Aseptic necrosis in HIV seropositive patients: a possible etiologic role for megestrol acetate

Severe bilateral knee osteonecrosis in a young man with human immunodeficiency virus

We present a young man with a background Human Immunodeficiency virus (HIV) who presented with bilateral knee pain and reduced mobility. Subsequent imaging of the knees demonstrated florid osteonecrosis (ON), which was managed conservatively. ON is seen more commonly in HIV patients than the general population, however the underlying mechanism for this association is remains unclear. An awareness of this disease is imperative to appropriately identify and manage such patients.

Glucocorticoids in osteonecrosis of the femoral head: a new understanding of the mechanisms of action

Glucocorticoid (GC) usage is the most common non-traumatic cause of osteonecrosis of the femoral head (ON). Despite the strong association of GC with ON, the underlying mechanisms have been unclear. Investigators have proposed both direct and indirect effects of GC on cells. Indirect and direct mechanisms remain intimately related and often result in positive feedback loops to potentiate the disease processes. However, the direct effects, in particular apoptosis, have recently been shown to be increasingly important. Suppression of osteoblast and osteoclast precursor production, increased apoptosis of osteoblasts and osteocytes, prolongation of the lifespan of osteoclasts and apoptosis of endothelial cells (EC) are all direct effects of GC usage. Elevated blood pressure through several pathways may raise the risk of clot formation. High-dose GC also decreases tissue plasminogen activator activity (t-PA) and increases plasma plasminogen activator inhibitor-1 (PAI-1) antigen levels increasing the procoagulant potential of GC. Inhibited angiogenesis, altered bone repair and nitric oxide metabolism can also result. Also, GC treatment modulates other vasoactive mediators such as endothelin-1, noradrenalin and bradykinin. Thus, GCs act as a regulator of local blood flow by modulating vascular responsiveness to vasoactive substances. Vasoconstriction induced in intraosseous femoral head arteries causes femoral head ischemia. GCs also cause ischemia through increased intraosseous pressure, which subsequently decreases the blood flow to the femoral head by apoptosis of ECs as well as elevating the level of adipogenesis and fat hypertrophy in the bone marrow. It is difficult to predict which patients receiving a specific dose of GC will develop ON, indicating individual differences in steroid sensitivity and the potential of additional mechanisms. The textbook model of ON is a multiple hit theory in which, with a greater number of risk factors, the risk of ON increases. While more effort is needed to better comprehend the role of GC in ON, newer data on GC action upon the endothelial cell and the regional endothelial bed dysfunction theory sheds new light on particular GC mechanisms. Better understanding of GC pathomechanisms can lead to better treatment options.

Thrombophilia in human immunodeficiency virus-infected patients with osteonecrosis: Is there a real connection? The first case-control study

Several reports have described an increased incidence of osteonecrosis in human immunodeficiency virus-infected patients (HIV+), but the cause has not been established. The association between thrombophilia and osteonecrosis in HIV+ was studied. A case-control study in HIV+, 19 cases and 38 controls, was designed. Magnetic resonance imaging was made in both groups to confirm or exclude hip osteonecrosis. The extensive tests of thrombophilia were measured, and the clinical data were recorded, nadir of CD4(+) cell count and well-known risk factors for osteonecrosis. Thrombophilia has been frequently found both in patients with and without osteonecrosis (thrombophilia, 68.4% vs 60.5%), but no specific thrombophilia tests were significantly associated with osteonecrosis. A low nadir of CD4(+) (<60 cells/microL) and corticoid use were significantly (P < .05) associated with osteonecrosis. In multivariate analysis, only nadir of CD4(+) <60 cells/microL remained a predictor of osteonecrosis (odds ratio = 7.33; 95% confidence interval, 1.80-29.82, P = .005). Thrombophilia might have a limited role in the development of osteonecrosis in HIV+. Nadir of CD4(+) <60 cells/microL and corticoid use were main factors.

Avascular necrosis of the femoral head: vascular hypotheses

Vascular hypotheses provide compelling pathogenic mechanisms for the etiology of avascular necrosis of the femoral head (ANFH). A decrease in local blood flow of the femoral head has been postulated to be the cause of the disease. Several studies in human and animal models of ANFH have shown microvascular thrombosis. Endothelial cell damage could be followed by abnormal blood coagulation and thrombus formation with any resulting degeneration distal to the site of vascular occlusion. Other studies suggest that thrombophilia, particularly impaired fibrinolysis, plays a potential role in thrombus formation in ANFH. Reduction in shear stress due to decreased blood flow could lead to apoptosis of endothelial cells, which can ultimately contribute to plaque erosion and thrombus formation. Dysregulation of endothelial cell activating factors and stimulators of angiogenesis or repair processes could also affect the progression and outcome of ANFH. Likewise, regional endothelium dysfunction (RED), referred to as a potential defect in endothelial cells located in the feeding vessels of the femoral head itself, may also have a crucial role in the pathogenesis of ANFH. Molecular gene analysis of regional endothelial cells could also help to determine potential pathways important in the pathogenesis of ANFH.

