Are body soreness and shoulder subluxation weeks after ferumoxytol (ferumoxytol) likely due to the medication or my hypermobile Ehlers-Danlos Syndrome (EDS)?

Body Soreness and Shoulder Subluxation After Ferumoxytol in Hypermobile Ehlers-Danlos Syndrome

Your body soreness and shoulder subluxation are most likely related to your hypermobile Ehlers-Danlos Syndrome (hEDS) rather than ferumoxytol administration. While ferumoxytol can cause certain adverse reactions, joint instability and prolonged body soreness weeks after administration are not among its documented side effects.

Understanding the Relationship Between Symptoms and Causes

Ferumoxytol Side Effects

According to the FDA drug label for ferumoxytol, the most common adverse reactions include:

• Headache (3.4%)
• Nausea (1.8%)
• Dizziness (1.5%)
• Fatigue (1.5%)
• Diarrhea (1%)
• Back pain (1%) 1

These side effects typically occur during or shortly after administration and do not persist for weeks. Notably, joint instability or subluxation is not listed among the adverse reactions to ferumoxytol.

Hypermobile Ehlers-Danlos Syndrome Manifestations

Hypermobile Ehlers-Danlos Syndrome is characterized by:

• Joint hypermobility and instability
• Tissue fragility
• Chronic musculoskeletal pain
• Recurrent joint subluxations/dislocations 2

Shoulder subluxation is a well-documented manifestation of hEDS due to the inherent joint instability caused by connective tissue abnormalities. The American Heart Association recognizes that EDS is associated with tissue fragility, which can manifest in various ways including joint instability 2.

Clinical Assessment of Your Symptoms

Shoulder Subluxation

Shoulder subluxation in hEDS patients is common due to:

• Connective tissue fragility affecting joint capsule integrity
• Ligamentous laxity around the glenohumeral joint
• Poor muscular support due to underlying collagen abnormalities 2

The "dead arm syndrome" described in recurrent transient anterior subluxation of the shoulder is commonly seen in individuals with joint hypermobility 3.

Body Soreness

Generalized body soreness is a hallmark symptom of hEDS and represents:

• Chronic pain from joint instability
• Myalgia from compensatory muscle tension
• Tissue microtrauma from everyday activities 4

Management Recommendations

For shoulder subluxation in hEDS:

1. Positioning and supportive devices

   • Consider appropriate slings or braces for shoulder stabilization 5
   • Avoid positions that place the shoulder at risk for subluxation

2. Physical therapy

   • Focus on strengthening the rotator cuff and scapular stabilizers
   • This is the only treatment proven efficacious in reducing joint instability and generalized pain in hEDS 4

3. Pain management

   • Neuromodulators such as gabapentin or pregabalin may help manage neuropathic pain components 2
   • Avoid opioids for chronic pain management due to limited efficacy and risk of addiction 2

Important Considerations

• Multidisciplinary approach: EDS management requires coordination between rheumatology, physical therapy, and pain management 2
• Avoid invasive procedures: Patients with vascular EDS should avoid invasive diagnostic procedures due to tissue fragility 2
• Nutritional support: Some evidence suggests nutritional supplements (including vitamin C, magnesium, and glucosamine) may help support connective tissue health, though evidence is limited 6

When to Seek Immediate Medical Attention

While your symptoms are likely related to hEDS, seek immediate medical attention if you experience:

• Sudden, severe pain different from your usual EDS pain
• Signs of vascular complications (if you have vascular EDS)
• Progressive neurological symptoms
• Inability to reduce the subluxation

In summary, the temporal relationship between ferumoxytol administration and your symptoms weeks later, combined with the known manifestations of hEDS, strongly suggests that your hypermobile EDS is the primary cause of your current symptoms rather than the medication.