Transient hyperphosphatasemia after pediatric liver transplantation

Rare Case of Benign Transient Hyperphosphatasemia in a Complicated Multiorgan Adult Transplant Patient: Case Report and Literature Review

BACKGROUND

Transient hyperphosphatasemia, characterized by isolated highly elevated alkaline phosphatase (ALP) activity in the absence of liver or bone disease, is typically seen in children but rarely in adults. Here we report highly elevated ALP activity in a complicated multiple-organ transplant patient due to benign transient hyperphosphatasemia.

CASE REPORT

A 54-year-old male had a complicated past medical history including a bilateral lung transplant for cystic fibrosis in 2006, colonic resection due to colon cancer in December 2011 and subsequent chemotherapy which ended in June 2022. He also had combined liver and kidney transplant in 2022 at our academic medical center. Post-transplant, he was treated with triple drug immunosuppressant therapy (tacrolimus, mycophenolic acid, and prednisone). Although his alkaline phosphatase (ALP) activity was 83 U/L, it continued to increase three months after combined liver and kidney transplant even though other liver enzymes were mildly elevated but total bilirubin remained within their reference ranges. Flecainide was discontinued but his ALP remained high, peaking at 5904 U/L. Finally, lansoprazole, ergocalciferol (vitamin D2) and vitamin E supplement were discontinued as nonessential medications, and coincidently ALP activity started to decline. Conclusions After ruling out all possibilities that may cause elevated ALP, we concluded that this is a rare case of benign transient hyperphosphatasemia in an adult transplant recipient.

Transient Hyperphosphatasemia Following Pediatric Kidney Transplant

Introduction Transient hyperphosphatasemia (TH) is a rare benign condition of elevated serum alkaline phosphatase (AP) levels seen in healthy children. TH has been reported to occur in pediatric solid organ transplants, including kidney transplant patients. Little is known about TH in pediatric kidney transplant patients. Objective To evaluate the incidence and natural history of TH in pediatric kidney transplant patients. Methods A retrospective chart review of patients < 18 years of age who underwent kidney transplantation at the University of Pittsburgh Medical Center (UPMC) Children's Hospital of Pittsburgh between 2008 and 2019 was performed to identify patients with TH, defined as an AP level greater than 1,000 IU/L. Exclusion criteria included repeat kidney transplants or kidney transplant as part of a multiorgan transplant. Results One hundred seventy-six patients underwent a solitary kidney transplant, of which 87 were less than 12 years of age. Eleven patients (6.5%) were found to have TH, all of whom were < 12 years of age (12.8%) (median age: 5 years; range: 1 - 11 years). The median AP level prior to transplant was 183 IU/L (range: 104 - 309 IU/L) and the median peak AP was > 2,300 IU/L (range: 1,227 - 4,912 IU/L). The median time from a kidney transplant to the diagnosis of TH was 0.6 years (range: 0.3 to 7.7 years). The median length of time that TH persisted was 0.5 years (range: 0.2 to 0.9 years). The median estimated glomerular filtration rate (GFR) at the time of diagnosis of TH was 84 mL/min/1.73m2 per the bedside Schwartz equation (range: 45 to 152 mL/min/1.73m2). One patient had variable AP levels over nine months prior to resolution; the other 10 patients had a solitary peak of AP prior to resolution. No patient required treatment of elevated AP levels and the TH resolved spontaneously without intervention. No patients had significant abnormalities of markers of metabolic bone disease or were on active vitamin D, calcium, or phosphorus supplements. Two patients reported bone pain, and one patient was found to have avascular necrosis of the hip. Conclusions TH is a relatively common finding following a pediatric kidney transplant in pre-pubertal children less than 12 years of age. It primarily occurs in the first year following a kidney transplant and usually resolves without recurrence within one year of onset.

Transient hyperphosphatasemia after pediatric liver transplantation

BACKGROUND

Transient hyperphosphatasemia (TH), the incidence of which in healthy children is 1.5-2.8%, is associated with a temporary elevation of serum alkaline phosphatase (ALP) without any other liver function test (LFT) abnormalities. Fast α2 band, detected on agarose gel electrophoresis, is known to be a highly sensitive phenomenon in TH. The aim of this study was to elucidate the characteristics of TH after liver transplantation (LT).

METHODS

Five TH patients (6.0%) out of 83 who underwent LT between October 1996 and October 2014, were included in this study. Patient background, duration of TH, peak ALP, time course of ALP and its isoenzyme in TH, other LFT, and imaging results were retrospectively investigated.

RESULTS

Median patient age at the time of peak ALP during TH was 24 months (range, 16-98 months). Mean duration of TH was 111.0 ± 48.0 days. At 6887 IU/L, median ALP was elevated without any other LFT abnormalities. The first α2 band was detected in all patients, and the band disappeared at the same phase of ALP normalization. All of the patients improved without any treatment. The prevalence of TH was significantly higher in the patients after LT than in age-matched healthy children (P < 0.05).

CONCLUSIONS

The detection of fast α2 band in the early phase allows for effective diagnosis of TH after LT, and 3-4 month follow up without treatment is feasible.

Transient hyperphosphatasemia in three pediatric patients treated with cyclosporine

Transient hyperphosphatasemia (TH) is defined as marked elevation of serum alkaline phosphatase (ALP), predominantly its bone or liver isoform. It is a rare condition and is usually detected on laboratory examination in patients without any clinical symptoms. In typical patients with TH, ALP spontaneously normalizes, but no apparent cause of TH has been identified. Some drugs are suspected triggers of TH, but no clear evidence of their association with TH has been shown to date. We herein report three cases of TH in pediatric patients. Two patients were treated with cyclosporine for frequently relapsing nephrotic syndrome, and one was also taking cyclosporine for aplastic anemia. Interestingly, ALP immediately decreased after termination of cyclosporine in two patients, whereas TH lasted 4 months in the one patient who continued cyclosporine. Clearly, cyclosporine is associated with the pathophysiology of TH in children.

