An Uncommon Case of Bilateral Pathologic Hip Fractures: Antiviral Drug-induced Osteomalacia in a Patient with Hepatitis B

Clinical management of hypophosphatemic osteomalacia induced by adefovir and tenofovir: Insights from a case report

RATIONALE

Hypophosphatemic osteomalacia is a rare chronic metabolic bone disease characterized by low serum phosphate levels owing to genetic or acquired causes. This article presents a case report of the clinical management, challenges encountered, and prognosis of secondary hypophosphatemic osteomalacia induced by defovir and tenofovir.

PATIENT CONCERNS

A 55-year-old male patient had been experiencing persistent dull chest pain and fatigue for more than a year. The patient had chronic hepatitis B infection for over 10 years, with regular use of adefovir dipivoxil capsules for more than 10 years. Five months before admission, the patient was switched to tenofovir alafenamide fumarate tablets.

DIAGNOSES

After obtaining clinical manifestations, medical history, and examination results, tumor-induced osteomalacia was excluded, and the final diagnosis was drug-induced hypophosphatemic osteomalacia.

INTERVENTIONS

Adefovir dipivoxil and tenofovir alafenamide were discontinued, and the patient was switched to entecavir disintegration tablets for antiviral therapy. He was advised to follow a high-phosphate diet, receive phosphorus supplementation and calcitriol capsules to promote calcium absorption, obtain moderate sun exposure, and take measures to prevent falls and fractures.

OUTCOMES

Serum phosphate levels showed a gradual upward trend, with the most recent measurement being 0.85 mmol/L. The bone density gradually improved and reached normal levels in the most recent assessment. The symptoms of fatigue and chest pain were resolved.

LESSONS

Accurate diagnosis requires a combination of clinical presentation, medical history, biochemical and radiological findings, and, if available, measurement of fibroblast growth factor 23 (FGF 23). The role of national, provincial, or regional centers for rare diseases is crucial for conducting unconventional tests and providing access to rare medications.

Impact of Hepatitis B virus infection on postoperative complications and length of stay in elderly patients with hip fracture: A retrospective cohort study

BACKGROUND

Osteoporosis and subsequent fractures are common in the chronic hepatitis B (CHB) population, especially in the elderly. This study investigated the effects of hepatitis B virus (HBV) infection on postoperative outcomes following hip fracture surgery.

METHODS

The study identified elderly patients who underwent hip fracture surgery at three academic tertiary care centres between January 2014 and December 2020. Propensity score matching was performed to compare the outcomes of 1,046 patients with HBV infection to 1,046 controls.

RESULTS

The seroprevalence of HBV among elderly patients undergoing hip surgery was 4.94%. The HBV cohort had significantly higher rates of medical complications (28.1 vs. 22.7%, p = 0.005), surgical complications (14.0 vs. 9.7%, p = 0.003), and unplanned readmissions (18.9 vs. 14.5%, p = 0.03) within 90 days of surgery. Patients with HBV infection were more likely to have increased length of stay (6.2 vs. 5.9 days, p = 0.009) and in-hospital charges (¥52,231 vs. ¥49,832, p < 0.00001). Multivariate logistic regression suggested that liver fibrosis and thrombocytopenia were independent risk factors for major complications and extended LOS.

CONCLUSION

Patients with HBV infection were at greater risk of adverse postoperative outcomes. We should pay more attention to the considerable burden of perioperative management of CHB patients. Due to the high proportion of undiagnosed patients in the Chinese elderly population, universal HBV screening should be considered preoperatively.

Total hip arthroplasty for treatment of femoral neck fracture due to hypophosphatemic osteomalacia: a retrospective case series with mean follow-up of five years

BACKGROUND

To retrospectively characterize the clinical characteristics and efficacy of total hip arthroplasty and the important factors needing attention in hypophosphatemic osteomalacia (HO) patients with hip involvement.

PATIENTS AND METHODS

We performed a review of seven patients (two women and five men) referred to our clinic with a final diagnosis of HO who received total hip arthroplasty between 2010 and 2018. Five patients (Group 1) received proper medical management with or without aetiologic therapy, while the other two patients (Group 2) did not receive due to misdiagnosis. The mean follow-up duration was 5.1 ± 2.0 years.

RESULTS

The patients in Group 1 had significant relief of pain and improved laboratory results. The mean Harris Hip Score of Group 1 increased from 44.2 ± 6.0 to 94.0 ± 3.0, and the mean VAS score decreased from 8.8 ± 0.4 to 1.8 ± 0.7. However, the progressive extensive pain score in Group 2 had no obvious improvement, with the Harris Hip Score increasing from 45.5 ± 0.5 to 60 ± 28.0 and the VAS score decreasing from 9.0 ± 1.0 to 6.5 ± 2.5.

CONCLUSION

THA appears to be an effective method for hip arthritis or joint deformities resulting from hypophosphatemic osteomalacia. A satisfactory outcome of the surgery depends on the early etiological identification, the treatment of hypophosphatemia, a careful operation, and the operative strategies, as well as proper medical treatment.

Fanconi syndrome induced by adefovir dipivoxil: a case report and clinical review

More than 150 cases of Fanconi syndrome (FS) or hypophosphatemia osteomalacia induced by low-dose adefovir dipivoxil (ADV) have been reported since 2002, when ADV was introduced for the long-term treatment of hepatitis B virus (HBV) infection. Because the life expectancy of HBV-infected individuals has increased, the adverse effects of long-term treatment with antiviral therapies are increasingly observed, and nephrotoxicity is one of the most severe adverse effects of ADV. Therefore, the number of cases may be far higher than reported. Moreover, ADV-induced FS is often misdiagnosed or diagnosed long after it first develops. ADV-induced FS may seriously decrease patient quality of life and lead to bone fractures and even disability. Although progress has been made in the identification of biomarkers and treatments, few systematic clinical guidelines or clinical reviews for FS induced by ADV have been reported. In this study, we highlighted the recent progress toward understanding of FS induced by ADV, described a clinical case, and summarized the primary characteristics and laboratory findings of this disease.

Bilateral sub-trochanteric femur fragility fractures in a patient on antiretroviral therapy: a case based discussion and review of literature

BACKGROUND

The burden of HIV/AIDS is ever increasing, affecting populations all over the world. Along with the disease, its effects and consequences on bone health are also on a rise. A commonly used drug in managing HIV, "Tenofovir" has been shown to affect bone health, specifically on prolonged usage. Osteomalacia and osteoporosis secondary to drug induced Fanconi syndrome and the disease itself, could lead to pathological/fragility fractures with trivial trauma.

CASE DESCRIPTION

A 45 year old female on antiretroviral drugs (ART) for HIV, presented with right hip pain and inability to bear weight. She has had similar symptoms previously in the left hip which resolved after 6 weeks of limited weight bearing. Anteroposterior and lateral radiographs of pelvis with hips showed bilateral sub-trochanteric fractures; healed on the left side and displaced on the right side. The patient was managed with cessation of tenofovir and right side proximal femoral nail anti-rotation (PFNA). Patient was lost to follow up but had started to ambulate independently with a cane, by the end of 6 weeks, before she succumbed to systemic complications.

CONCLUSION

Patients receiving antiretrovirals especially tenofovir should be regularly investigated for their renal impairment and bone health. Fixation of pathological fractures and early mobilization are important to prevent prolonged bed immobilization and associated complications in these immunocompromised patients.