USMLE Guide: Pediatric Renal and Urinary Disorders

Introduction

This guide aims to provide an overview of common pediatric renal and urinary disorders. It is intended to help medical students prepare for the United States Medical Licensing Examination (USMLE) and build a foundation of knowledge in this area.

Table of Contents

1. Overview of Pediatric Renal and Urinary Disorders
   • Definition and Epidemiology
   • Classification
2. Congenital Anomalies of the Kidney and Urinary Tract
   • Vesicoureteral Reflux (VUR)
   • Hydronephrosis
   • Polycystic Kidney Disease (PKD)
3. Glomerular Diseases
   • Acute poststreptococcal glomerulonephritis (APSGN)
   • Minimal Change Disease (MCD)
   • IgA Nephropathy (Berger's Disease)
4. Renal Tubular Disorders
   • Fanconi Syndrome
   • renal tubular acidosis (RTA)
   • Nephrogenic diabetes insipidus (NDI)
5. Urinary Tract Infections (UTIs)
   • Acute Pyelonephritis
   • Cystitis
6. Nephrotic Syndrome
   • Minimal Change Disease (MCD)
   • Focal Segmental Glomerulosclerosis (FSGS)
   • Membranous Nephropathy
7. Renal Neoplasms
   • wilms tumor (Nephroblastoma)
   • Renal Cell Carcinoma (RCC)
8. Renal Failure and Dialysis
   • acute kidney injury (AKI)
   • Chronic Kidney Disease (CKD)
   • Dialysis Modalities: Hemodialysis vs. Peritoneal Dialysis
9. Renal Transplantation
   • Indications and Contraindications
   • Immunosuppressive Medications
10. Conclusion

Overview of Pediatric Renal and Urinary Disorders

• Definition and Epidemiology: Pediatric renal and urinary disorders refer to a wide range of conditions affecting the kidneys and urinary tract in children. They can result from congenital anomalies, acquired diseases, or infections. These disorders contribute significantly to childhood morbidity and may have long-term implications for renal function.
• Classification: Pediatric renal and urinary disorders can be broadly classified into congenital anomalies, glomerular diseases, renal tubular disorders, urinary tract infections (UTIs), nephrotic syndrome, renal neoplasms, renal failure, and renal transplantation.

Congenital Anomalies of the Kidney and Urinary Tract

Vesicoureteral Reflux (VUR)

• Definition: Retrograde flow of urine from the bladder into the ureters and potentially up to the kidneys.
• Diagnosis: Voiding cystourethrogram (VCUG) is the gold standard for diagnosis.
• Management: Treatment options include prophylactic antibiotics, surgical correction, or observation depending on the severity and presence of complications.

Hydronephrosis

• Definition: Dilatation of the renal pelvis and calyces due to urinary tract obstruction.
• Diagnosis: Ultrasonography is the initial imaging modality of choice.
• Management: Treatment depends on the underlying cause, ranging from observation, medical therapy, to surgical intervention.

Polycystic Kidney Disease (PKD)

• Definition: Genetic disorder characterized by the presence of multiple cysts in the kidneys.
• Types: Autosomal Dominant PKD (ADPKD) and Autosomal Recessive PKD (ARPKD).
• Diagnosis: Imaging studies such as ultrasound or computed tomography (CT) can confirm the diagnosis.
• Management: Supportive care, blood pressure control, and management of complications.

Glomerular Diseases

Acute Poststreptococcal Glomerulonephritis (APSGN)

• Definition: Immune-mediated inflammation of the glomeruli following a streptococcal infection.
• Clinical Features: Hematuria, proteinuria, hypertension, edema, and oliguria.
• Diagnosis: Clinical presentation, positive streptococcal serology, and characteristic renal biopsy findings.
• Management: Supportive care, antibiotics for active infection, and management of complications.

Minimal Change Disease (MCD)

• Definition: The most common cause of nephrotic syndrome in children, characterized by minimal changes on renal biopsy.
• Clinical Features: Massive proteinuria, hypoalbuminemia, generalized edema, and hyperlipidemia.
• Diagnosis: Clinical presentation, urine analysis, and characteristic renal biopsy findings.
• Management: Corticosteroid therapy is the mainstay of treatment.

IgA Nephropathy