In this article, we will discuss lesions caused by COVID-19.
Although there is a lot of speculation that being infected with COVID-19 is just a common cold, or nothing serious, I will introduce the lesions in each organ from infected cases.Knowing this means that we can deepen our awareness of countermeasures against infection and our understanding of what we have been infected with.
Lesions of the respiratory system
The main symptoms in people infected with COVID-19 appear in the lungs, and respiratory failure is the main cause of death.
SARS-CoV-2 enters human cells by binding to the ACE2 receptor, which is highly expressed in alveolar type 2 cells (AT2), and can account for the vulnerability of the respiratory system.
Research has elucidated the pathology observed on gross and microscopic examination.
Findings included mottled to diffuse sclerosis, severe interstitial congestion, and thromboembolism, and histology showed vitreous membranes, extensive capillary congestion, and microthrombi in alveolar capillaries, consistent with exudative diffuse alveolar injury.While the aforementioned findings are similar to those seen in acute respiratory distress syndrome (ARDS), COVID-19-related ARDS is unique due to the dissociation between the severity of hypoxemia and the relative maintenance of pulmonary mechanics.
It has been proposed that patients who meet the criteria for COVID-19-related ARDS, but develop it, can be classified as type 1 "non-ARDS" or type 2 "ARDS" according to their pulmonary compliance.
It is believed that their distinction can be based on their response to CT scan or, albeit substandard, positive end-expiratory pressure (PEEP).
Type 1 patients show severe hypoxemia with moderate pulmonary compliance, while type 2 patients show severe hypoxemia with inadequate pulmonary compliance.
This has important clinical implications in determining management in the ICU.
Cardiovascular Lesions
In addition to respiratory involvement, systemic inflammation in response to SARS-CoV2 infection can cause increased myocardial metabolic demand and myocardial oxygen supply/demand mismatch, leading to myocardial injury.
Myocardial injury has then been shown to be independently associated with high mortality and a variety of complications such as ARDS and electrolyte disturbances, and increases the risk of arrhythmias.
In patients with coronary artery disease, there is also an increased awareness of acute plaque rupture and, ultimately, acute coronary artery involvement.
In addition, a surge in pro-inflammatory cytokines as part of the systemic inflammatory response to COVID-19 leads to other changes including myocarditis and myocardial fibrosis, resulting in edema and pericarditis.
Interestingly, these changes are seen in younger patients who are not hospitalized and have been reported to be associated with adverse events and poor prognosis.
Furthermore, new evidence indicates that the cardiac changes induced by COVID-19 may not be short term and limited.
According to a study by Puntmann et al. that included 100 patients with COVID-19 recovery, left ventricular ejection fraction was lower and troponin T levels were significantly elevated compared to healthy, risk factor-matched controls.
After 71 days of follow-up, 78% of patients had abnormal cardiac magnetic resonance findings.
These patients may be in the very early stages of cardiac involvement, a view that probably warrants longer follow-up to identify potential long-term complications, especially in patients with persistent symptoms attributable to COVID-19.
Liver involvement
The symptoms of COVID-19 that are associated with the abdomen have been well established, but the underlying mechanisms are not understood.
ACE2 receptors found on intestinal cells and esophageal epithelial cells play an important role in regulating intestinal inflammation.
This may be partially responsible for typical gastrointestinal symptoms such as diarrhea, nausea, and vomiting, which can occur with or without respiratory symptoms.And even after the virus has been eliminated in the respiratory tract, there are traces of the virus in the feces, raising future questions and challenges.
In addition, in a radiological study of 412 patients, CT scans of ICU patients revealed abnormalities in the bowel wall in 31% of patients or portal vein gas in 20% of patients.In addition, abdominal ultrasound, performed primarily for abnormal LFTs, showed bile stasis, a precursor of liver injury, in 54% of patients.
