Gowers' intrasyringeal hemorrhage associated with Chiari type I malformation in Noonan syndrome

Neurosurgical aspects of Noonan syndrome

PURPOSE

Noonan syndrome (NS) is a rare neurodevelopmental syndrome characterized by dysmorphic features, congenital heart defects, neurodevelopmental delay, and bleeding diathesis. Though rare, several neurosurgical manifestations have been associated with NS, such as Chiari malformation (CM-I), syringomyelia, brain tumors, moyamoya, and craniosynostosis. We describe our experience in treating children with NS and various neurosurgical conditions, and review the current literature on neurosurgical aspects of NS.

METHODS

Data were retrospectively collected from the medical records of children with NS who were operated at a tertiary pediatric neurosurgery department, between 2014 and 2021. Inclusion criteria were clinical or genetic diagnosis of NS, age < 18 years at treatment, and need for a neurosurgical intervention of any kind.

RESULTS

Five cases fulfilled the inclusion criteria. Two had tumors, one underwent surgical resection. Three had CM-I, syringomyelia, and hydrocephalus, of whom one also had craniosynostosis. Comorbidities included pulmonary stenosis in two patients and hypertrophic cardiomyopathy in one. Three patients had bleeding diathesis, two of them with abnormal coagulation tests. Four patients were treated preoperatively with tranexamic acid, and two with Von Willebrand factor or platelets (1 each). One patient with a clinical bleeding predisposition developed hematomyelia following a syringe-subarachnoid shunt revision.

CONCLUSIONS

NS is associated with a spectrum of central nervous system abnormalities, some of which with known etiology, while in others a pathophysiological mechanism has been suggested in the literature. When operating on a child with NS, a meticulous anesthetic, hematologic, and cardiac evaluation should be conducted. Neurosurgical interventions should then be planned accordingly.

New insights on Noonan syndrome's clinical phenotype: a single center retrospective study

BACKGROUND

Noonan syndrome (NS) is a clinically and genetically heterogeneous disorder. Since its clinical phenotype is often mild and difficult to differentiate from other syndromes, its diagnosis can be challenging and its prevalence in the pediatric population is most certainly underestimated. The difficulty in identifying Noonan syndrome is also increased by the fact that genetic tests are currently not able to detect an underlying mutation in around 10% of the cases.

METHODS

This is a retrospective, observational study conducted at the Institute for Maternal and Child "Burlo Garofolo" in Trieste, Italy. We recruited all the patients with clinical and/or genetic diagnosis of NS who were evaluated at the Department of Pediatrics between October 2015 and October 2020. Statistical analyses were performed with IBM SPSS Statistics software. The association between discrete variables has been evaluated through chi-squared test, indicating statistically significant p with Pearson test or Fischer test for variables less than 5.

RESULTS

We recruited a total of 35 patients affected by Noonan syndrome. In 24 patients (75%) we identified an underlying genetic substrate: 17 patients had a mutation on PTPN11 (61%), 2 in SOS1, KRAS and SHOC2 (7% each) and only 1 in RAF1 (4%). 25% of the subjects did not receive a genetic confirm. As for the phenotype of the syndrome, our study identified the presence of some clinical features which were previously unrelated or poorly related to NS. For example, renal and central nervous system abnormalities were found at a higher rate compared to the current literature. On the contrary, some features that are considered very suggestive of NS (such as lymphatic abnormalities and the classical facial features) were not frequently found in our population.

CONCLUSIONS

In our analysis, we focused on the main phenotypic features of NS, identifying various clinical manifestation that were not associated with this genetic condition before. This could be helpful in raising the knowledge of NS's clinical spectrum, facilitating its diagnosis.

Management of failed Chiari decompression and intrasyringeal hemorrhage in Noonan syndrome: illustrative cases

BACKGROUND

Noonan syndrome (NS) is a rare genetic RASopathy with multisystem implications. The disorder is typically characterized by short stature, distinctive facial features, intellectual disability, developmental delay, chest deformity, and congenital heart disease. NS may be inherited or arise secondary to spontaneous mutations of genes in the Ras/mitogen activated protein kinase signaling pathways.

OBSERVATIONS

Numerous case reports exist detailing the association between NS and Chiari I malformation (CM-I), although this relationship has not been fully established. Patients with NS who present with CM-I requiring operation have shown high rates reoperation for failed decompression. The authors reported two patients with NS, CM-I, and syringomyelia who had prior posterior fossa decompressions without syrinx improvement. Both patients received reoperation with successful outcomes.

LESSONS

The authors highlighted the association between NS and CM-I and raised awareness that patients with these disorders may be at higher risk for failed posterior fossa decompression, necessitating reoperation.

