TG and hypothyroidism: Although NTIS is probably the most common cause of hypothyroidism, the current consensus advises against the administration of thyroid hormones to patients with NTIS as thyroid hormones increase respiratory rate, oxygen consumption, energy expenditure and heat production, NTIS is considered an adaptive response to counteract catabolism during illness [33], and this is the primary reasoning against administration of thyroid hormone to patients with NTIS [34].