🫁 Fever Pathophysiology in Children Simulator

Pathogen Invasion Triggers Pyrogenic Cytokine Release

Placeholder: immune cells detect pathogens and release fever-inducing cytokines.

• IL-1, IL-6: Key cytokines (Placeholder short caption)
• Macrophages: Source cells (Placeholder short caption)
• PAMPs: Trigger (Placeholder short caption)
• 0–2 h: Onset window (Placeholder short caption)

Innate immune activation

Placeholder: pathogen recognition activates cytokine-releasing immune cells.

Cytokines Reach the Hypothalamic Thermoregulatory Center

Placeholder: IL-1 and IL-6 signal the brain via the OVLT circumventricular organ.

• OVLT: Entry route (Placeholder short caption)
• Blood-brain: Barrier crossed (Placeholder short caption)
• IL-1R, gp130: Receptor (Placeholder short caption)
• ~2–4 h: Delay (Placeholder short caption)

Circumventricular signaling

Placeholder: cytokines act near leaky capillaries bypassing the blood-brain barrier.

Prostaglandin E2 Raises the Hypothalamic Set-Point

Placeholder: PGE2 synthesis shifts the thermoregulatory set-point upward.

• PGE2: Mediator (Placeholder short caption)
• COX-2: Enzyme (Placeholder short caption)
• EP3 receptor: Target (Placeholder short caption)
• 1–3°C: Typical shift (Placeholder short caption)

Prostaglandin pathway

Placeholder: COX-2 converts arachidonic acid to PGE2 in the preoptic area.

Shivering and Vasoconstriction Drive Heat Production

Placeholder: the body shivers and constricts vessels to reach the new set-point.

• Shivering: Muscle response (Placeholder short caption)
• Vasoconstriction: Skin response (Placeholder short caption)
• Chills, cover-seeking: Behavior (Placeholder short caption)
• Up to 5x: Heat gain (Placeholder short caption)

Effector mechanisms

Placeholder: hypothalamus drives shivering thermogenesis and skin vasoconstriction.

Body Temperature Stabilizes at the Elevated Set-Point

Placeholder: temperature plateaus once it matches the new set-point.

• Fastigium: Phase (Placeholder short caption)
• 38–40°C: Plateau temp (Placeholder short caption)
• Defervescence: Resolution (Placeholder short caption)
• Set-point falls: Sweating onset (Placeholder short caption)

Equilibrium and resolution

Placeholder: temperature holds steady until cytokine signaling declines.

Defervescence

Placeholder: falling set-point triggers sweating and vasodilation to cool down.

Placeholder highlight: children can spike fevers rapidly but usually resolve quickly.