Bannwarth Syndrome and Weight Loss: An Atypical Case of Neurologic Lyme Disease

Bannwarth syndrome is a neurologic manifestation of Lyme disease most commonly described in Europe. However, cases are increasingly recognized in the United States. Physicians from the Mayo Clinic previously described several patients with neuroinvasive Lyme disease living in Minnesota and Wisconsin. In those cases, patients presented with peripheral neuropathy, a key feature of Bannwarth syndrome.

Bannwarth syndrome is characterized by severe nerve root pain (radiculopathy), peripheral neuropathy, and sometimes facial nerve palsy. The condition represents a form of neuroborreliosis, meaning infection of the nervous system by Borrelia burgdorferi. While commonly reported in Europe, physicians in the United States are increasingly recognizing similar neurologic presentations.

A 2019 case report by Diaz and colleagues describes an unusual presentation of Bannwarth syndrome in a 60-year-old man in the United States.¹ The patient developed several atypical symptoms including abnormal liver function tests and significant weight loss.

An Unusual Presentation of Bannwarth Syndrome

The patient initially presented with elevated liver function tests and an unexplained weight loss of approximately 25 pounds.

Over the following three weeks he developed progressive back pain along with symptoms of peripheral neuropathy, including arm and leg weakness, numbness in his hands and a right facial droop. Shortly after admission to the hospital, the patient developed a complete facial palsy.

“Throughout this time, severe central back pain persisted requiring neuropathic pain agents and opiates for adequate pain control,” writes Diaz.

Neurologic Findings

An EMG and nerve conduction study demonstrated prolonged distal latencies and slowed conduction velocity consistent with polyradiculopathy.

A spinal tap revealed lymphocytic pleocytosis (96%) and elevated protein levels (156 mg/dL), findings consistent with inflammatory meningoradiculitis seen in neurologic Lyme disease.

Laboratory Evaluation

Serologic testing and spinal fluid were positive for Lyme disease by Western blot IgG. The serologic test revealed only one IgM band. A CSF-to-serum antibody index assay was not performed.

Because the patient had abnormal liver function tests (transaminitis), physicians considered anaplasmosis as a possible cause. However, testing for anaplasmosis was negative.

Serologic tests were positive for Babesia, though no parasites were detected on blood smear.

The patient’s clinical presentation ultimately led physicians to diagnose a variant form of Bannwarth syndrome caused by Lyme disease.

Treatment and Recovery

The patient was treated with four weeks of intravenous ceftriaxone.

“On follow-up at 2 months, facial paralysis, pain, motor, and sensory deficits had resolved with return to baseline weight and liver function tests,” the authors reported.

Why This Case Matters

Bannwarth syndrome is characterized by painful radiculopathy, neurologic deficits, and sometimes facial nerve palsy. While commonly described in Europe, clinicians in the United States may be less familiar with the syndrome.

In this case, the presence of atypical symptoms such as weight loss and liver dysfunction made diagnosis more challenging.

Diagnosing Bannwarth syndrome can be difficult because symptoms often overlap with other neurologic disorders. Patients may initially be evaluated for spinal disorders, autoimmune disease, or other infections before Lyme disease is considered. In regions where Lyme disease is common, clinicians should include neuroborreliosis in the differential diagnosis when patients present with severe radicular pain and neurologic deficits.

“Our case demonstrates the importance of consideration of Bannwarth syndrome in the differential diagnosis of meningoradiculitis, even in the setting of atypical features such as liver dysfunction and weight loss,” writes Diaz.

Clinical Perspective

This case highlights the need for clinicians to consider Bannwarth syndrome when evaluating patients with painful radiculopathy, neuropathy, varying degrees of motor weakness, and lower motor neuron facial nerve palsy.

Although the syndrome is more frequently reported in Europe, cases of neuroborreliosis consistent with Bannwarth syndrome are increasingly recognized in the United States.

This case illustrates how Lyme disease can produce unusual neurologic and systemic symptoms. Recognizing Bannwarth syndrome early may allow timely treatment and prevent prolonged neurologic complications.

Editor’s note: This case suggests the need to consider Bannwarth syndrome in patients living in the United States who present with painful radiculopathy, neuropathy, varying degrees of motor weakness, and lower motor neuron facial nerve palsy—even when atypical symptoms such as weight loss or liver dysfunction complicate the clinical picture.

What is Bannwarth syndrome?

Bannwarth syndrome is a neurologic manifestation of Lyme disease characterized by severe radicular pain, neuropathy, and sometimes facial nerve palsy. It represents a form of neuroborreliosis affecting the nervous system.

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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