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-adrenergic receptor, given the symptoms of hypertension, dilated pupils, and diaphoresis, which are characteristic of a catecholamine crisis, such as that seen in pheochromocytoma or paraganglioma 1.

Key Symptoms and Receptor Involvement

The symptoms described, including visual hallucinations (which could be part of an acute psychotic episode or a severe anxiety state), thinking he is in a police station (altered mental status), hypertension, dilated pupils, and diaphoresis, suggest a condition associated with excessive catecholamine release. This condition is known as a catecholamine crisis, which can be life-threatening and requires immediate medical attention.

Catecholamine Crisis and α-Adrenergic Receptors

Catecholamine crises are often associated with pheochromocytomas or paragangliomas, which are tumors that produce excess catecholamines (like norepinephrine and epinephrine) 1. The α-adrenergic receptor is primarily involved in the vasoconstrictive effects of catecholamines, leading to hypertension, which is a hallmark of these crises. The use of α-adrenoceptor blockers, such as phenoxybenzamine or doxazosin, is a critical component of managing these crises, as they can help control blood pressure and reduce the risk of cardiovascular complications 1.

Management Considerations

In managing a patient with suspected catecholamine crisis, it is crucial to:

• Initiate α-adrenoceptor blockade to control hypertension and prevent further complications.
• Monitor the patient closely for signs of hemodynamic instability.
• Consider the use of β-adrenoceptor blockers if tachycardia develops, but only after adequate α-blockade has been established to avoid worsening hypertension.
• Ensure the patient is well-hydrated and consider preoperative measures to reduce the risk of orthostatic hypotension, as outlined in the management of pheochromocytoma and paraganglioma 1.

Conclusion Based on Evidence

Given the clinical presentation and the evidence from recent guidelines on the management of pheochromocytoma and paraganglioma 1, the most appropriate receptor involved in this patient's condition is the α-adrenergic receptor. Management should prioritize controlling the catecholamine-induced hypertension and other symptoms through the use of α-adrenoceptor blockers, among other supportive measures.

From the FDA Drug Label

Abuse and dependence of benzodiazepines have been reported Withdrawal symptoms, similar in character to those noted with barbiturates and alcohol have occurred following abrupt discontinuance of diazepam. These withdrawal symptoms may consist of ... hallucinations

The GABA_A receptor is involved in the presentation of a young man with visual hallucinations, thinking he is in a police station, with hypertension, dilated pupils, and diaphoresis, as benzodiazepines act on this receptor and withdrawal from them can cause such symptoms 2.

From the Research

Receptor Involved in Psychosis

The receptor involved in a young man presenting with visual hallucinations, thinking he is in a police station, with hypertension, dilated pupils, and diaphoresis is the N-methyl-d-aspartate (NMDA) receptor.

• The NMDA receptor is a neurotransmitter receptor that plays a critical role in information encoding in the hippocampus, a region of the brain involved in psychosis 3.
• Blockade of the NMDA receptor by noncompetitive antagonists can lead to psychotomimetic effects, including hyperlocomotion and psychotic-like behavioral abnormalities 4.
• The specific subunits of the NMDA receptor, such as GluN2A, GluN2B, and GluN2D, have been implicated in various neurological and psychiatric disorders, including schizophrenia and psychosis 5.

Clinical Presentation

The clinical presentation of the young man, including visual hallucinations, disordered thought, and socio-emotional impairments, is consistent with psychosis.

• Psychosis is a mental condition characterized by hallucinations, delusions, and disordered thought, and can be caused by a variety of factors, including NMDA receptor dysfunction 3, 6.
• The presence of hypertension, dilated pupils, and diaphoresis may indicate a state of hyperarousal or sympathetic nervous system activation, which can be associated with NMDA receptor blockade 4.

Diagnosis and Treatment

Diagnosis and treatment of NMDA receptor-related psychosis typically involve a combination of clinical evaluation, laboratory tests, and pharmacological interventions.

• Serum NMDAR antibodies have been reported in a minority of patients with first-episode psychosis, and their role in psychosis onset and response to antipsychotic treatment is unclear 6.
• Treatment with antipsychotic medications, such as amisulpride, may be effective in reducing symptoms of psychosis, even in patients with NMDAR antibody seropositivity 6.
• In some cases, immunotherapy may be considered, particularly if there is evidence of cerebrospinal fluid inflammatory changes or other paraclinical evidence suggestive of a likely benefit from immunotherapy 6.