Question 1

What are plasma catecholamines?

Accepted Answer

Plasma catecholamines are circulating neurotransmitters and hormones—epinephrine, norepinephrine and dopamine—released by the adrenal medulla and sympathetic nerves. Measured in blood to assess sympathetic activity and to help diagnose conditions such as pheochromocytoma, autonomic dysfunction and severe stress responses. Levels change rapidly, are affected by posture, exercise and drugs, and require special sample handling because of a short half-life.

Question 2

What do high catecholamine levels indicate?

Accepted Answer

High catecholamine levels indicate increased sympathetic (fight-or-flight) activity. Causes include acute stress, severe illness, certain medications, hypoglycemia, and catecholamine-secreting tumors (pheochromocytoma/paraganglioma). Persistent elevation may produce hypertension, palpitations, sweating, headaches, tremor and anxiety. Ongoing high levels warrant medical evaluation, biochemical testing, and investigation for underlying causes.

Question 3

What are the 4 catecholamines?

Accepted Answer

The primary catecholamines are dopamine, norepinephrine (noradrenaline) and epinephrine (adrenaline). A fourth compound often listed is L‑DOPA (levodopa), the immediate biosynthetic precursor that contains a catechol group. For clinical testing and management, laboratories usually focus on the three endogenous catecholamines.

Question 4

How do you prepare for a plasma catecholamine test?

Accepted Answer

Before a plasma catecholamine test: tell your doctor all medicines and supplements (some must be stopped). Avoid caffeine, nicotine, alcohol, decongestants, and strenuous exercise for 24 hours. Rest quietly, lying or seated, for about 20–30 minutes before sampling; arrive calm and on time. Follow any fasting or specific medication-withdrawal instructions given by your clinician.

Question 5

What is the difference between urine and plasma catecholamines?

Accepted Answer

Urine catecholamines (often collected over 24 hours) measure cumulative excretion of catecholamines and metabolites (metanephrines, VMA), reflecting total production and useful for screening. Plasma catecholamines or plasma free metanephrines measure real‑time circulating levels, detecting acute changes. Plasma testing can be more sensitive for certain tumors but is affected by posture, stress, diet and medications, whereas urine reduces short‑term variability.

Question 6

What diseases are linked to catecholamines?

Accepted Answer

Abnormal catecholamine levels are linked to pheochromocytoma and paraganglioma (catecholamine‑secreting tumors), hypertension and related heart problems (arrhythmias, cardiomyopathy, ischemia, stress‑induced takotsubo), Parkinson’s disease (dopamine deficiency), autonomic causes of orthostatic hypotension, psychiatric conditions (anxiety, depression, ADHD), metabolic disturbances including insulin resistance and metabolic syndrome, stress‑related disorders, and drug‑withdrawal syndromes.

Question 7

What blood tests show autoimmune encephalitis?

Accepted Answer

Blood tests useful include neuronal autoantibody panels (serum and CSF)—anti‑NMDA receptor, LGI1, CASPR2, AMPAR, GABA‑B—and paraneoplastic antibodies (Hu, Yo, Ri, Ma2). Routine labs: CBC, electrolytes, liver/renal function, glucose, thyroid tests, and inflammatory markers (ESR, CRP). General autoimmune screens (ANA, ANCA) and tumour markers may also be checked to identify triggers.

Question 8

What are the diagnostic criteria for autoimmune encephalitis?

Accepted Answer

Autoimmune encephalitis is diagnosed by subacute onset (within 3 months) of working‑memory loss, altered mental status or psychiatric symptoms, seizures or new focal deficits; supportive tests (medial‑temporal or other MRI abnormalities, CSF pleocytosis/oligoclonal bands, or EEG encephalopathic slowing/epileptiform activity); detection of neuronal autoantibodies confirms diagnosis; and alternative infectious, metabolic, toxic or neoplastic causes must be excluded.

Question 9

What is CSF autoimmune profile?

Accepted Answer

A CSF autoimmune profile is a panel of cerebrospinal fluid tests that detect autoantibodies and inflammatory markers linked to autoimmune neurological disorders. It typically examines neuronal surface and intracellular antibodies (e.g., NMDAR, LGI1, CASPR2), oligoclonal bands, IgG index, and general CSF cell count/protein. Results support diagnosis of autoimmune encephalitis or other CNS autoimmune diseases and guide immunotherapy and further investigation.

Question 10

What are the biomarkers for autoimmune encephalitis?

Accepted Answer

Key biomarkers for autoimmune encephalitis include neuronal autoantibodies in CSF or serum (cell‑surface: anti‑NMDA, LGI1, CASPR2, AMPAR, GABA‑B; intracellular: GAD65, anti‑Hu), CSF inflammatory changes (lymphocytic pleocytosis, elevated protein, oligoclonal bands), MRI limbic hyperintensities, characteristic EEG patterns (e.g., extreme delta brush), PET abnormalities, and serum–CSF antibody concordance; response to immunotherapy supports diagnosis.

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