hypermetabolic

Hypermetabolic describes a state in which the body's resting energy expenditure is markedly elevated relative to normal values. Clinically, it is often defined as resting energy expenditure exceeding predicted values by more than about 20%, though exact thresholds vary. Hypermetabolism can involve the whole body or reflect regional increases in metabolic activity, and it may persist beyond the acute illness in some conditions.

Common causes include thyrotoxicosis or hyperthyroidism, sepsis and severe infections, major trauma or extensive burns, and other states of significant physiological stress such as surgery or cancer. Medications that stimulate the sympathetic nervous system (for example, certain beta-adrenergic agonists or vasopressors) and prolonged fever or environmental heat can contribute. In neonates and critically ill patients, the metabolic response to injury can be prolonged and particularly pronounced.

Clinical features often include increased heat production with fever, tachycardia, sweating, weight loss, muscle wasting, and fatigue. In critical illness, oxygen consumption and carbon dioxide production rise, contributing to a hypermetabolic catabolic state that can complicate recovery and wound healing.

Diagnosis relies on measuring actual energy expenditure, most accurately with indirect calorimetry. Predictive equations can estimate energy needs but may be inaccurate in illness. Evaluation also includes assessing the underlying cause through thyroid function tests, infection workup, inflammatory markers, and imaging as appropriate.

Management focuses on treating the underlying cause and supporting metabolic needs. Nutritional support with higher caloric and protein intake, often via enteral feeding, is common. Pharmacologic strategies may include antithyroid therapy for thyrotoxicosis and beta-blockade to blunt sympathetic drive in some cases, along with general critical-care measures, such as fluids, temperature control, and physical rehabilitation.