Postpartum spinal wedge fractures in a 27-year-old epileptic anorectic woman

Pregnancy and Lactation-Associated Osteoporosis: Bone Histomorphometric Analysis and Response to Treatment with Zoledronic Acid

Pregnancy and lactation-associated osteoporosis (PAO) is a rare condition with little known pathophysiology. Most cases are diagnosed in the third trimester of pregnancy or in the first weeks postpartum, particularly in first pregnancies. Vertebral fractures are most commonly observed and characterised by prolonged severe pain, functional limitations and a loss of height. Measurements of bone mineral density and biochemical markers of bone remodelling are the clinical methods most commonly used for the management of these patients. However, a bone biopsy with histomorphometric analysis has been considered to be the gold-standard. Few studies have evaluated the histomorphometry in patients with this clinical condition and none of them performed the procedure at the beginning of the clinical assessment. In this study, we report a case of PAO in a 31-year-old postpartum patient who had undergone a twin pregnancy. We describe the clinical, laboratory tests and imaging features. Bone histomorphometry showed a high resorption rate and excellent evolution after 1 year of treatment with intravenous zoledronic acid. Our data suggest that osteoclastogenesis plays a central role in the pathophysiological processes of this disease.

Bisphosphonates in pregnancy and lactation-associated osteoporosis

INTRODUCTION

Pregnancy and lactation-associated osteoporosis (PLO) is an uncommon condition characterized by the occurrence of fracture(s) during late pregnancy or the puerperium. The aetiology is uncertain, and its management and natural history poorly defined.

METHODS

We report a series of 11 women with PLO seen at our institution over the past 20 years, with follow-up ranging from 1 to 19 years.

RESULTS

Ten women presented with painful low-trauma vertebral fractures, at a median of 1 month postpartum. In nine cases the fractures were multiple (median: 3, range: 2-5). At least one recognised risk factor for osteoporosis (low body weight, smoking history, family history of osteoporosis/fracture, vitamin D insufficiency) was present in nine patients. Bone density was in the osteoporotic range at the spine (mean T score: -2.8), with less marked reduction at the proximal femur (mean T score: -1.9). Nine patients received bisphosphonate treatment, for a median duration of 24 months. In the five women who received a bisphosphonate within 1 year of presentation, spinal bone density increased by 23% over baseline values after 2 years of treatment (p=0.0014). Of the 5 women who had subsequent pregnancies, one, who had declined bisphosphonate therapy after the initial presentation, sustained a fracture in the postpartum period. Two patients (both of whom were followed for at least 10 years) sustained fractures outside of pregnancy.

CONCLUSIONS

PLO is therefore associated with significant morbidity, a high prevalence of recognized risk factors for osteoporosis and a risk of recurrence in subsequent pregnancies. Bisphosphonate therapy administered soon after presentation substantially increases spinal bone density in patients with PLO.

Bone in the pregnant mother and newborn at birth

BACKGROUND

Changes in maternal bone during pregnancy may affect fetal bone mineralization.

ISSUES

The biphasic changes in maternal bone histology (temporary loss of cancellous bone in early pregnancy restored by term gestation) are consistent with corresponding blood biochemistry changes; increased bone resorption markers in the first trimester, while bone formation markers increased in the last trimester. Postpartum bone mineral density (BMD) by DEXA is increased at cortical bone and decreased at trabecular bone sites compared with prepregnancy values. The mean reduction of spine BMD is 3.5% from prepregnancy to immediate postpartum. Neonatal bone mineral content (BMC) is different by season of birth, low weight relative to gestation, and having a diabetic mother. Lower total body BMC and high bone resorption marker in winter vs. summer-born newborns was related to low vitamin D, indicating alterations of fetal bone metabolism by maternal D deficiency. Lower BMC and decreased bone formation marker in infants born small for gestational age than those born appropriate for gestation may relate to reduced transplacental mineral transfer. Low BMC in infants of diabetic mother was correlated inversely with poor control of maternal diabetes during early pregnancy.

CONCLUSIONS

During pregnancy, maternal bone mineral metabolism are changed, and influences on fetal bone mineralization occur in utero.

