# Clinical Cases: Pediatric Renal Disorders

## Case 1: Nephrotic Syndrome

### Patient Demographics
- **Age:** 4-year-old male
- **Sex:** Male

### Chief Complaint
"My son's face looks puffy and his eyes are swollen, especially in the morning."

### History of Present Illness
A 4-year-old boy is brought to the clinic by his mother who noticed progressive facial swelling over the past week. She first noticed puffiness around his eyes upon waking, but now his entire face appears swollen. Over the past two days, she has also noticed swelling in his legs and that his shoes no longer fit. She reports he has been urinating less frequently, and his urine appears "foamy." He had an upper respiratory infection approximately two weeks ago that resolved without treatment. He has no history of hematuria, abdominal pain, or fever. He has been eating well but seems more tired than usual.

### Physical Examination
- **Vital Signs:** Temperature 37.0C, HR 95 bpm, RR 20/min, BP 98/62 mmHg
- **General:** Well-appearing boy with noticeable facial edema
- **HEENT:** Periorbital edema bilaterally, no pharyngeal erythema
- **Cardiovascular:** Regular rate and rhythm, no murmurs
- **Respiratory:** Clear to auscultation bilaterally, no increased work of breathing
- **Abdomen:** Soft, mildly distended with shifting dullness suggesting ascites, no hepatosplenomegaly
- **Extremities:** 2+ pitting edema to mid-shins bilaterally, scrotal edema present
- **Skin:** No rashes or lesions

### Laboratory Findings
- **Urinalysis:** Protein 4+, no blood, no WBCs, oval fat bodies present
- **Urine protein/creatinine ratio:** 8.5 (nephrotic range >2)
- **Serum albumin:** 1.8 g/dL (low; normal 3.5-5.0)
- **Total cholesterol:** 385 mg/dL (elevated)
- **Triglycerides:** 290 mg/dL (elevated)
- **BUN:** 18 mg/dL (normal)
- **Creatinine:** 0.4 mg/dL (normal)
- **C3 complement:** 125 mg/dL (normal)
- **C4 complement:** 32 mg/dL (normal)

### Diagnosis
**Nephrotic syndrome, presumed minimal change disease**

### Clinical Reasoning
This child presents with the classic tetrad of nephrotic syndrome: massive proteinuria (protein/creatinine ratio 8.5), hypoalbuminemia (1.8 g/dL), generalized edema, and hyperlipidemia. His age (peak incidence 2-6 years), male sex, normal blood pressure, lack of hematuria, normal renal function, and normal complement levels all support the diagnosis of minimal change disease, which accounts for approximately 80% of childhood nephrotic syndrome. A kidney biopsy is not indicated initially, as most children will respond to corticosteroid therapy.

### Management
1. **Corticosteroid therapy:** Prednisone 2 mg/kg/day (maximum 60 mg) for 6 weeks daily, followed by 1.5 mg/kg every other day for 6 weeks with gradual taper
2. **Dietary modifications:** Sodium restriction during active disease; no protein restriction
3. **Monitor for complications:** Watch for infection (especially pneumococcal), thrombosis, and hypovolemia
4. **Vaccinations:** Ensure pneumococcal vaccination is up to date; avoid live vaccines during high-dose steroids
5. **Education:** Teach parents to monitor for relapse with urine dipstick testing

### Clinical Image
![Child with periorbital edema characteristic of nephrotic syndrome](case_01_image.jpg)

**Image Description:** Clinical photograph demonstrating periorbital edema in a child with nephrotic syndrome, showing characteristic morning puffiness around the eyes.

**Source:** Wikimedia Commons - Medical gallery of Mikael Haggstrom
**URL:** https://commons.wikimedia.org/wiki/File:Nephrotic_syndrome.jpg
**License:** CC0 Public Domain

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## Case 2: Post-Streptococcal Glomerulonephritis

### Patient Demographics
- **Age:** 7-year-old female
- **Sex:** Female

### Chief Complaint
"My daughter's urine looks like cola and her face is puffy."

### History of Present Illness
A 7-year-old girl presents with her mother who noticed dark brown "cola-colored" urine this morning. The mother also notes that her daughter's face looks swollen, especially around her eyes. Two weeks ago, the child had a sore throat with fever that resolved over several days without antibiotic treatment. She has had no recent skin infections. The child reports mild headache and decreased urine output over the past day. She denies dysuria, frequency, or flank pain.

### Physical Examination
- **Vital Signs:** Temperature 37.2C, HR 88 bpm, RR 18/min, BP 138/92 mmHg (elevated for age/height)
- **General:** Alert, mildly uncomfortable appearing girl
- **HEENT:** Periorbital edema bilaterally, no pharyngeal erythema currently
- **Cardiovascular:** Regular rate and rhythm, S1/S2 normal, no murmurs
- **Respiratory:** Clear to auscultation, no respiratory distress
- **Abdomen:** Soft, non-tender, no hepatosplenomegaly
- **Extremities:** Mild pretibial edema bilaterally
- **Neurologic:** Alert, no focal deficits

### Laboratory Findings
- **Urinalysis:** Blood 3+, protein 2+, RBC >50/hpf, RBC casts present, dysmorphic RBCs
- **Urine protein/creatinine ratio:** 1.2 (elevated but not nephrotic range)
- **BUN:** 28 mg/dL (elevated)
- **Creatinine:** 0.9 mg/dL (elevated for age)
- **Serum albumin:** 3.2 g/dL (low-normal)
- **C3 complement:** 45 mg/dL (LOW; normal 90-180)
- **C4 complement:** 28 mg/dL (normal)
- **ASO titer:** 680 IU/mL (elevated; normal <200)
- **Anti-DNase B:** Positive

### Diagnosis
**Post-streptococcal glomerulonephritis**

### Clinical Reasoning
This child presents with the nephritic syndrome: gross hematuria (tea/cola-colored urine), hypertension, edema, and mild renal insufficiency occurring 1-2 weeks after streptococcal pharyngitis. The finding of RBC casts and dysmorphic RBCs confirms glomerular origin of bleeding. The characteristic laboratory profile shows depressed C3 with normal C4 (indicating alternative complement pathway activation), and elevated streptococcal serologies (ASO and anti-DNase B) confirm recent streptococcal infection. This is the classic presentation of post-infectious glomerulonephritis.

