHP1-18 for nephronophthisis, CTNS for cystinosis)
  • Renal ultrasound (small kidneys, corticomedullary cysts in NPHP)
πŸ’Š Most Accurate Treatment
  • Acute TIN: discontinue offending drug; prednisone if severe
  • Chronic TIN/nephronophthisis: supportive, manage CKD complications
  • Cystinosis: cysteamine (oral + eye drops), kidney transplant
Reference: Nelson 22e, Ch 561.1–561.4, Tables 561.1, 561.2

πŸ“– Chapter 562: Vascular Diseases & Hematuria

πŸ” Screening
  • Urinalysis (hematuria, no RBC casts) + BP
  • 24h urine calcium (hypercalciuria), sickle cell screen
  • Doppler ultrasound for suspected nutcracker or RVT
πŸ”¬ Diagnostic Tests
  • Renal vein thrombosis: Doppler ultrasound, CT angiography
  • Nutcracker: left renal vein Doppler (aortomesenteric ratio >3-5)
  • Hypercalciuria: spot Ca/Cr >0.2, 24h Ca >4 mg/kg/d
πŸ’Š Most Accurate Treatment
  • RVT: anticoagulation (LMWH/heparin) if bilateral/IVC extension; supportive for unilateral
  • Sickle cell nephropathy: ACEi/ARB for proteinuria; hydroxyurea
  • Idiopathic hypercalciuria: thiazide diuretic (HCTZ), potassium citrate, high fluids, sodium restriction (NO calcium restriction)
  • Nutcracker: observation; surgery for severe cases
Reference: Nelson 22e, Ch 562.1–562.4

πŸ“– Chapter 563: Congenital Anomalies & Cystic Kidney

πŸ” Screening
  • Prenatal ultrasound (echogenic kidneys, oligohydramnios β†’ ARPKD)
  • Family history (ADPKD, tuberous sclerosis)
  • BP monitoring, urinalysis
πŸ”¬ Diagnostic Tests
  • Renal ultrasound: large echogenic with microcysts (ARPKD); macrocysts with liver cysts (ADPKD)
  • Genetic testing: PKHD1 (ARPKD), PKD1/PKD2 (ADPKD), NPHP1-18 (nephronophthisis)
  • Liver ultrasound for congenital hepatic fibrosis (ARPKD)
πŸ’Š Most Accurate Treatment
  • ARPKD: BP control (ACEi/ARB), respiratory support, dialysis/transplant; consider combined kidney-liver transplant
  • ADPKD: BP control (ACEi/ARB), tolvaptan in adults; screen for aneurysms (family hx)
  • Nephronophthisis: supportive, renal transplant
Reference: Nelson 22e, Ch 563.1–563.3, Tables 563.1, 563.2

πŸ“– Chapter 564: Hemorrhagic Cystitis

πŸ” Screening
  • Urinalysis (RBCs, no bacteria in viral/chemical)
  • History of cyclophosphamide, radiation, or bone marrow transplant
πŸ”¬ Diagnostic Tests
  • Urine culture (exclude bacterial UTI)
  • Urine PCR: adenovirus, BK virus (post-BMT)
  • Cystoscopy (severe or refractory)
πŸ’Š Most Accurate Treatment
  • Cyclophosphamide-induced: Mesna + hyperhydration
  • Viral: supportive; reduce immunosuppression; cidofovir for BK
  • Exercise-induced: reassurance, resolves in 48h
Reference: Nelson 22e, Ch 564.1–564.3

πŸ“– Chapter 565: Clinical Evaluation of Proteinuria

πŸ” Screening
  • Urine dipstick (albumin-sensitive) – avoid false + (alkaline pH)
  • First morning urine for uPr/Cr ratio
πŸ”¬ Diagnostic Tests
  • Spot uPr/Cr (normal <0.2 mg/mg >2y; nephrotic >2.0)
  • 24h urine protein (<100 mg/mΒ²/d normal)
  • Microalbuminuria (30-300 mg/g Cr) in diabetics
πŸ’Š Treatment Guidance
  • Transient: none, reassurance
  • Orthostatic: benign, no treatment
  • Fixed proteinuria: nephrology referral, renal biopsy if >1g/d, HTN, or reduced GFR
Reference: Nelson 22e, Ch 565, Table 565.1

