Pseudofracture of the neck of femur secondary to osteomalacia

Nutritional osteomalacia is a metabolic bone disorder common among the Asian female immigrant population in the United Kingdom. We describe the case of a female of Asian origin, who was found to have a unilateral undisplaced pseudofracture of the neck of the femur during pregnancy. Although not operated on the fracture was treated successfully with calcium and vitamin D supplement therapy. Within one month of treatment, the bone pain subsided and she was able to bear full weight. Subsequent radiological follow-up showed the pseudofracture to have healed sufficiently with no evidence of avascular necrosis.

There should be a high index of suspicion of this disease, particularly among Asian patients presenting with persistent and non-specific musculoskeletal pain.

Osteomalacia and secondary hyperparathyroidism after kidney transplantation: Relationship to vitamin D deficiency

Secondary hyperparathyroidism is highly prevalent in patients with end-stage renal disease. After successful kidney transplantation, however, parathyroid glands gradually involute to normal size with subsequent normalization of intact parathyroid hormone (PTH), serum calcium, and phosphorous concentrations. This report describes a 48-year-old diabetic end-stage renal disease patient who underwent a successful cadaveric kidney transplant. Serum calcium and phosphorous concentrations normalized within 6 months. Three years later, he presented with complaints of proximal muscle weakness that was progressively worsening. Physical examination revealed temporal wasting and proximal muscle weakness. Detailed neurologic examination was unremarkable except for decreased vibratory sensation in both feet. Laboratory data showed stable allograft function (serum creatinine, 1.3 mg/dL), hypocalcemia, and hypophosphatemia with markedly elevated alkaline phosphatase level (726 IU/L) and intact PTH level (947 pg/mL). Further laboratory evaluation revealed poor nutritional status and severe deficiency of 25(OH)D (4.0 ng/mL). Past medical history included remote episodes of acute pancreatitis due to prior alcohol abuse. Computed tomography of the abdomen showed calcific atrophic pancreas, and steatorrhea was confirmed on stool studies. Decreased bone mineral density was noted by computed tomography bone density scan. Secondary hyperparathyroidism and osteomalacia had developed due to severe vitamin D deficiency, occurring as a result of previously unrecognized, minimally symptomatic pancreatic exocrine insufficiency. Treatment with vitamin D, calcium, and pancreatic enzyme replacement led to remarkable resolution of clinical symptoms and secondary hyperparathyroidism (intact PTH, 65 pg/mL after therapy) and resulted in significant improvement in bone mineralization. Factors associated with vitamin D deficiency in the chronic kidney disease and post-transplant patient population are reviewed.

Oncogenic osteomalacia: exact tumor localization by co-registration of positron emission and computed tomography

In oncogenic osteomalacia, the causative tumor is almost always difficult to find. A novel diagnostic approach is presented that facilitates a precise and rapid localization of the associated lesion by PET-CT co-registration using the radiotracer (68)Ga-DOTANOC.

INTRODUCTION

Oncogenic osteomalacia (OOM) is an uncommon disorder characterized by hyperphosphaturia, hypophosphatemia, decreased vitamin D(3) serum levels, and osteomalacia. The paraneoplastic syndrome is exclusively driven by a small somatostatin receptor (sst)-positive tumor that produces phosphatonins, proteins that cause renal phosphate loss. OOM can be cured completely on tumor removal. However, the exact tumor localization is the most challenging step, because the lesion is notoriously difficult to detect by common imaging techniques.

MATERIALS AND METHODS

A 60-year-old woman complained of severe pain in her back and chest wall, muscle weakness, and reduced physical activity for >1 year. She suffered a metatarsal fracture and presented with hyperphosphaturia and hypophosphatemia. OOM was suspected, and a meticulous search for the tumor was initiated by conventional imaging techniques, sst-mediated imaging using (111)In-octreotide scintigraphy, and (68)Ga-DOTANOC-based positron emission tomography (PET)-CT co-registration. (68)Ga-DOTANOC is a novel radiopharmaceutical compound in which the somatostatin analog octreotide is modified at position 3, chelated with DOTA, and complexed with (68)Gallium. (68)Ga-DOTANOC has an improved affinity to sst2 and sst5 relative to other radiopeptides.

