🔷 Definition
Functional neurological symptom disorder (conversion disorder) is characterized by neurologic symptoms such as weakness, abnormal movements, or nonepileptic seizures, which involve abnormal nervous system functioning rather than structural disease.
🔷 DIAGNOSIS
🔻 Functional neurologic symptom disorder is not a diagnosis of exclusion.
🔻 Clinicians no longer need to determine that the symptom is not feigned, does not.
🔻 Depend upon excluding other recognized disorders. Do not specify a time frame for symptoms.
A DSM-5-TR diagnosis of functional neurological symptom disorder requires each of the following criteria:
🔻 One or more symptoms of altered voluntary motor or sensory function
🔻 Clinical findings that demonstrate incompatibility between the symptom and recognized
neurologic or general medical conditions.
🔻 The symptom or deficit is not better explained by another medical or mental disorder.
🔻 The symptom or deficit causes significant distress, psychosocial impairment, or warrants medical evaluation.
The diagnosis rests upon positive clinical findings. Normal findings on physical examination (eg, reflexes) or normal laboratory tests do not provide positive evidence of functional neurological symptom disorder.
🔷 Subtypes
🔸 Seizures or attacks
🔸 Weakness or paralysis
🔸 Abnormal movement
🔸 Sensory loss or anesthesia
🔸 Special sensory symptom
🔸 Speech symptom
🔸 Swallowing symptom
🔸 Mixed symptoms
The diagnosis of functional neurological symptom disorder does not require clinicians to establish that the symptom is not intentionally produced.
🔷 DIFFERENTIAL DIAGNOSIS
🔹 Neurologic disorders:
The differential diagnosis for functional neurological symptom disorder includes many general medical disorders and all neurologic diseases, including multiple sclerosis, myasthenia gravis, movement disorders, stroke, epilepsy, and spinal disorders.
In addition, more unusual neurologic diseases such as stiff person
syndrome, autoimmune limbic encephalitis, and frontal lobe epilepsy may present with unusual features.
Frequency of incorrectly diagnosing other neurologic disorders (eg, epilepsy or multiple sclerosis) in patients who ultimately are found to have functional neurological
symptom disorder is approximately 6 to 11 percent.
Many patients have both functional neurological symptom disorder and a recognized neurologic condition.
🔹 Somatic symptom disorder
🔹 Depersonalization/derealization disorder
🔹 Feigned symptoms
🔹 Factitious disorder
🔹 Malingering