The incidence and natural history of osteonecrosis in HIV-infected adults

BACKGROUND

Osteonecrosis is increasingly recognized as a debilitating complication of human immunodeficiency virus (HIV) infection, but the natural history has not been well described. We previously documented a high prevalence (4.4%) of magnetic resonance imaging (MRI)-documented osteonecrosis of the hip in a cohort of 339 asymptomatic HIV-infected patients. The present study was designed to determine the incidence of newly diagnosed osteonecrosis in this cohort and to describe the natural history of osteonecrosis in HIV-infected patients.

METHODS

Asymptomatic HIV-infected patients with a previous hip MRI negative for osteonecrosis underwent follow-up MRI. Patients with asymptomatic or symptomatic osteonecrosis were enrolled in a natural history study, which included serial MRIs and a physiotherapy follow-up.

RESULTS

Two hundred thirty-nine patients underwent a second MRI a median of 23 months after the initial MRI. Osteonecrosis of the femoral head was diagnosed in 3 patients (incidence, 0.65 cases per 100 person-years). During the period of January 1999 through April 2006, symptomatic hip osteonecrosis developed in 13 clinic patients (incidence, 0.26 cases per 100 person-years). Among 22 patients enrolled with symptomatic hip osteonecrosis, 18 had bilateral involvement of the femoral heads, and 7 had osteonecrosis involving other bones. Two (11%) of 18 asymptomatic patients and 13 (59%) of 22 symptomatic patients underwent total hip replacement. The percentage of involvement of the weight-bearing surface of the femoral head and the rate of progression to total hip replacement was significantly greater (P<.001) in symptomatic patients than in asymptomatic patients.

CONCLUSIONS

HIV-infected patients are at approximately 100-fold greater risk of developing osteonecrosis than the general population. Disease progression is slower in asymptomatic patients than in symptomatic patients. Given the high frequency of total hip replacement in symptomatic patients, studies to assess preventive and treatment strategies are essential.

Contrast-Enhanced MRI and Micro-CT Adopted for Evaluation of a Lipid-Lowering and Anticoagulant Herbal Epimedium-Derived Phytoestrogenic Extract for Prevention of Steroid-Associated Osteonecrosis

We developed an alternative steroid-associated osteonecrosis (ON) rabbit model using a combination of a single injection of low-dose lipopolysaccharide (LPS) and three subsequent injections of pulsed high-dose methylprednisolone (MPS).The usefulness of this experimental ON model was evaluated using both conventional and advanced bio-imaging techniques, including contrast-enhanced dynamic MRI and a high-resolution micro-CT. Details on establishment of methodology are described, which were adopted into an efficacy study on a herbal Epimedium-derived phytoestrogenic extract (HEPE) developed for prevention of steroid-associated ON using an established rabbit model. The underlying mechanisms of HEPE for prevention of steroid-associated ON were found to be associated with inhibition of both intravascular thrombosis and extravascular bone marrow lipid deposition, the two known mechanistic pathways in pathogenesis of ON. Our experimental results provide for potential clinical trials or applications of HEPE in the prevention of ON among hig-hrisk patients undergoing steroid treatment.

Nontraumatic osteonecrosis of the femoral head: ten years later

The etiology of osteonecrosis of the hip may have a genetic basis. The interaction between certain risk factors and a genetic predisposition may determine whether this disease will develop in a particular individual. The rationale for use of joint-sparing procedures in the treatment of this disease is based on radiographic measurements and findings with other imaging modalities. Early diagnosis and intervention prior to collapse of the femoral head is key to a successful outcome of joint-preserving procedures. The results of joint-preserving procedures are less satisfactory than the results of total hip arthroplasty for femoral heads that have already collapsed. New pharmacological measures as well as the use of growth and differentiation factors for the prevention and treatment of this disease may eventually alter our treatment approach, but it is necessary to await results of clinical research with long-term follow-up of these patients.

Symptomatic bone disorders in HIV-infected patients: incidence in the Aquitaine cohort (1999-2002)

BACKGROUND

Since the inception of highly active antiretroviral therapy (HAART), mortality among HIV-infected patients has decreased, but this has been accompanied by the appearance of several complications.

OBJECTIVES

To estimate the incidence of symptomatic bone disorders in HIV-infected patients of the Aquitaine cohort (from south-west France) for the period 1999-2002, and to describe cases.

METHODS

We retrospectively studied the records of 2700 patients of the Aquitaine cohort, which was derived from a hospital-based surveillance system of HIV infection in France. All cases of symptomatic bone disorders diagnosed from 1 January 1999 to 30 June 2002 were reviewed.