RESULTS

Whereas common imaging techniques such as CT failed to localize the tumor, (111)In-octreotide scintigraphy was able to detect the lesion, but only PET-CT using (68)Ga-DOTANOC revealed the exact tumor localization in the right femoral head. On tumor resection, the well being of the patient improved significantly, and biochemical parameters returned to normal.

CONCLUSIONS

(68)Ga-DOTANOC-based PET-CT is a novel and powerful approach to detect sst-positive tumors in a timely manner and to provide highly resolved images facilitating the development of a therapeutic strategy.

Acquired fanconi syndrome with osteomalacia secondary to monoclonal gammopathy of undetermined significance

A 60-year-old woman was admitted because of multiple bone pain. Examination revealed hypophosphatemic osteomalacia and acquired Fanconi syndrome. Further exploration revealed monoclonal gammopathy of undetermined significance (MGUS) excreting urinary Bence Jones protein (kappa light chain). Renal biopsy showed non-specific tubulointerstitial nephritis, yet neither crystalline inclusions in the cytoplasm of the tubular epithelium nor myeloma casts nor amyloid deposits were found. She was treated with supplementation by phosphate, alkali agents, and vitamin D, and responded well to the treatment symptomatically and biochemically. MGUS was observed without chemotherapy. Myeloma had not developed after 10 months follow-up.

Osteomalacia from Mg-containing antacid: a case report of bilateral hip fracture

Non-prescribed antacid drugs that contain magnesium and aluminum are widely used in the treatment of gastritis and peptic ulcer. One of the side effects of these antacid drugs is that they bind phosphate in the gut and result in its malabsorption. In this paper, a 42-year-old female patient who used magnesium hydroxide (Magnesie calcinee powder 100 g) to benefit from its laxative feature, and developed osteomalacia after losing 90 kg in 2 years will be presented by going through the related literature. She had widespread joint pain and could hardly walk without the help. Ca, P and vitamin D were at lower limit of normal, ALP, Mg and PTH were increased in her laboratory tests. There were stress fractures at the femur neck and at the upper part of the tibia in plane radiographies. The patient was hospitalized with the diagnosis of osteomalacia and she was treated successfully.

Acquired hypophosphatemia osteomalacia associated with Fanconi’s syndrome in Sjögren’s syndrome

Sjögren's syndrome is an autoimmune disorder involving exocrine glands that occurs alone or in association with various autoimmune and connective tissue diseases. The severity of Sjögren's syndrome ranges from isolated sicca syndrome to severe complications such as vasculitis, lung and renal involvement. Overt or latent renal tubular acidosis caused by autoimmune tubulointerstitial nephritis, is a common extraglandular manifestation in Sjögren's syndrome. Osteomalacia is a rare complication of renal tubular acidosis, and it was reported to be associated with distal renal tubular acidosis in Sjögren's syndrome. We report a 60-year-old woman who presented with multiple bone deformity and general muscle weakness. Osteomalacia was secondary to Fanconi's syndrome, and the Fanconi's syndrome was a result of renal involvement in Sjögren's syndrome. Fanconi's syndrome is a rare kidney manifestation in Sjögren's syndrome. It may be latent and may precede the subjective sicca symptoms. These findings suggest that evidence for Sjögren's syndrome should be sought in adult patients with unexplained osteomalacia and renal tubular acidosis, even in the absence of subjective sicca syndrome. Conversely, in patients with Sjögren's syndrome, early investigation and treatment of renal tubular dysfunction may prevent future complications, such as osteomalacia.

