Preterm heart failure and refractory lactic acidosis caused by congenital hypothyroidism: A case report and review of literature

Table 1 Changes in blood indexes before and after levothyroxine treatment during hospitalization

Blood index (unit)	Before treatment	After treatment	Reference range
BNP (pg/mL)	3959.67	13.26	(0-100)
cTnI (μg/L)	0.484	0.047	(0-0.06)
CK-MB (μg/L)	77.67	8.85	(0-5)
CK (U/L)	1039	89	(39-192)
Ammonia (μmol/L)	99.9	34.5	(10-47)
Pyruvate (μmol/L)	240.7	79.9	(20-100)
β-hydroxybutyric acid (mmol/L)	0.78	0.15	(0-0.27)

BNP: B-type natriuretic peptide; cTnI: Cardiac troponin I; CK-MB: Creatine kinase-MB; CK: Creatine kinase.

Table 2 Changes in thyroid function tests and levothyroxine dosage

Age	T4 (nmol/L)	FT4 (pmol/L)	TSH (mIU/L)	TGAb (U/mL)	TPOAb (U/mL)	Dosage of L-T4
35 days	12.80	1.03	> 150.000	NE	NE	12.5 μg/kg/day
47 days	220.30	31.85	1.433	< 15.0	165.3	8 μg/kg/day
73 days	134.10	22.65	0.703	< 15.0	109.3	4.77 μg/kg/day
4 months	116.00	16.87	5.099	NE	NE	3.02 μg/kg/day
6 months	129.20	16.83	2.556	NE	NE	1.89 μg/kg/day
9 months	141.30	18.60	2.371	NE	NE	1.85 μg/kg/day
12 months	99.60	18.35	2.830	NE	NE	1.62 μg/kg/day
18 months	111.2	21.01	5.104	NE	NE	12.5 μg qod
27 months	113.7	17.61	4.884	NE	NE	12.5 μg every 2 days
36 months	105.0	16.83	4.657	NE	NE	Stop
37 months	119.8	20.88	4.080	NE	NE	Stop
Reference range	77.4-171.57	12.26-21.67	1.7-9.1	< 60	< 60

T4: Thyroxine; FT4: Free thyroxine; TSH: Thyroid-stimulating hormone; TGAb: Thyroglobulin antibody; TPOAb: Thyroid peroxidase antibody; L-T4: Levothyroxine; NE: No mention.