Lyme disease is an infection caused by the bacterium Borrelia burgdorferi, primarily transmitted to humans through the bite of an infected blacklegged tick. While often recognized for its distinctive rash and systemic symptoms, the infection can affect various body systems. This article explores the potential link between Lyme disease and digestive issues, specifically diarrhea, which is a less common manifestation.
Diarrhea as an Atypical Symptom of Lyme Infection
Diarrhea is not considered one of the classic, primary symptoms used by medical professionals to diagnose early-stage Lyme disease. The initial presentation is far more commonly characterized by a localized skin lesion and general flu-like malaise. However, the Borrelia spirochete is a highly mobile bacterium that can disseminate throughout the body, potentially involving the gastrointestinal tract.
A small percentage of patients with early Lyme borreliosis, estimated between 5% and 23%, have reported various digestive symptoms, including diarrhea, abdominal pain, nausea, or vomiting. This direct gastrointestinal involvement, sometimes referred to as GI borreliosis, is attributed to the presence of the bacteria within the gut lining. The spirochetes can trigger an inflammatory response in the stomach, small intestine, or colon, potentially leading to conditions like gastritis or colitis.
When gastrointestinal symptoms occur directly due to the infection, they are typically transient and mild, appearing alongside the initial wave of systemic symptoms. Scientific literature, primarily case studies, has documented the presence of Borrelia burgdorferi DNA and inflammation in the GI tissue of some patients. This suggests that a direct, bacteria-driven mechanism can contribute to digestive distress.
The Recognizable Stages and Symptoms of Lyme Disease
The typical course of Lyme disease is commonly divided into three clinical phases. The first phase, known as Early Localized disease, usually begins days or weeks after the tick bite. This stage is most recognizable by the Erythema migrans rash, an expanding, often circular red area that may or may not resemble a bull’s-eye pattern.
Accompanying the rash, patients frequently experience non-specific constitutional symptoms that mimic a common flu. These include fever, chills, fatigue, headache, and generalized muscle and joint aches. If the infection is not addressed promptly, it progresses to the Early Disseminated stage weeks to months after the initial infection.
During the disseminated phase, the bacteria spread to other parts of the body, potentially affecting the heart, nervous system, and joints. Neurological symptoms such as meningitis, radiculopathy (nerve pain), or facial nerve palsy (Bell’s palsy) are common manifestations. Lyme carditis, which can cause heart rhythm irregularities, is a less frequent but serious complication.
The final stage, Late Disseminated disease, can occur months to years after the initial infection and is frequently characterized by Lyme arthritis. This typically presents as episodes of pain and swelling in one or more large joints, most often the knee.
Gastrointestinal Issues Stemming from Treatment or Co-Infections
The most frequent reasons a patient with a Lyme disease diagnosis experiences diarrhea are related to the treatment regimen or the presence of a co-infection. Standard treatment involves oral antibiotics such as doxycycline, amoxicillin, or cefuroxime. These medications target the Borrelia bacteria but also disrupt the balance of the gut microbiome, a condition known as dysbiosis.
This disruption of beneficial gut bacteria can lead to antibiotic-associated diarrhea, a common side effect of many broad-spectrum antibiotics. A more serious complication of this imbalance is the overgrowth of the bacterium Clostridioides difficile. C. difficile infection causes severe, watery diarrhea, abdominal cramping, and can lead to life-threatening inflammation of the colon.
Another significant factor is the possibility of co-infection, as the same tick that transmits Borrelia burgdorferi can simultaneously transmit other pathogens. Co-infections like Anaplasmosis and Babesiosis are frequently associated with gastrointestinal distress, including diarrhea. For instance, Anaplasmosis, caused by the bacterium Anaplasma phagocytophilum, often presents with nausea, vomiting, and diarrhea alongside fever and muscle aches.
These co-infections are more reliably linked to diarrhea than Lyme disease alone. When a patient presents with Lyme and significant diarrhea, a physician will often investigate the possibility of these other tick-borne diseases. Addressing these concurrent illnesses often requires additional, specific treatment protocols beyond those used for Lyme alone.
Medical Evaluation and Addressing Digestive Distress
When a patient presents with suspected or confirmed Lyme disease and concurrent diarrhea, the medical evaluation focuses on determining the underlying cause to provide targeted treatment. The first step involves a differential diagnosis, where the healthcare provider rules out common causes of digestive upset, such as food poisoning, irritable bowel syndrome, or other infectious gastroenteritis.
If the patient is currently taking antibiotics for Lyme, the physician must immediately consider antibiotic-associated diarrhea and the risk of C. difficile infection. Specific stool tests are used to check for the presence of C. difficile toxins. A positive result necessitates a change in the antibiotic regimen and specific treatment for the infection.
The physician will also investigate the possibility of co-infections, as their symptoms often overlap with Lyme but demand different treatments. Blood tests may be ordered to check for evidence of pathogens like Anaplasma or Babesia. Addressing these co-infections with specific anti-parasitic or alternative antibiotic agents can resolve the associated digestive issues.
Regardless of the cause, supportive management is provided to address the digestive distress. This often includes recommending dietary modifications, such as following a bland diet, and ensuring adequate hydration to replace fluids lost due to diarrhea. Probiotic supplementation, given separately from the antibiotic dose, is a common strategy to help restore the gut microbiome and mitigate antibiotic effects.