Postprandial hyperthermia causes
Postprandial hyperthermia can occur from normal meal thermogenesis that increases energy expenditure and body temperature after ingestion of carbohydrate and/or protein. [1] Some disorders cause exaggerated autonomic or vasoactive mediator responses to eating, which can present with heat/flushing and elevated measured temperature after meals. [2]
Normal meal thermogenesis
Meal thermogenesis is characterized by increased energy expenditure and an increase in body temperature within minutes after consuming carbohydrate and/or protein. [1] Brown adipose tissue activation is implicated as a driver of postprandial thermogenesis. [1]
Rapid gastric emptying after upper GI surgery
Dumping syndrome is caused by rapid gastric emptying and is more common after certain surgeries involving the stomach or esophagus. [2] Early dumping syndrome can include vasomotor symptoms such as flushing, perspiration, and tachycardia that occur within about 1 hour after a meal. [3] Late dumping syndrome can occur 1 to 3 hours after a high-sugar meal and is associated with endocrine-metabolic symptoms driven by rapid glucose and insulin changes. [2]
Food allergy and anaphylaxis-spectrum reactions
Food allergy reactions commonly begin within minutes to 2 hours after ingestion of the trigger food. [4] Severe systemic allergic reactions can include temperature elevation as part of a systemic inflammatory response. [4]
Neuroendocrine mediator syndromes triggered by eating
Carcinoid syndrome is caused by metastatic neuroendocrine tumors that secrete vasoactive substances such as serotonin. [5] Carcinoid syndrome symptoms include episodic flushing that can be triggered by food and can be accompanied by systemic physiologic instability during attacks. [6]
Evaluation triggers that suggest non-benign causes
Postprandial hyperthermia associated with flushing, hypotension, tachycardia, wheezing, or severe GI symptoms supports consideration of mediator-driven syndromes rather than physiologic meal thermogenesis. [3] Postprandial hyperthermia temporally linked to a specific food supports consideration of food allergy. [4] Postprandial hyperthermia temporally linked to meals soon after gastric or esophageal surgery supports consideration of dumping syndrome. [2]
Clinical context features that help differentiate etiologies
Normal meal thermogenesis typically follows carbohydrate and/or protein ingestion and occurs shortly after eating. [1] Dumping syndrome typically clusters around rapid onset of symptoms after meals, often within an hour for early dumping and within 1 to 3 hours for late dumping. [2] Food allergy typically shows a consistent temporal relationship to the specific ingested allergen. [4] Carcinoid syndrome typically shows episodic attacks with mediator-driven symptoms such as flushing. [6]