Lyme Meningitis Symptoms: When Lyme Disease Mimics Dementia
Lyme meningitis may resemble dementia
Confusion and weakness can complicate diagnosis
Treatment may improve some neurologic symptoms
Lyme meningitis symptoms may include headache, neck stiffness, fatigue, nausea, weakness, confusion, and cognitive problems. In older adults, however, the presentation may be less typical and can resemble dementia or another neurologic disorder.
In one reported case, an 80-year-old man with Lyme disease developed aseptic meningitis and findings consistent with normal pressure hydrocephalus. His confusion and cognitive decline initially appeared similar to dementia.
Because Lyme disease can affect multiple body systems, patients may also experience other Lyme disease symptoms before or during neurologic involvement.
Can Lyme disease cause meningitis?
Lyme disease can involve the nervous system and lead to meningitis. This neurologic manifestation occurs when the infection is associated with inflammation of the membranes surrounding the brain and spinal cord.
Patients may develop recognizable meningitis symptoms, such as headache, neck stiffness, nausea, or sensitivity to light. Others may have less specific neurologic symptoms, including profound fatigue, weakness, confusion, memory problems, or changes in behavior.
A stiff neck after a tick bite should prompt consideration of Lyme meningitis, particularly when it occurs with headache, fever, facial weakness, confusion, or other neurologic symptoms in a Lyme-endemic region.
These atypical presentations can make Lyme disease diagnosis particularly difficult, especially in an older patient who may already be undergoing evaluation for dementia or another neurologic condition.
Lyme meningitis symptoms in an older patient
An 80-year-old man was admitted to a hospital in Pennsylvania, an area endemic for Lyme disease, because of increasing weakness and confusion.
He had experienced “several days of nausea with decreased appetite, generalized malaise, fatigue, and weakness,” according to the authors.
Cerebrospinal fluid studies suggested aseptic meningitis. A CT scan also showed dilated ventricles, which can be seen with normal pressure hydrocephalus.
The patient underwent treatment for normal pressure hydrocephalus, and his symptoms initially improved.
Positive Lyme disease test during hospitalization
On the fourth day of hospitalization, the man tested positive for Lyme disease by Western blot, with reactivity reported on the 23-kDa and 39-kDa bands.
“Healthcare providers treating patients with NPH should consider Lyme disease as a differential diagnosis because of the multiple reported cases of NPH secondary to Lyme disease.”
“The patient was subsequently diagnosed with aseptic meningitis secondary to Lyme,” the authors state.
This case illustrates why Lyme disease may need to be considered when a patient in an endemic area develops unexplained meningitis, confusion, or cognitive decline.
How is Lyme meningitis diagnosed?
The evaluation of suspected Lyme meningitis may include a neurologic examination, blood tests, brain imaging, and analysis of cerebrospinal fluid obtained through a lumbar puncture.
CSF findings may suggest aseptic meningitis, meaning that inflammation is present even though routine bacterial cultures do not identify one of the more common causes of bacterial meningitis.
Typical Lyme meningitis CSF findings may include a lymphocytic pleocytosis and elevated protein. However, results must always be interpreted alongside the patient’s symptoms, examination findings, exposure risk, and other laboratory evidence.
Lyme antibody testing may provide additional evidence, but laboratory results must be interpreted alongside the patient’s symptoms, exposure risk, physical examination, and other diagnostic findings.
This is especially important because Lyme disease tests can be negative early in the illness, and no individual test result should be interpreted without clinical context.
Lyme meningitis and normal pressure hydrocephalus
Normal pressure hydrocephalus, often abbreviated as NPH, is associated with enlarged brain ventricles and may cause difficulty walking, impaired bladder control, and cognitive decline.
In this patient, imaging showed dilated ventricles, while CSF findings suggested meningitis. The combination raised the possibility that inflammation associated with Lyme disease contributed to his neurologic presentation.
Although this is an uncommon presentation, the authors noted that other cases of normal pressure hydrocephalus associated with Lyme disease have been reported.
Can Lyme meningitis mimic dementia?
Confusion, impaired memory, slowed thinking, personality changes, and difficulty functioning independently may resemble dementia. When these symptoms develop over a relatively short period, clinicians may investigate potentially reversible causes.
