What are the key questions to ask when evaluating a patient presenting with weakness (asthenia)?

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From the Guidelines

When assessing weakness, particularly in the context of musculoskeletal pain or functional neurological disorders, it is crucial to undertake a comprehensive physical examination and assessment that includes neurological screening tests, evaluation of mobility, muscle strength, and understanding the patient's background and symptoms. This approach is supported by recent clinical guidelines, such as those outlined in the British Journal of Sports Medicine 1, which emphasize the importance of a thorough physical examination. Key aspects to focus on include:

  • Understanding the patient's symptoms, including when and how they started, exacerbating and easing factors, variability, severity, and impact on function 1.
  • Assessing physical impairments that significantly influence the patient's symptoms to guide treatment selection, as recommended in the best practice guide for patellofemoral pain 1.
  • Evaluating the patient's mobility and muscle strength, as part of a physical examination 1.
  • Delivering knee-targeted exercise therapy and deciding on supporting interventions, with education underpinning all interventions, for conditions like patellofemoral pain 1.
  • Supporting self-management of symptoms, which is particularly important in functional neurological disorders, and should be considered through all aspects of occupational therapy 1. By prioritizing these aspects, healthcare professionals can provide comprehensive care that addresses the patient's specific needs and promotes the best possible outcomes in terms of morbidity, mortality, and quality of life.

From the FDA Drug Label

Anticholinesterases Concomitant use of anticholinesterase agents (e.g., neostigmine, pyridostigmine) and corticosteroids may produce severe weakness in patients with myasthenia gravis. To assess weakness in patients taking prednisone, consider the following:

  • Concomitant use of anticholinesterase agents: Patients taking anticholinesterase agents (e.g., neostigmine, pyridostigmine) and corticosteroids may experience severe weakness, particularly those with myasthenia gravis.
  • Myasthenia gravis: Patients with myasthenia gravis should be closely monitored for signs of weakness when taking corticosteroids, especially if they are also taking anticholinesterase agents.
  • Withdrawal of anticholinesterase agents: If possible, anticholinesterase agents should be withdrawn at least 24 hours before initiating corticosteroid therapy to minimize the risk of severe weakness 2.

From the Research

Questions to Ask for Weakness

When evaluating a patient with muscle weakness, several questions can help determine the underlying cause. These questions include:

  • What is the pattern and severity of the weakness? 3
  • Are there any associated symptoms, such as fatigue or pain? 3, 4
  • What is the patient's medication history, and could any medications be contributing to the weakness? 3
  • Is there a family history of muscle weakness or other related conditions? 3
  • Are there any abnormal findings on physical examination, such as muscle atrophy or abnormal reflexes? 4

Laboratory Tests

Laboratory tests can also be helpful in evaluating muscle weakness. These may include:

  • Electrolyte measurements to evaluate for electrolyte imbalances 3, 4
  • Thyroid-stimulating hormone assay to evaluate for endocrine causes 3, 4
  • Creatine kinase level to evaluate for muscle damage 3, 4
  • Complete blood count with differential to evaluate for anemia, infection, or other conditions 5
  • Electromyography to evaluate for myopathy, neuropathy, or disease of the neuromuscular junction 3, 4

Special Considerations

In certain populations, such as the elderly, muscle weakness may present with atypical or nonspecific features 6. In these cases, a comprehensive and cost-effective evaluation is necessary to determine the underlying cause of the weakness. Additionally, certain conditions, such as frailty and sarcopenia, can present with generalized weakness in older adults 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Evaluation of the patient with muscle weakness.

American family physician, 2005

Research

Understanding the complete blood count with differential.

Journal of perianesthesia nursing : official journal of the American Society of PeriAnesthesia Nurses, 2003

Research

Evaluation of the elderly patient with weakness: an evidence based approach.

Emergency medicine clinics of North America, 1999

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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