Hence, this can lead to symptoms such as: This leads to an excess of adrenaline, and leads to constant activation of the "flight or fight response". Clinical Relevance - PhaeochromocytomaĪ Phaeochromocytoma is a neuroendocrine tumour of the adrenal medulla, specifically the chromaffin cells which secrete adrenaline as discussed previously. The "fight or flight response" is a key survival mechanism, and causes a number of physiological changes, such as increased cardiac output and increased glycogenolysis in liver and muscle tissue. It exhibits its actions through α and β adrenoreceptors (G protein coupled receptors), both in the central nervous system and in the periphery. Adrenaline is mainly associated with the " fight or flight response", and noradrenaline also plays a role in the activation of the sympathetic nervous system as a neurotransmitter in post-ganglionic synapses. The synthesised adrenaline is stored in vesicles before being released into the blood stream. Both adrenaline and noradrenaline are produced from the amino acid tyrosine, through multiple reactions. The adrenal medulla is mainly responsible for the synthesis of the catecholamines, adrenaline and noradrenaline, but also has other secretory functions such as the production of dopamine. Typically, treatment involves surgical resection of the tumour, however alpha adrenoceptor blockers often need to be given prior to surgery to minimize complications. Hypertension can lead to increased pressure in vital circulations, such as in the brain and in the kidney, which can be lethal. These patients present with extremely high blood pressures, typically greater than 180/120 mmHg.
Whilst the above symptoms are all possible, the most typical presentation is intermittent attacks of headaches, excessive sweating and tachycardia. In some situations it can lead to a hypertensive crisis.
This leads to an excess of adrenaline, and leads to constant activation of the “flight or fight response”.
A Phaeochromocytoma is a neuroendocrine tumour of the adrenal medulla, specifically the chromaffin cells which secrete adrenaline as discussed previously.
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