What receptor is involved in a young man presenting with visual hallucinations, thinking he is in a police station, with hypertension (high blood pressure), dilated pupils, and diaphoresis?

From the Guidelines

The patient's presentation is most consistent with excessive adrenergic activity, specifically involving the α-adrenoceptor. The patient's symptoms, including visual hallucinations, thinking he is in a police station, hypertension, dilated pupils, and diaphoresis, are indicative of a hyperadrenergic state, which can be caused by an excess of catecholamines such as norepinephrine 1. This condition is often associated with pheochromocytoma or paraganglioma, particularly those producing norepinephrine, as evidenced by elevated plasma and/or urine normetanephrine levels 1.

Key Points:

• The α-adrenoceptor is the primary receptor involved in the patient's symptoms, given the presence of hypertension and other signs of adrenergic excess 1.
• The use of α-adrenoceptor blockers, such as phenoxybenzamine or doxazosin, is a common treatment approach for managing hyperadrenergic symptoms in patients with norepinephrine-producing tumors 1.
• It is crucial to carefully monitor patients and adjust treatment as necessary to prevent complications, including hemodynamic instability 1.
• The patient's presentation does not typically align with serotonin syndrome or the involvement of other receptors like NMDA or GABA, as the primary symptoms suggest adrenergic rather than serotonergic or glutamatergic/GABAergic dysfunction. Some possible considerations for the patient's management include:
• Preoperative biochemical screening to confirm the diagnosis and guide treatment 1.
• The use of metyrosine or calcium channel blockers as adjunctive therapy to control refractory hypertension or as presurgical monotherapy in specific cases 1.
• Employing a high-sodium diet, administering saline, and using compressive stockings to reduce the risk of preoperative orthostatic hypotension and postoperative hypotension 1.

From the Research

Symptoms and Receptor Involvement

The symptoms presented by the young man, including visual hallucinations, thinking he is in a police station, hypertension, dilated pupils, and diaphoresis, can be associated with various neurological and psychiatric disorders.

• The NMDA receptor is implicated in several major nervous system disorders, including schizophrenia, which can present with psychotic symptoms such as hallucinations and delusions 2, 3, 4, 5, 6.
• Anti-NMDA receptor encephalitis is a synaptic autoimmune disorder that targets NMDARs in the brain, leading to their removal from the synapse, and can manifest with prominent psychiatric symptoms, including psychosis 6.
• The specific expression and distribution of NMDA receptor subunits are deeply involved in neural excitability, plasticity, and synaptic deficits, and dysfunction of these receptors has been implicated in various neurological and psychiatric disorders 4.

NMDA Receptor Dysfunction

• NMDA receptor dysfunction has emerged as a common theme in several major nervous system disorders, including schizophrenia, and either hyperactivity or hypofunction of NMDARs could contribute to disease pathophysiology 2.
• The GluN2D subunit of the NMDA receptor has been implicated in NMDA receptor antagonist-induced psychosis 4.
• NMDARs are members of the ionotropic glutamate receptor family and are entwined with numerous fundamental neurological functions within the central nervous system (CNS), and numerous neuropsychiatric disorders may arise from their malfunction 5.