Differential Diagnosis for Deep Tissue Pains, Muscle Weakness, and Joint Instability Triggered Iatrogenically

• Single Most Likely Diagnosis
  • Steroid-Induced Myopathy: This condition is a common side effect of long-term corticosteroid use, which can lead to muscle weakness, pain, and potentially joint instability due to the muscle's role in supporting joints. The iatrogenic trigger (e.g., medication side effect) fits well with this diagnosis.
• Other Likely Diagnoses
  • Osteonecrosis: Iatrogenic causes, such as long-term steroid use or certain medications, can lead to osteonecrosis, which causes deep tissue pain and can result in joint instability if the bone collapses.
  • Iatrogenic Neuropathy: Certain medical procedures or medications can cause nerve damage, leading to muscle weakness, pain, and potentially joint instability if the nerves controlling muscle function are affected.
• Do Not Miss Diagnoses
  • Osteomyelitis or Septic Arthritis: Although less likely, these conditions can be triggered by medical procedures (e.g., joint injections, surgery) and would be catastrophic if missed. They can cause deep tissue pain, muscle weakness around the affected joint, and significant joint instability.
  • Cauda Equina Syndrome: This is a serious condition that can result from iatrogenic causes (e.g., spinal injections, surgery) and requires immediate attention. It can cause severe pain, muscle weakness, and instability in the lower back and legs.
• Rare Diagnoses
  • Ehlers-Danlos Syndrome (EDS): While not typically iatrogenic in onset, certain types of EDS can be exacerbated by medical procedures, leading to increased joint instability and potentially deep tissue pains and muscle weakness.
  • Rhabdomyolysis: This rare condition involves the breakdown of muscle tissue and can be triggered by certain medications or medical procedures. It leads to muscle pain, weakness, and potentially severe complications if not promptly treated.