Nutritional Diseases: Obesity and Malnutrition

Nutritional diseases encompassing obesity and malnutrition represent major public health challenges affecting perioperative outcomes and systemic organ function. Obesity is quantified primarily through body mass index, with classifications ranging from overweight to severe obesity at 40 kg/m² or higher, though central adiposity measured by waist-to-hip ratio proves more predictive of cardiovascular and metabolic complications than total body weight alone. The pathophysiology underlying obesity involves chronic caloric surplus leading to adipose tissue expansion, inflammatory cytokine release, and widespread metabolic dysfunction affecting multiple organ systems simultaneously. Obesity generates significant comorbidities including metabolic syndrome, characterized by concurrent central obesity, dyslipidemia, hypertension, and dysglycemia; respiratory complications such as obstructive sleep apnea and obesity hypoventilation syndrome that reduce functional residual capacity and cause rapid desaturation; cardiovascular disease including systemic hypertension and increased cardiac output demands; hepatic steatosis and nonalcoholic fatty liver disease; and increased thrombotic risk. Treatment approaches range from lifestyle modification and pharmacological intervention with agents like liraglutide to surgical options including restrictive procedures such as sleeve gastrectomy and combined restrictive-malabsorptive approaches like Roux-en-Y gastric bypass. Anesthetic management of obese patients requires careful preoperative screening for sleep-disordered breathing using validated questionnaires, strategic airway positioning through ramping techniques, extended preoxygenation with positive pressure ventilation to prolong safe apnea duration, and judicious pharmacologic dosing based on lean body weight for most agents while using total body weight for specific medications like succinylcholine. Malnutrition, present in approximately one-third of hospitalized patients, impairs wound healing and increases infection susceptibility, requiring universal screening through validated tools and preoperative nutritional optimization. Specific micronutrient deficiencies stemming from malabsorption or chronic alcoholism produce characteristic disease patterns including thiamine deficiency causing beriberi, cobalamin deficiency resulting in megaloblastic anemia and peripheral neuropathy, and ascorbic acid deficiency leading to scurvy.