Non-Cardiogenic Pulmonary Edema, Nephrotic Syndrome
Nephrotic syndrome is identified by a significant proteinuria more than 3.5 g/day, hypoalbuminemia less than 3.5 g/dl, and peripheral edema. It associated with risks of thrombosis, infection, and hyperlipidemia due to loss of plasma protein. Several studies have shown patients with nephrotic syndrome do not develop non-cardiogenic pulmonary edema. However, we report a case of nephrotic syndrome caused by diabetic nephropathy and presented with non-cariogenic pulmonary edema.
A 37-year old man with a past medical history of diabetes mellitus, hypertension, dyslipidemia, Charcot foot, who presented with dyspnea, orthopnea, and non-productive cough for two days. He had been developing progressive abdominal distention and lower extremity (LE) swelling for three weeks before admission. He denies chest pain, fever, or chills. He appeared uncomfortable and hypoxic and had abdominal distension with bilateral LE edema. Initial laboratory test revealed BUN of 33, creatinine of 1.8, Bicarbonate of 34, and albumin of 2.1. Random urine protein-to-creatinine ratio was 8.36. He had a normal complement three and four levels. Hepatitis panel, HIV, anti-GBM Ab, ANCA, ANA, anti-dsDNA, and RA were negative. EKG showed sinus rhythm, and the echocardiogram revealed normal systolic and diastolic function with an ejection fraction of 55-60%. Chest X-ray was consistent with volume overload and pulmonary edema. Kidney ultrasound was unremarkable. However, his kidney biopsy confirmed diabetic nephropathy as a cause of his nephrotic syndrome. During this admission, he was diuresed with furosemide, metolazone, and acetazolamide with significant improvement of his volume status. The patient required oxygen supplementation to keep oxygen saturation above >91%. However, it was improved with diuresis and was slowly weaned off oxygen. He was discharged home off oxygen supplement.
The causes of nephrotic syndrome can be divided into two groups consisting of primary and secondary causes. The most common secondary cause is diabetic nephropathy. Nephrotic syndrome usually manifests by LE edema, weight gain, fatigue, and dyspnea secondary to pleural effusions. Several studies have shown patients with nephrotic syndrome do not develop non-cardiogenic pulmonary edema. However, there are two cases published in the medical literature of patients presenting with nephrotic syndrome and non-cardiogenic pulmonary edema. The first case describes a patient that was diagnosed with nephrotic syndrome and pulmonary edema due to bilateral renal artery stenosis. The second case details a patient with non-cardiogenic pulmonary edema and nephrotic syndrome due to collapsing glomerulopathy.
We report this case to make clinicians aware that patients with nephrotic syndrome can present with non-cardiogenic pulmonary edema and hypoxia as their initial presentation. This complication is effectively managed with diuresis.