Neurological manifestations of COVID-19 and other coronavirus infections: A systematic review

BACKGROUND

Increasing research reports neurological manifestations of COVID-19 patients. SARS-CoV-2 shares homology with other human coronaviruses that have also had nervous system involvement.

OBJECTIVE

To review the neurological aspects of SARS-cov2 and other coronavirus, including transmission pathways, mechanisms of invasion into the nervous system, and mechanisms of neurological disease.

METHODS

We conducted a systematic review of articles in PubMed, SCOPUS and EMBASE data bases. Reviewed evidence is presented in sections of this manuscript which includes pathogenesis, neuro-invasion, encephalitis, Guillain-Barré, ADEM, multiple sclerosis, polyneuropathy, and cerebrovascular disease.

RESULTS

A total 67 studies were included in the final analysis of experimental studies, case reports, series of cases, cohort studies, and systematic reviews related to neurological manifestations of SARS- CoV-2 and other human coronavirus infections. The SARS-CoV-2 receptor is expressed in the nervous system. Common reported symptoms included hyposmia, headaches, weakness, altered consciousness. Encephalitis, demyelination, neuropathy, and stroke have been associated with COVID-19. Infection through the cribriform plate and olfactory bulb and dissemination through trans-synaptic transfer are some of the mechanisms proposed. Invasion of the medullary cardiorespiratory center by SARS-CoV-2 may contribute to the refractory respiratory failure observed in critically-ill COVID-19 patients.

CONCLUSION

An increasing number of reports of COVID-19 patients with neurological disorders add to emergent experimental models with neuro-invasion as a reasonable concern that SARS-CoV-2 is a new neuropathogen. How it may cause acute and chronic neurologic disorders needs to be clarified in future research.

Preclinical report on allogeneic uterus transplantation in non-human primates

STUDY QUESTION

Is it possible to perform allogeneic uterus transplantation (UTx) with a donation from a live donor in a non-human primate species and what immunosuppression is needed to prevent rejection?

SUMMARY ANSWER

Allogeneic UTx in the baboon is a donor- and recipient-safe surgical procedure; immunosuppression with induction therapy and a triple protocol should be used.

WHAT IS KNOWN ALREADY

UTx may become a treatment for absolute uterine factor infertility. Autologous UTx models have been developed in non-human primates with reports on long-term survival of the uterine grafts. STUDY DESIGN, SIZEAND DURATION: This experimental study included 18 female baboons as uterus donors and 18 female baboons as uterus recipients. The follow-up time was 5-8 weeks.

PARTICIPANTS/MATERIALS, SETTING AND METHODS

Uterus retrieval was performed with extended hysterectomy including bilateral uterine and internal iliac arteries and ovarian veins. After UTx, with vascular anastomoses unilateral to the internal iliac artery and the external iliac vein, the uterus recipients received one of the following: no immunosuppression (n = 4); monotherapy (oral slow release tacrolimus) (n = 4) or induction therapy (antithymocyte globulin) followed by triple therapy (tacrolimus, mycophenolate, corticosteroids; n = 10). Surgical parameters, survival, immunosuppression and rejection patterns were evaluated.

MAIN RESULTS AND THE ROLE OF CHANCE

The durations of uterus retrieval and recipient surgery were around 3 and 3.5 h, respectively. The total ischemic time was around 3 h. All the recipients and the donors survived the surgery. All the recipients presented rejection to some extent within the first weeks following UTx. In one recipient, the uterus was of normal appearance at the end of the study period. In spite of occasional high (>60 ng/ml) blood levels of tacrolimus, there was no evidence of nephrotoxicity.

LIMITATIONS AND REASONS FOR CAUTION

This initial non-human primate allogeneic UTx study indicates that further research is needed to optimize immunosuppression protocols in order to avoid uterine rejection.

WIDER IMPLICATIONS OF THE FINDINGS

The findings suggest that allogeneic UTx in primate species is feasible but continued work on this issue is needed.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by the Swedish Research Council, ALF University of Gothenburg, Hjalmar Svensson Foundation and by Jane and Dan Olsson Research Foundation. The authors do not have any competing interest.

Mycobacterial lymphadenitis in eastern Sydney

BACKGROUND

There has been a resurgence of tuberculosis (TB) in the developed world, especially extrapulmonary manifestations, of which lymphadenitis is the most common. We reviewed all cases of mycobacterial lymphadenitis notified in the eastern suburbs of Sydney from 1989 to 1996.

AIMS

To review all cases of mycobacterial adenitis in eastern Sydney.

METHODS

This was a retrospective review of the medical records of 54 patients (aged 1.2 to 84 years), recruited from all notifications of TB presenting as lymphadenitis at Prince of Wales, Sydney Children's and St Vincent's Hospitals.

RESULTS

There were two distinct groups: Group 1, patients with Mycobacterium tuberculosis (MTB), n = 37 (68.5%), Group 2, patients with atypical mycobacteria, n = 17 (31.5%). For Group 1, 83.3% were foreign born and 18.9% were positive for the human immunodeficiency virus (HIV). Disease involved single node groups in 73% (the cervical chain was involved in 70.1%). Complete resolution of lymphadenopathy at conclusion of treatment occurred in 73.1%. Outcome was not documented in 13.5%, of the rest; 83.8% completed treatment; 2.7% were lost to follow up before treatment concluded; 2.7% were still being seen at the time of writing and 10.8% died within six months of treatment starting (all were HIV positive). HIV positive patients had more diffuse disease. Group 2 were all Australian born. They comprised children less than six years who were all HIV negative and adults (aged 30-55 years) who were all HIV positive. The children were all treated surgically with 80% having complete resolution of their modes. Those adults with HIV had a mortality of 83.3% during treatment.

CONCLUSIONS

In eastern Sydney lymphadenitis caused by MTB in the HIV negative population is mostly seen in those who are immigrants. Our large proportion of HIV positive patients tended to have diffuse disease and a high mortality. The reporting of outcomes was poor and in a greater than expected number of outcome and follow up were inadequately documented.