Effect of menatetrenone (vitamin K2) treatment on bone loss in patients with anorexia nervosa

Osteoporosis is a common complication of anorexia nervosa (AN). Although weight recovery and resumption of menses are important goals in AN treatment, they are often achieved only after a prolonged period of recovery. Therefore, it becomes important to find therapies with the potential to prevent further decreases in bone mineral density (BMD). We conducted a non-randomized study of the effects of menatetrenone (vitamin K2) on bone loss in patients with AN. Lumbar BMD was longitudinally measured by Dual Energy X-ray Absorptiometry (DXA) in 10 patients with AN who chose to receive menatetrenone treatment (MED+ group) and 11 patients who did not (MED- group). During the mean 0.9-year follow-up period, the BMD of the lumbar vertebrae of the MED+ group decreased significantly less than that of the MED- group (-2.8% and -6.9%, respectively). Among bone metabolism markers, gamma-carboxyglutamic acid osteocalcin significantly increased (128.6% and 28.3%, respectively) and urine deoxypyridinoline significantly decreased (-44.5% and -13.7%, respectively) more in the MED+ group than in the MED- group. These differences in BMD and bone metabolism markers may be attributable to menatetrenone treatment. The results suggest that menatetrenone may be beneficial in the prevention of bone loss in patients with AN. Randomized placebo-controlled studies are needed to confirm these findings.

Osteoporosis in pregnancy

Osteoporosis has long been described in pregnant women who developed vertebral fractures in the last trimester or shortly after delivery without underlying disorders. However, this condition appears to be relatively rare and the clinical features, associated metabolic abnormalities and a pathological mechanism have not been fully established. This paper reviews available data on osteoporosis and pregnancy and briefly discusses the relationship between pregnancy and bone mass, calcium homeostasis, systemic skeletal hormones and local factors to help explain the pathophysiology of this unique disorder.

Osteoporotic stress fractures in anorexia nervosa: etiology, diagnosis, and review of four cases

Anorexia nervosa (AN) is a chronic eating disorder characterized by self-imposed semi-starvation that affects 1% of adolescent females. AN predisposes to osteoporosis through hypothalamic dysfunction, which may lead to elevated cortisol as well as diminished estrogen and progesterone. The osteoporosis associated with AN affects both trabecular and cortical bone and increases the risk of osseous fracture. Fractures in this population may go unrecognized, because planar X-rays may be nondiagnostic for 6 weeks or more. Four women with AN ranging in ages from 22 to 34 with skeletal pain and nondiagnostic roentgenographs are described. Stress fractures in these patients were subsequently identified by bone scan. Although moderate exercise in patients with AN-associated osteoporosis may be beneficial, strenuous exercise can be detrimental, with its potential risk of stress fractures and exacerbation of the underlying neurohormonal abnormalities. This risk for fracture may persist well after improvement in the patient's AN.

Bone metabolism and osteopenia in eating disorders

Bone loss is a potentially debilitating condition in women with eating disorders. Complications may include failure to achieve peak bone mass, increased risk of premature fractures, and inability to reach the height potential. We therefore conducted a comprehensive evaluation of 58 women with anorexia nervosa (AN), bulimia (BUL) and anorexia/bulimia (AB), comparing bone mineral density (BMD) to physical parameters, biochemical indices, and markers for bone formation and resorption. BMDs were significantly lower in patients with AN than in those with AB and BUL, and overt osteopenia was uncommon in AB and BUL. Hypercortisolism was the best laboratory marker to assess the risk of osteopenia in patients with AN. However, there were no associated changes in bone formation or resorption parameters. No direct correlation was found between BMD and body mass index, estrogen deficiency, tubular reabsorption of phosphorus, serum vitamin D, PTH, BGP, or alkaline phosphatase levels. Although the prognosis for complete recovery to normal BMD is poor, treatment of the underlying depressive disorder, improvement in nutrition with increased weight, and spontaneous resumption of menses are associated with restoring bone health.