Transient benign hyperphophatasemia

BACKGROUND AND AIM

Sometimes, a temporary increase in alkaline phosphatase level is found in healthy infants and toddlers without evidence of liver or bone disease. The condition is customarily termed transient benign hyperphosphatasemia of infancy and early childhood. Most textbooks do not refer to the condition. The aim of the study was to promote broader awareness of transient benign hyperphosphatasemia.

METHODS

We completed a systematic review of the literature using the principles underlying the UK Economic and Social Research Council guidance on the conduct of narrative synthesis and the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement.

RESULTS

The 142 reports retained for analysis included 813 cases (male:female ratio 1.1:1.0): 80 in subjects older than 18 years and 733 in subjects 18 years or younger. The alkaline phosphatase ratio, calculated by dividing the measured level by the upper limit of normal, was ≥5.0 in ≈70% and the duration of the elevation was ≤4 months in 80% of the cases. Transient benign hyperphosphatasemia often followed a benign infection, but available data fail to demonstrate a causal link. The prevalence of transient benign hyperphosphatasemia ranged from 1.1% to 3.5% in infants 2 to 24 months of age.

CONCLUSIONS

Transient benign hyperphosphatasemia is likely the most common cause of hyperphosphatasemia among healthy infants and toddlers. Sometimes it also occurs in older children and adults, indicating that the traditional term transient benign hyperphosphatasemia of infancy and early childhood may not be correct. The elevation in alkaline phosphatase persists for >4 months in ≈20% of the cases. Recognition of this benign condition is crucial to avoid unnecessary investigations.

Isolated increase in serum alkaline phosphatase after liver transplantation: risk factors and outcomes analysis

BACKGROUND

Isolated increase in serum alkaline phosphatase (IISAlp) is frequently observed in liver transplant recipients visiting outpatient clinics. However, whether the increase is associated with risk factors or poor survival is unknown.

METHODS

We retrospectively reviewed the medical records of liver transplant recipients who were followed up during 1999-2009 and had IISAlp 1 month after liver transplantation, which was sustained for at least 6 months. Clinical parameters, survival, and risk factors were analyzed and compared between recipients who survived longer than 6 months after transplantation.

RESULTS

Among 307 liver transplant recipients, 44 had IISAlp. Compared with the control group, the patients with IISAlp were more frequently of the pediatric population, recipients of female donor or living-related partial liver grafts, and found to have biliary-related pretransplant disorders, lower body weight, and shorter warm ischemic time (P < 0.01). One patient with IISAlp died of acute myeloid leukemia during the follow-up period. The mean time to observation of IISAlp after liver transplantation was 6.3 ± 0.8 months. The mean follow-up duration was 5.5 ± 0.2 years. Stepwise multivariate analysis showed that being a pediatric or living-related liver transplant recipient was an independent risk factor for IISAlp, with adjusted hazard ratios (95% confidence interval) of 5.41 (2.59-11.28) and 3.0 (0.98-9.27), respectively.

CONCLUSIONS

Therefore, being a pediatric or living-related liver transplant recipient was an independent risk factor for IISAlp. However, IISAlp was not associated with poor survival after liver transplantation. Hence, patients who have undergone liver transplantation do not require frequent routine examination of serum alkaline phosphatase levels.

Transient hyperphosphatasemia in pediatric renal transplant patients--is there a need for concern and when?

TH of infancy and early childhood is characterized by transiently increased S-ALP, predominantly its bone or liver isoforms. There are neither signs of metabolic bone disease or hepatopathy corresponding to the increased S-ALP, nor a common underlying/triggering disease. TH may also occur in children post-renal Tx, which may raise significant concerns and anxiety. We describe four patients aged 2.8-7 yr in whom the TH occurred at 11-34 (median = 28) months after Tx and lasted from 40 to 105 (median = 63) days. No obvious cause/trigger of TH could be found; the clinical status and bone turnover were not altered. In cases of TH post-Tx, we recommend the evaluation of basic biochemical indices and wrist X-ray. If these results are normal, TH is most likely the diagnosis and the S-ALP can be monitored over the next three months without further testing. In patients with persisting TH for more than three months and/or in children with pre-existing or suspected metabolic bone disease, further evaluation may be indicated. In conclusion, TH is a benign disorder in patients post-Tx. Detailed investigation including bone biopsy is only indicated in patients with persisting TH.

Benign transient hyperphosphatasemia in infants and children: a prospective cohort

A total of 20 children with benign transient hyperphosphatasemia were prospectively evaluated with no additional investigations recommended except repeat serologic evaluation in 2-3 months. The average age of our patients was 2.5 years (range: 1 year 2 months-5 years 10 months). The serum levels of alkaline phosphatase averaged 2383 IU/L (range: 1013-5700 IU/L). Levels returned to normal within several months. This condition should be recognized by the clinician in order not to put patients through lengthy, expensive and unnecessary investigations.

Benign transient hyperphosphatasemia associated with Epstein-Barr virus enteritis in a pediatric liver transplant patient: a case report

Transient hyperphosphatasemia was found in a 3-year-old male liver transplant recipient. The condition was associated with diarrheal disease due to the Epstein-Barr virus (EBV). Immunosuppression was tapered and valganciclovir prescribed for 3 months, after which the diarrhea resolved and the EBV polymerase chain reaction assays became negative. After 6 months, alkaline phosphatase levels normalized. Isolated elevation of alkaline phosphatase in conjunction with enteric infection is a rare condition. No further diagnostic or therapeutic interventions except treatment of the underlying infection are needed, as this has been shown to be a benign, transient condition.