RESULTS

Fourteen cases of bone disorders were diagnosed, eight cases of aseptic osteonecrosis and six cases of severe osteoporosis, representing incidences of 0.3/1000 patient-years [95% confidence interval (CI): 0.14-0.62] and 0.22/1000 patient-years (95% CI: 0.09-0.52), respectively. All patients with aseptic osteonecrosis were male, while all but one with osteoporosis were female. The ages of patients ranged from 36 to 54 years for osteonecrosis and from 39 to 50 for severe osteoporosis. At the time of clinical diagnosis, all patients were treated with nucleoside reverse transcriptase inhibitors (duration of treatment ranging from 19 to 123 months for osteonecrosis and from 46 to 132 months for severe osteoporosis). Ten patients were treated with nonnucleoside reverse transcriptase inhibitors [duration of treatment ranging from 6 to 31 months for osteonecrosis (n=6) and from 4 to 29 months for severe osteoporosis (n=4)]. Thirteen patients were treated with protease inhibitors [duration of treatment ranging from 12 to 62 months for osteonecrosis (n=8) and from 3 to 44 months for severe osteoporosis (n=5)]. All osteonecrosis and five osteoporosis patients had at least one known risk factor or comorbidity associated with the bone disorder occurrence.

CONCLUSIONS

In our study, the aetiology of clinical bone disorders seemed to be multifactorial, as almost all the patients had at least one possible risk factor in addition to HAART exposure.

Osteoporosis associated with megestrol acetate

Megestrol acetate is a progestational agent for treatment of metastatic breast cancer and endometrial cancer. Megestrol has also been used as an appetite stimulant for patients with human immunodeficiency virus and malignancy who experience cachexia and wasting; also, megestrol can be beneficial in relieving hot flashes in women and men. Megestrol has been shown to have a glucocorticoidlike effect and has been associated with substantial suppression of plasma estradiol levels. We describe 2 patients who recently presented to our Metabolic Bone Disease Clinic with severe osteoporosis complicated by multiple vertebral fractures experienced while the patients were receiving high-dose megestrol therapy. The patients had evidence of adrenal axis suppression but recovered fully after megestrol was discontinued. We speculate that megestrol was an important factor in the development of osteoporosis and subsequent fractures. Further study is warranted to clarify the relationship between megestrol and its potential for adversely affecting the skeleton.

Osteonecrosis in six HIV-infected patients receiving highly active antiretroviral therapy

OBJECTIVE

To report 6 cases of osteonecrosis in HIV-infected patients treated with highly active antiretroviral therapy (HAART) and compare the observed risk factors with those of published cases.

CASE SUMMARIES

Osteonecrosis was diagnosed between 1999 and 2002 in 6 of 417 HIV-infected patients in our department of infectious diseases. At the time of diagnosis, mean patient age was 42 years, and 5 patients had developed AIDS. Mean CD4+ lymphocyte count was 563.5 cells/mm(3) and viral load was undetectable (<50 copies/mL) in 5 patients. The patients' mean body mass index was 22.5 kg/m(2). Four had lipodystrophy. All were receiving HAART, including a protease inhibitor in 4 patients; the remaining 2 patients had a history of protease inhibitor treatment. Median time from the first antiretroviral therapy to osteonecrosis diagnosis was 46.5 months. Established risk factors were the use of corticosteroids in 2 patients and dyslipidemia in all patients. All of the patients developed pain and functional impotence of the hip or ankle joints. Osteonecrosis of the hip was bilateral in 4 cases. Three patients required surgical intervention, all of whom had favorable outcomes.

DISCUSSION

HIV-infected patients are at a higher risk for the development of osteonecrosis and are more likely to be exposed to predisposing factors to its development. The HAART implication as a predisposing factor remains controversial.

CONCLUSIONS

The pathogenesis of osteonecrosis in HIV-infected individuals may be multifactorial; the reasonable approach for clinicians consists of treating concomitant predisposing conditions that might further cause osteonecrosis.

Antiretroviral treatment and osteonecrosis in patients of the Swiss HIV Cohort Study: a nested case-control study

We examined risk factors for avascular bone necrosis (AVN) particularly focusing o the question of whether antiretroviral treatment (ART) is associated with the emergence of osteonecrosis. After 11 years of following the entire cohort, 26 patients were found to have AVN. Compared to 260 concurrent HIV-infected controls, at risk when cases were diagnosed, patients with AVN had lower CD4 cell count nadirs (median 86.5 versus 137.5 cells/microl, p = 0.010) and suffered significantly more often from Pneumocystis pneumonia, cerebral toxoplasmosis, CMV retinitis, and atypical mycobacteriosis and had a significantly higher body mass index than controls. Duration of ART before AVN was not significantly different between cases and controls (2.92 versus 2.17 years, p = 0.30). In conclusion, AVN could not be attributed to time on antiretroviral treatment, but patients with AVN had histories of more severe immunosuppression and a higher body mass index than controls.

