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

Figure 1 Chest radiography changes before and after levothyroxine treatment. A: Admission chest radiograph (2 days before levothyroxine) showed cardiomegaly and pulmonary congestion; B: Post-levothyroxine chest radiograph revealed marked improvement.

Figure 2 Cardiac color doppler ultrasound changes during levothyroxine treatment. A and B: Cardiac ultrasound (pre-levothyroxine and 2 days post-levothyroxine) revealed left ventricular hypertrophy and left heart enlargement (orange arrows); C and D: Ultrasound (29 days post-levothyroxine) showed improvement in left heart size and left ventricular hypertrophy (orange arrows); E and F: Ultrasound (92 days post-levothyroxine) showed normalized cardiac structure (orange arrows).

Figure 3 Lactate and bicarbonate levels before and after levothyroxine treatment. Lactate levels rose progressively post-admission and declined following levothyroxine treatment. Bicarbonate levels trended inversely to lactate. L-T4: Levothyroxine; HCO₃^-: Bicarbonate.