Neurologic symptoms from Lyme disease and COVID-19 show striking overlap, creating diagnostic confusion when patients develop headaches, brain fog, encephalopathy, and dizziness after infection. More than 80% of COVID-19 patients suffered neurologic complications in a 509-patient study — the same symptoms Lyme disease patients have reported for decades. This overlap means some Lyme disease cases are now being misdiagnosed as Long COVID, while others with both infections face compounded neurologic damage that clinicians struggle to untangle.

COVID-19 Study Reveals Massive Neurologic Impact

In their study, “Frequent neurologic manifestations and encephalopathy‐associated morbidity in Covid‐19 patients,” Liotta and colleagues describe neurologic manifestations in 509 patients with confirmed COVID-19. The authors sought to identify the incidence of neurologic complications in COVID-19 patients.

The Striking Findings

The study found:

• More than 8 out of 10 COVID-19 patients suffered from neurologic complications.
• Nearly 1 out of 3 COVID-19 patients suffered from headaches, encephalopathy, and dizziness, which are also common neurologic symptoms in Lyme disease.
• Other symptoms included myalgia and fatigue, which occurred in 43% of patients at the onset of illness and in 79% of patients during COVID-19 disease.
• COVID-19 patients with encephalopathy were less likely to have a good outcome.
• COVID-19 patients with encephalopathy were hospitalized 3 times longer than COVID-19 patients who did not have encephalopathy.

The 80%+ neurologic complication rate is staggering. This isn’t a minority of severe cases — this is the majority of COVID-19 patients experiencing neurologic symptoms during acute illness.

The Lyme Disease Parallel

Nearly one-third of COVID-19 patients suffered from headaches, encephalopathy, and dizziness. These same symptoms have been reported in Lyme disease patients for decades — often dismissed as anxiety, stress, or “medically unexplained symptoms.”

The overlap is not coincidental. Both infections can cause:

• ✅ Severe headaches
• ✅ Brain fog and cognitive dysfunction
• ✅ Encephalopathy (altered mental status)
• ✅ Dizziness and balance problems
• ✅ Myalgia and fatigue

These aren’t vague complaints. These are measurable neurologic complications from post-infectious inflammation and direct neuroinvasion.

What Is Encephalopathy?

Author’s Note: Encephalopathy typically refers to altered sensorium and central nervous system (CNS) dysfunction. There is no standardized test for encephalopathy. It appears the authors diagnosed their cases of encephalopathy using clinical judgment.

Encephalopathy has been associated with a poor outcome in other diseases. Some patients with Lyme encephalopathy have had a poor outcome. I have found that patients with this condition can be more challenging to treat.

Encephalopathy manifests as confusion, altered consciousness, difficulty concentrating, memory problems, and impaired cognitive function. It represents brain dysfunction from infection, inflammation, or metabolic derangement — not a specific diagnosis but a clinical syndrome requiring investigation.

The Brain Fog Connection

The authors encourage further research and studies of encephalopathy in patients including those with “Covid-19 who complain of protracted inability to concentrate or decreased short-term memory (referred to as ‘brain fog’).”

Brain fog — the inability to concentrate, process information, or maintain short-term memory — is now recognized as a hallmark of Long COVID. But Lyme disease patients have reported identical symptoms for decades, often without recognition or appropriate treatment.

The COVID-19 pandemic has validated what Lyme patients have been saying: post-infectious brain fog is real, measurable, and debilitating.

Multiple Potential Causes

There are several potential causes of encephalopathy in this group of COVID-19 patients, which include: systemic disease and inflammation, coagulopathy, direct neuroinvasion by the virus, endotheliitis, post-infectious autoimmune mechanisms, intensive care unit delirium, sedation and analgesia doses, disruption of sleep/wake cycles, and infectious complications.

But due to limitations from the COVID-19 pandemic, the authors were unable to determine the exact cause of their patients’ encephalopathy.

This uncertainty mirrors the Lyme disease experience. Multiple overlapping mechanisms likely contribute to neurologic symptoms: direct spirochetal invasion of the nervous system, inflammatory cytokines, autoimmune processes, vascular inflammation, and autonomic dysfunction.

Although I am unable to determine the cause of encephalopathy in Lyme disease patients, I encourage doctors to recognize the condition, so that prompt treatment may occur, improving the chances for a complete recovery.

Screening for Encephalopathy

The authors advocate for broader recognition and targeted treatment of encephalopathy. “Broad recognition and screening for encephalopathy as a contributor to disease severity in Covid-19 may have utility in resource allocation and potential to improve patient outcomes,” writes Liotta.

