Transient hyperphosphatasaemia of infancy following rotavirus infection

Benign transient hyperphosphatasemia in the pediatric population: a single center cohort study

OBJECTIVES

Alkaline phosphatase (ALP) can be increased in a benign condition known as benign-transient hyperphosphatasemia (BTH). We aimed to evaluate the demographic, and clinical characteristics of infants and children with BTH.

METHODS

In our retrospective study, infants and children diagnosed with BTH between September 2019 and September 2023 were included.

RESULTS

Of 249 children with elevated ALP levels, 95 (38.1 %) had BTH. The mean age at diagnosis of children with BTH was 2.4 ± 1.3 years (min 0.6 - max 6.2 years). ALP mean value was 2,587 ± 1252 U/L (min 972 - max 5757 U/L). ALP value was an average 7.4 ± 3.6 times higher than the corresponding upper limit of normal. The second measurement was made after an average of 13.2 ± 6 days, and a statistically significant difference was detected compared to the first value, with a decrease of 61 ± 23 % in the ALP value (p<0.001). ALP value returned to normal in an average of 44 ± 29.2 days. Elevated ALP was detected during infection in 49 (51.6 %) children. When the sample was divided into those under 2 years of age and aged 2 and over, no statistical difference was observed in ALP levels in the time it took for ALP levels to return to the normal range (p=0.480).

CONCLUSIONS

BTH should be kept in mind if high serum ALP is detected in children without clinical or laboratory suspicion of bone or liver disease. In the follow up detecting a significant decrease trend compared to the first value may be guiding for BTH.

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 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.

Elevated Alkaline Phosphatase in Children: An Algorithm to Determine When a "Wait and See" Approach is Optimal

Due to the possibility of underlying hepatobiliaryor bone diseases, the diagnostic work up of a child with elevated alkaline phosphatase (AP) levels can be quite costly. In a significant proportion of these patients, elevated AP is benign, requiring no intervention: hence, known as transient hyperphosphatasemia (THP) of infants and children. A 27-month old previously healthy Caucasian female was found to have isolated elevation of AP four weeks after the initial symptoms of acute gastroenteritis. One month later, when seen in hepatobiliary clinic, signs and symptoms of gastrointestinal, hepatobiliary, or bone disease were absent and physical examination was normal. The diagnosis of THP was made, and, as anticipated, AP levels normalized after four months. Using this case as an example, we suggest an algorithm that can be utilized as a guide in a primary care setting to arrive at the diagnosis of THP and avoid further tests or referrals.

Transient rise in alkaline phosphatase activity in adults

Benign transient hyperphosphatasia (BTH) is a condition that occurs mainly in infants and children and is characterised by a transient increase of serum alkaline phosphatase (ALP) activity up to several fold the adult upper reference limit (URL). The present report concerns BTH in 2 patients, aged 59 and 52 years old, who showed no evidence of bone or liver disease but had an increase in ALP activity up to 20-fold and 13-fold the adult URL, respectively. The diagnosis of BTH in the first case was made retrospectively, and after excluding liver and bone disease. However, in the second case the diagnosis was made early in the course of the disease, by performing an ALP isoenzyme electrophoresis test. Lengthy and extensive investigations were avoided in the second case. These cases highlight the occurrence of this condition in adulthood as well as in infancy and childhood.

Idiopathic severe elevation of serum alkaline phosphatase following adult renal transplantation: case reports

