Case Presentation: A 19 year-old woman without significant past medical history was admitted to the medicine service with shortness of breath, nausea, and severe edema. Over the past 2-3 months, she had experienced worsening diffuse swelling and associated 30-lb weight gain. In the few days prior to admission, she had increased cough and difficulty breathing as well as nausea, vomiting, abdominal pain, and diarrhea. Upon presentation, she was tachycardic to 122 bpm and hypoxic; she required 4L supplemental O2 via nasal cannula to maintain O2 saturation >88%. Physical exam revealed diminished breath sounds in the bases, 2+ pitting edema in bilateral lower extremities, tender cervical lymphadenopathy, and diffusely tender, mildly distended abdomen. Initial laboratory evaluation was notable for creatinine 1.24, albumin 1.1, sodium 131, total cholesterol 480, and triglycerides 473. 24-hour urine collection revealed 6.28 g of protein. IgG level was markedly low at 95 (normal 767-1590), with IgA and IgM levels on the low end of their respective normal ranges. Chest CT showed diffuse bilateral tree-in-bud and ground glass opacities. Abdominal x-ray was unremarkable, and renal ultrasound was negative for thrombosis, hydronephrosis, or other structural abnormalities. C.difficile stool testing was also negative.
She was given IV albumin supplementation, diuresed, and started on antibiotics for community acquired pneumonia. Evaluation for secondary etiologies of nephrotic syndrome, including autoimmune panel, HBV/HCV/HIV serologies and other infectious work-up (sputum and blood cultures, fungal serologies, etc.), and monoclonal protein studies, was negative. Renal biopsy was performed, and pathology revealed podocyte effacement and other findings confirming minimal change disease (MCD). Bronchoscopy showed diffuse bronchitis but no other endobronchial abnormalities; infectious studies from bronchial specimens were negative. Therefore, she was started on high dose prednisone and given IVIG approximately 24 hours later.

Over the course of her 5-day admission, she made remarkable clinical improvement. She was successfully weaned off of supplemental oxygen, her gastrointestinal symptoms resolved, and she felt much better overall.

Discussion: Nephrotic syndrome can precipitate severe multisystem organ dysfunction even in previously healthy young adults, such as acute hypoxic respiratory failure secondary to immune compromise and gastrointestinal distress. In severe cases, inpatient evaluation should include infectious, autoimmune, hematologic, and structural renal disease assessments. Though MCD more commonly presents in children, it remains an important cause of nephrotic syndrome in adults, and the mainstay of treatment is high-dose systemic steroids. IVIG can be used as a supplemental treatment when there is severe hypogammaglobulinemia and subsequent immune compromise.

Conclusions: 1. Acute nephrotic syndrome can precipitate severe multisystem organ dysfunction, including acute respiratory failure and immune compromise, even in previously healthy adults.
2. Diagnosis of MCD should include evaluation for alternative infectious, autoimmune, and neoplastic etiologies of nephrotic syndrome. Renal biopsy can provide the most definitive diagnosis, typically revealing podocyte effacement and no atypical immunoglobulin deposits.
3. Prompt diagnosis of severe MCD in the inpatient setting can facilitate successful, expedient treatment with steroids and, if appropriate, IVIG.