Severe acute respiratory syndrome (SARS) and Middle East Respiratory Syndrome (MERS) are two previous viral infection outbreaks similar to the current COVID-19 pandemic. Studies that have looked at long-term health problems in survivors of these two outbreaks report reduced lung function and reduced ability to exercise in some survivors up to 6 months after discharge from hospital. Mental health problems including stress, anxiety and depression were observed in up to one-third of survivors at 6 months and beyond. The quality of life was observed to be low even 12 months after discharge from the hospital. Rehabilitation clinicians and services should anticipate similar health problems in survivors of COVID-19, investigate them accordingly and plan suitable and timely treatments to enable best possible recovery and quality of life for them. Objective: To determine long-term clinical outcomes in survivors of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) coronavirus infections after hospitalization or intensive care unit admission. Data sources: Ovid MEDLINE, EMBASE, CINAHL Plus, and PsycINFO were searched. Study selection: Original studies reporting clinical outcomes of adult SARS and MERS survivors 3 months after admission or 2 months after discharge were included. Data extraction: Studies were graded using the Oxford Centre for Evidence-Based Medicine 2009 Level of Evidence Tool. Meta-analysis was used to derive pooled estimates for prevalence/severity of outcomes up to 6 months after hospital discharge, and beyond 6 months after discharge. Data synthesis: Of 1,169 identified studies, 28 were included in the analysis. Pooled analysis revealed that common complications up to 6 months after discharge were: impaired diffusing capacity for carbon monoxide (prevalence 27%, 95% confidence interval (CI) 15-45%); and reduced exercise capacity (mean 6-min walking distance 461 m, CI 450-473 m). The prevalences of post-traumatic stress disorder (39%, 95% CI 31-47%), depression (33%, 95% CI 20-50%) and anxiety (30%, 95% CI 10-61) beyond 6 months after discharge were considerable. Low scores on Short-Form 36 were identified beyond 6 months after discharge. Conclusion: Lung function abnormalities, psychological impairment and reduced exercise capacity were common in SARS and MERS survivors. Clinicians should anticipate and investigate similar longterm outcomes in COVID-19 survivors.

The localised PET cerebral correlates of the painful experience in the normal human brain have previously been demonstrated. This study examined whether these responses are different in patients with chronic atypical facial pain. The regional cerebral responses to nonpainfil and painful thermal stimuli in six female patients with atypical facial pain and six matched female controls were studied by taking serial measurements of regional blood flow by PET. Both groups displayed highly significant differences in responses to painful heat compared with non-painful heat in the thalamus, anterior cingulate cortex (area 24), lentiform nucleus, insula, and prefrontal cortex. These structures are closely related to the "medial pain system". The atypical facial pain group had increased blood flow in the anterior cingulate cortex and decreased blood flow in the prefrontal cortex. These findings show the importance of the anterior cingulate cortex and the reciprocal (possibly inhibitory) connections with the prefrontal cortex in the processing of pain in patients with this disorder. A hypothesis is proposed to explain the mechanisms of cognitive and pharmacological manipulation of these pain processes.

A group of four patients with RA were examined to test the hypothesis that there is a change in the endogenous opioid system in the brain during inflammatory pain. Regional cerebral opioid receptor binding was quantified using the opioid receptor antagonist [11C] diprenorphine and positron emission tomography (PET). In the four patients studied in and out of pain, significant increases in [11C]diprenorphine binding were seen in association with a reduction in pain. Increases were seen in most of the areas of the brain that were sampled apart from the occipital cortex. Significant region-specific increases over and above the more generalized changes were also seen in the frontal, cingulate and temporal cortices in addition to the straight gyrus. These findings are consistent with the hypothesis that there are substantial increases in occupancy by endogenous opioid peptides during inflammatory pain.

Central neuropathic pain (CNP) is pain resulting from damage to the central nervous system. Up till now, it has not been possible to identify a common lesion or pharmacological deficit in these patients. This preliminary study in a group of patients with CNP with predominantly post-stroke pain, demonstrates that there is significantly less opioid receptor binding in a number of cortical and sub-cortical structures that are mostly, but not exclusively, within the medial pain system in patients compared to age-matched pain-free controls. The reductions in opioid receptor binding within the medial system were observed mainly in the dorsolateral (Brodman area 10) and anterior cingulate (Brodman area 24 with some extension into area 23) and insula cortices and the thalamus. There were also reductions in the lateral pain system within the inferior parietal cortex (Brodman area 40). These changes in binding could not be accounted for by the cerebral lesions shown by CT or MRI, which were outside the areas of reduced binding and the human pain system. To our knowledge this is the first systematic demonstration of a reduction in opioid receptor-binding capacity in neurones within the human nociceptive system in patients with CNP. This may be a key common factor resulting in undamped nociceptor activity within some of the structures that are predominantly within the medial nociceptive system. If confirmed, these findings may explain why certain patients with CNP require high doses of synthetic opiates to achieve optimum analgesia. The findings also raise the possibility of new pharmacological approaches to treatment.