Idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF), also known as cryptogenic fibrosing alveolitis, is a rare, progressive respiratory illness characterised by the thickening and stiffening of lung tissue due to the formation of scar tissue. It is a type of chronic pulmonary fibrosis that leads to an irreversible decline in lung function.

Signs and Symptoms

Symptoms of IPF typically develop gradually and include shortness of breath and a dry cough. Patients may also experience fatigue, and clubbing of the fingers and toes. Complications can include pulmonary hypertension, heart failure, pneumonia, and pulmonary embolism. The average life expectancy after diagnosis is about four years.

Causes and Risk Factors

The cause of IPF is unknown (idiopathic), but several risk factors have been identified, including cigarette smoking, acid reflux disease (GERD), certain viral infections, and genetic predisposition. The disease mechanism involves scarring of the lungs, often following repetitive injury to alveolar epithelial cells. Abnormal wound healing processes and excessive collagen deposition are key pathological features.

Diagnosis

Diagnosing IPF involves ruling out other potential causes of interstitial lung disease (ILD) and confirming the presence of a usual interstitial pneumonia (UIP) pattern on high-resolution computed tomography (HRCT). In some cases, a lung biopsy may be necessary. Multidisciplinary collaboration between pulmonologists, radiologists, and pathologists is very important for accurate diagnosis.

Differential Diagnosis

The symptoms of IPF can mimic other conditions, such as asthma, chronic obstructive pulmonary disease (COPD), and congestive heart failure. Differential diagnosis includes ruling out other forms of ILD, such as hypersensitivity pneumonitis, advanced sarcoidosis, and drug-induced lung disease.

Treatment

Pulmonary Rehabilitation and Oxygen Therapy

Pulmonary rehabilitation and supplemental oxygen are common supportive treatments for IPF. Rehabilitation can improve exercise tolerance, quality of life, and alleviate symptoms. Oxygen therapy is recommended for patients with significantly low oxygen levels at rest.

Medications

Two main medications are approved for IPF: pirfenidone and nintedanib. Pirfenidone reduces disease progression and lung function decline, while nintedanib, a triple angiokinase inhibitor, also slows lung function decline.

Lung Transplantation

Lung transplantation is an option for eligible patients and has been shown to significantly reduce mortality. Bilateral lung transplantation may offer better outcomes than single lung transplantation.

Palliative Care

Palliative care focuses on symptom relief and improving patient comfort. This includes the use of chronic opioids for severe dyspnea and cough, psychological support, and managing comorbid conditions.

Prognosis

IPF has a poor prognosis, with a median survival time of 2 to 5 years after diagnosis. The 5-year survival rate ranges from 20% to 40%, which is lower than that of several malignancies. The GAP index, based on gender, age, and lung physiology variables, is used to predict mortality in IPF patients.

Epidemiology

IPF is the most common form of idiopathic interstitial pneumonia (IIP) and has an estimated prevalence of 14.0 to 42.7 per 100,000 persons in the USA. It is more common in men and is usually diagnosed in individuals over 50 years of age. Incidence rates vary, with recent estimates in the US ranging from 6.8 to 16.3 per 100,000 persons.

Research

Research into IPF continues, with investigations into new treatments, including monoclonal antibodies, lysophosphatidic acid receptor antagonists, and stem cell therapies. Machine learning algorithms are also being developed to improve early diagnosis and predict risk.

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Self-assessment MCQs (single best answer)

Which of the following is NOT a common symptom of Idiopathic Pulmonary Fibrosis (IPF)?

What is the average life expectancy after a diagnosis of IPF?

Which of the following is NOT a known risk factor for IPF?

Which imaging technique is primarily used to confirm the presence of a usual interstitial pneumonia (UIP) pattern in IPF?

Which medication is a triple angiokinase inhibitor used to slow lung function decline in IPF patients?

What type of lung transplantation is considered to potentially offer better outcomes for IPF patients?

Which index is used to predict mortality in IPF patients?

What is the estimated prevalence of IPF in the USA?

Which of the following is NOT a complication associated with IPF?

Which of the following treatments focuses on symptom relief and improving patient comfort in IPF?