Dilated Optic Nerve Sheath in Mucopolysaccharidosis I: Common and Not Necessarily High Intracranial Pressure

Hydrocephalus is one of the earliest manifestations of mucopolysaccharidosis I-Hurler syndrome, and delayed treatment of hydrocephalus can lead to neurocognitive delay or even death. Optic nerve sheath diameter has been established as a noninvasive measurement to detect elevated intracranial pressure. This study aimed to establish correlations between optic nerve sheath diameter and opening pressure. Forty-nine MR images and opening pressures in patients with mucopolysaccharidosis I-Hurler syndrome were retrospectively reviewed from 2008 to 2020. The optic nerve sheath diameter was measured 3 mm posterior to the posterior margin of the globe (retrobulbar) and 10 mm anterior to the optic foramen (midpoint segment), and the average was taken between the 2 eyes. Opening pressure was measured with the patient in the lateral decubitus position with controlled end-tidal CO2 on the same day as the MR imaging. The average retrobulbar optic nerve sheath diameter was 5.33 mm, higher than the previously reported measurement in healthy controls, in patients with idiopathic intracranial hypertension, and there was a positive correlation between age and the optic nerve sheath diameter measured at the retrobulbar or midpoint segment (retrobulbar segment, R 2 = 0.27, P < .01; midpoint segment, R 2 = 0.20, P < .01). However, there was no correlation between retrobulbar or midpoint segment optic nerve sheath diameter and opening pressure (retrobulbar segment, R 2 = 0.02, P = .17; midpoint segment, R 2 = 0.03, P < .12). This study shows a higher average optic nerve sheath diameter in patients with mucopolysaccharidosis I-Hurler syndrome than in healthy controls regardless of the location of the measurement. However, the degree of optic nerve sheath dilation does not correlate with opening pressure, suggesting that increased optic nerve sheath diameter is an ocular manifestation of mucopolysaccharidosis I-Hurler syndrome itself rather than a marker of elevated intracranial pressure.

Supporting Cancer Patients Who Are Also Parents: Establishment of a Cross-Sector Service for Families With Adolescent and Young Adult Children

Background and context: Traditionally adult hospitals focus on the patient and less on their family. Adolescent and young adult children of cancer patients (AYA offspring) have significant psychosocial burdens associated with their parent's cancer however they are often invisible within hospitals with no clear referral pathways to community-based support. AYA offspring are 3-6 times more likely than peers to have clinically elevated levels of distress which increases with age. Research shows that 1 of the greatest concerns for parents is how to communicate about cancer with their children, and 1 of the greatest needs for AYA offspring is information about their parent's cancer and talking with their parents about it. Aim: CanTeen, a national AYA cancer community support organization, sought to address these needs by embedding a Parent Support Worker within the social work teams of tertiary hospitals for patients who are parents of AYA children. This service aims to assist with specific parenting challenges that arise due to a cancer diagnosis and establish a referral pathway for AYA offspring to CanTeen for support. Strategy/Tactics: Cofunding with philanthropic organizations was sought and CanTeen executives engaged in advocacy work with senior hospital management, demonstrating the need for the service and a plan to embed it within the existing hospital social work team and services. Program/Policy process: A new Parent Support Worker role was established to provide social work care to parents of AYA children following a parent's cancer diagnosis. The service provides support with parenting issues that arise due to the diagnosis as well as staff education, secondary consultations, and referrals of AYA offspring to CanTeen. A service improvement approach has been established with the collection of monitoring data measuring volume of referrals/sessions, capacity building of other staff, information given to young people and referrals to CanTeen. A service evaluation seeking feedback from patients and relevant hospital staff is also underway. Outcomes: To date, philanthropic funding and hospital support was gained to establish a pilot program placing a Parent Support Worker in 3 hospitals. Early indications are that this novel service is integrating well into established hospital teams and processes, and adding considerable value with the provision of this focused family support. What was learned: This advocacy initiative is highlighting the benefits of a model of care in adult hospitals that centrally considers family and the strength of a well-planned cross-sector service initiative.

Population-based cohort study of variation in the use of emergency cholecystectomy for benign gallbladder diseases

Background

The aims of this prospective population-based cohort study were to identify the patient and hospital characteristics associated with emergency cholecystectomy, and the influences of these in determining variations between hospitals.

Methods

Data were collected for consecutive patients undergoing cholecystectomy in acute UK and Irish hospitals between 1 March and 1 May 2014. Potential explanatory variables influencing the performance of emergency cholecystectomy were analysed by means of multilevel, multivariable logistic regression modelling using a two-level hierarchical structure with patients (level 1) nested within hospitals (level 2).

Results

Data were collected on 4744 cholecystectomies from 165 hospitals. Increasing age, lower ASA fitness grade, biliary colic, the need for further imaging (magnetic retrograde cholangiopancreatography), endoscopic interventions (endoscopic retrograde cholangiopancreatography) and admission to a non-biliary centre significantly reduced the likelihood of an emergency cholecystectomy being performed. The multilevel model was used to calculate the probability of receiving an emergency cholecystectomy for a woman aged 40 years or over with an ASA grade of I or II and a BMI of at least 25·0 kg/m2, who presented with acute cholecystitis with an ultrasound scan showing a thick-walled gallbladder and a normal common bile duct. The mean predicted probability of receiving an emergency cholecystectomy was 0·52 (95 per cent c.i. 0·45 to 0·57). The predicted probabilities ranged from 0·02 to 0·95 across the 165 hospitals, demonstrating significant variation between hospitals.