Unique presentation and management of Gowers intrasyringal hemorrhage

Context: Intrasyringal hemorrhage was first described in literature in the renowned Lectures on Diseases of the Nervous System by Sir William Richard Gowers [Gowers W. A lecture on syringal haemorrhage into the spinal cord. Lancet [Internet]; 162(4180):993-997. [cited 2019 August 19]. Available from https://www.sciencedirect.com/science/article/pii/S0140673601362785]. The pathophysiology of this disease is a hemorrhage within a preexisting intramedullary fluid-filled cavity or hydrosyringomyelia in the spinal cord. Most common symptoms of this disease are numbness, weakness, paresthesia in the extremities and gait disturbances. Since first noted in 1903, there have been just fourteen confirmed cases of this disease reported in literature, making it extremely rare and difficult to study.Findings: Here we discuss a unique presentation of Gowers intrasyringal hemorrhage. The patient is a male in his late teens with no prior established neurological history. He presented at our institution four days post suspected injury with persistent mild left upper extremity numbness and weakness. The patient was admitted and underwent an MRI of the cervical spine without intravenous contrast. The imaging findings confirm subacute on chronic Gowers intrasyringal hemorrhage in the setting of a Chiari 1 malformation. This patient underwent neurosurgical intervention four months post initial presentation and had complete postoperative resolution of his interval non-progressive but persistent symptoms.Clinical relevance: This unique case suggests immediate surgical intervention may not always be necessary for treating Gowers intrasyringal hemorrhage.

Chiari I malformation and Noonan's syndrome: Shared manifestations of RASopathy

Neurologic sequalae of Noonan syndrome have been postulated in the literature. A topic of significance is the role of RASopathy in the shared pathophysiology of Noonan Syndrome and Chiari I malformation. In this unique case report, we present a patient with concomitant Noonan Syndrome and Chiari I with 4th ventricular outflow obstruction. The case highlights the importance of close clinical suspicion in this patient population. We utilize the case to delve into intricacies of the known pathophysiology and encourage ongoing investigation.

The eponymous legacy of Sir William Richard Gowers (1845-1915): A revealing letter

The eponymous legacy of Sir William Richard Gowers (1845-1915) was the subject of a comprehensive appraisal first written for this journal late last year. Since the completion of that work, a revealing February 1903 letter has come to light recording, amongst other things, Gowers' firsthand and somewhat private opinions concerning some of his own eponymous contributions to medicine. This addendum to the primary author's original article will review and contextualize this very interesting find as it relates to Gowers' eponymous legacy. Gowers' "ataxic paraplegia" (referred to as "Gowers' disease" in the letter) and "syringal hemorrhage" are specially considered, and his broader neological contributions are also briefly addressed. For completion, a number of other previously unnoticed eponyms are added to the already impressive list of medical entities named in Gowers' honor, and a more complete collection of eponyms found in Gowers' Manual are tabulated for consideration.

A novel rasopathy caused by recurrent de novo missense mutations in PPP1CB closely resembles Noonan syndrome with loose anagen hair

Noonan syndrome is a rasopathy caused by mutations in multiple genes encoding components of the RAS/MAPK pathway. Despite its variable phenotype, limited genotype-phenotype correlations exist. Noonan syndrome with loose anagen hair (NS-LAH) is characterized by its distinctive hair anomalies, developmental differences, and structural brain abnormalities and is caused by a single recurrent missense SHOC2 mutation. SHOC2 forms a complex with protein phosphatase 1 (PP1C). Protein phosphatases counterbalance kinases and control activation of signaling proteins, such as the mitogen-activated protein kinases of the RAS/MAPK pathway. Here we report four patients with de novo missense mutations in protein phosphatase one catalytic subunit beta (PPP1CB), sharing a recognizable phenotype. Three individuals had the recurrent PPP1CB c.146G>C, p.Pro49Arg mutation, the fourth had a c.166G>C, p.Ala56Pro change. All had relative or absolute macrocephaly, low-set and posteriorly angulated ears, and developmental delay. Slow growing and/or sparse hair and/or an unruly hair texture was present in all. Three individuals had feeding difficulties requiring feeding tubes. One of two males had cryptorchidism, another had pectus excavatum. Short stature was present in three. A female with the recurrent mutation had a Dandy-Walker malformation and optic nerve hypoplasia. Mild ventriculomegaly occurred in all, cerebellar tonsillar ectopia was seen in two and progressed to Chiari 1 malformation in one individual. Based on the combination of phenotypic findings and PPP1CB's effect on RAF dephosphorylation within the RAS/MAPK pathway, this novel condition can be considered a rasopathy, most similar to NS-LAH. Collectively, these mutations meet the standardized criteria for pathogenicity. © 2016 Wiley Periodicals, Inc.