SARS-CoV2-mediated hepatotoxicity can occur directly through binding of the virus to ACE2 receptors found on cholangiocytes and hepatocytes, or indirectly through the release of cytokines as part of the immune response.
This may exacerbate hepatocyte damage and cholangiocyte dysfunction.In addition, the liver as the primary site of drug metabolism for antiviral drugs such as lopinavir/ritonavir, which are widely used in COVID-19, can tolerate further iatrogenic damage during treatment.
Skin lesions
With regard to skin manifestations, they were first reported in an Italian cohort study.Approximately 20% of patients hospitalized with COVID-19 showed signs of skin lesions without any exposure to the new drug.
The rash appeared before (9%) or after admission (11%) and was described as erythematous, widespread urticaria, or resembling varicella.
Since then, skin manifestations have been most comprehensively classified in a cross-sectional study of 375 patients with COVID-19 and skin lesions.
The five groups that were identified were.
(1) Erythema edema with some vesicles or pustules
2) Other vesicular eruptions
3) Urticarial lesions
4) Macules
5) reticular plaques or necrosis.
Lesion types were related to age and disease severity, both of which increased from Group 1 to Group 5.
Not all skin manifestations in this study were directly caused by SARS-CoV-2, as the patients received a variety of drug treatments.For example, hydroxychloroquine can cause skin reactions, including the rare Stevens-Johnson syndrome, which presents with a pruritic erythematous maculopapular rash that spreads rapidly from the distal end.
Clinician awareness of the potential for cutaneous involvement may aid in the diagnosis and management of patients with COVID-19.
Neurologic Symptoms
Neurologic manifestations of COVID-19 infection include anosmia and loss of taste.
These are also commonly recognized as the major symptoms.
A systematic review of 41 studies found that the neurological manifestations of COVID-19 can be divided into three main categories.
1) Neurological diseases comorbid with COVID-19
2) Non-specific neurological symptoms caused by systemic reactions and partially by the neuroinvasive behavior of the virus.
Specific neurological symptoms and diseases including encephalitis, myelitis and seizures.In a study of 125 neurological or psychiatric disorders over a three-week period, 31% were associated with encephalopathy and 16 patients, including 16 patients, showed altered mental status.
Cerebrovascular disease was seen in 46% of patients with ischemic stroke and 7% with intracerebral hemorrhage, with most patients having risk factors and being over 60 years old.
Mainly, markers of macrovascular disease and accelerated thrombogenic state were found, suggesting a causal relationship.However, proving causality is difficult because of the very large number of SARS-CoV-2 cases and the high percentage of stroke patients with other risk factors.
Magnetic resonance imaging has shown small asymptomatic infarcts and elevated blood D-dimer levels in many COVID-19 patients.The current best explanation for cerebrovascular events is the hypercoagulable state SARS-CoV-2 triggers due to activation of inflammatory and thrombogenic pathways and consequent destabilization of carotid plaques.
Author's Conclusions
This article briefly describes how COVID-19 affects different organs. SARS-CoV2 exerts direct damage to target tissues through binding to ACE2 receptors and indirect effects mediated by systemic inflammation and prothrombotic states. Highlighting the pulmonary and extrapulmonary manifestations of COVID-19 on an open access platform such as that provided by Oxford Medical Case Reports will help clinicians to better understand the impact of COVID-19 on the lung. Highlighting the pulmonary and extrapulmonary manifestations of COVID-19 in an open access platform such as that provided by Oxford Medical Case Reports will help clinicians better understand and manage the multisystem manifestations of this disease during the impending second wave of infection.
Ranu Baral, Omar Ali, Iona Brett, Johannes Reinhold, Vassilios S Vassiliou, COVID-19: a pan-organ pandemic, Oxford Medical Case Reports, Volume 2020, Issue 12, December 2020, omaa107,
Conclusion
From this, we have learned about the pathological aspects of each organ.
It is becoming increasingly clear that this disease is not just a respiratory disease, and as more research is done, guidelines will be developed and more will be revealed.
