From the Guidelines
Yes, sarcoidosis can cause peripheral neuropathy, specifically small fiber neuropathy (SFN), which occurs in approximately 40-60% of sarcoidosis patients. Sarcoidosis is a multisystem inflammatory disorder that can affect various parts of the body, including the nervous system. When it impacts the peripheral nerves, it can lead to peripheral neuropathy, characterized by neuropathic symptoms and dysautonomia due to loss of thinly myelinated and unmyelinated nerve fibres 1. The symptoms of SFN in sarcoidosis patients may include:
- Paraesthesias
- Allodynia
- Numbness
- Pain syndromes
- Gastrointestinal dysmotility
- Diaphoresis
- Orthostasis
- Palpitations
- Other symptoms associated with dysautonomia The diagnosis of SFN can be confirmed by specialized tests such as skin biopsy for intraepidermal nerve fibre density, nerve fibre density assessed by corneal confocal microscopy, quantitative sudomotor axon reflex test (QSART), and thermal threshold testing 1. Treatment for SFN in sarcoidosis patients includes agents specific for the condition, such as intravenous immunoglobulin (IVIg) and anti-TNF therapy, as well as supportive care for neuropathic symptoms 1. It is essential to note that the diagnosis of SFN is probably highly underreported due to lack of awareness among clinical physicians 1. Therefore, it is crucial to screen for SFN-associated symptoms in sarcoidosis patients using validated instruments like the SFN Screening List 1.
From the Research
Sarcoidosis and Peripheral Neuropathy
- Sarcoidosis is a multisystem disorder that can cause peripheral neuropathy, a rare but treatable manifestation of the disease 2.
- Peripheral neuropathy in sarcoidosis can present in various forms, including distal symmetric polyneuropathy, asymmetric polyradiculoneuropathy, and small fiber neuropathy 3.
- The diagnosis of sarcoidosis-related peripheral neuropathy is often based on the identification of characteristic neurologic findings in an individual with proven systemic sarcoidosis, as established by clinical, imaging, or histologic findings 4.
Clinical Manifestations
- Peripheral neuropathy in sarcoidosis can manifest as cranial neuropathy, aseptic meningitis, mass lesions, encephalopathy, vasculopathy, seizures, hypothalamic-pituitary disorders, hydrocephalus, myelopathy, and myopathy 4, 5.
- Sarcoid granulomas can occur in any anatomic substrate in the nervous system, causing protean manifestations that have earned neurosarcoidosis the sobriquet "the great mimic" 5.
- The clinical spectrum of sarcoidosis-related peripheral neuropathy includes nodular myopathy, acute myopathy, and chronic myopathy 6.
Treatment
- Corticosteroids are the cornerstone of treatment for sarcoidosis-related peripheral neuropathy, especially in the acute stage 2, 5.
- Steroid-sparing agents such as methotrexate, mycophenolate mofetil, and azathioprine are used for prolonged therapy to minimize steroid toxicity 5.
- Anti-tumor necrosis factor agents may help in refractory cases, and the use of TNF-alpha inhibitors has notably increased in recent times 5, 6.