“Prospective cognitive and neurologic-focused evaluations through specialized clinics dedicated to further diagnostic assessment and tailored rehabilitation needs could play a significant role in recovery from this pandemic,” the authors write.

This recommendation should extend to Lyme disease. Neurologic symptoms — including encephalopathy, brain fog, and cognitive dysfunction — deserve systematic screening and specialized evaluation, not dismissal as anxiety.

Expertise Improves Outcomes

Johnson and colleagues reported better outcomes in Lyme disease patients who were treated by doctors with expertise in treating Lyme disease.

Specialized care matters. Physicians experienced with post-infectious complications — whether from Lyme disease, COVID-19, or other infections — achieve better patient outcomes than those applying standardized protocols without individualization.

The Diagnostic Challenge

The overlap between COVID-19 and Lyme disease neurologic symptoms creates diagnostic confusion. Patients with Long COVID may actually have undiagnosed Lyme disease. Patients with Lyme disease may be told their symptoms are Long COVID. Some patients may have both infections, compounding neurologic damage.

The solution requires testing for both when neurologic symptoms persist after known or suspected infection. Geographic history, tick exposure, timing of symptom onset, and response to treatment all provide clues.

Clinical Perspective

This study validates what Lyme disease patients and clinicians have known for decades: infections can cause severe, persistent neurologic complications including headaches, brain fog, encephalopathy, dizziness, and fatigue.

The 80%+ rate of neurologic complications in COVID-19 mirrors what I see in my Lyme disease practice. The majority of patients — not a small minority — experience some degree of neurologic involvement. The symptoms aren’t “just stress” or “just anxiety.” They’re measurable brain dysfunction from infection and inflammation.

The encephalopathy findings are particularly important. Patients with altered mental status, confusion, or severe cognitive dysfunction had worse outcomes and three times longer hospitalizations. This severity demands aggressive treatment, not watchful waiting or psychiatric referral.

The brain fog emphasis is long overdue. COVID-19 patients describing “inability to concentrate or decreased short-term memory” are now taken seriously and referred for cognitive rehabilitation. Lyme disease patients reporting identical symptoms have been dismissed for years. The pandemic has created an opportunity to extend the same validation and care to all post-infectious patients.

The call for “specialized clinics dedicated to further diagnostic assessment and tailored rehabilitation needs” should include Lyme disease. Both conditions benefit from physicians experienced with post-infectious complications who understand the complexity of neurologic recovery.

Finally, the acknowledgment that exact mechanisms remain unclear is honest. We don’t fully understand why some COVID-19 patients develop severe encephalopathy while others don’t. We don’t fully understand why some Lyme patients develop persistent neurologic symptoms while others recover quickly. But uncertainty about mechanism shouldn’t prevent recognition, investigation, and treatment.

Frequently Asked Questions

Can COVID-19 and Lyme disease both cause brain fog?

Yes. Both infections cause post-infectious cognitive dysfunction described as “brain fog” — difficulty concentrating, impaired short-term memory, and slowed processing speed. The mechanisms likely overlap: inflammation, immune dysregulation, and neuroinvasion.

How common are neurologic symptoms in COVID-19 vs Lyme disease?

This study found 80%+ of COVID-19 patients had neurologic complications. In Lyme disease, neurologic involvement occurs in 10-15% of untreated cases, though cognitive symptoms like brain fog may be more common and underrecognized.

Can Lyme disease be misdiagnosed as Long COVID?

Yes. The overlapping symptoms — fatigue, brain fog, headaches, autonomic dysfunction — mean some Lyme disease cases are attributed to Long COVID without appropriate testing. Geographic history and tick exposure should prompt Lyme testing.

What is encephalopathy in Lyme disease?

Lyme encephalopathy refers to brain dysfunction causing altered mental status, confusion, cognitive impairment, and personality changes from spirochetal invasion of the central nervous system. Like COVID encephalopathy, it requires prompt recognition and treatment.

Should all Long COVID patients be tested for Lyme disease?

Patients with persistent post-COVID neurologic symptoms who live in or have traveled to Lyme-endemic areas should be tested for Lyme disease, especially if symptoms include neurologic involvement beyond typical Long COVID patterns.

Do COVID and Lyme neurologic symptoms respond to treatment?

Yes. This study showed COVID encephalopathy patients had worse outcomes, emphasizing need for treatment. Similarly, Lyme encephalopathy improves with antibiotics, though recovery may be gradual. Expertise in treating post-infectious complications improves outcomes for both conditions.

Can you have both COVID-19 and Lyme disease?

Yes. Some patients may have concurrent or sequential infections, compounding neurologic damage. When symptoms are severe or atypical for one infection alone, testing for both should be considered, particularly in endemic areas.