key: cord-0846706-x3fxyl7r authors: Shehab, Diaa; Abdulsalam, Ahmad Jasem; Reebye, Rajiv N. title: Complex Regional Pain Syndrome as a Sequale of COVID-19 Pneumonia date: 2022-05-02 journal: Rev Neurol (Paris) DOI: 10.1016/j.neurol.2022.03.013 sha: ed837656898e0720ce0656c808e86fd17ade9bfe doc_id: 846706 cord_uid: x3fxyl7r nan progressive dyspnea. He was obese, with no known previous medical illness. On arrival, his vital signs showed an axillary temperature of 38.7°C, pulse rate of 114 beats per minute, indicating sinus rhythm; respiratory rate of 22 per minute; noninvasive blood pressure of 140/86 mm Hg; and oxygen saturation of 88% (on room air). Laboratory analysis revealed lymphocytopenia (800 cells/mm 3 ) with an elevated C-reactive protein level of 58.0 mg/L. The real-time polymerase chain reaction (RT-PCR) assay of the nasopharyngeal swab specimen obtained from the patient was positive for coronavirus disease (COVID-19). Thus, a diagnosis COVID-19 pneumonia was made. Shortly after admission, the patient's condition deteriorated to severe respiratory distress, requiring intubation and mechanical ventilation; therefore, he was transferred to the intensive care unit. He received 4 days of lopinavir-ritonavir and hydroxychloroquine therapy, with mild clinical improvement during his 1-month stay in the intensive care unit. After attaining clinical improvement, he was weaned off mechanical ventilation. Two months after hospital discharge, the patient started complaining of left foot congestion, warmth, and throbbing pain, with change in color to red and purple (Fig. 1A) . On the following day, he presented to the emergency department because of ongoing severe pain. On examination, the left foot had warmth, erythema, and edema, with hyperpigmented skin on the second toe. The capillary refill time and peripheral pulses were normal. The blood chemistries and left foot radiography result were unremarkable. He was misdiagnosed as having cellulitis and treated with intravenous ceftriaxone (2 g/day) and oral clindamycin (1800 mg/day) for 1 week. He later sought a second opinion from the physical medicine and rehabilitation outpatient clinic. All laboratory test results (erythrocyte sedimentation rate and levels of C-reactive protein, parathormone, bone alkaline phosphatase, and serum and urinary calcium/phosphate and vitamin D) were normal. Electromyography and nerve conduction studies of the foot, and the erythrocyte sedimentation rate were normal. Magnetic resonance imaging of the foot This case study describes a patient who abruptly developed CRPS type 1 after contracting COVID-19 infection. The diagnosis of CRPS is a composite of characteristic clinical signs [1] . CRPS is defined as continuous pain disproportional to the triggering trauma with the associated clinical signs (temperature asymmetry, skin color or trophic changes, edema and sweating, muscular weakness, tremor, or dystonia) based on the Budapest criteria [1] . Since the beginning of the COVID-19 pandemic, several neurological manifestations have been reported in these patients, ranging from mild symptoms [2] . The involvement of the autonomic nervous system in SARS-CoV-2 infection has been rarely reported in the literature. Physicians involved in the treatment of SARS-CoV-2 are encountering patients with a wide spectrum of central and peripheral nervous system manifestation [3] . An explanation for the peripheral nervous system involvement could be "molecular mimicry," that is, the cross-reactivity of natural immunoglobulins, formed in response to a bacterial or viral antigen with specific proteins on the myelin, axon, or neuromuscular junction [4] . Dysautonomia symptoms have also been observed in patients with COVID-19, including diarrhea and sweat dysfunction. This is similar to the dysautonomia reported with other viral infections. The presence of dysautonomia in patients with COVID-19 should be further studied to appropriately diagnose and manage post-COVID-19 patients. To our knowledge, only one case of CRPS post COVID-19 is documented the literature [5] . Although the respiratory manifestations of SARS-CoV-2 infection are well recognized, its neurological manifestations have not been adequately studied to date. Critically ill patients are at a greater risk of developing neurological symptoms during the course of the disease. Physicians should be aware of these symptoms and evaluate patients early so as to avoid the dissemination of the disease and improve patients' prognosis. References: Terminology, criteria, and definitions in complex regional pain syndrome: challenges and solutions Dysautonomia: an overlooked neurological manifestation in a critically ill COVID-19 patient Central and peripheral nervous system involvement by COVID-19: a systematic review of the pathophysiology, clinical manifestations, neuropathology, neuroimaging, electrophysiology, and cerebrospinal fluid findings Neurobiology of COVID19 Complex regional pain syndrome after severe COVID-19 -A case report