Effects of weight gain and resumption of menses on reduced bone density in patients with anorexia nervosa

The bone mineral density (BMD) of the lumbar vertebrae (L2-L4) and of the whole body were measured in cross-sectional and longitudinal studies in female patients with eating disorders, using dual photon absorptiometry before and after weight gain with or without resumption of menses. In the cross-sectional study, the low-body-weight anorectic patients, with or without bulimia nervosa, were found to have lower BMD of the lumbar vertebrae associated with severe weight loss, low physical activity, and earlier onset and longer duration of amenorrhea. In the longitudinal study, 11 patients attained subnormal body weight (70%SBW < or = approximately < 85% SBW), 10 patients attained normal body weight (> or = 85%SBW, 6 patients of them resumed regular menses) after treatment. The BMD of the lumbar vertebrae was found to increase with weight gain, but not to the control level. The BMD was further increased with the resumption of menses in patients with anorexia nervosa. These results suggest that resumption of menses, in addition to weight gain, is essential to normalize reduced bone mineral density.

Reduced bone density and major hormones regulating calcium metabolism in anorexia nervosa

Bone density of lumbar vertebrae (L2 to L4) and the whole body in 29 patients with anorexia nervosa were measured by dual photon absorptiometry, and the results were compared with those of 10 age-matched normal controls. The patients had significantly lower bone mineral density (BMD) in L3 and L2-4 than controls. However, there was no difference in whole-body BMD. L3 and L2-4 BMD was positively correlated with body weight and was negatively correlated with duration of illness and amenorrhea. Patients who had been more active 6 months before the time of the study had significantly higher L3 BMD than the less active patients. Most patients had an abnormally low serum estrogen level, whereas the mean serum levels of thyroid hormone (T3, T4), cortisol, calcitonin, parathyroid hormone and vitamin D were within the normal range. No correlation was found between L3 or L2-4 BMD and the levels of these hormones. These results suggest that severe weight loss, low physical activity, longer duration of amenorrhea and deficiency of estrogen contribute to bone loss in patients with anorexia nervosa, whereas calcium-regulating hormones such as parathyroid hormone, calcitonin and vitamin D are unlikely to be a primary contributor to bone loss.

Post-pregnancy osteoporosis associated with hypercalcaemia

A lactating 31-year-old woman who developed four vertebral fractures 1-2 months after the delivery of her first child is described. She was hypercalcaemic (serum calcium up to 2.99 mmol/l), and urinary excretion of both calcium and hydroxyproline (an index of bone resorption) were markedly elevated. Serum levels of parathyroid hormone and 1,25-dihydroxyvitamin D were suppressed, but parathyroid hormone-related peptide was above normal. There was severe axial osteopenia, as assessed by dual-energy X-ray absorptiometry. The biochemical abnormalities were reversed within 2 weeks of weaning, with the exception of the parathyroid hormone-related peptide concentration, which declined more gradually. This appears to be the first description of the abnormalities in calcium metabolism and bone density from early in the course of post-pregnancy osteoporosis and it indicates that this condition is associated with high levels of osteolysis which return to normal after weaning. This rapid reversal of the metabolic abnormalities accounts for the inconclusive nature of previous descriptions of post-pregnancy osteoporosis, in which investigations were more delayed. It also emphasizes the importance of weaning in the management of women presenting with this condition. A possible aetiological role for parathyroid hormone-related peptide is discussed.

Investigation of osteopaenia in anorexia nervosa

Sixty-nine female patients, mean age 27.5 years (range 20-40), with a past or current history of anorexia nervosa (DSM III-R) had spinal trabecular bone density assessed by single energy quantitative CT scan. Current exercise and dietary calcium levels were assessed by detailed questionnaires and categorized. A semi-structured interview was used to record weight, menstruation, exercise and dietary calcium intake histories from early adolescence. Serum sex hormones and total calcium assays were measured. Bone density was significantly lower in the patients compared to 31 controls. Bone density was significantly positively correlated with body mass index, and negatively correlated with illness duration and duration of amenorrhoea. Exercise levels, dietary calcium intake and taking an oestrogen pill did not correlate significantly with bone density. Recovered patients did not have osteopaenia but they had shorter illness histories than non-recovered patients. Management to minimise bone loss should focus on weight gain and resumption of normal menstruation.