Functional disorders and Sjogren's: Updated 12-22-2023
Have you been diagnosed with fibromyalgia (FM), irritable bowel syndrome (IBS), or functional neurological disorder (FND). If so, you are not alone. Many Sjogren’s patients are diagnosed with these functional disorders, sometimes for decades, before Sjogren’s disease is suspected. Clinicians default to these labels when they do not have an obvious explanation for the patient’s symptoms. Even patients with obvious Sjogren’s features have long delays to diagnosis because of a lack of clinician familiarity with the disease. See the Sjogren’s is common page to learn why most Sjogren’s patients remain undiagnosed.
What are functional disorders? Functional disorders are defined as abnormal bodily processes that occur without tests or physical findings that can confirm the condition. Most functional disorders are syndromes, but not all syndromes (e.g., postural orthostatic tachycardias syndrome, POTS) are functional disorders. Functional disorders are usually viewed as partly (IBS) or fully (FND) psychosomatic. When clinicians default to psychological explanations, this places the burden on the patient to address their own symptoms, depriving them of a proper diagnosis and medical management.
A functional disorder should never be diagnosed without a thorough evaluation. Not looking for the disease or not knowing how to test for it does not mean it is functional.
Sjogren’s is a well-characterized, systemic disease, not a syndrome or a functional disorder.
A syndrome is a cluster of symptoms of unknown or multiple causes. When the underlying cause of the symptoms is discovered, labels such as “fibromyalgia” should usually be dropped.
What is functional neurological disorder (FND)?
FND is a psychological explanation for neurological symptoms. It is the current term used for conversion disorder, hysteria, or somatoform disorder. Sjogren’s patients are sometimes told they have FND when clinicians are unfamiliar with the diverse neurological manifestations of the disease. No Sjogren’s patient should be labeled with FND without a comprehensive neurological evaluation. Autonomic disorders and small fiber neuropathies are the most common neurological features found in Sjogren's. These are frequently overlooked and labeled as FND because they require specialized testing for diagnosis. True FND is rare. See the Self-Advocacy section below if you are told you have FND.
What about myalgic encephalomyelitis/ chronic fatigue syndrome (ME/CFS)?
ME/CFS is a complex chronic disease that impacts multiple systems in the body, including the nervous and immune systems. It is not a functional disorder. Biomarkers have been found in ME/CFS patients, although these require specialized tests that are not available outside of research settings. ME/CFS patients, like Sjogren’s patients, are often treated dismissively or told that their symptoms are psychogenic.
Sjogren’s and ME/CFS have overlapping features. Sjogren’s patients with debilitating fatigue and dysautonomia are often misdiagnosed as having ME/CFS. It is possible that Sjogren’s disease may coexist with ME/CFS. It is also possible that there is a Sjogren’s-specific condition that mimics ME/CFS. ME/CFS-like symptoms in Sjogren’s are poorly understood and minimally studied. Because these symptoms have a devastating impact on patients’ lives, learning what causes Sjogren's fatigue and other ME/CFS-like symptoms should be a research priority.
Why are so many Sjogren’s patients diagnosed with functional disorders?
a. Gender bias
About 90% of Sjogren’s patients are female. There is a well-documented history of gender bias in medical care. Women’s reports of symptoms are often treated as exaggerated, inaccurate, or caused by poor health habits. Sjogren’s patients who describe debilitating mental or physical fatigue are often told that they are anxious, depressed, or too fat.