πŸ“– Chapter 566: Conditions Associated with Proteinuria

πŸ” Screening
  • Dipstick on random sample, then first morning void
  • Spot uPr/Cr to quantitate
πŸ”¬ Diagnostic Tests
  • First morning uPr/Cr β†’ normal = orthostatic; elevated = fixed (pathologic)
  • Serum albumin, Cr, complement, ANA, renal biopsy
  • Urine protein electrophoresis (albumin vs LMW proteins)
πŸ’Š Treatment
  • Orthostatic: reassurance, no treatment
  • Glomerular proteinuria: ACEi/ARB, treat underlying GN
  • Tubular proteinuria: address underlying cause (cystinosis, drugs)
Reference: Nelson 22e, Ch 566.1–566.3, Table 566.1

πŸ“– Chapter 567: Nephrotic Syndrome

πŸ” Screening
  • Urine dipstick (3-4+ protein), uPr/Cr >2.0
  • Serum albumin (<2.5 g/dL), cholesterol, triglycerides
πŸ”¬ Diagnostic Tests
  • First episode in 1-12y without atypical features: no biopsy, treat as MCNS
  • Renal biopsy if age <1 or >12, steroid resistance, gross hematuria, HTN, low C3
  • Genetic testing (NPHS1, NPHS2, WT1, LAMB2) for congenital or steroid-resistant
πŸ’Š Most Accurate Treatment
  • Initial: prednisone 60 mg/mΒ²/d Γ—4-6 wk β†’ alternate day Γ—4-6 wk (KDIGO 2021)
  • Frequent relapses/steroid-dependent: cyclophosphamide, CNI (cyclosporine/tacrolimus), MMF, rituximab
  • Steroid-resistant: CNI + steroids; consider genetic testing, rituximab
Reference: Nelson 22e, Ch 567.1–567.3, Tables 567.2, 567.3, Fig 567.4 (KDIGO algorithm)

πŸ“– Chapter 568: Tubular Function

πŸ” Screening
  • Serum electrolytes, BUN, Cr, Ca, POβ‚„, Mg
  • Urine electrolytes, FENa, FeUrea
πŸ”¬ Diagnostic Tests
  • Urine osmolality, water deprivation test (concentrating ability)
  • Fractional excretion tests (FENa, FEUrea, FEPOβ‚„)
  • Renal tubular acidosis workup (urine pH, urine anion gap)
πŸ’Š Treatment Principles
  • Correct electrolyte disturbances (Na, K, Mg, POβ‚„)
  • Thiazides for hypercalciuria, loop diuretics for edema
  • Treat underlying genetic tubulopathy (specific supplements)
Reference: Nelson 22e, Ch 568

πŸ“– Chapter 569: Renal Tubular Acidosis

πŸ” Screening
  • Non-anion gap metabolic acidosis (Cl↑, HCO₃↓) with normal GFR
  • Serum K+ (hypoK in type I/II, hyperK in type IV)
πŸ”¬ Diagnostic Tests
  • Urine pH during acidosis: >5.5 = distal (type I); <5.5 = proximal (type II)
  • Fractional excretion of HCO₃⁻ (>15% = proximal)
  • Urine anion gap (positive in RTA, negative in diarrhea)
  • Genetic testing (ATP6V1B1, SLC4A1, CTNS)
πŸ’Š Most Accurate Treatment
  • Proximal (type II): NaHCO₃/citrate 10-20 mEq/kg/d; phosphate for Fanconi
  • Distal (type I): NaHCO₃/citrate 2-4 mEq/kg/d; thiazides if hypercalciuria
  • Type IV: correct hyperkalemia (Kayexalate, furosemide), fludrocortisone if aldosterone deficiency
Reference: Nelson 22e, Ch 569.1–569.4, Table 569.4

