A re-evaluation of the "fish vertebra" sign in sickle cell hemoglobinopathy

Multilevel “fish vertebrae” in a patient with tumor-induced osteomalacia

Background and importance: “Fish vertebra” is an uncommon anomaly of vertebral body shape, consisting of central depression of the superior and inferior vertebral surfaces. It has been associated with various conditions: osteoporosis, osteomalacia, hyperparathyroidism, Paget disease, sickle cell disease, multiple myeloma and systemic lupus erythematosus.

Clinical presentation: A 29-year-old male patient, previously treated for ankylosing spondylitis (with NSAIDs and TNFα inhibitor), without any clinical improvement, was admitted to our Neurosurgical Department. He complained of difficult gait, possible only with the aid of a cane, low back pain and bilateral hip pain, but without leg pain. He denied any history of recent trauma. Neurological examination was normal. Plain thoracic and lumbar spine X-rays revealed multilevel “fish vertebrae”. Lumbar spine MRI and contrast thoraco-abdominal CT scan showed fractures of multiple structures: left L4 pedicle, right L4 lamina and pars interarticularis, right II-VII costal arches, left I-V costal arches and bilateral sacral alae. We performed extensive laboratory tests that detected low seric phosphorous and PTH levels, with increased alkaline phosphatase, indicating a possible endocrinological cause for this condition. Subsequently, we decided to transfer the patient to an Endocrinological Department. A diagnosis of hypophosphatemic osteomalacia was established and increased FGF23 levels, later determined, suggested it was tumor-induced osteomalacia. Whole-body MRI was unable to locate the tumor, but Gallium-68 DOTATATE PET/CT revealed a small (15 mm in diameter), hyperfixating mass in the head of the right femur. The patient was treated with oral calcitriol and phosphate, with alleviation of symptoms. Surgical excision of the tumor was recommended, but the patient decided to postopone the operation.

Conclusion: Modern medical imaging and biochemical testing have made the leap from merely observing vertebral biconcavities to diagnosing their cause and, consequently, the possibility to adequately treat uncommon causes of “fish vertebra”, such as neuroendocrine tumor-induced osteomalacia.

Chronic iron deficiency as an emerging risk factor for osteoporosis: a hypothesis

Iron is essential in oxygen transport and participates in many enzymatic systems in the body, with important roles in collagen synthesis and vitamin D metabolism. The relationship between iron and bone health comes from clinical observations in iron overload patients who suffered bone loss. The opposite scenario—whether iron deficiency, with or without anemia, affects bone metabolism—has not been fully addressed. This is of great interest, as this nutrient deficiency is a worldwide public health problem and at the same time osteoporosis and bone alterations are highly prevalent. This review presents current knowledge on nutritional iron deficiency and bone remodeling, the biomarkers to evaluate iron status and bone formation and resorption, and the link between iron and bone metabolism. Finally, it is hypothesized that chronic iron deficiency induces bone resorption and risk of osteoporosis, thus complete recovery from anemia and its prevention should be promoted in order to improve quality of life including bone health. Several mechanisms are suggested; hence, further investigation on the possible impact of chronic iron deficiency on the development of osteoporosis is needed.

Relationship between vitamin D deficiency and bone fragility in sickle cell disease: a cohort study of 56 adults

BACKGROUND

Recent studies suggest that patients with sickle cell disease (SCD) have profound vitamin D (VD) deficiency. Limited data exist on the effect of VD deficiency on bone fragility in these patients.

OBJECTIVES

To assess the prevalence of VD deficiency in adults with SCD and its consequences on bone metabolism and fragility.

METHODS

This prospective study included 56 SCD adult patients (mean age 29.8 ± 9.5 years), in a clinically steady state. Clinical and laboratory data were recorded. Bone mineral density (BMD) was measured using dual X-ray absorptiometry. Fracture history, BMD, avascular osteonecrosis, H-shaped vertebra and markers of mineral metabolism were compared between two groups of patients presenting very low (≤ 6 ng/mL, n=26) (group 1) and low (>6 ng/mL, n=26) (group 2) 25(OH)D concentration, respectively.

RESULTS

Median 25(OH)D concentration was 6 ng/mL. VD deficiency (25(OH)D <10 ng/mL) was found in 42 out of 56 patients (75%) and secondary hyperparathyroidism in 40 (71.4%). History of fracture was documented in 17 patients (30.3%), osteopenia and/or osteoporosis in 39.6% of patients. Overall, patients of group 1 were more likely to have sustained a fracture (42.8%) compared to patients of group 2 (17.8%) (p=0.04). These patients had also lower body mass index and significantly higher parathyroid hormone, C-terminal telopeptides of type I-collagen and bone-specific alkaline phosphatase serum levels. There was no difference between group for BMD, avascular osteonecrosis history, H-shaped vertebra, and disease severity markers.

