Congenital Hypothyroidism: Role of Nuclear Medicine.

Thyroid scintigraphy holds a key place in the etiologic workup of neonatal hypothyroidism. Routine screening for this disorder in maternity hospitals in industrialized countries, for nearly 40 years, has permitted early treatment and thereby helped to prevent its physical and mental complications. Neonatal hypothyroidism affects approximately 1 in 3000 births. The most common causes are abnormal thyroid gland development and defective hormone synthesis by an eutopic thyroid gland. The incidence of the latter has risen in recent years, for reasons that remain unclear. A thorough etiologic workup helps to determine the disease type. Current guidelines recommend thyroid imaging by means of ultrasound and scintigraphy. Ultrasound should be done by a practitioner trained to examine the cervical region of newborns, as the thyroid is very small and must be distinguished from the particular aspect of the "thyroid empty lodge." Ultrasound lacks sensitivity for detecting small ectopic glands but is the gold standard for measuring thyroid dimensions. Scintigraphy provides an etiologic diagnosis in most cases. The two isotopes used in this setting are technetium-99m and iodine-123. The latter isotope gives more contrast and allows the perchlorate discharge test to be performed to detect abnormal iodide organification in the neonate with an eutopic thyroid. If scintigraphy cannot be performed during the neonatal period, a postponed procedure can be achieved after 3 years of age. Close cooperation between the nuclear medicine physician and the pediatric endocrinologist is crucial for timely and optimized scintigraphy.

Cat-scratch disease and bone scintigraphy.

Cat-scratch disease is a bacterial infection caused by Bartonella henselae. Bone involvement is rare. We describe the case of a 7-year-old boy with a systemic form of the disease. He presented with a 15-day history of fever, altered general condition, weight loss and cough, associated with back pain, and right-sided coxalgia. Bone scintigraphy with Tc-99m hydroxymethylene diphosphonate showed spinal involvement, the iliac crest, the right ankle, and the right first metatarsal. Magnetic resonance imaging confirmed these locations. He was positive for anti-Bartonella henselae. The fever regressed before treatment with rifampicin began, and he made a full recovery.

[Nuclear medicine procedures in paediatric patients]. / Apport des techniques de la médecine nucléaire en pédiatrie.

The paediatricians rely primarily scintigraphic examinations in two situations: when they need functional information to decide operation (measurement of separate function of each kidney for example) or when they want to know if a bone disease is involved, in front of a sudden onset of musculoskeletal disorder. Kidney and bone scan represent 85% of applications for examinations. Some scintigraphic examinations have an essential role in the therapeutic evaluation and staging of malignancies such as MIBG-123 scintigraphy in neuroblastoma and FDG-18F scintigraphy in lymphoma. This presentation would not be complete without mentioning some tests whose indications in children are different from adults like the lung scan that evaluates separate functions of both lungs in diseases such as lung malformations and thyroid scintigraphy performed in cases of congenital hypothyroidism to determine the mechanism of this disease. Finally, to locate a Meckel's diverticulum in front of a gastrointestinal bleeding. Because of its indications, pediatric nuclear medicine concerns a high proportion of very young children, and must take into account the specificities of this age.

Randomized trial of oral versus sequential IV/oral antibiotic for acute pyelonephritis in children.

OBJECTIVE: To confirm whether oral antibiotic treatment is as efficacious as sequential intravenous/oral antibiotic treatment in the prevention of renal scarring in children with acute pyelonephritis and scintigraphy-documented acute lesions. METHODS: In a prospective multicenter trial, children aged 1 to 36 months with their first case of acute pyelonephritis, a serum procalcitonin concentration ≥0.5 ng/mL, no known uropathy, and a normal ultrasound exam were randomized into 2 treatment groups. They received either oral cefixime for 10 days or intravenous ceftriaxone for 4 days followed by oral cefixime for 6 days. Patients with acute renal lesions detected on early dimercaptosuccinic acid scintigraphy underwent a follow-up scintigraphy 6 to 8 months later. RESULTS: The study included 171 infants and children. There were no significant differences between the 2 groups in any clinical characteristic. Initial scintigraphy results were abnormal for 119 children. Ninety-six children were measured for renal scarring at the follow-up scintigraphy (per protocol analysis population). The incidence of renal scarring was 30.8% in the oral treatment group and 27.3% for children who received the sequential treatment. CONCLUSIONS: Although this trial does not statistically demonstrate the noninferiority of oral treatment compared with the sequential treatment, our study confirmed the results of previously published reports and therefore supports the use of an oral antibiotic treatment of primary episodes of acute pyelonephritis in infants and young children.

Impressive renal damage after acute pyelonephritis in a child.

Urinary tract infection (UTI) is one of the most common bacterial infections in children, and its role in the pathogenesis of scarred kidney is debated. We report on a 7-year-old child who presented with severe UTI. The early (day 4) renal computed tomography (CT) scan showed normal-sized kidneys (110 mm on the left, 105 mm on the right), whereas the control CT scan and dimercaptosuccinic acid (DMSA) scan, performed 1 and 2 months later, respectively, showed a small scarred right kidney (60 mm) with a 12% residual function. An intermittent right vesicoureteral reflux (VUR) was diagnosed by direct isotopic cystography and then treated by Cohen vesicoureteral reimplantation. The patient remained free of infectious recurrence, hypertension, or renal function decrease. This report demonstrates that one episode of acute pyelonephritis can lead to severe renal scarring. Whereas antenatal lesions are thought to have a stronger role in the causal pathway for reflux nephropathy than is UTI in addition to VUR, this observation reminds us that UTI can truly play an important role in damaging kidneys.

[To study the safety and effectiveness of heminephroureterectomy by horizontal lumbar posterior approach for duplicated systems in infants]. / Néphro-urétérectomie polaire pour duplication pyélo-urétérale par voie lombaire postérieure chez le nourrisson.

PURPOSE: To study the safety and effectiveness of heminephroureterectomy by horizontal lumbar posterior approach for duplicated systems in infants. MATERIALS AND METHODS: Thirty-three heminephroureterectomies by lumbar posterior approach were performed in 31 infants at a mean age of 6.7 +/- 5.5 months (range: 1 to 26 months) from January 1994 to December 2005. RESULTS: The mean operative time was 121 +/- 35 minutes (range: 60 to 190 minutes). No intra-operative complication was observed. Blood loss was minimal (< 20 ml) in all cases. The mean hospital stay was 4.6 days (range: 2 to 7 days). No postoperative complication (urinoma, infection or haemotoma) occurred. No atrophy or major functional loss of the remaining moiety was observed. The mean follow-up was 52.6 +/- 40 months (range: 1 to 151 months). CONCLUSIONS: The lumbar posterior approach is safe and reproducible and provides an obvious cosmetic benefit in comparison to the standard anterolateral lumbotomy. It represents a procedure of choice for open heminephroureterectomy in infants.