Overview
Epinephrine, also known as adrenaline, is a hormone and neurotransmitter produced by the adrenal medulla, as described in the document. It plays a central role in the body’s fight-or-flight response, enabling rapid physiological adaptation during stress, danger, or emergency situations. Epinephrine acts on multiple organ systems simultaneously to prepare the body for immediate action by increasing heart rate, blood pressure, and energy availability.
Epinephrine is synthesized from the amino acid tyrosine through a multi-step catecholamine biosynthesis pathway, with phenylethanolamine N-methyltransferase as the final enzyme responsible for its formation. Cortisol regulates this final step, linking adrenal cortical and medullary function. Once released into the bloodstream, epinephrine binds to alpha and beta adrenergic receptors, producing widespread cardiovascular, respiratory, metabolic, and neurological effects.
In clinical practice, epinephrine measurement is important for evaluating adrenal function and diagnosing rare catecholamine-secreting tumors. It is also widely used as a life-saving medication in emergencies such as anaphylaxis, cardiac arrest, and severe asthma.
Symptoms
Abnormal epinephrine levels can produce a range of symptoms related to excessive or deficient adrenergic activity, as outlined in the document. Elevated epinephrine levels are commonly associated with symptoms of sympathetic overactivity. These include high blood pressure, sudden and severe headaches, anxiety, excessive sweating, palpitations, and rapid or irregular heartbeats. Patients may also experience tremors, restlessness, and feelings of panic.
Low epinephrine levels may result in inadequate stress response. Symptoms can include fatigue, dizziness, poor stress tolerance, low blood pressure, and weakness. Because epinephrine supports cardiovascular stability and glucose availability during stress, deficiency may impair the body’s ability to respond to physiological challenges.
It is important to note that symptoms are often episodic and may fluctuate due to the pulsatile release of epinephrine. Laboratory testing helps confirm abnormal hormone levels when symptoms suggest an underlying disorder.
Causes
Altered epinephrine levels arise due to disorders affecting the adrenal medulla, pituitary regulation, or catecholamine synthesis pathways, as described in the document. Excess epinephrine production may occur in rare tumors such as pheochromocytoma or neuroblastoma. These tumors produce catecholamines autonomously, leading to sustained or episodic hormone elevation.
High epinephrine levels may also be associated with genetic syndromes and adrenal or pituitary abnormalities. Stress, both physical and psychological, can transiently increase epinephrine release as part of a normal physiological response.
Low epinephrine levels may result from adrenal insufficiency, pituitary dysfunction, or genetic disorders affecting catecholamine synthesis. Damage to adrenal tissue or impaired enzymatic activity can reduce hormone production, leading to insufficient adrenergic signaling.
Risk Factors
Risk factors for abnormal epinephrine levels are primarily linked to adrenal, pituitary, and genetic conditions. Individuals with adrenal tumors, inherited endocrine syndromes, or a family history of catecholamine-secreting tumors are at increased risk of elevated epinephrine levels.
Patients presenting with unexplained hypertension, recurrent headaches, anxiety attacks, excessive sweating, or palpitations should be evaluated for possible catecholamine excess. Genetic disorders affecting adrenal development or enzyme function increase the risk of low epinephrine levels.
Certain medications and medical conditions may influence epinephrine metabolism and action. Cardiovascular disease, thyroid disorders, and hormonal imbalances can modify adrenergic responsiveness and complicate the interpretation of epinephrine measurements.
Prevention
Epinephrine imbalance itself cannot always be prevented, but early identification and management of underlying causes play a key role in preventing complications, as emphasized in the document. Regular medical evaluation for individuals with suggestive symptoms allows timely diagnosis of adrenal or endocrine disorders.
Accurate sample collection and proper patient preparation are essential preventive steps for reliable testing. Because epinephrine release is sensitive to stress, ensuring appropriate rest and controlled conditions before sample collection helps prevent false elevations.
Managing known adrenal or pituitary disorders through regular follow-up reduces the risk of severe hormonal imbalance. In individuals diagnosed with catecholamine-secreting tumors, ongoing monitoring helps prevent cardiovascular complications.