CONCLUSION

This study suggests that VD deficiency is a key feature in SCD-bone disease. It is highly prevalent and associated with hyperparathyroidism, bone resorption markers, and history of fracture. The optimal supplementation regimen remains to be determined.

Tuberculous spondylodiscitis in a patient with a sickle-cell disease: CT findings

Background:

Although sickle-cell anemia (SCA) is common in black Americans, Sub-Saharan Africa and in the Mediterranean area, the disease is rare in the temperate climate zone. The manifestations of the disease are related mainly to the production of abnormal hemoglobin that leads to organ ischemia and increased susceptibility to infection caused by functional asplenia.

Case Report:

The authors present CT findings in a 39-year-old black woman diagnosed due to abdominal pain, lymphadenopathy and fever. CT of the thorax and abdomen demonstrated changes in the liver, spleen, and skeletal system suggestive of SCA complicated with spondylodiscitis in the thoracic spine.

Discussion:

Hepatomegaly and small calcified spleen are typical findings in older homozygotic patients with SCA. The lesions in the skeleton may be related either to intramedullary hematopoiesis or osteonecrosis and osteomyelitis. In the latter case, diffuse osteosclerosis and H-shaped vertebrae are most typical. Tuberculous spondylodiscitis is characterized by the location in the thoracic region, preferential involvement of anterior elements, relative sparing of intervertebral discs, and cold abscesses.

Morphometry of the thoracolumbar vertebrae in sickle cell disease

Patients with sickle cell disease (SCD) who have deformities and vertebral fractures due to osteoporosis may require surgery. Spinal surgeons must become familiar with the vertebral morphometry of patients with SCD and to that aim we have examined the morphometry of the thoracolumbar spine in these patients. A cohort of 100 patients with SCD was examined using plain thoraco lumbar anteroposterior/lateral radiographs and dual energy X-ray absorptiometry (DEXA). Vertebral morphometry (vertebral body diameters, pedicle, spinal canal and deformity) was assessed for different age groups. Results were compared to published studies of healthy subjects. The vertebral dimensions for the 16-20-year and the 21+-year-old groups were significantly smaller for females than males at most spinal levels, while measurements in the 6-10 years and 11-15 years age groups were similar across both sexes at most levels. No significant statistical difference was found between the diameters of the right and left pedicles. With the exception of the sagittal diameter, most of the dimensions of the vertebral bodies measured in SCD patients were less than those of healthy individuals; multiple deformities were also observed. Low bone density was noted in 32 patients. Our data highlight the differences in vertebral bone mineral density, anatomy and deformities in patients with SCD compared to healthy individuals. When considering surgical intervention for patients with SCD, it is important that pre-operative radiography and planning is undertaken, and that the surgeon is familiar with the geometry of the pedicles of the thoracolumbar vertebrae necessary for the safe insertion of pedicle screws. Osteoporosis must be considered when planning surgical interventions in these patients.

MR imaging of the spinal bone marrow

Adequate interpretation of a cervical, thoracic, or lumbar spine MR imaging examination includes a careful evaluation of the bone marrow. Detecting an abnormality in bone marrow may cause a diagnostic dilemma because the marrow in the spine can vary in appearance according to the patient's age, and can be affected by infectious, inflammatory, metabolic, and neoplastic processes. Its appearance can be affected as well by underlying degenerative disc disease, trauma, and numerous iatrogenic therapies, including vertebroplasty, radiation therapy, and medications. In addition to conventional MR imaging sequences, newer imaging techniques, such as diffusion weighting and opposedphase sequences, are being studied to help increase the diagnostic accuracy of spine and bone marrow evaluation and to help differentiate benign from malignant and infectious processes.

Bone and joint disease in sickle cell disease

Bone and joint disorders are the most common cause of chronic pain in patients who have sickle cell disease. The femoral head is the most common area of bone destruction in sickle cell patients, although other disease-related problems include avascular necrosis of the humeral head, changes in the thoracic and lumbar spine, infection with encapsulated organisms (Salmonella and Staphylococcus aureus are the most common), bone marrow disturbances, and dental effects. Complications can occur at any location: epiphyseal, metaphyseal, or diaphyseal. The location and the extensiveness of the problems determine the pain and structural damage. The hip joint is particularly vulnerable in sickle cell disease. This article highlights aspects of sickle cell disease that affect healthy bone and joint function and discusses treatment options.

Disseminated thrombosis-induced growth plate necrosis in rat: a unique model for growth plate arrest

Exposure of rats to 2-butoxyethanol (BE) produces early hemolytic anemia and disseminated thrombosis. This leads to infarctions in multiple organs, including bones and cartilage. BE, administered for different durations of exposure in two separate experiments, produced metaphyseal vascular thrombosis, growth plate infarction, and partial or complete physeal growth arrest. This reproducible model may serve as a useful tool in the study of some conditions that manifest growth plate damage. The suitability of this model for investigating the pathogenesis of growth plate necrosis and as a model for potential therapy for various human growth plate disorders are discussed.

