Edition 69 - 2018, July-August / Images

Images in Pediatric Endocrinology: CRANIAL NUCLEAR MAGNETIC RESONANCE (NMR) IMAGES IN RENAL OSTEODYSTROPHY – Ed. 69

Drs. Silvia Gil, Mariana Aziz, Mariana Costanzo

Servicio de Endocrinología. Hospital de Pediatría Juan. P Garrahan, Buenos Aires, Argentina

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Brain and sellar region nuclear magnetic resonance (NMR): normal brain parenchyma. No morphological or structural abnormalities in the sella, pituitary gland or hypothalamic-chiasmatic region is observed. Marked skull diffuse thickening with loss of the inner-outer table differentiation and slightly heterogeneous signal, hypo- and hyper-intense on T1, and Flair and hypo-intense on T2, associated with partial collapse of the subjacent cortical subarachnoid spaces. The remaining cortical spaces, as well as basal cisterns and ventricles were normal.

Compatible Diagnosis: Alterations of the skull associated with renal osteodystrophy (Saglikler Syndrome).

 

Case report

A patient diagnosed with Chronic Kidney Disease (CKD) was referred to the endocrinology department for stature growth evaluation.

The boy had been born full term with normal birth weight. CKD secondary to bilateral kidney dysplasia, and left vesico-ureteral stenosis was diagnosed, at 15 days of life. The patient remained on conservative treatment until 1.5 years old; at that moment, peritoneal dialyses were started, until 5.5 years of age when the patient received a cadaveric kidney transplant. Since then, the patient presented favorable evolution during follow-up, without signs of graft rejection or any other complication.

The patient is the first child of non-consanguineous parents. Healthy mother, height: 165 cm, menarche at 15 years of age; Healthy father, height: 170 cm, the age of pubertal development is unknown.

At time of first evaluation, the patient was receiving immunosuppressive therapy with Meprednisone 2 and 6 mg, every other day, Cyclosporine and Mycophenolate plus enalapril, magnesium, folic acid and Vitamin D.

Metabolic studies, renal function, blood cell count, liver function, as well as calcium and phosphorus metabolism were normal.

On physical examination at 9.4 years of age, weight was 42,8 kg (PC: 90-97), height: 132.8 cm (PC 25-50), BMI 24.3 kg/m2. The patient was clinically euthyroid with a non-palpable thyroid gland. Genital examination revealed Tanner stage G1, PH2 and testicles were palpable in the scrotum (4 ml).

Taking into account these findings, we assumed the patient as a boy with normal height, high BMI for age and early pubertal onset despite chronic disease and family history of pubertal delay. So, several studies were requested. Hormonal determinations confirmed he had precocious-early puberty (LH: 1 mIU/ml, FSH: 1.8 mIU/ml and Testosterone 0.4 ng/ml). Bone age was 10 years for a chronological age of 9.4 years.

We diagnosed central precocious/early puberty in a renal-transplanted patient. A brain MRI was ordered to rule out an organic cause. MRI showed normal brain and sellar regions, but the skull sequelae of chronic kidney disease could be observed in the films.

 

Comments

Progressive renal failure is associated with phosphate retention and impaired activation vitamin D, leading to hyperphosphatemia, hypocalcemia, increased secretion of parathyroid hormone (PTH), and hyperplasia of the parathyroid glands. Elevations in PTH occur early in renal insufficiency (creatinine clearance < 50 mL/min) in a physiologic attempt to increase phosphates excretion, normalize calcium, and increase vitamin D synthesis [1].

Chronic secondary hyperparathyroidism (sHPT) produces deleterious effects on bone and mineral metabolism. Renal osteodystrophy, loss of bone mineral density, bone pain, fractures and bone deformities are common complications of sHPT.  When theses abnormalities occur, particularly, in the skeleton of the skull and face, the disorder is known as Sagliker syndrome. These bone changes are observed particularly in children and teens, and may become irreversible-disastrous changes on facial features compromising quality of life [2].

Furthermore, patients with sHPT show vascular calcifications, muscular weakness, polyneuropathy, anorexia, anemia, poor growth, and depression. sHPT should be detected, and treated as soon as possible for mitigating its consequences. Early diagnosis and treatment are essential for better follow up of these patients.

The guidelines of the Kidney Disease Improving Global Outcomes (KDIGO [3]) suggest to keep PTH levels between two to nine times above the upper limit in patients in dialysis. The pharmacological treatment of sHPT included phosphate binders, calcitriol, vitamin D analogues, and calcimimetics (not approved for paediatrics patients) alone or in combination. In severe cases, when these interventions are ineffective, subtotal parathyroidectomy or parathyroidectomy with autotrasplant (PTX), is usually indicated, but an experienced surgeon should carry it out. The presence of these lesions in our patient was probably a consequence of the early compromise of renal function, in addition to inadequate compliance to treatment during the first years of life. After transplantation, the patient showed normal parameters of mineral metabolism.

References:

  1. Martinez I., Saracho R., Montenegro J., Llach F.:The importance of dietary calcium and phosphorus in the secondary hyperparathyroidism of patients with early renal failure. Am. J. Kidney Dis. 1997, 29, 496-502
  1. Parfitt AM. Renal Bone Disease: A new conceptual framework for the interpretation of bone histo-morphometry. Curr Opin Nephrol. Hypertens 2003, 12:387-403
  2. KDIGO Guidelines Kidney Disease: Improving Global Outcomes (KDIGO) CKD-MBD Update Work Group. KDIGO 2017 Clinical Practice Guideline Update for the Diagnosis, Evaluation, Prevention, and Treatment of Chronic Kidney Disease–Mineral and Bone Disorder (CKD-MBD). Kidney Int Suppl. (2017); 7:1–59.

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