August Introduction

Great case presentation you guys.
Something I now include in my history questions for the "funky neuro" category is recent travel in Hawaii/Southeast Asia. Commonly called "Rat Lung Disease" Angiostrongylus cantonesis infection produces a wide range of funky neuro symptoms. For those practicing in Hawaii (Big Island specifically) it is, in my experience, more common than GBS and is also diagnosed with LP. Info is available on cdc.gov.

I copied the first 3 paragraphs of the case summary and pasted into ChatGPT asking it to give me a differential diagnosis and suggested next steps in the evaluation and treatment of the patient. Here is what it spit out...

Based on the clinical history and the physical examination findings, this patient's presentation is concerning for a neurological process, possibly involving the spinal cord or peripheral nerves. His symptomatology of back pain, numbness in hands and feet bilaterally, and unsteady gait are alarming for a potentially serious underlying condition. Here is a differential diagnosis list with estimated likelihood percentages and recommended next steps for evaluation and treatment:

**Differential Diagnosis:**
1. Cervical Spondylotic Myelopathy (CSM) - 30%
2. Spinal Epidural Abscess (SEA) - 20%
3. Guillain-Barré Syndrome (GBS) - 20%
4. Multiple Sclerosis (MS) or other Demyelinating Disease - 15%
5. Transverse Myelitis - 10%
6. Spinal cord tumor - 3%
7. Other - 2% (Includes rare neurological disorders, Lyme disease, etc.)

**Next Steps in Evaluation:**

1. **Immediate Neurology Consult:** Given the neurological findings on physical examination and the patient’s story of progressive symptoms, immediate neurology involvement is warranted.
2. **MRI of Spine (Cervical and Lumbar):** This imaging is essential for the evaluation of potential structural or inflammatory lesions of the spinal cord. It can help to identify or rule out SEA, CSM, transverse myelitis, or a spinal cord tumor.
3. **Lumbar Puncture (LP):** If not contraindicated by the MRI findings (e.g., evidence of increased intracranial pressure or spinal cord compression), an LP can help to diagnose or rule out inflammatory or infectious processes. Analysis should include cell count, glucose, protein, and possibly oligoclonal bands and specific infectious studies.
4. **Electromyography (EMG) and Nerve Conduction Studies (NCS):** If GBS is suspected, these studies can be very useful.
5. **Blood Work:** Additional workup should include ESR, CRP, vitamin B12 level, Lyme titer, syphilis testing (RPR/VDRL), and possibly autoimmune markers (e.g., ANA, aquaporin-4, and MOG antibodies), based on clinical suspicion after initial workup.

**Treatment Plan:**

1. **Empiric Treatment:** If SEA is strongly suspected based on clinical or imaging findings, empiric antibiotic treatment should be initiated immediately after appropriate cultures have been obtained (blood cultures, and possibly from LP if performed).
2. **Neurosurgical Consultation:** If SEA or significant spinal cord compression is identified on imaging, urgent neurosurgical consultation is needed for possible surgical intervention.
3. **Steroids:** For suspected transverse myelitis, multiple sclerosis, or other inflammatory processes, high-dose steroids are often initiated after infection is ruled out.

**Patient Safety:**
1. Given the patient’s wide-based unsteady gait and inability to tandem walk, fall precautions should be initiated to ensure the patient’s safety during his hospital stay.

This patient needs urgent evaluation and treatment. Rapid involvement of neurology and potentially neurosurgery is critical, as many of the conditions in the differential diagnosis are time-sensitive and potentially reversible if treated promptly.

I then added the prompt "For the case discussed, a lumbar puncture was performed. LP results: Zero red blood cells (RBC), 3 WBCs (essentially negative), a protein of 197 mg/dL (normal is a range of 15-45 mg/dL), normal glucose. With this, please update the differential diagnosis and next steps." Here is the update:

With the lumbar puncture (LP) findings showing a markedly elevated protein level with normal glucose and essentially negative WBCs, this pattern is consistent with albuminocytologic dissociation. This pattern is classically seen in Guillain-Barré Syndrome (GBS) but can be seen in other neurological conditions as well. The absence of red blood cells (RBCs) and normal glucose make infectious and hemorrhagic causes less likely. The significantly elevated protein is a hallmark of several conditions, most notably GBS.

