Dr Shailesh Jain is Principal Consultant, Neurosciences at New Delhi
COVID in the last 18 months has shown a devastating effect on human life. Apart from affecting the lung, it also affected different parts of the body. However, it mainly affects the lung and increases level of ferritin, D-Dimer, CRP and cytokines eg IL-6. High levels of all these chemicals may have catastrophic effect on vital organs.
Neurological involvement is a spectrum of loss of olfactory senses to necrotising encephalitis and involving almost every aspect of central (CNS) and peripheral nervous system (PNS). Prevalence is around 0.1-1 per cent of COVID infections. Most complications are seen by second to fourth week of COVID infection. CNS-related events were more common than PNS manifestations. Common CNS manifestations are headache, disturbance in consciousness, dizziness, acute cerebrovascular disease, ataxia, and seizures. PNS symptoms are impairment in taste, smell, and vision. Musculoskeletal symptoms were observed in form of myalgias and nonspecific pain.
Stroke comprises of 60-70 per cent, encephalopathy 30-40 per cent and neuropathy around 6 per cent and all other neurological complications in 0.1 per cent cases of neurological cases related to COVID.
Neurological involvement is mainly categorised into CNS and PNS involvement. CNS involvements are in form of stroke, encephalopathy, delirium, psychoses, necrotising encephalitis and fungal infections eg. Fungal abscess or rhinocerebral mucormycoses. PNS involvements are facial palsy, acute inflammatory demyelinating neuropathy (AIDP) and paraesthesia in all limbs and myalgia.
Strokes are ischemic type usually due to large vessel occlusion with high degree of morbidity or mortality and it is more prevalent with diabetic, hypertensive and Coronary artery disease. It is also associated with large coronary occlusion or sudden cardiac death upto six-eight weeks after COVID. Most patients were found to have hypercoagulable state
Encephalopathy or delirium or psychoses were seen by third to fourth week of COVID. It is a non-specific term used to describe the acute impairment of brain function which presents clinically as alteration in the level of consciousness and triggered by viral infections. It is completely reversible with appropriate medications.
Neuropathy may be in form of facial palsy or severe weakness of all limbs in form of G B Syndrome. Both are completely reversible with medications. Headache, myalgia and paresthesia and fatigue are minor symptoms and it disturbs sleep but didn’t cause any disability. These recover with time and medications.
Some unusual complications are necrotising encephalitis and myelitis. They have high level of morbidity and mortality. Encephalitis is a serious condition with significant impact and burden. About 20–50 per cent of encephalitis cases are caused by viruses, and half of the cases have no known etiology. The disease causes a variety of neurological abnormalities, such as altered consciousness, hallucination, confusion, abnormal movement, and aphasia.
Smoking accelerate the process of atherosclerosis all over body and leads to endothelial dysfunction, thrombus formation and hypercoagulable state. It also aggravates dyslipidemia. It increases chances of cardiovascular disease in all forms eg CAD, CVA, PVD. It locally affects the lung parenchyma and make it vulnerable to COVID related lung damage and oxygenation of body. Coexistence of smoking related atherosclerosis and COVID induced hypercoagulable state increases chances of large vessel stroke.