Long COVID: Difference between revisions

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However, a number of putative pathophysiologic mechanisms have been suggested.
However, a number of putative pathophysiologic mechanisms have been suggested.


'''1) Long-term tissue damage'''
'''* 1) Long-term tissue damage''':
Long-term tissue damage can result in the persistence of symptoms in different organs. For example:
**Long-term tissue damage can result in the persistence of symptoms in different organs. For example:


* Respiratory symptoms
* Respiratory symptoms

Revision as of 16:25, 17 March 2022

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Definitions

Definitions of Long COVID

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Risk calculators and risk factors for Long COVID

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Symptoms of Long COVID

Causes & Risk Factors for Long COVID

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Treatment of Long COVID

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List of terms related to Long COVID

For COVID-19 main page, click here

For COVID-19 frequently asked inpatient questions, click here

For COVID-19 frequently asked outpatient questions, click here

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];

Synonyms and keywords: Long COVID Syndrome, long COVID, long-haul COVID, post-COVID-19 condition, post-COVID-19 syndrome, post-acute sequelae of COVID-19 (PASC), chronic COVID syndrome (CCS).

Overview

  • Shortly after the COVID-19 pandemic onset, emerging studies showed that a considerable proportion of patients with COVID-19 might exhibit sustained postinfection sequelae.

Historical Perspective

Definition

  • On October 6, 2021, World Health Organization (WHO) released a clinical case definition of the post-COVID-19 condition through a robust, protocol-based methodology (Delphi consensus), which engaged a diverse group of representative patients, patient-researchers, external experts, WHO staff, and other stakeholders from multiple geographies. It was acknowledged that this definition may change with emerging new evidence and continuously evolving our understanding of the consequences of COVID-19.
  • According to WHO clinical case definition, the post-COVID-19 condition is defined as:

There are concerns about the difficulty in defining cases[1].

Classification

There is no established system for the classification of long COVID.

Pathophysiology

The exact pathogenesis of long COVID is not fully understood. However, a number of putative pathophysiologic mechanisms have been suggested.

* 1) Long-term tissue damage:

    • Long-term tissue damage can result in the persistence of symptoms in different organs. For example:
  • Respiratory symptoms

Lung fibrosis may be the cause of respiratory symptoms, such as dyspnea, and cough.

  • Neurologic symptoms

Structural and metabolic abnormalities in the brain and brainstem may be the cause of neurologic symptoms such as headache, delirium, memory loss, anosmia, and fatigue.

  • Fatigue

Chronic fatigue occurs as a complex syndrome and a few mechanisms have been suggested. These include:[3,136,137].

    • Autonomic nervous system dysfunction
    • Inflammation
    • Channelopathies
    • Inadequate cerebral perfusion
  • Cardiovascular symptoms

Cardiac injury occurs in a substantial proportion of patients during acute COVID-19 episodes. Resulting cardiac abnormalities and myocardial inflammation may account for symptoms such as chest pain, heart palpitations, and tachycardia.

2) Ongoing inflammation Several studies have suggested the presence of an unresolved inflammation in patients recovering from COVID-19. This ongoing inflammation may result from a variety of reasons.

  • 1) Studies have shown the persistence of the virus in the gastrointestinal system (in the gastric and intestinal cells) after recovering from acute COVID-19 episodes due to the high expression of ACE2 receptors in these cells. increased fecal shedding of SARS-CoV-2 virus has been shown in some studies [138–140].[103]

This may trigger a state of immune activation and ongoing inflammation in the body and also may explain the relatively high prevalence (up to 30%) of gastrointestinal manifestations (e.g. appetite loss, nausea, vomiting, diarrhea, and abdominal discomfort) in patients with long COVID. [141,142].[29,32,46].

  • 2) Increased levels of pro-inflammatory markers(e.g. CRP, IL-6, and D-dimer) and lymphopenia occurs during acute COVID-19 episode and have been shown to be associated with long COVID symptoms, particularly myalgia, fatigue, and joint pain.
  • 3) Autoimmunity

Recently, T-cells and B-cells dysfunction have been suggested to promote long COVID pathophysiology similar to autoimmune diseases [104].

