Petrous carotid canal stenosis in malignant osteopetrosis: CT documentation with MR angiographic correlation

Haemodynamic stroke in a rare adult presentation of osteopetrosis

Osteopetrosis refers to a collection of metabolic bone diseases with impaired osteoclastic activity resulting in abnormally dense and dysplastic bone. Cranial involvement results in severe complications, including compressive nerve palsies, hydrocephalus and tonsillar herniation. Ischaemic stroke is very rarely reported in osteopetrosis, resulting from vascular impingement. We report a young adult woman with CLCN7 (Chloride Voltage-Gated Channel 7) gene-related osteopetrosis and ischaemic stroke resulting from diffuse and focal arterial stenosis and severe myelophthisic anaemia. Acute management included blood transfusions, lay-flat positioning and fever treatment, which resulted in partial recovery of her initial neurological deficits. Our case highlights this very rare stroke syndrome's unique mechanisms and treatment challenges.

Progressive skeletal defects caused by Kindlin3 deficiency, a model of autosomal recessive osteopetrosis in humans

The cellular and molecular mechanisms of bone development and homeostasis are clinically important, but not fully understood. Mutations in integrins and Kindlin3 in humans known as Leukocyte adhesion deficiencies (LAD) cause a wide spectrum of complications, including osteopetrosis. Yet, the rarity, frequent misdiagnosis, and lethality of LAD preclude mechanistic analysis of skeletal abnormalities in these patients. Here, using inducible and constitutive tissue-specific Kindlin3 knockout (K3KO) mice, we show that the constitutive lack of embryonic-Kindlin3 in myeloid lineage cells causes growth retardation, edentulism, and skull deformity indicative of hydrocephaly. Micro-CT analysis revealed craniosynostosis, choanal stenosis, and micrognathia along with other skeletal abnormalities characteristic of osteopetrosis. A marked progression of osteosclerosis occurs in mature to middle-aged adults, resulting in the narrowing of cranial nerve foramina and bone marrow cavities of long bones. However, postnatal-Kindlin3 is less critical for bone remodeling and architecture. Thus, myeloid Kindlin3 is essential for skeletal development and its deficiency leads to autosomal recessive osteopetrosis (ARO). The study will aid in the diagnosis, management, and treatment choices for patients with LAD-III and ARO.

Diagnosis and Management of Osteopetrosis: Consensus Guidelines From the Osteopetrosis Working Group

BACKGROUND

Osteopetrosis encompasses a group of rare metabolic bone diseases characterized by impaired osteoclast activity or development, resulting in high bone mineral density. Existing guidelines focus on treatment of the severe infantile forms with hematopoietic cell transplantation (HCT) but do not address the management of patients with less severe forms for whom HCT is not the standard of care. Therefore, our objective was to develop expert consensus guidelines for the management of these patients.

METHODS

A modified Delphi method was used to build consensus among participants of the Osteopetrosis Working Group, with responses to an anonymous online survey used to identify areas of agreement and conflict and develop a follow-up survey. The strength of recommendations and quality of evidence was graded using the Grading of Recommendations Assessment, Development and Evaluation system.

RESULTS

Consensus was found in the areas of diagnosis, monitoring, and treatment. We recommend relying on characteristic radiographic findings to make the diagnosis and found that genetic testing adds important information by identifying mutations associated with unique disease complications. We recommend ongoing monitoring for changes in mineral metabolism and other complications, including cranial nerve impingement, anemia, leukopenia, and dental disease. We suggest that calcitriol should not be used in high doses and instead recommend symptom-based supportive therapy for disease complications because noninfantile osteopetrosis has no effective treatment.

CONCLUSIONS

Scarcity of published studies on osteopetrosis reduce the ability to develop evidence-based guidelines for the management of these patients. Expert opinion-based guidelines for this rare condition are nevertheless important to enable improved care.

Internal Carotid Artery Hypoplasia: Role of Color-Coded Carotid Duplex Sonography

OBJECTIVES

The purpose of this study was to determine the role of color-coded carotid duplex sonography for diagnosis of internal carotid artery hypoplasia.

METHODS

We retrospectively reviewed 25,000 color-coded carotid duplex sonograms in our neurosonographic database to establish more diagnostic criteria for internal carotid artery hypoplasia.

