Yes, CIDP Patients Can Be Areflexic with Normal 5/5 Strength
Yes, patients with CIDP can absolutely present with absent deep tendon reflexes while maintaining normal (5/5) muscle strength. This represents the milder end of the CIDP spectrum and is well-documented in the literature.
Clinical Evidence for This Presentation
The research clearly demonstrates that CIDP exists on a spectrum of severity. A study specifically examining "minimal and asymptomatic CIDP" found patients with normal strength in all muscle groups despite absent or reduced tendon reflexes 1. These patients were referred for mild distal paresthesias, had normal strength throughout, yet showed absent tendon jerks (except knee jerks in one patient). Electrophysiology confirmed demyelinating neuropathy, and CSF protein was elevated in all cases 1. This minimal CIDP phenotype represented approximately 8% of their CIDP case series 1.
Why Reflexes Are Lost Before Strength
The dissociation between reflexes and strength occurs because:
- Reflexes are exquisitely sensitive to demyelination - Even subclinical demyelination significantly prolongs or abolishes reflex arcs before causing clinically detectable weakness
- Electrophysiologically recorded reflexes show abnormalities even when clinical reflexes appear normal - Studies show that 96% of CIDP patients had abnormal tendon reflex testing even when 7 patients had brisk or normal reflexes on clinical examination 2
- Absent reflexes are significantly more associated with CIDP than axonal neuropathies 3, making areflexia a sensitive early marker
Clinical Implications and Diagnostic Approach
When you encounter a patient with:
- Absent or diminished deep tendon reflexes
- Normal 5/5 strength
- Mild sensory symptoms (paresthesias, numbness)
You must pursue electrophysiological testing to evaluate for demyelinating polyneuropathy 1. The typical CIDP presentation includes progressive or relapsing symmetric proximal and distal weakness 4, but this minimal variant is well-recognized.
Key Diagnostic Steps:
- Nerve conduction studies are essential - they will show demyelinating features even with preserved strength 1
- CSF analysis - expect albuminocytologic dissociation (elevated protein with normal cell count) 1
- Consider electromyographically recorded reflexes if clinical reflexes seem preserved, as 60% of patients with normal clinical reflexes had abnormal electrophysiological reflexes 5
Common Pitfall to Avoid
Do not dismiss the possibility of CIDP simply because strength is preserved. The absence of weakness does not exclude CIDP, particularly in its early or minimal forms. The combination of areflexia with sensory symptoms warrants full electrodiagnostic evaluation regardless of preserved motor function 1. Delayed diagnosis can lead to progression that might have been prevented with early immunotherapy.
The guideline literature acknowledges "atypical forms of CIDP" 6, and these minimal presentations fall into this category. These patients typically respond well to immunotherapy despite their mild presentation 1.