Differential Diagnosis for Autoimmune Conditions Causing Psychosis with Catatonic Features

Single Most Likely Diagnosis

• Anti-NMDA Receptor Encephalitis: This condition is known for causing psychosis, including catatonic features, along with other neurological symptoms such as seizures and dyskinesias. It is an autoimmune disorder where antibodies target NMDA receptors in the brain, leading to a wide range of psychiatric and neurological symptoms.

Other Likely Diagnoses

• Systemic Lupus Erythematosus (SLE): SLE is a systemic autoimmune disease that can affect multiple organs, including the brain, leading to neuropsychiatric manifestations such as psychosis and catatonia.
• Hashimoto's Encephalopathy: This is a rare condition associated with Hashimoto's thyroiditis, characterized by encephalopathy, which can include symptoms of psychosis and catatonia, among other neurological manifestations.
• Multiple Sclerosis: While primarily known for its physical symptoms, multiple sclerosis can also cause psychiatric symptoms, including psychosis and catatonia, especially in the context of severe disease or during relapses.

Do Not Miss Diagnoses

• Vasculitis (e.g., Primary Central Nervous System Vasculitis): Vasculitis affecting the brain can lead to a variety of neurological and psychiatric symptoms, including psychosis and catatonia. Missing this diagnosis could lead to severe consequences, including death or significant brain damage, if not promptly treated.
• Paraneoplastic Syndromes: These are rare disorders that are triggered by an altered immune system response to a neoplasm. Psychiatric symptoms, including psychosis and catatonia, can be part of the presentation, and identifying the underlying cancer is crucial for treatment.

Rare Diagnoses

• Stiff Person Syndrome: An autoimmune disorder characterized by progressive stiffness and rigidity of the muscles, which can also include psychiatric symptoms such as anxiety, depression, and rarely, psychosis or catatonia.
• Morvan's Syndrome: A rare autoimmune condition associated with antibodies against voltage-gated potassium channels, which can cause a range of neurological symptoms, including psychosis, catatonia, and dyskinesias.
• Lyme Disease: In rare cases, Lyme disease can cause psychiatric symptoms, including psychosis and catatonia, especially in the context of late-stage disease or if left untreated.