A 5-year-old boy is brought to the emergency department with complaints of generalized swelling and decreased urine output over the past few days. His mother reports that he had periorbital puffiness in the mornings, which progressed to swelling in his legs and abdomen. He has no history of fever, sore throat, or recent illness. On examination, he has pitting edema, mild ascites, and normal blood pressure. Urinalysis reveals heavy proteinuria (4+), no hematuria, and microscopic examination shows no casts. Blood tests show hypoalbuminemia (1.7 g/dL) and hyperlipidemia. Which of the following is most characteristic of this disease?

A previously healthy 4-year-old girl is brought to the pediatric clinic by her parents due to progressive swelling over the past two weeks. They initially noticed puffiness around her eyes in the morning, which later progressed to swelling in her legs and abdomen. They also report that her urine appears frothy, but she has no complaints of pain, burning urination, or hematuria. She has been more fatigued than usual, but there is no fever, rash, joint pain, or recent infections. Her medical history is unremarkable, and she has no known allergies or previous hospitalizations. There is no family history of kidney disease, autoimmune conditions, or systemic illnesses. Physical Examination General: Alert but appears mildly fatigued Vital Signs: Blood Pressure: 98/60 mmHg (normal) Heart Rate: 90 bpm (normal) Respiratory Rate: 20 bpm (normal) Temperature: 98.6°F (37°C) HEENT: Periorbital edema, more pronounced in the morning Cardiovascular: No murmurs, normal heart sounds Respiratory: No crackles, no signs of fluid overload Abdomen: Mild ascites (fluid wave present) Extremities: Pitting edema in both lower limbs Neurologic: Alert and interactive, normal reflexes Diagnostic Workup 1.Urinalysis 3+ proteinuria No hematuria (no RBCs, no casts) No leukocytes or nitrites 2.24-hour Urine Protein >3.5 g/day equivalent, confirming nephrotic-range proteinuria 3.Serum Studies Hypoalbuminemia (1.8 g/dL) Hyperlipidemia (total cholesterol 290 mg/dL) Normal creatinine & BUN Normal complement levels (C3, C4) 4.Renal Ultrasound Normal kidney size and echotexture What is the first-line treatment for this patient?

A 6-year-old boy is brought to the pediatric clinic with progressive periorbital swelling and generalized edema over the past week. His parents have also noticed that his urine appears frothy. He has no fever, hematuria, or recent infections. On examination, blood pressure is normal, and there is pitting edema in his lower limbs. Laboratory findings show 3+ proteinuria, hypoalbuminemia (2.0 g/dL), and hyperlipidemia (total cholesterol 280 mg/dL). Serum creatinine is normal. Which of the following findings is most characteristic of this disease on kidney biopsy?

A 5-year-old boy is brought to the pediatric clinic with concerns about progressive swelling in the face and legs over the past week. The caregiver first noticed puffiness around the eyes in the morning, which has since worsened. They also report that his urine appears frothy and that he has been more tired than usual. History of Present Illness Onset: Symptoms started one week ago Swelling pattern: Periorbital edema in the morning, worsening to leg and abdominal swelling throughout the day Urinary symptoms: Frothy urine  No burning, urgency, or hematuria General symptoms: Increased fatigue No fever, rash, joint pain, or respiratory symptoms Medical History: No significant past medical history Family History: No known renal disease or autoimmune disorders Social History: Attends preschool, no recent infections or travel history Physical Examination General: Appears well but slightly fatigued Vital Signs: Blood Pressure: 98/62 mmHg (normal) Heart Rate: 88 bpm (normal) Respiratory Rate: 20 bpm (normal) Temperature: 98.6°F (37°C) HEENT: Periorbital edema, more pronounced in the morning Cardiovascular: Normal heart sounds, no murmurs Respiratory: No crackles or wheezing Abdomen: Mild ascites (fluid wave present) Extremities: Pitting edema in lower limbs Neurologic: Normal reflexes, alert and interactive Diagnostic Workup 1.Urinalysis 3+ proteinuria No RBCs or casts No leukocytes or nitrites 2.24-hour Urine Protein >3.5 g/day equivalent 3.Serum Studies Low albumin (2.1 g/dL) Hyperlipidemia (total cholesterol 280 mg/dL) Normal creatinine & BUN 4.Renal Ultrasound Normal kidney size and echotexture 5.Renal Biopsy Light Microscopy: Normal Electron Microscopy: Podocyte foot process effacement Which of the following is the most likely diagnosis in this case?