Benign transient hyperphosphatasaemia associated with adenovirus infection

Transient hyperphosphatasemia in a toddler with COVID-19 infection: A case report and literature review

BACKGROUND

Transient hyperphosphatasemia (TH) is a condition characterized by elevated serum alkaline phosphatase (ALP) in the clinical setting with no evidence of bone or liver disease among children under the age of 5. Typically, it will resolve spontaneously in a few months in the majority of cases. TH has been found to be associated with viral infections. Two cases of TH associated with coronavirus disease 2019 (COVID-19) infection in toddlers have been previously reported.

CASE SUMMARY

A previously healthy 2-year-old boy presented with fever and positive real-time polymerase chain reaction for COVID-19. Prior to his illness, the patient had been in close contact with his grandfather, who later developed COVID-19. The physical examination on admission was unremarkable. He remained asymptomatic throughout 7 d of hospitalization. On the 5th day of his illness, blood tests showed markedly elevated serum ALP (4178 U/L). Results from the simultaneous testing of the remaining liver profiles and metabolic bone panels were normal. Two months after discharge from the hospital, the patient continued to thrive well. The skeletal surveys revealed no significant abnormalities. The serum ALP declined into the normal range adjusted for his age. This evidence is consistent with the diagnosis of TH.

CONCLUSION

TH can occur in COVID-19-infected toddlers. Serial measurements of ALP levels have been shown to gradually decline into the normal range within a few months. Therefore, being aware of this transient abnormality will help clinicians to avoid additional unnecessary investigations.

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.