Functional Medicine: when the symptoms don't match the textbook (Walton 11/1/2023)

 A recording of this presentation is available HERE.

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Many thanks to senior resident, Dr. Rebecca Walton, for a thought-provoking Grand Rounds presentation this week on Functional Disorders. Such an important and challenging topic!

What are functional disorders, you ask? As the name implies, functional disorders is not one entity; it is an umbrella term for a group of syndromes including functional GI disorders (e.g. IBS), fibromyalgia, interstitial cystitis, chronic pelvic pain, chronic headaches, and chronic fatigue.

Functional disorders are all disorders that do not have an identifiable disease label (at least not in our world of allopathic medicine) and feature "normal labs" but negatively impact the functioning of the body. They tend to be chronic and some are relapsing.

Functional disorders can be challenging to treat, cause patients and providers frustration and distress, and are steeped in bias. Functional disorders have their roots in psychiatric disorders: Freud's conversion disorder, substitution of a somatic symptoms for a mental one; hysteria, medically unexplained symptoms in multiple organ systems, often tied to the presence of a uterus; and somatic symptom disorder, a significant focus on physical symptoms that results in major distress or problems functioning.

Functional disorders are common in primary care and impose an impressive healthcare burden:

• Functional GI disorders represent 12% of the workload in primary care and 30% of outpatient GI consultations
• Fibromyalgia affects 2-4% of the population, and can lead to up to 10 outpatient visits per person per year
• Chronic headaches, one of the most common complains for neurological referral, are found in 4-5% of the population and results in, on average, 9 days of missed work per year

Patient groups who are already marginalized and at risk for poor outcomes are at highest risk for functional disorders; these include women, rural populations, less educated patients, lower SES, and those with a history of physical or sexual abuse. 

There are much higher rates of functional disorders in female-identified persons than male-identified: interstitial cystitis (14x), fibromyalgia (6x), IBS (2x), chronic headache (2-3x), TMJ (1.5x). Healthcare provider bias plays a role in diagnosis and treatment. 

Dr. Walton wants us to be careful not to tell patients that it is "all in their head". In fact, the second part of Dr. Walton's presentation was an effort to educate us on the many ways in which these functional disorders are not just in people's heads.

Chronic Pain and Central Sensitization

Central Sensitization is a state of persistent neuronal dysregulation that leads to allodynia (pain to non-painful stimuli), hyperalgesia (abnormally heightened pain), and widespread pain. These symptoms seem to occur due to increased responsiveness to stimuli by the CNS. This is super interesting!

Attributes of patients with central sensitization:

• no objective tissue or laboratory findings
• a genetic and/or environmental predisposition
• stress as triggering or exacerbating symptoms
• dysfunctional pain or sensory processing
• do not respond to therapies used for pain (e.g. acetaminophen)

See the image below for a description of how this plays out pathophysiologically in both the central and peripheral nervous systems:

IBS

Moving on to IBS. There are many theories as to how IBS comes about. Many have biologic plausibility and evolving understanding. These include post-infectious IBS (e.g. after a bad gastroenteritis with shigella, salmonella and e coli), autoimmune theories (including anti vinculin and anti-CdtB antibodies), and dysbiosis. Did you know, for example, that people with IBS tend to have higher levels of bacteroides in their guts compared to healthy controls who tend to have higher levels of prevotella?

SIBO, which is characterized by abnormal bacterial growth in the small intestine (most of our gut microbiome resides in our LARGE intestine), can occur due to IBS and other motility issues. Common symptoms include bloating, flatulence, abdominal pain, and diarrhea, weakness, and fatigue. 

There is absolutely bidirectional communication between our gut and our CNS. Animal studies have shown the extreme stress leads to lifelong alterations in gut microbiome and the HPA access. Also CBT can not only increase serotonin levels in the gut but also decrease bacteroides (crazy cooL!!)

There is little argument that early trauma and adverse childhood events (ACEs) have a huge influence on IBS, and prevention of these events is key in preventing leaky gut, microbiome changes, and lifelong GI upset. 

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I will leave you with Dr. Walton's own takeaways

The brain matters, but it isn’t the whole picture
Those who are already facing healthcare discrimination are prone to having functional disorders and thus experience further neglect
There is ongoing research into these syndromes, and I hope that soon the “lack of biomedical markers” changes
Even without biomedical markers, these symptoms matter

Here is a list of references and further reading provided by Dr. Walton:

1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4479361/

2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4695775/

3. https://www.ncbi.nlm.nih.gov/books/NBK532253/

4. https://pubmed.ncbi.nlm.nih.gov/33479067/

5. https://pubmed.ncbi.nlm.nih.gov/32294476/

6. https://www.sciencedirect.com/science/article/abs/pii/S0049017222001111?via%3Dihub

7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2040193/

8. https://pubmed.ncbi.nlm.nih.gov/35156215/

9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7902126/

10. https://www.sciencedirect.com/science/article/abs/pii/S0049017207001473?via%3Dihub

11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3268359/

12. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6708662/

13. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4430499/

14. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6039952/

15. https://pubmed.ncbi.nlm.nih.gov/22180058/

16. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5860136/

17. https://pubmed.ncbi.nlm.nih.gov/34847963/

18. https://pubmed.ncbi.nlm.nih.gov/28888668/

19. https://www.nature.com/articles/mp201644

20. https://pubmed.ncbi.nlm.nih.gov/33268363/

21. https://www.nature.com/articles/mp201644

22. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10507713/