Osteonecrosis of the hip (Legg-Calvé-Perthes disease) in human immunodeficiency virus-infected children

OBJECTIVE

Osteonecrosis of the hip has been reported in human immunodeficiency virus (HIV)-infected adults; whether this is related to HIV infection or its treatment is unknown. There has been 1 report of osteonecrosis among HIV-infected children. Specifically, avascular necrosis of the hip consistent with Legg-Calvé-Perthes disease (LCPD) was reported in 3 HIV-infected children with AIDS from Spain in 1992. We evaluated the prevalence and incidence of LCPD, the pediatric equivalent of adult osteonecrosis of the hip, in HIV-infected children participating in a prospective cohort study of long-term outcomes in HIV-infected and HIV-exposed children-Pediatric AIDS Clinical Trials Group (PACTG) protocol 219.

METHODS

PACTG 219 enrolled 2014 HIV-infected and 849 HIV-exposed, uninfected children between April 1993 and September 2000. Children had periodic examinations with collection of clinical and laboratory data. The database was reviewed for reports of LCPD and other bone disorders. A prevalent case was defined as LCPD diagnosis preceding PACTG 219 enrollment and an incident case had to have occurred between enrollment and September 2000. A case-control study (matching on age, gender, and race/ethnicity, which are known to be associated with risk of LCPD and HIV infection status) was performed to investigate factors possibly associated with LCPD.

RESULTS

Six cases of LCPD (4 prevalent cases reported at study entry; 2 diagnosed during 5837 person-years of follow-up) were observed; LCPD was seen only in children with perinatal HIV infection. LCPD prevalence was 199 per 100 000 compared with an estimated general pediatric population prevalence of 23 per 100 000. Based on age-adjusted general population rates, the expected number of prevalent cases at PACTG 219 study entry would have been 0.44; the age-adjusted LCPD prevalence rate ratio was 9.0 (95% confidence interval [CI]: 8.3-9.7) for HIV-infected children compared with the general population. LCPD incidence was 34 per 100 000 person-years (95% CI: 0.42-124) compared with the estimated general population incidence of 6 per 100 000 person-years (95% CI: 5-7). Based on age-adjusted general population rates, the expected incidence of LCPD in PACTG 219 would have been 0.42; the age-adjusted relative risk of LCPD in HIV-infected PACTG 219 children was 4.8 (95% CI: 0.56-10.4). No cases were observed in uninfected children during 1919 person-years of follow-up on PACTG 219; the age-adjusted expected number of cases was 0.09. Median onset age was 7 years; 67% were of Hispanic or black race/ethnicity and 33% were female. Four of the 6 LCPD cases had received antiretroviral therapy before diagnosis; treatment was primarily with nucleoside reverse transcriptase inhibitors, and 2 had received protease inhibitors. Three of the LCPD cases had corticosteroid exposure before the diagnosis, but only 1 child had systemic exposure and the remaining 2 had topical exposure exclusively. In the case-control study, antiretroviral and corticosteroid therapy, CD4 cell percentage, birth weight, height for age and gender percentile, and triglyceride levels were not significantly associated with LCPD. However, the case-control study had limited power to evaluate possible associations.

CONCLUSION

Similar to HIV-infected adults, children with perinatal HIV infection have an increased risk for osteonecrosis of the hip, and clinicians should be alert to this diagnosis when HIV-infected children present with limp or hip pain. Whether LCPD is attributable to HIV infection itself, HIV-associated complications that could predispose to hypercoagulopathy, HIV-related therapies, or to the growth abnormalities in HIV-infected children is unknown and deserves additional evaluation.

The role of exercise in the prevention and treatment of wasting in acquired immune deficiency syndrome

Involuntary weight loss with lean tissue depletion is a serious and AIDS-defining complication of HIV infection. This article explores definitions of AIDS wasting syndrome (AWS), its etiology, methods of assessing body composition, and pharmacological treatments. Recent research literature on the role of exercise in the prevention and treatment of AWS is reviewed. Included are studies of the safety of exercise, the effects of exercise on the immune system, and the effects of exercise on weight gain and body composition as well as studies of exercise in combination with medications and other interventions. Implications for clinical practice are discussed.

Osteonecrosis and highly active antiretroviral therapy during HIV infection: report of a series and literature review

Osteonecrosis has shown an increased incidence in HIV-infected patients during the last few years, and has been looked as a side effect of highly active antiretroviral therapy, possibly related to hyperlipidemia. Five cases of osteonecrosis were observed among over 1300 patients with HIV disease. According to our experience, novel antiretroviral regimens do not represent a constant risk factor for avascular necrosis of bone during HIV infection.