Small fiber neuropathy; This literature-non-study case was reported in a literature article and describes the occurrence of SMALL FIBRE NEUROPATHY (Small fiber neuropathy) in a 64-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 prophylaxis.   LITERATURE REFERENCE:    Concurrent medical conditions included Vertigo, Undifferentiated connective tissue disease, Hyper IgE syndrome, Diabetes mellitus (not on any treatment) and Basal cell carcinoma.  On an unknown date, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced SMALL FIBRE NEUROPATHY (Small fiber neuropathy) (seriousness criterion medically significant). At the time of the report, SMALL FIBRE NEUROPATHY (Small fiber neuropathy) outcome was unknown.    DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Antinuclear antibody: (Positive) Positive. On an unknown date, Biopsy skin: revealed small fiber neuropathy. Specimens from the distal leg and proximal thigh were consistent with a mild length-dependent neuropathy affecting unmyelinated sensory fibers while specimens from the left ankle revealed occasional small axonal swellings in the epidermis and sub-epidermis. On an unknown date, Blood thyroid stimulating hormone: Normal. On an unknown date, Cardiovascular autonomic function test: (Negative) did not reveal any evidence of parasympathetic cardio-vagal dysfunction, adrenergic dysfunction, postural orthostatic tachycardia syndrome (POTS), small fiber neuropathy or orthostatic hypotension. On an unknown date, Chest X-ray: Showed no acute pathology. On an unknown date, Electrocardiogram: Showed normal sinus rhythm with nonspecific T-wave abnormality. On an unknown date, Electrocardiogram ambulatory: revealed a single event of four beats of ventricular tachycardia on review. On an unknown date, Electromyogram: did not reveal large fiber neuropathy. On an unknown date, Nerve conduction studies: did not reveal large fiber neuropathy. On an unknown date, Ultrasound Doppler: (Negative) Negative. On an unknown date, Vital signs measurement: All within normal limits.  For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered SMALL FIBRE NEUROPATHY (Small fiber neuropathy) to be related.    No concomitant and treatment information were reported.  The patient presented to the emergency department with complaints of one day of chest discomfort, palpitations and left leg twitching and tingling. The patient was in her usual state of health up until she developed new symptoms including dull retrosternal pain, palpitations, lightheadedness and tingling in lower limbs. This was approximately three weeks after receiving the third dose of the Moderna vaccine.   The patient described her symptoms as paroxysmal tingling affecting mainly the feet, left more than right. The patient denied back pain, focal weakness, gait changes, or falls. Patient denied skin rash or loss of muscle bulk. Patient had presented to the ED due to concern of deep vein thrombosis. The patient was asked to remain hydrated over the next few days and to reduce physical activity and was discharged from the ED. Patient complaints of tingling and numbness in the lower limbs were persistent for which the patient followed up with neurology. Patient underwent further workup for neuropathy and palpitations.  Author stated that the fact that these neurological side effects occur after vaccine administration supports a causal relationship between these vaccinations and neurological complications.  Company comment: This is a literature non-study case concerning a 64-year-old female patient with medical history of positive antinuclear antibody (ANA), suspected undifferentiated connective tissue disease, Hyper IgE syndrome, Diabetes mellitus and Basal cell carcinoma, who experienced the unexpected, serious (medically significant) event of Small fibre neuropathy. The patient developed dull retrosternal pain, palpitations, lightheadedness and paroxysmal tingling in lower limbs (more on the left) approximately 3 weeks after receiving the third dose of mRNA-1273 vaccine. The patient was seen at an emergency department and was suspected of deep vein thrombosis however the doppler ultrasound were negative and the electrocardiogram, chest x-ray and thyroid-stimulating hormone were unremarkable. The patient was discharged and advised to remain hydrated and reduce physical activity. Holter monitor was placed during follow up and revealed a single event of four beats of ventricular tachycardia. The tingling and numbness of the lower limbs persisted and the patient underwent autonomic testing and Nerve conduction study/electromyography (EMG) which were unremarkable. Skin biopsy from the distal leg and proximal thigh were consistent with a mild length-dependent neuropathy affecting unmyelinated sensory fibers while specimens from the left ankle revealed occasional small axonal swellings in the epidermis and sub-epidermis. Further treatment details were not provided in the case. The outcome of the event was unknown at the time of the report. Medical history of positive antinuclear antibody (ANA), suspected undifferentiated connective tissue disease, Hyper IgE syndrome, Diabetes mellitus and Basal cell carcinoma remain as risk factors for the event. The benefit-risk relationship of mRNA-1273 is not affected by this report.   Most recent FOLLOW-UP information incorporated above includes: On 29-Sep-2022: Live follow up received by safety on 30-Sep-2022 included an email with full text article and contains significant information: Reporter information, literature information, medical history, lab data and event information were updated.; Sender's Comments: This is a literature non-study case concerning a 64-year-old female patient with medical history of positive antinuclear antibody (ANA), suspected undifferentiated connective tissue disease, Hyper IgE syndrome, Diabetes mellitus and Basal cell carcinoma, who experienced the unexpected, serious (medically significant) event of Small fibre neuropathy. The patient developed dull retrosternal pain, palpitations, lightheadedness and paroxysmal tingling in lower limbs (more on the left) approximately 3 weeks after receiving the third dose of mRNA-1273 vaccine. The patient was seen at an emergency department and was suspected of deep vein thrombosis however the doppler ultrasound were negative and the electrocardiogram, chest x-ray and thyroid-stimulating hormone were unremarkable. The patient was discharged and advised to remain hydrated and reduce physical activity. Holter monitor was placed during follow up and revealed a single event of four beats of ventricular tachycardia. The tingling and numbness of the lower limbs persisted and the patient underwent autonomic testing and Nerve conduction study/electromyography (EMG) which were unremarkable. Skin biopsy from the distal leg and proximal thigh were consistent with a mild length-dependent neuropathy affecting unmyelinated sensory fibers while specimens from the left ankle revealed occasional small axonal swellings in the epidermis and sub-epidermis. Further treatment details were not provided in the case. The outcome of the event was unknown at the time of the report. Medical history of positive antinuclear antibody (ANA), suspected undifferentiated connective tissue disease, Hyper IgE syndrome, Diabetes mellitus and Basal cell carcinoma remain as risk factors for the event. The benefit-risk relationship of mRNA-1273 is not affected by this report.