  • 4) Other mechanisms

In a recent study using Invasive Cardiopulmonary Exercise Testing, the pathophysiologic mechanism of exercise intolerance in post-COVID-19 long-haul syndrome in COVID-19 patients without cardiopulmonary involvement has been investigated. The results of the study showed that Patients without cardiopulmonary disease who have recovered from COVID-19 demonstrate a marked reduction in peak oxygen consumption from a peripheral rather than a central cardiac limit, along with an exaggerated hyperventilation response during exercise. This shows that patients who have recovered from COVID-19 demonstrate reduced peak exercise aerobic capacity with impaired systemic oxygen extraction and abnormal ventilatory efficiency slope.

Epidemiology and Demographics

  • The reported incidence/prevalence of long COVID-19 varies in different studies mainly due to the absence of single terminology and definition.
  • One study found that up to 70% of individuals at low risk of mortality from COVID-19 experience impairment in one or more organs (including heart, lungs, kidneys, liver, pancreas, or spleen) 4 months after acute COVID-19 episode.
  • A meta-analysis, including 47,910 patients (age 17-87 years), estimated that 80% of the patients with SARS-CoV-2 infections developed one or more long-term (ranging from 14 to 110 days) symptoms.
  • Women seem to be more commonly affected by long COVID than men.

Risk Factors

Screening

There is insufficient evidence to recommend routine screening for long COVID.

Natural History, Complications, and Prognosis

  • The natural history, clinical course, long-term complications, and prognosis of long COVID-19 are still not completely understood.
  • Manifestations of the post-COVID-19 condition vary considerably in terms of organ involvement and severity of symptoms; however, they generally impact the everyday functioning of affected patients.
  • Symptoms might newly develop following initial recovery from an acute COVID-19 illness or occur as a persist from the initial episode.
  • Symptoms might also fluctuate or relapse over time.

Diagnosis

Diagnostic Study of Choice

History and Symptoms

Long COVID can involve almost every organ. The most common symptoms of long COVID include:

Physical Examination

Laboratory Findings

There are no diagnostic laboratory findings associated with long COVID. Symptoms do not correlate with the serology of SARS-CoV-2.

Electrocardiography

In patients with cardiopulmonary symptoms, an ECG may be needed.

X-ray

A chest x-ray may be helpful in the diagnosis of pulmonary complications of COVID such as lung damage (ie, ground glass opacities, consolidation, interlobular septal thickening), pleural effusion.

Echocardiography or Ultrasound

In selected patients with cardiopulmonary symptoms, echocardiography may be necessary.

CT scan

In patients with cardiopulmonary symptoms, a chest CT scan may be needed.

MRI

There are no MRI findings associated with long COVID. However, a cardiac MRI may be helpful in the diagnosis of myocarditis in COVID-19 patients.

Other Imaging Findings

There are no other imaging findings associated with long COVID.

Other Diagnostic Studies

In selected patients with cardiopulmonary symptoms, Holter monitoring, cardiopulmonary exercise testing (CPET), and pulmonary function tests may be necessary.

Treatment

Due to the diversity of symptoms and their severity, the mainstay of long COVID treatment is multidisciplinary and supportive. The management should focus on supporting self-management and individualized rehabilitation.

Medical Therapy

  • Olfactory/gustatory symptoms
    • In most patients with a loss or decrease in sense of smell or taste, symptoms improve slowly over several weeks and do not require medical intervention. Patients may need education on food and home safety.
    • In patients with persistent symptoms, olfactory training may be appropriate. If conservative management fails, referral to an otolaryngologist and specialized taste and smell clinic may also be considered.
  • Alopecia
    • There is no specific therapy for alopecia in COVID-19 patients, and it should be managed similarly to non-COVID-19 patients.
    • In patients with concomitant malnutrition, nutritional deficiencies should be corrected.

Primary Prevention

The most effective measure to prevent the post-COVID-19 condition is to prevent COVID-19. These primary prevention strategies include:

Secondary Prevention

There are no established measures for the secondary prevention of long COVID.

See also

References

  1. Wisk LE, Nichol G, Elmore JG (2022). "Toward Unbiased Evaluation of Postacute Sequelae of SARS-CoV-2 Infection: Challenges and Solutions for the Long Haul Ahead". Ann Intern Med. doi:10.7326/M21-4664. PMID 35254883 Check |pmid= value (help).