Differential Diagnosis for Unexplained Pain in a Child with Medical Complexity

When approaching a child with medical complexity presenting with unexplained pain, it's crucial to consider a broad range of potential causes. The differential diagnosis can be organized into the following categories:

• Single Most Likely Diagnosis

  • Chronic pain syndrome: This is a condition where pain persists over time and can be exacerbated by the child's underlying medical conditions, psychological factors, and environmental influences. It's a common issue in children with medical complexity due to their frequent exposure to painful procedures and the potential for central sensitization.

• Other Likely Diagnoses

  • Constipation: A very common cause of abdominal pain in children, which can be easily overlooked, especially in those with limited ability to communicate.
  • Gastroesophageal reflux disease (GERD): Can cause chest and abdominal pain, and is common in children with neurological impairments or those who are tube-fed.
  • Urinary tract infection (UTI): Especially in children with urinary catheters or neurogenic bladder, UTIs can be asymptomatic except for pain.
  • Musculoskeletal pain: Due to spasticity, contractures, or immobilization, which are common in children with neurological conditions.
  • Dental issues: Toothaches or gum disease can cause significant pain and may be overlooked, especially in non-verbal children.

• Do Not Miss Diagnoses

  • Appendicitis: Although less common, appendicitis can present atypically in children with medical complexity, and missing this diagnosis can be catastrophic.
  • Intussusception: A condition where a part of the intestine slides into an adjacent part, which can cause severe abdominal pain and is a surgical emergency.
  • Intra-abdominal shunt malfunction (in children with VP shunts): Can cause abdominal pain, vomiting, and altered mental status.
  • Osteomyelitis or septic arthritis: Especially in children with limited mobility or those who are immunocompromised, these infections can present with pain and may not have the typical signs of infection like fever or redness.
  • Malignancy: Although rare, cancer can cause unexplained pain in children and must be considered, especially with persistent or worsening symptoms.

• Rare Diagnoses

  • Mitochondrial disorders: Can cause episodic pain crises, among other symptoms, due to defects in energy production.
  • Erythromelalgia: A disorder characterized by burning pain, heat, and redness in the hands and feet.
  • Fabry disease: A genetic disorder that can cause episodes of severe burning pain in the hands and feet.
  • Complex regional pain syndrome (CRPS): A chronic pain condition characterized by severe burning pain at the site of an injury, which can be rare in children.

Each of these diagnoses requires careful consideration of the child's medical history, physical examination, and potentially, diagnostic tests to determine the underlying cause of their pain. A multidisciplinary approach, including pain specialists, can be invaluable in managing these complex cases.