Can Lyme Disease Cause Dementia?

Can Lyme disease cause dementia? In some patients, neurologic Lyme disease, also known as Lyme neuroborreliosis, can produce dementia-like symptoms including memory loss, cognitive decline, gait disturbance, and behavioral changes. Several case reports describe patients initially diagnosed with dementia whose symptoms were ultimately attributed to Lyme disease.

In a retrospective study entitled “Secondary dementia due to Lyme neuroborreliosis,” Kristoferitsch and colleagues describe several patients whose dementia-like syndromes were ultimately linked to Lyme neuroborreliosis.

Lyme Neuroborreliosis and Dementia-Like Symptoms

Lyme neuroborreliosis occurs when Lyme disease affects the central nervous system. Patients may develop cognitive impairment, memory problems, slowed thinking, mood changes, and gait disturbance. In rare cases, these symptoms can resemble degenerative dementias such as Alzheimer’s disease.

Rapid Improvement With Antibiotic Treatment

The authors describe the case of a 76-year-old woman who developed progressive cognitive decline, weight loss, nausea, gait disturbance, and tremor over a 12-month period. She was referred to a neurology clinic for evaluation.

Three months earlier she had been diagnosed with tension headaches and a depressive disorder. Medications did not improve her symptoms.

Brain imaging revealed bilateral white matter lesions and an old lacunar lesion located at the left striatum. Neurocognitive testing demonstrated “a severe decline of attention, memory and executive functions corresponding to subcortical dementia,” the authors write.

Lyme neuroborreliosis was diagnosed when cerebrospinal fluid (CSF) testing revealed a highly elevated Borrelia burgdorferi-specific antibody index indicating intrathecal antibody production.

After a three-week course of ceftriaxone, the woman “recovered rapidly,” the authors report.

Several years later, the patient reported no gait problems or cognitive impairment and had recently returned from an international trip.

Woman Admitted to Psychiatric Ward With Severe Dementia

A 71-year-old woman with rapidly progressing dementia and short periods of altered consciousness was admitted to a psychiatric hospital. Six months earlier she had experienced only mild forgetfulness.

MRI results showing slight mesiotemporal atrophy and neurocognitive testing initially supported a diagnosis of primary dementia.

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Later, the patient’s daughter reported a tick bite followed by a widespread rash. Lyme neuroborreliosis was suspected and confirmed through CSF testing.

After two weeks of ceftriaxone treatment, the woman’s symptoms subsided and her cognition improved.

READ MORE: 80-year-old man with Lyme encephalopathy instead of dementia

At a five-year follow-up visit, the woman’s cognition remained stable. Memory testing produced scores above the mean for women her age, “which strongly argued against any dementing process,” the authors write.

Features That May Suggest Lyme-Related Dementia

Several clinical findings may help distinguish dementia related to Lyme neuroborreliosis from degenerative dementias.

• Patients or family members often do not recall a tick bite or erythema migrans rash.
• Dementia associated with Lyme disease may progress more rapidly than typical neurodegenerative dementias.
• Significant weight loss can occur, sometimes reaching up to 20 kg per year.
• Symptoms such as headache, nausea, malaise, or vomiting are uncommon in degenerative dementias but may occur in Lyme neuroborreliosis.
• Early gait disturbance may make Alzheimer’s disease less likely.

In many reported cases, cognitive symptoms improved within days of antibiotic therapy.

Can Lyme Disease Cause Dementia?

Although uncommon, Lyme neuroborreliosis can produce dementia-like syndromes. Recognizing this possibility is important because Lyme-related cognitive decline may improve with appropriate antibiotic treatment.

“It is essential to be aware of this manifestation of Lyme neuroborreliosis,” the authors conclude, because early treatment may prevent permanent neurologic complications.

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Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.

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