How should you investigate shortness of breath in someone on methotrexate (methotrexate)

From the Guidelines

To investigate shortness of breath in someone taking methotrexate, a thorough clinical assessment and immediate discontinuation of methotrexate are crucial, as methotrexate can cause potentially life-threatening pulmonary toxicity, including interstitial pneumonitis and acute pneumonitis, with mortality rates of 15-20% in acute pneumonitis, as noted in various studies 1. When investigating shortness of breath in a patient on methotrexate, it is essential to consider the potential for methotrexate-induced lung toxicity, which can be severe and life-threatening. The first step should be a thorough clinical assessment, including vital signs, oxygen saturation, and a detailed history focusing on the onset, duration, and severity of symptoms.

• Key points to consider in the clinical assessment include:
  • Onset, duration, and severity of shortness of breath
  • Presence of other symptoms such as cough, fever, or chest pain
  • Past medical history, including preexisting lung disease
  • Medication history, including dose and duration of methotrexate therapy
• Immediate diagnostic steps should include:
  • Chest X-ray to look for interstitial infiltrates or ground-glass opacities
  • Pulmonary function tests to assess for restrictive patterns and decreased diffusion capacity
  • Laboratory tests, such as complete blood count, comprehensive metabolic panel, and inflammatory markers like C-reactive protein and erythrocyte sedimentation rate
• If the chest X-ray is abnormal or symptoms are severe, further diagnostic steps may include:
  • High-resolution CT scan of the chest for better visualization of lung parenchyma
  • Bronchoscopy with bronchoalveolar lavage to rule out infection and obtain samples for cytology
• Temporarily discontinuing methotrexate until pulmonary toxicity is ruled out is a critical step, as continued use of the medication can worsen lung toxicity and increase the risk of mortality, as highlighted in studies such as 1 and 1. Given the potential severity of methotrexate-induced lung toxicity, a comprehensive and prompt approach to investigation and management is necessary to minimize morbidity, mortality, and impact on quality of life. This approach should be guided by the most recent and highest-quality evidence available, such as the guidelines and studies referenced 1.

From the FDA Drug Label

Pulmonary function tests may be useful if methotrexate-induced lung disease is suspected, especially if baseline measurements are available.

To investigate shortness of breath in someone on methotrexate, pulmonary function tests may be useful, especially if baseline measurements are available. This is because methotrexate can cause lung disease, and pulmonary function tests can help assess lung function and detect any potential problems.

• Key considerations:
  • Methotrexate-induced lung disease is a potential cause of shortness of breath
  • Pulmonary function tests can help diagnose lung disease
  • Baseline measurements can provide a comparison for future tests 2 2 It is essential to closely monitor patients on methotrexate for signs of toxicity, including respiratory problems, and to adjust the dose or discontinue the drug if necessary.

From the Research

Investigating Shortness of Breath in Someone on Methotrexate

To investigate shortness of breath in someone on methotrexate, the following steps can be taken:

• Evaluate new pulmonary symptoms promptly, as methotrexate-induced pulmonary toxicity can be a life-threatening complication 3
• Perform chest radiography if an methotrexate-induced pulmonary reaction is suspected and abnormalities are noted on lung examination 3
• Discontinue methotrexate and institute supportive measures if pulmonary toxicity is suspected 4, 3
• Investigate the diagnosis of the patient's pulmonary complaints by looking for features of the underlying rheumatic process, infection, and other medical conditions 3
• Consider hospitalization and supplemental oxygen for patients with severe pulmonary compromise, and administer high-dose corticosteroids if necessary 3

Diagnostic Tools

The following diagnostic tools can be used to investigate shortness of breath in someone on methotrexate:

• Chest radiography 3
• High-resolution computed tomography (HRCT) scanning 5, 6
• Pulmonary function tests, including forced expiratory volume, forced vital capacity, diffusion capacity for carbon monoxide, and residual volumes 6

Management of Methotrexate-Induced Pulmonary Toxicity

The management of methotrexate-induced pulmonary toxicity includes:

• Discontinuation of methotrexate 4, 3
• Supportive measures, such as supplemental oxygen and hospitalization if necessary 3
• Administration of corticosteroids, such as methylprednisolone 5
• Consideration of folinic acid therapy to prevent myelosuppression and other toxic effects 7