Previous reports have shown various neurological manifestations in about 36.4% of patients infected with SARS-Cov-2. However, peripheral neuropathy was only reported once before. A 40-year-old healthy woman presented with two weeks of cough, nasal congestion, sore throat, intermittent fevers, fatigue, and myalgia but no weakness. She tested positive for the SARS-Cov-2. Physical exam showed no neurologic deficit. Two weeks later, respiratory symptoms were improving but she developed sudden leg pain, numbness, and weakness. She described it as a “pain crisis”. Neurological exam showed bilateral symmetrical, non-ascending lower extremity weakness and normal, symmetric reflexes. She had normal magnetic resonance imaging of the brain and spine, spinal fluid analysis, serum studies including creatinine kinase and C-reactive protein. She had elevated lactate dehydrogenase, low serum copper (72.9 (ref: 80.0-155.0 ug/dL)) and low vitamin B6 (14.6 (ref: 20.0-125.0 nmol/L)). A diagnosis of SARS-Cov-2-associated peripheral neuropathy was considered. We pursued empiric treatment with intravenous steroids (1000 mg methylprednisolone for three days), followed by a total of 2 g/kg of intravenous immunoglobulins (IVIG) given over five days. Pain management was done with gabapentin and ketorolac. We replaced copper and vitamin B6. Six weeks later, she reported improvement and was closer to baseline, but she endorsed residual, exertional, mild bilateral lower extremity pain, numbness, and weakness. Previous reports of treatment of SARS-Cov-2-associated neuropathy included corticosteroids and IVIG. Our patient saw the most symptomatic improvement with gabapentin. In our case, the preserved reflexes, lack of ascending pattern, sudden onset of symptoms, and normal cerebrospinal fluid (CSF) argued against Guillain-Barre syndrome. Copper deficiency can result in myelopathy but not peripheral neuropathy, so is unlikely the sole explanation. Awareness and early treatment of peripheral neuropathy in SARS-Cov-2 can result in improved clinical outcomes for patients.

No abstract

Cholesterol side-chain cleavage (CSCC) catalyzed by purified bovine adrenal mitochondrial cytochrome P-450scc is highly dependent on the vesicles that supply cholesterol. Six-fold higher rates are achieved with large unilamellar dioleoylphosphatidylcholine vesicles (diameter 150 nm) prepared by octyl glucoside (OG) dialysis (DOPC-LUV) than with small sonicated vesicles (diameter 30 nm) (DOPC-SUV) (Vmax = 25 and 4 min-1, respectively. Extensive dialysis that may remove OG decreased Vmax rates for DOPC-LUV almost to rates seen with DOPC-SUV. These dialyzed DOPC-LUV were, however, very sensitive to addition of OG (EC50 = 2.5 microM, 4.3-fold stimulation) while DOPC-SUV were only weakly affected (EC50 = 100 microM, 1.6-fold stimulation). This enhancement of CSCC in LUV by OG only occurred when the cholesterol:DOPC exceeded 0.1 and was associated with a 15-fold increase in the Km for cholesterol. Structural changes in both SUV and LUV at high cholesterol:DOPC ratios (0.1-1) were indicated by decreases in internal volume that were insensitive to OG and did not affect the external diameters. Stearic acid produced a similar stimulation of CSCC in LUV (EC50 = 50 microM) and had no effect on SUV. The Vmax for CSCC, produced by OG activation of DOPC-LUV, is comparable to the highest attained for cytochrome P-450scc (Tween 20/cholesterol). In LUV, a minor proportion of OG (1-5% of cholesterol) is thus sufficient to generate a domain of reactive cholesterol that maintains a near-optimum turnover. This increased CSCC was paralleled by increased binding of cholesterol to P-450scc, suggesting that this cholesterol is more readily donated by the membrane to the cytochrome.

Addition of bovine adrenal cytochrome P-450scc to small unilamellar dioleoylphosphatidylcholine vesicles (DOPC-SUV) produces a complex sequence of interactions, indicating exceptional cytochrome mobility. First, cholesterol transfer from cytochrome to vesicles indicated rapid dissociation of P-450scc oligomers and integration of monomers into the membrane (delta A 390-420 nm; t1/2 = 2 s). After 10-15 s, P-450scc-induced aggregation of the vesicles starts, as indicated by increased turbidity (delta A 448 or 520 nm; complete in 6-8 min). Fluorescence quenching experiments indicate that this aggregation does not lead to measurable vesicle fusion during this period. Aggregation is prevented by mild heat denaturation of P-450scc, by addition of anti-P-450scc IgG, and also by 1:1 complex formation with the electron donor adrenodoxin (ADX). P-450scc, therefore, links two vesicles through two separate domains involved in, respectively, membrane integration (lipophilic) and ADX binding (charged). Although completely bound by DOPC-SUV, as evidenced by Sephadex elution, P-450scc has access within 1 min to cholesterol in secondary SUV. This is indicated by spectral changes (cholesterol complex formation) and by metabolism of secondary vesicle cholesterol. Since cholesterol equilibrates slowly between vesicles (t1/2 = 1-2 h), these changes arise from P-450scc transfer. This transfer was maximally slowed after a 5-min preincubation with primary vesicles, reflecting more extensive integration into the membrane than is necessary for the rapid initial cholesterol transfer to P-450scc. P-450scc transfer probably results from simultaneous interaction of P-450scc with two vesicles that may also initiate aggregation. Weaker integration into primary dimyristoylphosphatidylcholine vesicles facilitates exchange but prevents aggregation. Integration and aggregation are both enhanced by incorporation of 10% phosphatidylinositol into SUV, while exchange is slowed. This mobility of P-450scc is most probably a consequence of the absence of amino-terminal anchoring. P-450scc-induced association of inner mitochondrial membrane segments may contribute to the exceptionally vesiculated structure of adrenal and ovarian mitochondria that parallels increased P-450scc content.

Neuroleptic malignant syndrome (NMS) is a rare, potentially lethal syndrome known to be related to the initiation of dopamine antagonist medications or rapid withdrawal of dopaminergic medications. It is a diagnosis of exclusion with a known sequela of symptoms, but not all patients experience these characteristic symptoms making it difficult at times to diagnose and treat. Herein, we present a unique case of NMS with unclear etiology and a unique clinical course. Our case report also raises the question of whether or not adjusting doses of previously prescribed neuroleptic medications can provoke NMS, providing valuable information for providers treating these complex patients.