Transient hyperphosphatasemia (TH) in infancy is a benign condition characterized by elevated alkaline phosphatase (ALP) levels severalfold the adult upper limits, occurring mainly in children under 5 years, without evidence of liver or bone disease, and a return to normal ALP levels by 4 months. Herein we have reported 3 cases of TH in adults following renal transplantation. The first case, a 47-year-old woman, blood group AB positive, had hypertensive renal disease. Five months after successful renal transplantation from a deceased donor she had a 50-fold increase in ALP. The second case, a 34-year-old man, blood group A positive, had renal failure due to IgA nephropathy. Nine weeks after a second renal transplant from a deceased donor a 25-fold increase in ALP was noted. The third case, a 45-year-old woman, blood group A positive, experienced renal failure 15 years earlier of unknown etiology. Thirteen years after her second renal transplant a 12-fold increase in ALP was observed during a routine follow-up. In all cases, the isolated ALP serum levels returned to normal limits within 12 weeks. Bone scans and abdominal ultrasounds during these periods were normal with no evidence of bone or liver disease. ALP isoenzyme electrophoresis revealed a pattern characteristic of TH of infancy and childhood. The 3 cases reported highlight the occurrence of benign TH in adults, with renal transplantation. However, liver disease, bone disease, and infection should be excluded first in these susceptible individuals on immunosuppression before establishing the diagnosis of TH.

Interpretation and clinical significance of alkaline phosphatase isoenzyme patterns

Alkaline phosphatase (ALP, EC 3.1.3.1) is a membrane-bound metalloenzyme that consists of a group of true isoenzymes, all glycoproteins, encoded for by at least four different gene loci: tissue-nonspecific, intestinal, placental, and germ-cell ALP. Through posttranslational modifications of the tissue-nonspecific gene, for example, through differences in carbohydrate composition, bone and liver ALP are formed. Nowadays, most commercially available methods for separating or measuring ALP isoenzymes are easy to perform and sensitive and allow for reproducible and quantitative results. As more isoenzymes and isoforms have been characterized, confusion has arisen due to the many different names they were given. For the sake of simplicity and because of structural analogies, we propose an alternative nomenclature for the ALP isoenzymes and isoforms based on their structural characteristics: soluble, dimeric (Sol), anchor-bearing (Anch), and membrane-bound (Mem) liver, bone, intestinal, and placental ALP. Together with lipoprotein-bound liver ALP and immunoglobulin-bound ALP, these names largely fit the many forms of ALP one can encounter in human serum and tissues. The clinically relevant isoenzymes are sol-liver, Mem-liver, lipoprotein-bound liver, and Sol-intestinal ALP in liver diseases, and Sol-bone and Anch-bone ALP in bone diseases. Many different isoenzyme patterns can be found in malignancies and renal diseases. This test provides the clinician with valuable information for diagnostic purposes as well as for follow-up of patients and monitoring of treatment. However, ALP isoenzyme determination will only provide clinically useful information if the patterns are correctly interpreted. In this respect, care should be taken to use the proper reference ranges, taking into account the age and sex of the patient. A normal total ALP activity does not rule out the presence of an abnormal isoenzyme pattern, particularly in children. Separating ALP into its isoenzymes adds considerable value to the mere assay of total ALP activity.

Benign transient hyperphosphatasia and HIV infection

The disorder, benign transient hyperphosphatasia, has been defined previously as a condition occurring in a normal child with spontaneous, transient elevation of alkaline phosphatase. We report three cases of hyperphosphatasia in patients with congenital HIV infection and underlying liver disease which appear to satisfy the criteria for benign transient hyperphosphatasia despite the presence of chronic disease. These three children, when compared with three normal children with transient hyperphosphatasia exhibited similar patterns of change in serum alkaline phosphatase. Extreme elevation of serum alkaline phosphatase in HIV infected patients does not of itself suggest alterations in clinical status nor indicate the need for extensive evaluation.

Transient hyperphosphatasaemia of infancy

In five patients with benign transient hyperphosphatasaemia (THP), high activities of so-called "atypical" alkaline phosphatase or fragment isoenzymes were detected. One case occurred after rotavirus infection. Incubation with neuraminidase suggested that "atypical" alkaline phosphatase originated from highly glycosylated bone and liver isoenzymes. This may have been due to virus-induced low isoenzyme clearance from serum. The course of isoenzyme activities in THP following rotavirus infection was followed. Determination of atypical alkaline phosphatase may be useful in the diagnosis of THP.