tailieunhanh - Ebook On rounds - 1000 internal medicine pearls: Part 2

Part 2 book “On rounds - 1000 internal medicine pearls” has contents: Fever, temperature regulation, and thermogenesis, infectious diseases, pulmonary, the gastrointestinal tract, pancreas, and liver, malignancy and paraneoplastic syndromes, neuromuscular disease, and other contents. | 8 Fever, Temperature Regulation, and Thermogenesis CHAPTER CENTRAL REGULATION OF CORE TEMPERATURE FEVER AND HYPERTHERMIA THERMOGENESIS HEAT GENERATION AND DISSIPATION DIURNAL VARIATION IN TEMPERATURE NIGHT SWEATS CENTRAL REGULATION OF CORE TEMPERATURE Temperature in humans is controlled by the hypothalamus around a set point of about 37 °C ( °F), by a complex series of mechanisms that permit the generation, conservation, and dissipation of heat. Homeothermy requires a balance of heat generation, heat conservation, and heat dissipation. This is accomplished by a remarkable series of coordinated cardiovascular and metabolic responses integrated in the hypothalamus, and fine tuned in the effector organs peripherally. These responses involve the autonomic nervous system, the skeletal musculature, arteries and veins, the sweat glands, and brown adipose tissue (BAT). FEVER AND HYPERTHERMIA Fever represents a resetting of the temperature set point up; antipyretics adjust the set point down when the latter is elevated by fever. Fever is distinct from hyperthermia. In hyperthermia the core temperature rises because heat dissipation mechanisms are impaired, or because heat production exceeds the capacity of heat dissipation mechanisms, not because of an increase in central temperature set point. Infections cause fever via cytokine release from inflammatory cells. In fact, the first cytokine described was called “endogenous pyrogen” since it was released from host leukocytes after exposure to bacteria. It had previously been thought that bacterial products per se caused the fever. Cytokines released from tumor cells also cause the fever that is associated with malignancy. THERMOGENESIS Thermogenesis, literally heat production, is not synonymous with fever. In warm-blooded mammals (homeotherms) basal heat production (or basal metabolic rate [BMR]) is the heat produced at rest by mitochondria throughout the body. BMR is regulated by thyroid hormones. Excessive .