I had a recent conversation with a patient. I told her we need to sort out other co-morbidities. Co-infections? No. This was a new term for this very Lyme literate patient. I was not saying the patient did not have Lyme disease. Not at all. Patients with Lyme disease frequently have a variety of other medical problems which contribute to their illness to varying extents. And, in some cases, it is not Lyme which is making the patient ill, regardless of what the Western Blot says: if the signs and symptoms do not fit -- Lyme may not be the primary issue. Or, perhaps Lyme's contribution to the illness is minor. For example:
Fatigue--profound fatigue, is almost invariably a prominent symptom. What else causes this? Other causes include hypothyroidism, B12 deficiency, anemia, depression and insomnia. After these are excluded, my patients are sent for sleep studies. Sleep disorders are a major cause of fatigue. Lyme patients have higher rates of sleep disorders compared to the general population. Patients may have obstructive sleep apnea (OSA) or central sleep apnea, a brain disease. Sleep apnea is associated with numerous other medical disorders: cardiovascular disease, diabetes and others. Sleep apnea is also associated with neuro-cognitive dysfunction -- sound familiar? And sleep apnea is associated with alterations of immune function. Specifically, high levels of inflammatory cytokines, TNF alpha, interleukins have been measured in these patients. Sleep apnea is a significant co-morbidity which interfers with the healing process.
Oher sleep orders are common as well. Restless leg syndrome is a common cause of poor quality, non-restorative sleep. This condition may be respond to supplementation with high doses of iron, sometimes intravenously, based on ferritin levels (it is not clear why these patients have profound depletion of iron). This movement disorder shares common features with Parkinson's disease, a movement disorder mediated by dopamine deficiency in the basal ganglia, a deep area of the brain. Both disorders are treated with dopamine agonists such as Mirapex. This should not be confused with cortical brain dysfunction--loss of executive dysfunction--related to insufficient dopamine activity in the cerebral cortex. This is treated with dopamine agonists such as stimulants which work in these areas of the brain.
A second sleep test, an MSLT can evaluate for narcolepsy and other disorders. Narcolepsy has been considered a disorder of arousal but is now understood to be a disorder of sleep. This may be effectively treated with Xyrem, a drug which is safe but suffers a bad reputation.
Sleep disorders: a common co-morbidity, cause fatigue and cognitive impairments, as well as mood changes and irritability. Not to say I don't start Lyme therapy early in the process - I must also fix the "non-Lyme" to see what remains.
This is but one example of numerous potential co-morbidities.
Patients may have: rare genetic disorders, rare metabolic disorders - or acquired mutisytem-disorders. One of my patient suffers with stiff man syndrome. This is a rare autoimmune disease caused by destruction of a GABA precursor. Another suffers with a toxic yeast syndrome which mimics chronic Lyme. Neuro-cognitive changes and new onset headaches may be caused a brain tumors or other cancers. It is know that Lyme may be associated with brain tumors.
Medical texts are ripe with esoteric diseases: mystery diagnoses. These are the patients that seek our help. It is not always Lyme.