Here is the updated differential diagnosis with adjusted likelihood percentages based on the LP results:

**Updated Differential Diagnosis:**
1. Guillain-Barré Syndrome (GBS) - 60%
2. Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) - 20%
3. Spinal cord tumor (may have blockage of spinal fluid flow leading to elevated protein) - 10%
4. Other - 10% (includes rare neurological disorders)

**Next Steps in Evaluation:**
1. **Electromyography (EMG) and Nerve Conduction Studies (NCS):** Given the elevated suspicion for GBS or CIDP based on LP findings, these tests are essential to further delineate the nature of this patient’s neuropathy. They can help distinguish between demyelinating and axonal forms of neuropathy and are fundamental for the diagnosis of GBS or CIDP.
2. **Neurology Consultation:** Continue close collaboration with neurology for ongoing evaluation and management.
3. **MRI of Spine (Cervical and Lumbar):** Even with these LP findings, imaging of the spinal cord remains crucial to exclude structural or compressive lesions.
4. **Further Laboratory Evaluation:** Consider additional workup for potential underlying etiologies, including infectious (e.g., HIV, Lyme disease, Hepatitis B and C), autoimmune, and paraneoplastic conditions.

**Treatment Plan:**
1. **Initiate Treatment for GBS:** If clinical suspicion remains high for GBS, and especially if EMG/NCS are consistent with this diagnosis, treatment should be initiated urgently. This generally involves either intravenous immunoglobulin (IVIG) or plasmapheresis.
2. **Manage Symptoms and Complications:** Ensure the patient’s respiratory function is closely monitored, as GBS can lead to respiratory failure. Regularly assess the patient's strength, reflexes, and ability to cough and take deep breaths. Implement fall precautions, physical therapy, and occupational therapy consults for mobility and self-care assistance.

**Patient Safety:**
1. **Respiratory Monitoring:** Given that GBS can lead to rapid deterioration of respiratory muscle strength, admit the patient to a setting where respiratory status can be closely monitored (e.g., Intermediate Care Unit or ICU).
2. **DVT Prophylaxis:** Given the potential for significant immobility with GBS or other neuromuscular conditions, assess the patient’s risk for deep venous thrombosis (DVT) and consider prophylactic measures (e.g., heparin, enoxaparin, or mechanical devices).

This patient needs urgent and close monitoring, as GBS and other conditions in the differential can progress rapidly and have significant morbidity and mortality, particularly if respiratory function becomes compromised.

Agreed...great presentation. One issue I wanted to add to discussion is regarding MRI/LP timingand back pain. I do pause whenever I have a person with low back pain, +/- neuro findings that I am considering an LP especially if they have a fever. Is there any clear guidance regarding timing of these? I would think doing an LP on what turns out to be a localized deep infection (ie epidural abscess or discitis) is frowned upon. On the other hand, not all of us have MRI at our fingertips.

Thanks for this great segment! We've had several similar cases in my department in the past few weeks. When I consulted our neurologist, he said he had seen an unusual number of GBS cases in other hospitals over the past month. I've been asking around, and anecdotally it seems an uptick in GBS cases has been noted in several other local hospitals. Has anyone else noticed this trend in your practice or heard anything similar?

Question about the case-

I have always thought that back pain looking like GBS (with neuro symptoms) that isnt feeling like a cord compression warrants consideration of transverse myelitis. this would cause back pain, BL LE weakness, and also would elevate the LP protein for similar reasons as GBS. Not that it matters too much, but it would have shown up on an MRI. I'm curious why neurology didnt consider this?

Thanks!