Insuffizienzfrakturen in der Rheumatologie

Stress fractures occur as insufficiency fractures, with a prevalence of 0.8% in patients with rheumatological illness. The main sites of insufficiency fractures are the pelvis and sacrum, parts of the tibia and fibula that are close to the joints, and the calcaneus and hip. Since the painful symptoms overlap with the clinical picture of the painful joint diseases and because of the low sensitivity of conventional diagnostic X-ray, insufficiency fractures are not diagnosed directly or their diagnosis is delayed. The high sensitivity of computer tomography, skeletal scintigraphy and nuclear magnetic resonance imaging should be exploited in the diagnosis of insufficiency fractures. The case report presented describes insufficiency fractures of the distal right tibia and fibula in an elderly female patient with rheumatoid arthritis being treated with long-term glucocorticoids. In addition to advanced age, female gender, immobility and rheumatoid arthritis requiring long-term cortisone, there are further risk factors for insufficiency fractures: fluoride treatment over many years in the past, hypovitaminosis D3, renal failure. The DXA bone density values of the neck of the femur and the lumbar vertebrae do not show any osteoporosis, and the calcium concentration in the serum is low; phosphate is raised and parathormone is normal; osteocalcin, beta crosslaps and alkaline phosphatase are raised. Bone biopsy specimens taken from the iliac crest and the proximal femur and investigated for the purpose of differential diagnosis revealed renal osteopathy with secondary hyperparathyroidism and osteomalacia. In elderly patients with kidney failure, the possibility of renal osteopathy must be considered as the possible cause of reduced bone quality with a raised risk of insufficiency fractures, even when the parathormone levels are normal. In view of the frequency of osteopathies in rheumatological patients, osteology is of enormous significance in rheumatology.

[A worrisome scintigraphy]

This report describes a patient who was admitted to the hospital with suspicion of occult neoplasia, widely spreading to bone. In fact, he had osteoporosis and osteomalacia due to hypovitaminosis D caused by chronic use of antiepileptic drugs.

Oncogenic osteomalacia: localization of underlying peripheral mesenchymal tumors with use of Tc 99m sestamibi scintigraphy

OBJECTIVE

To highlight a strategy for potential detection of mesenchymal tumors in oncogenic malacia, as illustrated by 3 cases.

METHODS

Three case reports are presented in which successful localization of the offending neoplasm was accomplished by using whole-body Tc 99m sestamibi scanning. Alternative localization techniques are also reviewed.

RESULTS

Oncogenic osteomalacia occurs infrequently and is caused by neoplasms that secrete phosphatonins, substances that interfere with proximal tubular resorption of phosphorus and can result in phosphaturia, hypophosphatemia, reduced 1,25-dihydroxyvitamin D concentration, and osteomalacia. Removal of the underlying neoplasm results in complete resolution of all biochemical, pathologic, and physical manifestations of this disorder, as shown in our 3 patients. Because the neoplasms are small and can occur in any tissue compartment, they are difficult to localize, a feature that often results in therapeutic failure.

CONCLUSION

We conclude that use of whole-body Tc 99m sestamibi scanning may be an appropriate and cost-effective initial strategy for the localization of peripheral phosphatonin-secreting tumors.

Utilidad de la gammagrafía ósea en el diagnóstico de osteomalacia secundaria en un paciente en tratamiento con tenofovir

It is reported a HIV infected patient under antiretroviral therapy including tenofovir therapy who was referred to the Nuclear Medicine Department to complete bone pain study. A bone scan was performed at 3 hours after the injection of 740 MBq of 99mTc-MDP, revealing an abnormal distribution with characteristic changes compatible with osteomalacia. In further analysis, a secondary hyperparathyroidism and osteomalacia were diagnosed in the context of Fanconi syndrome, an infrequent complication described in patients under treatment with tenofovir.