πŸ“– Chapter 570: Nephrogenic Diabetes Insipidus

πŸ” Screening
  • Polyuria, polydipsia, hypernatremia, dilute urine (Uosm <300)
  • Family history (X-linked AVPR2)
πŸ”¬ Diagnostic Tests
  • Water deprivation test + DDAVP challenge: no rise in Uosm after DDAVP = NDI
  • Genetic testing (AVPR2, AQP2)
  • Serum Na, Uosm, plasma AVP (high in NDI)
πŸ’Š Most Accurate Treatment
  • Unlimited free water, low-sodium/low-solute diet
  • Thiazide diuretics (paradoxical antidiuresis) + indomethacin
  • Amiloride for lithium-induced NDI
Reference: Nelson 22e, Ch 570

πŸ“– Chapter 571: Inherited Tubular Transport Abnormalities

πŸ” Screening
  • Hypokalemic metabolic alkalosis + BP normal (Bartter/Gitelman)
  • Spot urine Ca/Cr (high in Bartter, low in Gitelman)
  • Serum Mg (low in Gitelman)
πŸ”¬ Diagnostic Tests
  • Genetic testing: SLC12A1/KCNJ1/CLCNKB (Bartter); SLC12A3 (Gitelman)
  • Dent disease: LMW proteinuria + hypercalciuria + CLCN5/OCRL1 mutation
  • Liddle: HTN, hypokalemia, suppressed renin/aldosterone
πŸ’Š Most Accurate Treatment
  • Bartter: high Na/K, spironolactone, indomethacin
  • Gitelman: Mg + KCl supplementation, amiloride
  • Dent: ACEi/ARB, thiazides, manage CKD
  • Liddle: amiloride (ENaC blocker)
Reference: Nelson 22e, Ch 571.1–571.3, Tables 571.1, 571.2

πŸ“– Chapter 572: Renal Failure (AKI, CKD, ESKD)

πŸ” Screening
  • Serum creatinine, eGFR (bedside Schwartz, CKID U25)
  • Urinalysis, BP monitoring, growth parameters
  • Spot uPr/Cr (proteinuria as progression marker)
πŸ”¬ Diagnostic Tests
  • AKI: KDIGO criteria; urinary indices (FENa, FeUrea); renal US
  • CKD: GFR staging (1-5), renal biopsy, imaging
  • ESKD: GFR <15, dialysis indications
πŸ’Š Most Accurate Treatment
  • AKI: correct volume, treat hyperkalemia (Ca²⁺ first if ECG changes), dialysis if indicated
  • CKD: ACEi/ARB for HTN/proteinuria, phosphate binders + active vitamin D (CKD-MBD), ESA for anemia, rHuGH for growth
  • ESKD: peritoneal dialysis (infants), hemodialysis, kidney transplantation (preemptive living donor best)
Reference: Nelson 22e, Ch 572.1–572.3, Tables 572.1, 572.7, 572.8

πŸ“– Chapter 573: Kidney Transplantation

πŸ” Screening
  • Pre-transplant evaluation: HLA typing, crossmatch, PRA, CMV/EBV/BK serologies
  • Cardiac ECHO, urodynamics (if urologic disease)
  • Immunizations (live vaccines pre-transplant)
πŸ”¬ Diagnostic Tests
  • Renal allograft biopsy (for rejection: TCMR, AMR with C4d)
  • Plasma BK PCR (surveillance), EBV PCR (PTLD risk)
  • Donor-specific antibody (DSA) monitoring
πŸ’Š Most Accurate Treatment
  • Induction: basiliximab or ATG
  • Maintenance: tacrolimus + MMF Β± prednisone
  • Rejection: TCMR β†’ steroids/ATG; AMR β†’ plasmapheresis/IVIG/rituximab
  • BK virus: reduce immunosuppression, consider cidofovir
  • PTLD: reduce immunosuppression, rituximab, chemotherapy
Reference: Nelson 22e, Ch 573, OPTN/SRTR guidelines