Trigger of Type 2 Lepra reaction with acute foot drop following Covid‐19 vaccination (2022)

With massive vaccination drive going on worldwide against Covid-19 infection, the researchers have encountered many side-effects ranging from trivial to serious ones. Few neurological side-effects such as Guillain–Barre syndrome (GBS), facial nerve palsy, transverse myelitis as well as small fibre neuropathy have also been reported post Covid-19 vaccination. However, there are no documented reports of trigger of Type 2 Lepra reaction post Covid-19 vaccination. Therefore, we are presenting a case of acute foot drop with Type 2 Lepra reaction in a patient of Borderline lepromatous Hansen’s patient following Covid-19 vaccination. A 60-year-old male, known case of Borderline lepromatous leprosy with Type 2 reaction who had taken multibacillary multidrug therapy (MB-MDT) for 18 months and was released from treatment based on negative slit skin smear and repeat biopsy reports in July 2020. The patient had three episodes of Type 2 reaction after stopping MDT with last episode seen in January 2021, which was well controlled with maintenance dose of Thalidomide (100 mg twice daily) after an initial course of oral steroids. The patient was asymptomatic for last 5 months. In May 2021, the patient developed a mild episode of Type 2 lepra reaction, which was seen 5 days after taking first dose of Covishield vaccine. Two months later, the patient presented to our OPD with a similar episode of Type 2 reaction having more severity along with right foot drop and on taking detailed history the patient revealed that all the symptoms developed within 3–4 days of his second dose of Covishield vaccination and foot drop was noticed after 7 days of vaccine. There was no prior trigger history. Clinically, multiple crops of erythematous, tender papules, and nodules were noted on his trunk and extremities associated with right foot drop. On nerve examination, there was thickening and tenderness of bilateral common peroneal nerve and right tibial nerve. All other nerves were uninvolved. All routine laboratory tests were normal. Nerve conduction study (NCS) showed sensorimotor mixed (demyelinating + axonal) neuropathy affecting nerves of both lower limbs, that is, bilateral common peroneal and right tibial nerve. Also, right ulnar and bilateral sural nerve was non-recordable in NCS. MRI of cervical and lumbosacral region revealed no compressive cause of the foot drop. Treatment was started with dexamethasone injection (2cc daily), followed by tapering doses of steroids for 2 weeks, thalidomide 100 mg BD and clofazimine 100 mg TDS which provided symptomatic resolution of cutaneous lesions and associated fever. There was significant improvement in degree of foot drop and nerve tenderness. The Abrupt onset of Type 2 reaction along with foot drop in the patient soon after the Covid-19 vaccination, and exclusion of other known aetiologies, supports a possible temporal association of vaccination induced neuritis and trigger of Type 2 reaction. Leprosy reactions (Type 1 and Type 2) are immunological events that can affect 8–33% of Hansen’s patients, reaching up to 64.5% in some regions, which can manifest before, during, or after multidrug therapy (MDT).1, 2 Neutrophils are associated with ENL, as the lesional skin showed an intense perivascular neutrophilic infiltrate throughout the dermis and on stimulation with lipopolysaccharide(LPS) of Mycobacterium leprae, neutrophils in ENL patients release TNF-alpha and IL-8.3 This supports the role of neutrophils as effector cells actively producing pro-inflammatory cytokines and not only as migratory cells following chemo-attractants. Also, upon SARS-CoV-2 infection, extensive neutrophilic infiltration was noted in lung tissues of autopsied Covid-19 patients and increased neutrophil to lymphocyte ratio is seen in severe disease. Therefore, it is proposed that change in neutrophil counts in peripheral blood and tissues may be closely associated with pathological injury in Covid-19 patients.2, 4 Hence, we put forward above-mentioned hypothesis of Trigger of Type 2 reaction following Covid-19 vaccination based on the neutrophilic mechanism of immunological response in body. However, this hypothesis is only a possibility and needs to be established in future. Neuritis is an occurrence both in Type 1 and Type 2 lepra reaction, although rare in Type 2 reaction. However, the neural damage in Type 2 reaction requires several reactive episodes as the pathomechanism involving the damage in Type 2 reaction is a conduction block due to acute oedema, whereas the damage in Type 1 reaction is due to chronic demyelination.5 In our case, acute foot drop seen in patient had a temporal association with vaccine as it was seen few days after the second dose of Covid-19 vaccine. Neurological complications following Covid-19 vaccination has been documented in recent literature which is mentioned in Table 1. -Ischaemic stroke -Facial nerve palsy -Cervical myelitis In this current Covid-19 pandemic and with global vaccination drive going on worldwide, it is critically important for clinicians to timely diagnose any neurological complications and other side-effects related to Covid-19 vaccination as there are very few literature suggesting the same. The trigger of Type 2 Lepra reaction should also be kept in mind in such patients presenting with acute manifestations following Covid-19 vaccination. Large real world clinical studies can help to establish this association. The patients in this manuscript have given written informed consent to publication of their case details. None declared. None. All authors have contributed equally to the manuscript. The data that support the findings of this study are available from the corresponding author upon reasonable request.