RESULTS

A definitive diagnosis of internal carotid artery hypoplasia was made in 9 patients. Diagnostic findings on color-coded carotid duplex imaging include a long segmental small-caliber lumen (52% diameter) with markedly decreased flow (13% flow volume) in the affected internal carotid artery relative to the contralateral side but without intraluminal lesions. Indirect findings included markedly increased total flow volume (an increase of 133%) in both vertebral arteries, antegrade ipsilateral ophthalmic arterial flow, and a reduced vessel diameter with increased flow resistance in the ipsilateral common carotid artery. Ten patients with distal internal carotid artery dissection showed a similar color-coded duplex pattern, but the reductions in the internal and common carotid artery diameters and increase in collateral flow from the vertebral artery were less prominent than those in hypoplasia. The ipsilateral ophthalmic arterial flow was retrograde in 40% of patients with distal internal carotid artery dissection. In addition, thin-section axial and sagittal computed tomograms of the skull base could show the small diameter of the carotid canal in internal carotid artery hypoplasia and help distinguish hypoplasia from distal internal carotid artery dissection.

CONCLUSIONS

Color-coded carotid duplex sonography provides important clues for establishing a diagnosis of internal carotid artery hypoplasia. A hypoplastic carotid canal can be shown by thin-section axial and sagittal skull base computed tomography to confirm the final diagnosis.

Magnetic resonance imaging appearances in primary and secondary angiosarcoma of the breast

Angiosarcomas are malignant tumours of endovascular origin. They are rare tumours accounting for 0.04-1% of all breast malignancies. Two different forms are described: primary, occurring in young women, and secondary angiosarcoma, which occurs in older women with a history of breast-conserving surgery and radiation therapy. Imaging findings on mammography and ultrasound are non-specific, but magnetic resonance imaging with dynamic contrast enhancement is more informative. We present two cases - one of primary and one of secondary angiosarcoma - and review the imaging findings.

[Albers-Schönberg's disease with ocular manifestation]

Albers-Schönberg's disease is a rare disease (one case in 100,000 inhabitants), asymptomatic in the majority of cases. It belongs to the four clearly individualized forms of human osteopetrosis and has an autosomal dominant transmission. It induces generalized osteosclerosis, and most symptoms result from complications such as fractures following mild injury, compression of cranial nerves, especially the optic nerve, by stenosis of extracranial ostia, but also osteomyelitis of the lower maxilla. The treatment of Albers-Schönberg's disease is disappointing and only symptomatic, although the responsible genetic anomaly was recently identified. We report here the case of a 54-year-old woman, whose diagnosis of the disease has been known since adolescence, who presented with unilateral loss of vision and perimetric deficit due to papilla edema resulting from stenosis of the optic canal and benign intracranial hypertension.

Neurological aspects of osteopetrosis

The osteopetroses are caused by reduced activity of osteoclasts which results in defective remodelling of bone and increased bone density. They range from a devastating neurometabolic disease, through severe malignant infantile osteopetrosis (OP) to two more benign conditions principally affecting adults [autosomal dominant OP (ADO I and II)]. In many patients the disease is caused by defects in either the proton pump [the a3 subunit of vacuolar-type H(+)-ATPase, encoded by the gene variously termed ATP6i or TCIRG1] or the ClC-7 chloride channel (ClCN7 gene). These pumps are responsible for acidifying the bone surface beneath the osteoclast. Although generally thought of as bone diseases, the most serious consequences of the osteopetroses are seen in the nervous system. Cranial nerves, blood vessels and the spinal cord are compressed by either gradual occlusion or lack of growth of skull foramina. Most patients with OP have some degree of optic atrophy and many children with severe forms of autosomal recessive OP are rendered blind; optic decompression is frequently attempted to prevent the latter. Auditory, facial and trigeminal nerves may also be affected, and hydrocephalus can develop. Stenosis of both arterial supply (internal carotid and vertebral arteries) and venous drainage may occur. The least understood form of the disease is neuronopathic OP [OP and infantile neuroaxonal dystrophy, MIM (Mendelian inheritance in man) 600329] which causes rapid neurodegeneration and death within the first year. Although characterized by the finding of widespread axonal spheroids and accumulation of ceroid lipofuscin, the biochemical basis of this disease remains unknown. The neurological complications of this disease and other variants are presented in the context of the latest classification of the disease.