Men often encounter the “men don’t get Sjogren’s" bias, which is simply untrue.
b. The “too hard basket”. Rheumatologists are stretched for time. It takes more than a 10-15-minute clinic visit a few times a year to provide comprehensive Sjogren’s care. Because Sjogren’s medical education is largely absent, many clinicians carry the 20th century view that Sjogren's is mostly limited to sicca (dryness). Sjogren's is never just a dryness or "glandular" disease. Widespread clinician education about the systemic nature of the disease is long overdue.
c. Clinicians are not trained to recognize or diagnose neuro-Sjogren’s. Few clinicians are aware that neurological features are common in Sjogren’s, regardless of antibody status (202, 203). Autonomic disorders and small fiber neuropathy are often misattributed to FND. The scattered distribution and strange symptoms seen in Sjogren’s non-length dependent small fiber neuropathy make this condition particularly susceptible to being called FND (203). This Twitter (X) thread explains why ganglionopathy (neuronopathy) is often mistaken for FND. Ganglionopathy often causes patchy sensory loss and odd motor symptoms such as weakness and ataxia (wobbly walking) that vary over time. They may improve with repeat testing and/ or looking at the limb while moving it. This condition is probably underdiagnosed in Sjogren's. Scattered manifestations and varying motor skills and strength often leads patients to being labeled, inappropriately, with FND.
d. No monitoring guidelines There are no formal guidelines for monitoring the systemic aspects of Sjogren’s disease, other than the Sjogren’s Foundation’s Pulmonary Clinical Practice Guidelines. The lungs (pulmonary) are just one of many systems that should be monitored. Because there is no standard practice for monitoring Sjogren’s, rheumatologists vary widely in their approach. Sjogren’s has long been downplayed by the rheumatology profession as a nuisance sicca (dryness) disease. Patients who are told they have sicca-limited disease rarely get adequate care. Undetected systemic manifestations such as lung and kidney disease may lead to irreversible damage. Timely diagnosis and treatment improve outcomes.
Until widespread clinician education is offered, Sjogren’s care, overall, will remain suboptimal. When clinicians are given better tools and clear guidelines, they use them.
SELF-ADVOCACY TOOLS Articles from the peer-reviewed literature
See the Clinician Handouts page to learn how to choose and prepare articles. Preparing in advance takes time but improves the likelihood that a clinician will be receptive to the information.
if you are told you have FND, print out and share this article by Nagata et al (253), which shows that the majority of FND patients have undiagnosed autonomic disorders. Dysautonomia cannot be picked up by routine neurological examination. FND is often a default diagnosis because most clinicians are not trained to recognize or diagnose autonomic disorders. They are taught to stop looking for the underlying causes in patients with multisystem complaints, because this could reinforce what they consider to be maladaptive health anxiety/ FND.
This is tragic, because autonomic disorders are treatable neurological manifestations of Sjogren's disease. Once a patient is noted to have anxiety based symptoms, often have a hard time being believed or taken seriously during future medical encounters.
Use the Nagata article along with the resources on the Autonomic Disorders page to advocate for an evaluation.
Highlight these sentences in the discussion of the Nagata article:
" Although motor and sensory symptoms in FNSD/CD patients can be ruled in or out as consistent with neurological dysfunction by neurologists, it is more difficult to rule out a neurological basis for autonomic symptoms. In the present study, we found high rates of autonomic symptoms gastrointestinal and cardiovascular dysfunction) in addition to motor and sensory symptoms, were the main symptoms of FNSD/CD, suggesting that evaluation of autonomic symptoms is important for both the diagnosis of FNSD/CD and for understanding its pathophysiology. Anti-gAChR antibodies were initially identified in sera from If you are having trouble with memory, confusion, reduced concentration, or keeping track of things, ask your clinician to refer you for a neuropsychiatric evaluation"
The takeaway: Patients labeled with FND often have undiagnosed autonomic disorders.
Small fiber neuropathy Citation 203: Small fiber neuropathy (SFN), including non-length dependent SFN.
Shows non-length dependent SFN is often seen in Sjogren’s but dismissed as psychogenic because it does not follow the typical length dependent (stocking and glove) pattern.
Both citations 202 and 203 studies showed lower rates of positive SSA, higher rates of males impacted, and symptom onset frequently preceding sicca in Sjogren's neuropathy patients vs the Sjogren's patients overall.
Evidence for a biological basis of fatigue