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

Table 1 Laboratory tests of our patient during coronavirus disease 2019 infection and follow-up

Parameters	At admission		Follow-up after illness
	5th day of illness	9th day of illness	2nd month	6th month
ALP (U/L)	4178	4662	252	229
AST (U/L)	35.8	30.8	37.7	29.3
ALT (U/L)	17	15.9	16.5	18.8
TP (g/dL)	7.1	6.8	6.7	6.8
Alb (g/dL)	4.9	4.8	4.6	4.6
TB/DB (g/dL)	0.25/0.12	0.17/0.11	0.37/0.12	0.24/0.11
GGT (U/L)	12	-	-	-
Cr (mg/dL)	0.3	-	-	-
Ca (mg/dL)	9.9	-	9.7	-
P (mg/dL)	4.0	-	4.9	-
Mg (mg/dL)	2.2	-	2.26	-
iPTH (pg/mL)	21.3	-	26.4	-
25-OHD (ng/mL)	33.6	-	23.4	-

ALP: Alkaline phosphatase (normal range: 111-277 U/L; AST: Aspartate aminotransferase; ALT: Alanine aminotransferase; TP: Total protein; Alb: Albumin; TB: Total bilirubin; DB: Direct bilirubin; GGT: Gamma-glutamyl transferase; Ca: Calcium; P: Phosphate; Mg: Magnesium; iPTH: Intact parathyroid hormone.

Table 2 Clinical characteristics and laboratory tests in hyperphosphatasemia associated with coronavirus disease 2019 infection: our patient and previous reports

Clinical characteristics	Our patient	Erat et al[16], 2020	Tchidjou et al[17], 2020
Ethnicity	Thai	Turkish	French
Gender	M	F	M
Age (mo)	26	16	9
Symptom of COVID-19 infection
Fever	Yes	Yes	Yes
Upper respiratory tract symptom	No	Yes (Cough, oropharyngeal hyperemia)	Yes (Rhinitis)
Lower respiratory tract symptom	No	No	No
Gastrointestinal symptom	No	Yes (Nausea, diarrhea)	No
Laboratory tests
Peak ALP (U/L)	4662 (Normal: 111-277)	1860 (Normal: 145-420)	3384 (Normal: 46-116)
ALP ratioa	16.8	4.4	29
Cr (mg/dL)	0.21	0.22	0.43
AST (U/L)	36	34	37
ALT (U/L)	17	14	39
GGT (U/L)	12	13	8
Ca (mg/dL)	9.9	9.8	NA
P (mg/dL)	4	5.5	6.8
iPTH (pg/mL)	21.3	28.1	NA
25-OHD (ng/mL)	33.6	32	NA
Resolution of TH
Time turned to normal ALP level	Two months	One month	One month
ALP (U/L)	252	254	371

^aALP ratio: The measured ALP level divided by the upper limit of normal. ALP: Alkaline phosphatase; AST: Aspartate aminotransferase; ALT: Alanine aminotransferase; GGT: Gamma-glutamyl transferase; Ca: Calcium; COVID-19: Coronavirus disease 2019; P: Phosphate; Mg: Magnesium; iPTH: Intact parathyroid hormone; TH: Hyperphosphatasemia; NA: Not available.

Table 3 Viral infections associated with hyperphosphatasemia [13,23-27]

Respiratory syncytial virus

Influenza virus

Epstein-Barr virus

Adenovirus

Bocavirus

Cytomegalovirus

Rotavirus