Conclusion

Patients with similar characteristics presenting to different hospitals with acute gallbladder pathology do not receive comparable care.

Cardiac Ultrasound Findings in Infants with Severe (Hurler Phenotype) Untreated Mucopolysaccharidosis (MPS) Type I

BACKGROUND

Serious cardiac valve disease and left ventricular hypertrophy occur in most untreated older children with severe mucopolysaccharidosis type I. Although it is assumed that early intervention prevents these processes, evaluation of cardiac findings in these infants has not yet been reported.

METHODS

We reviewed echocardiograms of 13 untreated infants < 1 year of age with severe mucopolysaccharidosis type I who had undergone evaluation for hematopoietic cell transplantation. We recorded left ventricular chamber dimensions, septal and posterior wall thicknesses, ventricular function, and aortic sinus diameters. We evaluated mitral and aortic valves for increased thickness, regurgitation, and stenosis.

RESULTS

Average age (7M, 6F) was 221 (range 25-347) days. Left ventricular chamber dimension was ≥2 SD of normal in 3/13; wall thicknesses were ≥2 SD of normal in 2/13 infants. Systolic function was normal. Mitral valves were thickened in all infants; mitral regurgitation was present in 9/13, but significant in only three infants. Aortic valves were thickened in 10/13, but no infant had significant aortic regurgitation. Neither mitral nor aortic stenosis occurred. Aortic roots were dilated to ≥2 SD of normal in 5/13.

CONCLUSIONS

Characteristic cardiac features of severe mucopolysaccharidosis type I can be seen in infancy. Mitral and aortic valve thickening are nearly universally present, even in the youngest infants. In 20-30 % of infants, other abnormalities such as left ventricular dilation, increased wall thickness, and mild mitral/aortic regurgitation may occur. Aortic root dilation is a frequent finding. Early intervention with enzyme replacement therapy may minimize the incidence and severity of cardiac findings in these infants.

SUMMARY

Serious cardiac valve disease and left ventricular hypertrophy occur in most untreated older children with severe mucopolysaccharidosis type I. Although it is assumed that early intervention prevents these processes, evaluation of cardiac findings in these infants has not yet been reported. In our study of 13 infants with severe untreated MPS I < 1 year of age, mitral and aortic valve thickening was nearly universally present and aortic root dilation was frequent. Despite this, we found a lower incidence of left ventricular hypertrophy and both a lower incidence and milder expression of mitral and aortic valve dysfunction than previously reported in older children. These findings suggest that earlier intervention, including neonatal screening, may be of benefit to children with severe MPS I.

Research challenges in central nervous system manifestations of inborn errors of metabolism

The Research Challenges in CNS Manifestations of Inborn Errors of Metabolism workshop was designed to address challenges in translating potential therapies for these rare disorders, and to highlight novel therapeutic strategies and innovative approaches to CNS delivery, assessment of effects and directions for the future in the treatment of these diseases. Therapies for the brain in inborn errors represent some of the greatest challenges to translational research due to the special properties of the brain, and of inborn errors themselves. This review covers the proceedings of this workshop as submitted by participants. Scientific, ethical and regulatory issues are discussed, along with ways to measure outcomes and the conduct of clinical trials. Participants included regulatory and funding agencies, clinicians, scientists, industry and advocacy groups.

Engraftment and survival following hematopoietic stem cell transplantation for osteopetrosis using a reduced intensity conditioning regimen

Autosomal recessive osteopetrosis (OP) is a disease characterized by osteoclast dysfunction, leading to multisystem morbidity and death of most affected children. Hematopoietic stem cell transplantation (HSCT) is the treatment of choice for OP, but this patient population is particularly prone to post-transplant complications and death after myeloablative conditioning. To determine the potential of achieving improved overall outcomes in these patients by decreasing pre-transplant mortality, we investigated engraftment and survival following a reduced intensity regimen including busulfan, fludarabine and total lymphoid irradiation. We report outcomes in 11 patients. All six patients who received a bone marrow or peripheral stem cell graft engrafted with >75% donor chimerism. In contrast, all five recipients of unrelated cord blood as a stem cell source for a first graft failed to demonstrate donor hematopoietic chimerism. The day 100 and 6-month mortality was low at 9%. One year after HSCT, six of 11 patients (55%) were surviving. Our data suggest that this regimen results in low peri-transplant mortality without compromising engraftment when a marrow or peripheral stem cell graft is used. An umbilical cord blood graft, however, should be used with caution for patients with OP when this or a similar reduced intensity regimen is used.

