Long Covid

It is not known why in some people recovery is prolonged.

Persistent viraemia, due to weak or absent antibody response, relapse or re-infection, inflammatory and other immune reactions, deconditioning, and mental factors such as posttraumatic stress may all contribute.

Long term respiratory, musculoskeletal and neuropsychiatric sequalae have been described for other coronaviruses such as SARS and MERS and these have pathophysiological parallels for post-acute COVID-19.

Post COVID-19 symptoms vary widely and even the so called mild COVID-19 may be associated with long term symptoms such as:

• Cough
• Low grade fever
• Fatigue, all of which may relapse and remit.

Other reported symptoms include:

• Shortness of breath.
• Chest pain.
• Headaches.
• Neurocognitive difficulties.
• Muscle pains and weakness.
• Gastrointestinal upset.
• Rashes.
• Metabolic disruption such as poor control of diabetes.
• Thromboembolic conditions.
• Depression and other mental health conditions.

Skin rashes can take many forms including vesicular, maculopapular, urticarial or chilblain lesions on extremities, the so called Covid toe.

A degree of breathlessness is common after acute COVID-19. Severe breathlessness, which is rare in patients who were not hospitalised may require urgent referral. Breathlessness tends to improve with breathing exercises.

Pulse oximeters are extremely useful for assessing and monitoring respiratory symptoms after COVID-19 and their use in the home should not lead to anxiety.

Hypoxia may reflect impaired oxygen diffusion and is a recognised feature of COVID-19. It can be asymptomatic (so called silent hypoxia), or symptomatic. Some oximetry patterns reflecting the increased work of breathing or secondary pathology such as bacteria or pulmonary embolus.

Self-monitoring of oxygen saturations over three to five days should be useful in the assessment and reassurance of patients with persistent dyspnoea in the post-acute phase, especially in those patients whose saturations are normal, and no other cause for dyspnoea is found following thorough evaluation. An exertional desaturation test should be performed as part of the baseline assessment and patients with resting pulse oximetry readings of 96% and above whose symptoms suggest exertional desaturation, such as light headedness or severe breathlessness on exercise. In the absence of contraindications, such patients should be advised a repeat pulse oximeter reading after 40 steps on a flat surface self-testing and then after one minute of doing sit to stand as fast as they can, a fall of 3% in saturation reading on mild exertion is abnormal and requires investigation.

The British Thoracic Society guidelines define the target range of oxygen saturation as 94-98% and a level of 92% or lower as requiring supplementary oxygen unless the patient is in chronic respiratory failure. In the context of a normal assessment without any red flags, an oxygen saturation of 96% or above and the absence of desaturation on exertional tests is very reassuring.

Further investigation or referral in the first six weeks after COVID-19 in such patients is very rarely indicated and regular support by telephone and video consultation is suggested. Oxygen saturations of 95% or below, indicating substantially lower oxygen-haemoglobin desaturation require assessment and investigation. The patients should be provided with the safety netting service. Appropriate adjustments need to be made for patients with lung disease and known hypoxia, in whom the range of 88 to 92% would be considered acceptable.

Recovery after any severe debilitating illness may be prolonged.

Survivors of COVID-19 acute respiratory distress syndrome are at risk of long term impairment of lung function.

Serious interstitial lung disease seems to be rare in patients who are not hypoxic, though data on long term outcomes are not yet available.

Many patients are still recovering spontaneously in the first six weeks after COVID-19 and do not generally require fast track into any pulmonary rehabilitation programme.

Those who have had significant respiratory illness may benefit from pulmonary rehabilitation, defined as a multidisciplinary intervention based on personalised evaluation and treatment which includes, but is not limited to, exercise training, education and behavioural modification designed to improve the physical and psychological conditions of people with respiratory disease.

In the context of COVID-19, rehabilitation should be delivered by various virtual models, including video linked classes and home education booklets with additional telephone support.

The prolonged and profound nature of fatigue in some post-acute COVID-19 patients shares features with chronic fatigue syndrome described after other serious infections such as SARS, MERS and community acquired pneumonia. There is little published research evidence on the efficacy of either pharmacological or non-pharmacological interventions on fatigue after COVID-19.

Patient resources on fatigue management guidance for clinicians on return to exercise and graded return to performance for athletes in COVID-19 are currently based on indirect evidence. For example, for sportsman returning to exercise, which is summarised from the Stanford Hall statement:

1. After recovery from mild illness one week of low level stretching and strengthening for targeted cardiovascular sessions.
2. Very mild symptoms – limit activity to slow walking or equivalent. Increase rest periods if symptoms worsen, avoid high intensity training.
3. Persistent symptoms (such as fatigue, cough, breathlessness, fever) limit activity to 60% of maximum heart rate until two to three weeks after symptoms resolved.
4. Patients who had lymphopaenia or acquired oxygen, need respiratory assessment before returning and resuming exercise.
5. Patients who had cardiac involvement need cardiac assessment before resuming exercise.

There is much debate and controversy about the role of graded exercise and chronic fatigue generally and in COVID-19 patients in particular. Pending any direct evidence from research studies, it is suggested that exercise in patients should be undertaken cautiously and cut back if patients develop fever, breathlessness, severe fatigue or muscle aches.

It is important to have an understanding and supportive reassurance from the primary care physicians whom are crucial components of the management to these patients.

Perhaps 20% of patients admitted with COVID-19 have clinically significant cardiac occult involvement, maybe even commoner.

Cardiopulmonary complications include myocarditis, pericarditis, myocardial infarction, dysrhythmias and pulmonary emboli.

These may present several weeks after acute COVID-19.

They are commoner in patients with pre-existing cardiovascular disease, but they have also been described in young, previously active patients.

Various pathophysiological mechanisms have been proposed, including viral infiltration, inflammation and microthrombi, and down regulation of ACE2 receptors.

Chest pain is common in post-acute COVID-19.

The Clinical priority is to separate musculoskeletal and other non-specific chest pain. For example, the symptom described by a large patient led survey as lung burn from serious cardiovascular conditions.

This is where clinical assessment of post-acute COVID-19 chest pain should follow similar principles to that for any chest pain presentation. E.g. careful history, taking account of past medical history and risk factors, physical examination, backed up as indicated by investigations.

Where the diagnosis is uncertain, or the patient is acutely unwell, urgent cardiology referral may be needed and specialist assessment and investigations including echocardiography, computed tomography of the chest and cardiac magnetic resonance imaging are required.

COVID-19 is an inflammatory and hypercoagulable state with an increased risk of thromboembolic events.

Many hospitalised patients receive prophylactic anticoagulation.

Recommendations for anticoagulation on discharge vary – but higher risk patients are typically discharged from hospital with 10 days of extended thromboprophylaxis.

If the patient has been diagnosed with a thrombotic episode, anticoagulation and further investigation and monitoring should follow standard guidelines. However, it is not known how long patients remain hypercoagulable following COVID-19.

Left ventricular systolic dysfunction and heart failure after COVID-19 should be managed according to standard guidelines.

Intense cardiovascular exercise must be avoided for three months in all patients after myocarditis or pericarditis; athletes are advised to take three to six months of complete rest from cardiovascular training followed by specialist follow up with return to support guided by functional status, biomarkers, absence of dysrhythmias and evidence of normal ventricular systolic function.

Ischaemic stroke, seizures, encephalitis, cranial neuropathies have all been noted following COVID-19 infection, but fortunately they seem to be rare.

Patients suspected with these serious complications should be referred to a neurologist.

Common non-specific neurological symptoms which seem to co-occur with fatigue and breathlessness, include headache, dizziness and cognitive blunting, so called brain fog.

Until evidence based guidance appears and how to manage or when to refer such symptoms, it is recommended that supportive management of symptomology remains in primary care.