Usefulness of 201Tl and 99mTc MIBI scintigraphy in a case of oncogenic osteomalacia

A 45-year-old male was admitted with difficulty in walking due to leg pain. At the time of the first visit, a reduced serum phosphorus concentration and an increased serum alkaline phosphatase concentration of unknown etiology were observed. Either a whole body bone scintigraphy or CT of the neck, chest and abdominal region did not reveal any underlying disease. However both the whole body 201Tl scintigraphy and 99mTc MIBI SPECT showed accumulation in the right knee region, and a small tumor was detected by MRI examination. After a diagnosis of oncogenic osteomalacia due to this tumor was determined the tumor was surgically removed, and turned out to be a hemangiopericytoma. By removal of the tumor, either the symptoms or the laboratory data were improved significantly. In this case, both 201Tl scintigraphy and 99mTc scintigraphy MIBI were useful in identifying the location of the tumor which caused oncogenic osteomalacia.

Bone mineral density and bone scintigraphy in adult Saudi female patients with osteomalacia

OBJECTIVE

This prospective study was conducted to demonstrate the role of bone mineral density (BMD) and bone scan in the management of adult Saudi female patients with established diagnosis of osteomalacia.

METHODS

Bone scan using Tc99m methylene diphosphonate (MDP) and BMD of the lumbar spine and femoral neck using dual x-ray absorptiometry (DXA) were performed at the time of diagnosis 6 months and one year after therapy in 96 Saudi female patients attending the metabolic bone disease clinic at King Khalid University Hospital, Riyadh, Kingdom of Saudi Arabia, between January 1997 through to June 1999, aged between 20 and 73-years (mean 42 years). Alkaline phosphatase, calcium and inorganic phosphorus were measured for all patients before and after treatment. 25 Hydroxy Vitamin D was only measured with the first BMD measurements.

RESULTS

The bone profile showed typical biochemical abnormalities of osteomalacia. The bone scan showed feature of "superscan" in all patients and "pseudofractures" in 43 patients. Bone mineral density measurements were compared with that of normal Saudi subjects matched for age and sex. The BMD was significantly low at diagnosis and showed significant improvement after therapy. The improvement of bone density in response to therapy was more evident in lumbar spine than in femoral neck bone.

CONCLUSION

Our results showed that BMD in adult Saudi female patients with osteomalacia was markedly affected probably due to specific constitutional and environmental factors (inadequate exercise, lack of sun exposure and lack of intake of milk and dairy products). In addition, lumbar BMD and serum calcium appeared to be better markers to monitor therapy. Bone scan helped in demonstrating disease activity, the presence of pseudofractures.

Disorders of phosphate metabolism--pathomechanisms and management of hypophosphataemic disorders

Hypophosphataemia does not necessarily indicate phosphate (Pi) depletion. In acute emergencies such as septicaemia, alkalosis or re-feeding, hypophosphataemia may result from redistribution of Pi from the extracellular to the intracellular space. Hypophosphataemia from true Pi depletion gives rise to skeletal (osteomalacia) and extraskeletal (myopathy, cardiomyopathy) disorders. It is practically never the result of diminished nutritional intake. The most severe syndromes of Pi depletion result from diminished tubular Pi re-absorption and renal Pi wasting. In the differential diagnosis mainly four conditions have to be considered: (i) tumour-associated osteomalacia, (ii) X-linked hypophosphataemia (XLH), (iii) autosomal dominant hypophosphataemia, and (iv) hypercalcaemic renal phosphate wasting. Recent molecular insight has put fibroblast growth factor (FGF-23) into the centre of pathophysiological considerations because of (i) overproduction (tumour-associated osteomalacia) or (ii) hypothetically, accumulation resulting from mutations causing resistance to processing or degradation (autosomal dominant hypophosphataemia) or (iii) loss-of-function of a protease (PHEX) interfering with FGF-23 breakdown (XLH). In oncogenic osteomalacia the treatment of choice is resection of the tumour. Recently, pharmacological treatment has also become possible, i.e. administration of octreotide. XLH and autosomal dominant hypophosphataemia must be managed by oral administration of phosphate and calcitriol. In patients with gastrointestinal intolerance to phosphate or with severely symptomatic bone disease, prolonged intravenous administration of Pi is necessary.