LAUSR

A 14-year-old girl presented with fatigue, diarrhea, and generalized edema lasting for 10 days. She claimed that the diarrhea is watery without any blood or mucous, in the frequency of every 2–3 h and amount of 4 kg/day. She denied any vomiting, fever, cough, and abdominal or joint pain. In her past medical history, frequent upper respiratory tract infections were notable, and she had generalized edema with no proteinuria 3 months ago before her presentation. She was not sexually active and did not smoke cigarettes, drink alcohol, or use illicit drugs. Review of family history revealed that her mother and father were cousins. There was no known family history of kidney disease or inflammatory disease. On examination, she appeared pale. The temperature was 37.1 °C, the pulse 70 beats/min, the blood pressure 80/ 50 mmHg, and the respiratory rate 16 breaths/min. Her body weight was measured as 79 kg (> 95 percentile), height as 155 cm (25–50 percentile). Central obesity, widespread striae, macrodactyly, hemihypertrophy on the right lower extremity, and pretibial edema were documented (Fig. 1a-c). Mild abdominal tenderness was noticed extensively during the palpation, and the liver was painfully palpable 4 cm below the xiphoid. Deep tendon reflexes were absent in the lower limbs. The remainder of the examination was normal. Laboratory workup yielded the following: leukocyte count was 71.000/mm with 77% polymorphonuclear leukocytes (PNL), hemoglobin 15.4 g/dL, platelet count 291 K/uL, the levels of blood urea nitrogen (BUN) 37 mg/dL (N 5–18 mg/ dL), serum creatinine 1.1 mg/dL (N 0.5–1.0 mg/dL), albumin 1.3 g/dl (N 3.8–5.4 g/dL), sodium 128 mmol/L (N 136– 145 mmol/L), potassium 2.5 mmol/L (N 3.5–4.5 mmol/L), and gamma-glutamyl transferase (GGT) 250 U/L (N 9– 48 U/L); other biochemical findings were normal. Estimated glomerular filtration rate was calculated as 33ml/min/1.73m, according to Schwartz formula [1]. Urinalysis showed 4+ proteinuria, no glucosuria and no leukocytes. Twenty-four-hour urine test yielded nephrotic range proteinuria (5.2 g/m/day). Abdominal ultrasonography revealed hepatomegaly with normal contour and echogenicity, minimal intraabdominal fluid, and enlarged kidneys (length of the right kidney was 158 × 80 mm, length of the left kidney was 150 × 80 mm) with increased parenchymal thickness and echogenicity (grade 2) and decreased peripheral vascularity. Due to hyperleukocytosis with the nephrotic syndrome, she was referred to the pediatric hematology with a pre-diagnosis of leukemia (particularly chronic myeloid leukemia (CML)) and a peripheric smear was obtained with the result of dense myeloid cells. Bone marrow biopsy, karyotyping, and BCRABL cytogenetic analysis yielded negative results. The negative t (9;22) result, spontaneous regression of leukocyte count to 40.000/mm a day after, and lack of splenomegaly decreased the possibility of CML as a pre-diagnose and hematological follow-up was decided. Due to nephrotic syndrome in a child greater than 10 years of age and concomitant kidney failure, a kidney biopsy was performed to assess the underlying etiology. The biopsy results showed AA amyloidosis (global accumulation of homogenous acellular material in the glomeruli, resulting in expansion of mesangial areas and thickening of capillary basement membranes, and in the arteriolar walls, leading to severe narrowing of lumens. Muscular arteries showed patchy and minor deposition. In the interstitium, foam cell The answers to these questions can be found at https://doi.org/10.1007/ s00467-018-4153-6.