How do patients describe and localize weakness?

How Patients Describe and Localize Weakness

Patients describe weakness through specific verbal or non-verbal communications that help localize the affected areas, with descriptions varying based on their ability to communicate and the underlying cause of weakness.

Patient Descriptions of Weakness

• Communicative patients may describe weakness using various terms and rating scales, with the 0-10 Numeric Rating Scale (NRS) being the most valid and feasible tool for self-reporting patients in the ICU 1
• Patients may verbally state their symptoms or non-verbally point to numbers, words, or body diagrams to describe and localize their weakness 1
• For patients who can communicate, tools like the Condensed Form of the Memorial Symptom Assessment Scale and the Edmonton Symptom Assessment Scale allow for reporting of weakness along with other physical and psychological symptoms 1

Localization of Weakness

• Patients often localize weakness by pointing to specific body areas on outline diagrams when asked where they feel weakness 1
• In ICU-acquired weakness (ICUAW), patients typically describe generalized weakness affecting multiple muscle groups rather than focal weakness 1
• The Medical Research Council (MRC) score is used to assess muscle strength across 12 muscle groups, with an MRC sum score less than 48 (or mean MRC less than 4 per muscle group) defining ICU-acquired weakness 1

Assessment Methods Based on Communication Ability

For Communicative Patients:

• Verbal descriptions where patients can state the location and severity of weakness 1
• Non-verbal communication where patients point to affected areas on body diagrams 1
• Rating scales where patients can indicate severity by pointing to numbers (0-10 NRS) 1
• Speech language pathologists can help augment communication through alternative approaches such as alphabet boards, electronic speech-generating devices, or touch screens 1

For Non-Communicative Patients:

• Behavioral assessment using validated tools like the Medical Research Council (MRC) score 1
• Proxy reporting from family members or healthcare providers 1
• Observation of specific behaviors that may indicate weakness, such as inability to perform certain movements 1

Patterns of Weakness

• Patients with ICUAW typically present with symmetric weakness affecting multiple muscle groups 1
• Respiratory muscle weakness may be described as difficulty breathing or shortness of breath 1
• Expiratory muscle weakness can lead to increased residual volume in the lungs 1
• Diaphragmatic weakness often manifests as a fall in vital capacity when the patient is in a supine position compared to upright 1

Clinical Assessment Tools

• The six-point Medical Research Council (MRC) score is the recommended tool to assess muscle strength in ICU patients 1
• Handgrip strength dynamometry provides a simple diagnostic method for ICU-acquired weakness and can identify disorders before changes in body composition are detected 1
• Physical examination with Manual Muscle Testing (MMT) is used in 84% of studies to diagnose ICUAW 1

Common Pitfalls in Assessing Weakness

• Weakness may be confused with fatigue, which is a common co-existing symptom 2
• Patient descriptions may be influenced by cognitive impairment, especially in ICU settings 1
• Assessment tools requiring patient cooperation (like handgrip strength) have limitations in uncooperative or sedated patients 1
• Weakness can coexist with muscle tightness, potentially masking the true extent of weakness 2

Understanding how patients describe and localize weakness is crucial for accurate diagnosis and appropriate management, particularly in critical care settings where early identification can lead to better outcomes.