Continued neurocognitive development and prevention of cardiopulmonary complications after successful BMT for I-cell disease: a long-term follow-up report

I-cell disease or mucolipidosis type II, a rare inherited storage disorder of lysosomal enzyme localization, is characterized by dysostosis multiplex, progressive severe psychomotor retardation and death by 5-8 years from congestive heart failure and recurrent pulmonary infections. A 19-month old girl with I-cell disease received a bone marrow transplant (BMT) from an HLA-identical carrier brother. At the age of 7 years, 5 years after BMT, she has no history of respiratory infections. Her cardiac function remains normal with a shortening fraction of 47%, and she continues to gain neurodevelopmental milestones, albeit at a very slow rate. Musculoskeletal deformities have worsened despite BMT. This is the first report describing neurodevelopmental gains and prevention of cardiopulmonary complications in I-cell disease after BMT.

The mutational spectrum of human malignant autosomal recessive osteopetrosis

Human malignant infantile osteopetrosis (arOP; MIM 259700) is a genetically heterogeneous autosomal recessive disorder of bone metabolism, which, if untreated, has a fatal outcome. Our group, as well as others, have recently identified mutations in the ATP6i (TCIRG1) gene, encoding the a3 subunit of the vacuolar proton pump, which mediates the acidification of the bone/osteoclast interface, are responsible for a subset of this condition. By sequencing the ATP6i gene in arOP patients from 44 unrelated families with a worldwide distribution we have now established that ATP6i mutations are responsible for approximately 50% of patients affected by this disease. The vast majority of these mutations (40 out of 42 alleles, including seven deletions, two insertions, 10 nonsense substitutions and 21 mutations in splice sites) are predicted to cause severe abnormalities in the protein product and are likely to represent null alleles. In addition, we have also analysed nine unrelated arOP patients from Costa Rica, where this disease is apparently much more frequent than elsewhere. All nine Costa Rican patients bore either or both of two missense mutations (G405R and R444L) in amino acid residues which are evolutionarily conserved from yeast to humans. The identification of ATP6i gene mutations in two families allowed us for the first time to perform prenatal diagnosis: both fetuses were predicted not to be affected and two healthy babies were born. This study contributes to the determination of genetic heterogeneity of arOP and allows further delineation of the other genetic defects causing this severe condition.

Transplantability and therapeutic effects of bone marrow-derived mesenchymal cells in children with osteogenesis imperfecta

In principle, transplantation of mesenchymal progenitor cells would attenuate or possibly correct genetic disorders of bone, cartilage and muscle, but clinical support for this concept is lacking. Here we describe the initial results of allogeneic bone marrow transplantation in three children with osteogenesis imperfecta, a genetic disorder in which osteoblasts produce defective type I collagen, leading to osteopenia, multiple fractures, severe bony deformities and considerably shortened stature. Three months after osteoblast engraftment (1.5-2.0% donor cells), representative specimens of trabecular bone showed histologic changes indicative of new dense bone formation. All patients had increases in total body bone mineral content ranging from 21 to 29 grams (median, 28), compared with predicted values of 0 to 4 grams (median, 0) for healthy children with similar changes in weight. These improvements were associated with increases in growth velocity and reduced frequencies of bone fracture. Thus, allogeneic bone marrow transplantation can lead to engraftment of functional mesenchymal progenitor cells, indicating the feasibility of this strategy in the treatment of osteogenesis imperfecta and perhaps other mesenchymal stem cell disorders as well.

Clinical importance of pre-morteum blood lymphocytes in cadaver donor tissue typing

We have refined our immunomagnetic bead (IM bead) procedures to isolate pure and viable lymphocyte subpopulation from pre-morteum (PM) blood for cadaver donor HLA typing, preliminary and final crossmatches (XMs). The results of 1220 XMs were compared using T/B lymphocytes isolated either from PM blood or spleen/lymphnode (SPLN) tissue. IM bead technique was used to isolate T/B cells from PM blood and nylon wool column (NWC) technique was used to isolate T/B cells from SPLN. When we compared the outcome of 800 T-cell crossmatches using T cells from PM blood or SPLN of 5 separate cadaver donors, NWC TXMs tended to be more falsenegative for high PRA (> 10%, total 500 XMs) as well as low PRA (< 10%, total 300 XMs) did not reach statistical significance. In contrast, NW BXM (420 B XM) were found to be far more false negative than IM bead BXM regardless of the PRA of the patients. In order to ensure that NWC BXMs were indeed false negative, 23 sera with known anti-DR antibodies were BXMed where antigen-specific B cells were isolated by both the techniques. Our results showed that IM bead BXM identified the DR specificities greater than 90% of the time, the titers of ab specificities were stronger (1:8). In comparison, NWB cell XMs were weak (titers 1:2), and the false negative rate for some ab was as high as 73%. Using IM bead and NWC techniques we compared our turnaround time (TAT) for cadaver donor typing, preliminary and final XMs.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary hepatic lymphoma in an adolescent treated with hepatic lobectomy and chemotherapy

A case of B-cell non-Hodgkin's lymphoma, confined to the liver, in a 17-year-old boy is reported. The patient was treated with an extended left hepatectomy and combination chemotherapy: Cytoxan (cyclophosphamide), vincristine, prednisone, and methotrexate (COMP). The patient remains disease free at 1 year.