Surreal illustration of nerve pathways showing varied reflex responses in Guillain-Barré Syndrome.

Guillain-Barré Syndrome: When Reflexes Surprise You

Beau Callahan in Health & Wellness December 2025 • 4 min read.

"A rare case highlights hyperreflexia as an unusual sign of Guillain-Barré Syndrome, challenging typical diagnostic expectations."

Guillain-Barré Syndrome (GBS) is generally known as an acquired autoimmune disorder affecting the peripheral nerves. It leads to muscle weakness and, crucially, a loss of reflexes (areflexia). Think of it as your immune system mistakenly attacking your nerves, leading to a range of symptoms. Typically, doctors look for this areflexia to help diagnose GBS.

However, what happens when a patient with GBS symptoms shows increased reflexes (hyperreflexia) instead? This is a less common, but important, variation of the syndrome. This article delves into a fascinating case study where a patient exhibited just that—hyperreflexia in all four limbs—pushing doctors to think outside the typical GBS presentation.

We'll explore the details of this unusual case, focusing on how the diagnosis was made despite the unexpected reflexes and what this means for understanding and diagnosing GBS in the future. This challenges assumptions and highlights the need to consider atypical symptoms in complex conditions.

The Curious Case of Hyperreflexia in GBS: What Happened?

Surreal illustration of nerve pathways showing varied reflex responses in Guillain-Barré Syndrome.

A 42-year-old man sought medical help, reporting progressive weakness in all four limbs over ten days. Interestingly, he had no sensory complaints, and his bowel and bladder functions were normal. There was a history of diarrhea a week before the weakness began.

What made this case particularly interesting was the physical examination. While his limbs were weak, and he struggled to move or lift his head, his reflexes were not absent as expected in GBS. Instead, they were unusually strong (hyperreflexia) throughout his body. His mental functions and sensory systems were normal.

Proximal Leg Muscles: 3/5 strength (on a scale used by doctors)
Distal Leg Muscles: 2/5 strength
Upper Limb Muscles: 3/5 strength
Deep Tendon Reflexes: Brisk throughout

To confirm the diagnosis, doctors performed a lumbar puncture, analyzing his cerebrospinal fluid (CSF). The results showed elevated protein levels without an increase in cells, which is a classic sign of GBS. Additionally, nerve conduction studies revealed reduced nerve conduction velocities and conduction blocks, further supporting the diagnosis of GBS despite the atypical hyperreflexia.

Why This Case Matters: Expanding Our View of GBS

This case underscores that GBS can present with unexpected symptoms like hyperreflexia. Although areflexia is a typical diagnostic criterion, its absence shouldn't automatically rule out GBS, especially when other clinical and diagnostic findings align.

The occurrence of hyperreflexia in GBS may be linked to specific variants of the syndrome, such as axonal GBS, or may relate to the timing of the examination in the disease course. Some studies have noted this phenomenon more frequently in certain populations, such as Chinese and Japanese patients with the AMAN variant. Often, the brisk reflexes could result from early disease stages or specific nerve involvement patterns that influence reflex responses.

Ultimately, this case serves as a reminder for healthcare professionals to maintain a broad perspective when evaluating patients with suspected GBS, considering the possibility of hyperreflexia and utilizing a comprehensive approach to diagnosis. Further research is needed to fully understand the mechanisms behind these atypical presentations and refine diagnostic criteria for GBS.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.3329/jemc.v7i2.32658, Alternate LINK

Title: Hyperreflexia ? An Uncommon Presentation Of Guillain-Barré Syndrome

Subject: General Medicine

Journal: Journal of Enam Medical College

Publisher: Bangladesh Journals Online (JOL)

Authors: Ns Neki, Gagandeep Singh Shergill, Amanpreet Kaur

Published: 2017-06-04

Everything You Need To Know

What exactly is Guillain-Barré Syndrome and how does it affect the body's nervous system?

Guillain-Barré Syndrome is an autoimmune disorder where the body's immune system mistakenly attacks the peripheral nerves. This attack can lead to muscle weakness and a loss of reflexes, known as areflexia. Because the nerves are damaged, they can't properly transmit signals to the muscles, leading to impaired movement and other neurological symptoms. The exact cause of GBS is not fully understood, but it often follows a bacterial or viral infection.

What is the usual expectation regarding reflexes in patients with Guillain-Barré Syndrome, and how does hyperreflexia challenge this?

Areflexia, or the absence of reflexes, is a typical finding in Guillain-Barré Syndrome. Doctors often look for areflexia when diagnosing GBS. However, hyperreflexia, which is increased reflexes, can sometimes occur, as seen in the case study. The presence of hyperreflexia instead of areflexia doesn't necessarily rule out GBS, especially when other clinical signs and diagnostic test results align with the syndrome.

How did hyperreflexia manifest in the described patient, and what diagnostic tests helped confirm the Guillain-Barré Syndrome diagnosis?

In the described case, the patient exhibited progressive weakness in all four limbs but, surprisingly, showed hyperreflexia instead of areflexia. The patient had muscle strength of 3/5 in proximal leg and upper limb muscles and 2/5 in distal leg muscles. Despite the atypical reflexes, a lumbar puncture revealed elevated protein levels in the cerebrospinal fluid, and nerve conduction studies indicated reduced nerve conduction velocities and conduction blocks. These findings, combined with the patient's clinical presentation, supported the diagnosis of Guillain-Barré Syndrome.

Why is it important to recognize cases of Guillain-Barré Syndrome that present with hyperreflexia instead of the typical areflexia?

The case underscores the importance of considering atypical presentations in GBS. While areflexia is a common diagnostic criterion, this case demonstrates that hyperreflexia can occur. If doctors relied solely on the absence of areflexia to rule out GBS, they might miss such cases. It highlights the need for a comprehensive diagnostic approach that considers all clinical findings and laboratory results to ensure accurate diagnosis and appropriate treatment.

Besides reflex testing, what other diagnostic tests are crucial in identifying Guillain-Barré Syndrome, especially when symptoms are not typical?

Diagnostic tests like lumbar puncture and nerve conduction studies can help confirm GBS, even when symptoms are atypical. A lumbar puncture can reveal elevated protein levels without an increase in cells in the cerebrospinal fluid, which is a classic sign of GBS. Nerve conduction studies can show reduced nerve conduction velocities and conduction blocks, indicating nerve damage. These tests provide crucial evidence that, along with clinical observations, can help doctors make an accurate diagnosis.