Unusual manifestations of osteoarticular tuberculosis

Unusual manifestations of osteoarticular tuberculosis, especially tubercular osteomyelitis, are described. Diagnostic problems may arise and lead to delay in treatment if these conditions are not considered in the differential diagnosis. The importance of bacteriologic and histopathologic confirmation of the disease is stressed.

Differential diagnosis: a reasonable clinical approach

The reasonable clinical approach to the patient who has low back pain includes a search for any of the red flags that would prompt consideration of additional diagnostic testing for serious underlying disease. The common patterns of back pain would be explored in an effort to categorize the patient's symptoms and to begin formulation of a diagnostic impression. Re-evaluation of the patient in light of his response (or lack of response) to these measures is an essential component of the clinical assessment. Finally, some consideration must be given to the various biopsychosocial factors that may affect prognosis, particularly in patients who have more chronic pain and disability-related issues.

Gaucher disease: a heterogeneous clinical complex for which effective enzyme replacement has come of age

Gaucher disease, the most common form of lysosomal storage disease, is the result of autosomal recessive inheritance of a lysosomal enzyme glucocerebrosidase deficiency, which produces defective hydrolysis of glucosylceramide that accumulates in reticuloendothelial (tissue macrophage) cells. The current review focuses on Type 1 (the nonneuronopathic) or adult Gaucher disease and defines the clinical manifestations (splenomegaly, hepatomegaly, bony lesions, and clinical metabolic dysfunction) in relationship to the known enzymatic defect. The clinical diversity and variability in symptoms and signs, the age at onset of the clinical manifestations and their rate of progression, and the heterogeneity of the organs involved are reviewed. Extensive delineation of the nature of the enzyme defect and the recent molecular characterization of the enzyme mutants has not provided an explantation for the remarkable clinical phenotypic heterogeneity. Enzyme assays now provide an excellent method for diagnosis. Effective enzyme replacement therapy emphasizes the value of early diagnosis and has altered the costs and potential risks of older therapeutic indications for splenectomy or cytokine therapy. Enzyme efficacy raises questions about the specific indications for replacement treatment and the most desirable rate and duration of enzyme delivery.

Pathologic vertebral compression in spinal malignancy secondary to intervertebral disk expansion

A retrospective analysis of the MR appearance of the intervertebral disks in 17 patients with spinal malignancy was performed. Disk expansion, related to neoplastic structural weakening of the bone in the face of unaltered disk biomechanics, was present in 20% of all visualized disks in association with a 77% incidence of malignant involvement of the vertebral bodies studied. This compared with a frequency in benign disk expansion (i.e., osteoporosis) of 2% in the age-matched, but randomly selected, control group. On careful review, there was no strict correlation between disk expansion and patient symptoms. Although this finding may be seen in non-neoplastic conditions, it is felt that the higher incidence of disk expansion associated with osseous vertebral malignancy nevertheless reflects the underlying gravity of the pathologic changes accompanying neoplasia.

Osteoarticular manifestations in sickle-cell disorders

The osteoarticular manifestations of the main sickling disorders (homozygous sickle cell-HbSS anaemia-, double heterozygous-HbS-beta thalassaemia, double heterozygous HbS-C disease and sickle cell-trait) are reviewed; They may be grouped into 3 main categories: vaso-occlusive, infective and metabolic. The pathophysiology and pathogenesis as well as the treatment are discussed.

The incidence of cone epiphyses and ivory epiphyses of the hand in Nigerian children

Radiographs of the left hand of 594 children from Ibadan, Nigeria were inspected for skeletal anomalies to determine differences in the incidence of cone and ivory epiphyses for the rich and poor children and differences in incidence for four hemoglobin types. Ivory epiphyses ovvurred more often in children in the lower socio-economic class and children with hemoglobin AA. The cone epiphyses observed in Hb SS children were primarily a result of bone infarcts, while cones in children of other hemoglobin types appeared to be normal variants. The incidence of ivory epiphyses was higher in the Nigerian children than in American black children in the Ten-State Nutrition Survey. The incidence of cone epiphyses was much lower than those reported for other normal populations.

Complete remodeling of the vertebrae in a child successfully treated for acute lymphocytic leukemia (ALL)

This report describes a 10-year-old white boy who presented with acute lymphocytic leukemia (ALL) and several collapsed thoracolumbar vertebrae in 1965. His ALL was successfully treated, and he has been disease-free for over 10 years. He has now completely remodeled all of the collapsed vertebrae.