CLINICAL MATTER
Nothing causes an “outbreak” of a disease more than a celebrity claiming to have that condition. The most recent revelation from a supermodel that she had Lyme disease has resulted in a deluge of consults from patients in my clinic wondering whether they had the same problem. Even my niece who was recently bitten by a tick from her dog asked me whether she was at risk.
As an infectious diseases doctor, I have taken care of Lyme disease patients during my training in the US. Acute Lyme disease and its complications can be devastating and sometimes fatal if not treated properly. Lately, there has also been much controversy about so-called “chronic Lyme disease,” which is much more difficult to define as a genuine medical condition. As for the Philippines, I have not seen a single Lyme disease case locally, and there is a very good reason for that.
Lyme disease is an infection caused by the bacteria Borrelia burgdorferi. It is a spiral-shaped bacteria known as a spirochete, similar to the causative agents of leptospirosis (Leptospira) and syphilis (Treponema pallidum). It is acquired from a tick bite. Not all types of ticks can transmit Lyme. The specific tick that transmits Lyme disease is the black-legged deer tick (Ixodes scapularis).
Ixodes ticks are infected with Borrelia burgdorferi as juveniles (larva or nymphs) from the wild reservoir of Lyme disease, the white-footed mouse. Adult Ixodes ticks cannot get Lyme disease from deer, and neither can Lyme-infected ticks transmit Lyme disease to deer. This means that these ticks can only get infected with Lyme disease in areas of the world where there are white-footed mice infected with Borrelia burgdorferi. The most common route of infection is when infected nymphs from the mice bite humans directly. Another infection route is when the infected nymphs transfer to a deer host and grow into infected adults, which can then bite and infect humans. The distribution of Lyme disease worldwide is dependent on the presence of the white-footed mouse, which is its primary reservoir.
Signs and symptoms of acute Lyme disease occur a few days after being bitten by an infected tick. Around 70 to 80 percent of infected persons develop a characteristic “erythema migrans” rash, which is skin redness that radiates out from the site of the tick bite. The inner portions of the rash may begin clearing even as it gets bigger, and the rash with the bite in the middle ends up looking like a “bull’s eye,” hence it is also called a target rash. Concurrent fever, chills, and muscle and joint pains are common. Swollen lymph nodes, especially in the region of the tick bite, can also occur. Some people may develop facial palsy (Bell’s palsy).
Without prompt antibiotic treatment, Lyme disease progresses and starts to affect the heart and the nervous system. Swelling of joints, neck stiffness, and severe headaches can also occur. Numbness and tingling of the hands and feet and nerve pain are common. Inflammation of the brain and spinal cord (encephalitis) and irregular heartbeat from swelling of the heart (myocarditis) are among the more serious complications, which can become fatal.
Testing for Lyme disease is not readily available in the Philippines. It is a two-step process involving screening for antibodies and doing a special antibody test called a Western Blot. The antibody test may not be positive early in the disease because it takes the body six to eight weeks to produce antibodies from the time of infection.
Treatment for Lyme disease in the early stages is with oral antibiotics such as doxycycline, amoxicillin, or cefuroxime. Typically, an erythema migrans rash along with a history of a tick bite from a known endemic area for Lyme is enough to initiate treatment. Bell’s palsy from suspected Lyme disease is treated with doxycycline. For more severe manifestations of neurologic and cardiac disease, IV antibiotics such as ceftriaxone may be needed. Other treatments specific to the affected organ systems may be necessary. Do not take any antibiotics without consulting a doctor.
Recently, there has been a lot of confusion between the persistence of some symptoms of Lyme disease after successful treatment and so-called “chronic Lyme disease.” Persistence of joint pains, fatigue, and difficulty thinking beyond six months after successful treatment of Lyme disease with antibiotics is termed Post-treatment Lyme Disease Syndrome (PTLDS). It is a bit like long Covid-19 in the way that some of the damage caused by Lyme disease can take a long time to heal or may persist in some cases. The main difference between PTLDS and “chronic Lyme disease” is that PTLDS is not thought to have any bacteria left that needs further antibiotic treatment. To diagnose PTLDS, the blood tests for Lyme must be positive, and appropriate treatment has to have been given. Clinical trials for PTLDS using additional antibiotic regimens have failed to demonstrate any benefit. The good news is that in most cases, PTLDS improves over time.
In contrast, “chronic Lyme disease” has become a catch-all term that suggests that different symptoms, including chronic pain, fatigue and neurological problems, are a result of Lyme disease. Unfortunately, in many of these cases, there is no objective evidence of Lyme disease whether through positive serologic testing or a history of exposure in an endemic area. Those purportedly suffering from “chronic Lyme disease” have had some pseudoexperts recommend prolonged administration (up to 10 weeks) of IV antibiotics. Three clinical trials have failed to consistently show a benefit for this kind of treatment even in those with evidence of previous Lyme infection. Moreover, some patients had severe side effects from the long-term antibiotic treatment. One other potentially disastrous consequence of misattributing symptoms to “chronic Lyme disease” is that an underlying disease like cancer that is causing the symptoms might be missed. At this time, mainstream medical experts do not support the use of the term “chronic Lyme disease.”
Why am I so confident that my niece wasn’t suffering from Lyme disease? Well, the reservoir for Lyme disease, the white footed mouse, is not present in the Philippines. She has no history of travel to any Lyme-endemic areas. But perhaps the biggest reason I’m sure she doesn’t have Lyme disease is that she was bitten by the wrong tick. A dog tick (Dermacentor), unlike the deer tick (Ixodes), does not carry Lyme disease. Without the right tick and without the correct reservoir host, there is no reason to suspect Lyme and a dog tick bite is, pardon the pun, barking up the wrong tree.