### Management
1. **Supportive care:** No specific treatment alters disease course
2. **Sodium and fluid restriction:** 1-2 g sodium daily to manage edema and hypertension
3. **Antihypertensive therapy:** Loop diuretics (furosemide) for volume overload; add calcium channel blocker if needed
4. **Antibiotics:** Penicillin if evidence of ongoing streptococcal infection (to prevent spread, not to treat GN)
5. **Monitoring:** Daily weights, blood pressure, urine output; repeat C3 at 6-8 weeks (should normalize by 8-12 weeks)
6. **Prognosis:** Excellent; >95% of children recover completely

### Clinical Image
![Cola-colored urine specimen from glomerulonephritis](case_02_image.jpg)

**Image Description:** Urine specimen demonstrating the characteristic dark tea or cola-colored appearance of glomerular hematuria, due to hemoglobin degradation during transit through the nephron.

**Source:** Radiopaedia
**URL:** https://radiopaedia.org/cases/glomerulonephritis-macroscopic-haematuria
**License:** CC BY-NC-SA 3.0

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## Case 3: Hemolytic Uremic Syndrome

### Patient Demographics
- **Age:** 2-year-old female
- **Sex:** Female

### Chief Complaint
"She's been having bloody diarrhea for five days and now she's barely peeing and looks pale."

### History of Present Illness
A 2-year-old girl is brought to the emergency department by her parents with a five-day history of bloody diarrhea. The diarrhea began as watery stools three days before becoming bloody. She attended a family barbecue one week ago where she ate undercooked ground beef. Over the past 24 hours, she has become increasingly lethargic, her urine output has decreased significantly, and her parents note she appears very pale. She has had decreased oral intake but no vomiting. No other family members are ill.

### Physical Examination
- **Vital Signs:** Temperature 37.4C, HR 145 bpm, RR 28/min, BP 102/68 mmHg, SpO2 99%
- **General:** Pale, lethargic toddler, irritable when examined
- **HEENT:** Pale conjunctivae, dry mucous membranes
- **Cardiovascular:** Tachycardic, regular rhythm, flow murmur present
- **Respiratory:** Clear to auscultation, mild tachypnea
- **Abdomen:** Mildly distended, diffuse tenderness, hyperactive bowel sounds
- **Extremities:** Cool extremities, capillary refill 3 seconds, no edema
- **Skin:** Pallor, petechiae on trunk and extremities
- **Neurologic:** Lethargic but arousable, no focal deficits

### Laboratory Findings
- **CBC:** Hemoglobin 6.8 g/dL, WBC 18,000/uL, Platelets 35,000/uL
- **Peripheral smear:** Schistocytes (fragmented RBCs), helmet cells present
- **Reticulocyte count:** 8% (elevated)
- **BUN:** 65 mg/dL (elevated)
- **Creatinine:** 3.2 mg/dL (markedly elevated)
- **LDH:** 2,500 U/L (markedly elevated)
- **Haptoglobin:** <10 mg/dL (undetectable)
- **Urinalysis:** Blood 2+, protein 1+
- **Stool culture:** Pending; Shiga toxin assay positive
- **Coagulation studies:** PT and PTT normal

### Diagnosis
**Hemolytic uremic syndrome (HUS) - typical/diarrhea-associated**

### Clinical Reasoning
This child presents with the classic triad of HUS: microangiopathic hemolytic anemia (low hemoglobin with schistocytes on smear), thrombocytopenia, and acute kidney injury, following bloody diarrhea caused by Shiga toxin-producing E. coli. The history of undercooked ground beef consumption is consistent with E. coli O157:H7 infection. The elevated LDH and undetectable haptoglobin confirm hemolysis, while normal coagulation studies help exclude DIC. Typical (diarrhea-associated) HUS is distinguished from atypical HUS, which occurs without preceding diarrheal illness.

### Management
1. **Supportive care:** Primary treatment is supportive; no specific therapy alters disease course
2. **NO ANTIBIOTICS:** Antibiotics may increase toxin release and worsen outcomes
3. **Fluid and electrolyte management:** Careful fluid balance; avoid both dehydration and overload
4. **Dialysis:** Indicated for severe oliguria, hyperkalemia, or uremia; initiate peritoneal or hemodialysis as needed
5. **Transfusion:** RBC transfusion for symptomatic anemia (Hgb <7 g/dL or hemodynamic compromise)
6. **Platelet transfusion:** Avoid unless active bleeding (may worsen microvascular thrombosis)
7. **Monitoring:** Strict intake/output, daily weights, twice-daily chemistry, neurologic checks
8. **Prognosis:** Most children (>85%) recover renal function; some develop chronic kidney disease

### Clinical Image
![Peripheral blood smear showing schistocytes in HUS](case_03_image.jpg)

**Image Description:** Peripheral blood smear demonstrating schistocytes (fragmented red blood cells) and helmet cells characteristic of microangiopathic hemolytic anemia in hemolytic uremic syndrome.

**Source:** Wikimedia Commons
**URL:** https://commons.wikimedia.org/wiki/File:Schistocytes_in_HUS.jpg
**License:** CC BY-SA 3.0