Somatic symptom disorder (SSD) and functional neurologic disorder (FND), aka conversion disorder), although similar, have different antecedents and refer to different clinical presentations.

SSD applies to those patients who experience thoughts or feelings related to physical symptoms, such as pain or weakness, that are excessive enough to create disproportionate focus or distress and interfere with functioning. Symptoms are typically multiple and may involve single or multiple body systems (including cardiopulmonary, gastrointestinal, genitourinary, musculoskeletal, and neurologic complaints) as well as pain and fatigue. SSD can and does occur in the context of other medical/pain disorders. SSD is a common diagnosis, affecting 10-15% of the child and adolescent population presenting to primary care physicians. Females are about ten times more likely to carry an SSD diagnosis than males, and incidence peaks between adolescence to about age 30. [Ibeziako: 2019]

FND occurs when there is a problem with decreased function of the central nervous system, typically presenting with psychogenic seizures, difficulty walking or swallowing, and/or motor-sensory deficits, but there is no underlying structural disease such as multiple sclerosis or epilepsy. The distinctive feature of FND is that symptoms/signs do not follow known neurologic patterns. Examples include loss of sensation on the whole right hand (in a glove distribution), whereas numbness would occur in a peripheral or regional nerve distribution. Individuals with functional neurologic disorders continue to have symptoms even when testing does not show any neurologic problems. The symptoms in FND are biological and not simply a physical manifestation of a mental health concern. However, the etiology is a complex interplay between the mind and the body. SSDs may develop as a byproduct of physical or psychological triggers. It is important to recognize that patients do not have control over these symptoms and are not malingering, which is defined in DSM-5 as the “intentional production of false or grossly exaggerated physical or psychological symptoms, motivated by external incentives.”

ICD-10 Coding

Consider somatic symptom disorder when a child or adolescent has more severe symptoms than expected for an existing medical condition or are unrelated to any medical cause that can be identified. Pain is the most common reported symptom. Other common presentations include fatigue or low energy, abdominal distress (pain, nausea, vomiting), breathing difficulties, rapid heart rate, dizziness, fainting, and disordered movements. It is important to remember that the defining feature of SSD is the way the patient interprets and reacts to the symptoms. The specific physical symptoms may vary over time.

Diagnostic testing is of questionable utility and can be expensive; however, it is not unusual for children and adolescents with SSDs to undergo extensive testing or evaluation from a variety of medical subspecialties before the diagnosis is reached. In a meta-analysis performed in adults, evaluation did not decrease somatic symptoms. [Rolfe: 2013] Repeated or expansive testing may lead to side effects of the tests themselves, a risk of false-positive results, symptom exacerbation, and is associated with decreased patient and family satisfaction with care.

Genetic factors, which may be revealed by family history, and medical illness or injury are risk factors for developing SSDs. Comorbid anxiety and depression are present in up to 60% of patients with SSD. Significant distress and anxiety surrounding physical symptoms are also markers but can present as overfocus or obsessive thinking about symptoms.

Functional disability is common as excessive symptom focus disrupts normal function, especially attending school, and participation in other activities may also be disrupted.

Screening

Lifestyle Changes

Medical Monitoring and Support

Physical Rehabilitation

Cognitive Behavioral Therapy

Medications

• Behavioral Therapies (see NV providers [19])
  A mainstay of the management of SSD and all patients should be referred.
• Pediatric Neurology (see NV providers [5])
  May be helpful in diagnosis of a SSD, although management will more likely be done by physical medicine and rehabilitation and/or primary care.
• Pediatric Physical Medicine & Rehabilitation (see NV providers [3])
  May be helpful for patients with functional disability e.g., deconditioning, trouble walking, etc.) and for management.