Introduction

Acute respiratory distress syndrome was first used in 1967 to define the acute abnormality in bilateral lungs.¹ It is the main cause of respiratory system failure in critical illnesses. In ARDS, an increase in permeability of the alveoli capillary membrane develops, leading to hypoxemia and non-cardiogenic pulmonary oedema. Acute respiratory distress syndrome is most often seen in patients with autoimmune disease. Affective management requires an understanding of the pathophysiology of ARDS and the effect of autoimmune disease and its treatment.²

Pathophysiology of acute respiratory distress syndrome in autoimmune disease patients

In ARDS, the permeability of the capillaries increases, and damage to the capillaries and alveolar epithelium leads to alveolar space. The alveolar space leads to the accumulation of protein-rich fluid inside the alveoli, causing alveolar damage and the release of pro-inflammatory cytokines like tumour necrosis factors, interleukin-1, and interleukin-6. The release of cytokines also activates toxic mediators like reactive oxygen species and proteases. This free radical production causes oxidative cell damage, and neutrophil activation causes inflammation in both lungs. Several pathways are involved in the ARDS mechanism. Due to ARDS, the lung size decreases, which is known as “baby lungs”.¹

Clinical presentations               

In patients with autoimmune disease, the following clinical symptoms may develop, such as severe tachypnea, abnormal breathing, with the need for supplemental oxygen of ≥6 L/min and bilateral infiltrates.

Diagnosis

• Echocardiography: for the evidence of cardiac function, to check for arrhythmias, ischemia, etc
• Biomarker detection for pulmonary oedema
• Sputum detection for bacterial infections
• Blood culture test for secondary infection detection

In each case, the type of immune deficiency determines the effective management of the anti-infectious treatment. High-resolution CT scans can also determine the cause of acute respiratory failure.³

Clinical course

The first few days of ARDS are characterised by severe hypoxemia with a positive end-expiratory pressure. Bilateral infiltrates are also present in initial cases.  Some patients recover from hypoxemia, while some remain oxygen-dependent. Also, some patients with ARDS are left with reduced lung function.

Complications

Patients with ARDS are at risk of developing ventilator-related complications or critical illnesses, such as barotrauma, nosocomial infection, multi-organ failure, deep vein thrombosis, GIT bleeding, etc.⁴

Management of acute respiratory distress syndrome in autoimmune disease patients

The management of ARDS depends on the underlying cause of the disease.

Identify and treat the underlying cause

• Evaluate the activity of the autoimmune disease: used to determine if the ARDS is going to worsen the underlying autoimmune disease. This may require lab tests (for instance, inflammatory markers) and clinical assessment
• Modify immunosuppressive therapy: manipulating the doses or agents of immunosuppressive drugs. For example, raising corticosteroids should be beneficial, in case the ARDS is secondary to an inflammatory process

Supportive care

• Oxygen therapy: Supplemental oxygen should be used to ensure a saturation of ≥ 90%. If the case is not so severe, HFNC (high-flow nasal cannula) or NIV (non-invasive ventilation) can be employed
• Invasive mechanical ventilation: high severity may necessitate the placement of endotracheal ventilation. The protocol for lung-protective technique involves the use of low tidal volume ventilation, such as 6 ml/kg of predicted body weight

Fluid management

Care should be taken so as not to over-resuscitate with fluids, since this can aggravate pulmonary oedema. Diuretics may be instituted as needed, and fluid balance maintained.

Pharmacologic interventions

• Corticosteroids: despite the reduction of inflammation by corticosteroids, the dose and timing should be tailored to the individual based on risk-benefit considerations to prevent aggravating side effects
• Other immunomodulators: Drugs such as tocilizumab may be used for the inflammatory response associated with conditions such as systemic lupus erythematosus or rheumatoid arthritis

Monitoring and supportive therapies

• Continuous monitoring: continuously monitor and evaluate vital signs, respiratory status, and laboratory markers. The treatment plan should be modified according to clinical response
• Nutritional support: Enteral nutrition should be offered as soon as possible, especially in mechanically ventilated patients

Multidisciplinary care

• Rheumatologists, pulmonologists, and critical care specialists should be consulted for holistic care. While regular interdisciplinary meetings rarely positively affect treatment programs, they can facilitate communication among caregivers

Other therapies

• Antibiotics: the appropriate antibiotics should be given accordingly, if there is an infection or it's confirmed
• Pulmonary rehabilitation: continue pulmonary rehabilitation as part of the effective treatment in the recovery phase for enhanced lung functioning and general quality of life⁵

Summary

Managing ARDS in an autoimmune disease patient is complex, and it requires advanced treatment that treats both the respiratory illness and the autoimmune disease. By using a combination of both supportive and pharmacological management, patients can benefit from the therapy.

FAQs

Which are the most common autoimmune diseases associated with ARDS?

• Systemic lupus erythematosus
• Rheumatoid arthritis
• Scleroderma
• Pulmonary fibrosis
• COVID-19 disease⁶

What is the differential diagnosis of ARDS in relation to other respiratory conditions?

ARDS is generally distinguished from conditions like heart failure or pneumonia based on the following factors:

• Chest imaging: chest X-rays and CT scans have bilateral infiltrates in ARDS, while heart failure will typically present with cardiomegaly and pleural effusions³

Are there risks involved with immunosuppressive treatment in patients with ARDS?

Yes, even immunosuppressive treatment incurs the risk of the development of infections, which can complicate ARDS. These risks can only be mitigated by close monitoring and changes in therapy.

What is the common side effect of the drug used to treat ARDS?

Common side effects associated with treatments for ARDS, mainly corticosteroids, include:

• Weight gain
• Fluid retention
• Hyperglycemia
• Gastrointestinal bleeding⁷

What is the prognosis of patients with ARDS caused by autoimmune diseases?

The prognosis may be quite variable because of the different grades of severity of ARDS, the disease of the disease, and the patient's general condition. Early diagnosis and intervention can make a big difference.⁵

What can caregivers do for patients with ARDS?

Support providers on their part can provide emotional support, assist with personal care, or aid with medication management. Self-learning about ARDS and what it entails can also effectively empower patients to advocate for their needs.

What are some of the sentinel signs that ARDS is deteriorating? 

Sentinel signs that indicate deterioration of ARDS are:

• Difficulty in breathing
• A decrease in oxygen levels by 15 points
• Changes in mental status (altered mentation, agitation)²