Effective low-dose sirolimus regimen for kaposiform haemangioendothelioma with Kasabach-Merritt phenomenon in young infants.

AIMS: Management of kaposiform haemangioendotheliomas (KHE) with Kasabach-Merritt phenomenon is challenging in young infants who are subjected to developmental pharmacokinetic changes. Sirolimus, sometimes combined with corticosteroids, can be used as an effective treatment of KHE. Simultaneously, toxicities such as interstitial pneumonitis related to the use of sirolimus may be fatal. As infants have a very low CYP3-enzyme expression at birth, which rises during ageing, we hypothesize that a reduced metabolization of sirolimus might lead to high sirolimus serum levels and low dose may be sufficient without the side effects. METHODS: A case series of 5 infants with kaposiform haemangioendothelioma with Kasabach-Merritt phenomenon was analysed retrospectively. All infants were treated with sirolimus 0.2 mg/m2 every 24 or 48 hours according to their age. Prednisone was added to the therapy for additional effect in 4 patients. RESULTS: In all patients, low dose of sirolimus led to therapeutic sirolimus levels (4-6 ng/mL). All infants (aged 4 days-7 months) had a complete haematological response, without serious adverse events. In all patients, the Kasabach-Merritt phenomenon resolved, the coagulation profile normalized and tumour size reduction was seen. CONCLUSION: Low-dose sirolimus treatment is safe for infants with kaposiform haemangioendothelioma and Kasabach-Merritt phenomenon. It is essential to realize that during the first months of life, metabolism is still developing and enzymes necessary to metabolise drugs like sirolimus still have to mature. To avoid toxic levels, the sirolimus dosage should be based on age and the associated pharmacological developments.

Subclinical changes in the juvenile crystalline macular dystrophy in Sjögren-Larsson syndrome detected by optical coherence tomography.

PURPOSE: To study morphologic changes in the macula by optical coherence tomography (OCT) in patients with a crystalline macular dystrophy due to the autosomal recessive neurocutaneous Sjögren-Larsson syndrome (SLS). DESIGN: Retrospective observational case series. PARTICIPANTS: Twenty-seven eyes of 14 patients, mean age 14.6 (range, 3-24) years, with biochemically and genetically proven SLS underwent clinical and OCT investigation between September 2004 and September 2006. METHODS: All patients underwent full ophthalmologic examination including slit-lamp biomicroscopy and binocular ophthalmoscopy. Optical coherence tomography of all eyes was performed using the macular thickness map protocol of Stratus OCT. MAIN OUTCOME MEASURES: Macular morphology in clinical examination and OCT. RESULTS: Beside clinically visible perimacular crystalline deposits in all eyes of all study participants, macular morphology and reflectivity were significantly changed on OCT compared with healthy eyes. We found focal hyperreflectivities in all study eyes within the perifoveal ganglion cell layer and the inner plexiform layer, corresponding to the clinical localization of retinal crystals. More interestingly, a cystoid foveal degeneration on OCT was present in the majority of patients with SLS (18/27 eyes, or 67% of all eyes studied), varying from multiple microcystoid spaces to cystoid foveal atrophy. In general, patients who were severely affected on OCT showed intense changes on previously performed cerebral magnetic resonance spectroscopy. CONCLUSIONS: Patients with SLS show a childhood-onset crystalline macular dystrophy with cystoid foveal atrophy on OCT in most cases. The intraretinal deposition of lipid metabolites may lead to Müller cell degeneration with subsequent formation of cystoid spaces or atrophic changes within the fovea. Because this macular dystrophy is present in all examined patients with SLS, familiarity with this maculopathy seems important for the diagnosis of this rare systemic disease.