Sastry UMK, Jayranganath M, Kumar RK, et al. - Researchers conducted this prospective observational study to identify the clinical profile and management of thiamine-responsive acute pulmonary hypertension (PH). The sample consisted of infants presenting with severe PH without any other significant heart or lung disease. History of symptoms, clinical examination, echocardiography, and basic investigations have been performed. Dietary patterns of mothers have been recorded. In total, 250 infants, mean age 3.2 ± 1.2 months, had severe PH and 231 infants responded to thiamine. The main symptoms were fast breathing, poor feeding, vomiting, and aphonia. On examination, tachypnoea, tachycardia, and hepatomegaly were detected. According to findings, still prevalent in selected parts of India is thiamine deficiency. It may cause life-threatening PH in exclusively breast-feeding infants of mothers on a restricted diet consisting mainly of polished rice. It can lead to infant mortality. The administration of thiamine on the basis of clinical suspicion leads to a remarkable recovery. In order to tackle this fatal disease, a high level of knowledge and thiamine supplementation is required in the appropriate geographical areas.