Infections, medication effects, metabolic disorders, hydrocephalus, and inflammatory neurologic conditions can all contribute to cognitive impairment. Lyme disease may also be considered when a patient has compatible symptoms and a plausible history of tick exposure.
This does not mean that every case of dementia is caused by Lyme disease. Instead, this case demonstrates that neurologic symptoms associated with Lyme disease may sometimes complicate or resemble an underlying cognitive disorder.
Lyme meningitis treatment and recovery
The patient was treated with intravenous and oral doxycycline. His dementia did not completely resolve and was thought to be “likely due to primary dementia or other condition.”
Depending on the clinical presentation and severity of neurologic involvement, Lyme meningitis treatment may include oral doxycycline or intravenous ceftriaxone. Treatment decisions should be individualized based on the patient’s symptoms, examination findings, and overall medical condition.
The incomplete recovery suggests that more than one condition may have contributed to his cognitive impairment. Lyme meningitis, normal pressure hydrocephalus, an underlying dementia, or another neurologic disorder may have played a role.
Recovery from neurologic Lyme disease varies. Some symptoms may improve after appropriate antibiotic treatment, while cognitive or functional problems may persist when there are coexisting medical or neurologic conditions.
“In the case of our patient, infectious meningitis was suspected due to this patient reportedly having had fevers and leukocytosis. Additionally, Lyme disease is among the most common reportable infections in Pennsylvania,” the authors state.
Authors’ conclusion
“Lyme disease … can present with multiple complications, including arthritis, heart rhythm defects, facial nerve palsy, impaired memory, and meningitis. Hence, Lyme disease should be considered as part of the differential etiology of meningitis.”
Frequently Asked Questions
What are the symptoms of Lyme meningitis?
Lyme meningitis symptoms may include headache, stiff neck, fever, nausea, fatigue, weakness, light sensitivity, confusion, and memory problems. Some patients may have less typical symptoms, particularly older adults.
Can Lyme disease cause meningitis?
Yes. Lyme disease can involve the nervous system and may be associated with inflammation of the membranes surrounding the brain and spinal cord. This condition is commonly referred to as Lyme meningitis.
Can Lyme meningitis resemble dementia?
Lyme meningitis may cause confusion, impaired memory, slowed thinking, or behavioral changes that resemble dementia. However, patients may also have an underlying cognitive disorder that does not fully resolve after treatment.
Does Lyme meningitis always cause a stiff neck?
No. Although neck stiffness is a recognized meningitis symptom, not every patient experiences it. Some patients primarily report fatigue, headache, nausea, weakness, confusion, or other neurologic symptoms.
How is Lyme meningitis diagnosed?
Diagnosis may involve a neurologic examination, Lyme antibody testing, brain imaging, and cerebrospinal fluid analysis. Results must be interpreted within the context of the patient’s symptoms and exposure history.
Can Lyme meningitis be treated?
Lyme meningitis is treated with antibiotics selected according to the patient’s clinical presentation. Treatment may include oral doxycycline or intravenous ceftriaxone. Many patients improve, but recovery may be incomplete when another neurologic condition is also present.
Clinical Takeaway
Lyme meningitis is an uncommon but important neurologic manifestation of Lyme disease. In older adults, fatigue, weakness, confusion, memory problems, and other cognitive changes may be mistaken for dementia or attributed entirely to normal aging.
Clinicians practicing in Lyme-endemic regions should consider Lyme disease when evaluating aseptic meningitis, unexplained cognitive decline, or possible normal pressure hydrocephalus.
Early recognition and appropriate treatment may improve neurologic symptoms, although recovery can remain incomplete when another cognitive or neurologic disorder is also present.
Related Articles
Read more about neurologic presentations and complications of Lyme disease:
Lyme disease presents as brachial plexopathy and meningitis
One year after infection, patient shows signs of Lyme meningitis
Lyme meningitis leading to hyponatremia
References
- Liu R, Polly M, Lennon RP, Reedy-Cooper A. Meningitis in the Guise of Dementia: Lyme-Induced Normal Pressure Hydrocephalus. Clin Med Res. 2023;21(4):226-229. doi: 10.3121/cmr.2023.1829. PMID: 38296639.
Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.
Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention
