Most commonly, patients may experience fatigue, generalized weakness, brain fog, and dyspnea, but symptoms can include arthralgias, myalgias, cough, chest discomfort, palpitations, anosmia, dysgeusia, nausea, abdominal pain, diarrhea, headache, poor sleep, difficulty concentrating, memory impairment, depression, and anxiety. Postural orthostatic tachycardia syndrome (POTS) is a frequent occurrence.
As more is learned about the long-term effects of COVID-19 in some individuals, durable cutaneous manifestations have been observed. See skin and oral mucosal manifestations of COVID-19.
A preprint (not yet peer-reviewed) prospective longitudinal cohort study in the United Kingdom analyzed 336 652 subjects who tested positive for SARS-CoV-2. Of these, 9323 subsequently developed long COVID, defined as symptoms lasting for more than 28 days, and 1459 had post-COVID syndrome, defined as more than 12 weeks of symptoms. Review of symptom clusters in these subjects identified 3 main clusters of syndromes occurring within and across wild-type, delta, and alpha variants. (It is thought that the SARS-CoV-2 omicron variant is much less likely to lead to long COVID compared with the original, wild-type virus.) These clusters are cardiorespiratory, central neurologic, and multiorgan symptoms; a lesser cluster of gastrointestinal symptoms was also noted. Other researchers have clustered into main categories of cardiorespiratory syndrome, fatigue syndrome, and neuropsychiatric syndrome, with lesser clusters of gastrointestinal syndrome and hepatobiliary syndrome.
Symptoms can persist beyond 6 months in some individuals, although patients most often progressively improve with time. Eventually, most patients report returning to their usual state of health.
The pathophysiology of PCCs is still unknown. There are no specific laboratory abnormalities or imaging findings necessary for the diagnosis of PCCs.
PCCs can develop regardless of initial COVID-19 illness severity. Risk factors include older age, partial or no vaccination, female sex, more than 5 symptoms in the first week of acute infection, and comorbid illness, such as diabetes and chronic kidney disease.
In a large study, about one-fifth of fully vaccinated patients diagnosed with breakthrough infection reported having long-COVID symptoms at 6 weeks after diagnosis. Another published study in September 2021 found that vaccination was protective against development of PCCs; those who were fully vaccinated when they contracted SARS-CoV-2 developed PCCs at approximately half the rate of those who were unvaccinated when they contracted SARS-CoV-2 (5.2% versus 10.7%, respectively).
Related topics: multisystem inflammatory syndrome in adults (MIS-A), multisystem inflammatory syndrome in children (MIS-C)
U09.9 – Post COVID-19 condition, unspecified
1119303003 – Post-acute COVID-19
Differential Diagnosis & Pitfalls
- Myalgic encephalomyelitis (chronic fatigue syndrome)
- Postural orthostatic tachycardia syndrome
- Mast cell activation syndrome
- Connective tissue diseases (eg, systemic lupus erythematosus, rheumatoid arthritis)
- Bacterial or viral pneumonia – look for current fevers and chills
- Bronchiectasis – look for significant, chronic sputum production
- Pulmonary fibrosis
- Pulmonary embolism
- Asthma / chronic obstructive pulmonary disease (COPD)
- Gastroesophageal reflux disease (GERD)-associated cough
- Acute coronary syndrome / myocardial infarction
- Congestive heart failure
- Renal failure (acute kidney injury, chronic kidney disease) / uremia
- Generalized anxiety disorder
- Posttraumatic stress disorder
- Postintensive care syndrome
- Cerebral venous sinus thrombosis
- Hypothyroidism or hyperthyroidism
- Parkinson disease – associated with anosmia