Differential Diagnosis for Severe Pain

• Single most likely diagnosis
  • Acute musculoskeletal injury (e.g., fracture, sprain, or strain): This is often the most common cause of severe pain, especially if the pain is localized to a specific area and follows a traumatic event.
• Other Likely diagnoses
  • Renal colic (kidney stone): Characterized by severe, crampy pain that radiates from the flank to the groin, often accompanied by nausea and vomiting.
  • Migraine or cluster headache: These primary headache disorders can cause severe, debilitating pain, usually on one side of the head, and may be accompanied by other symptoms like photophobia or aura.
  • Appendicitis: Severe abdominal pain, often starting near the navel and then moving to the lower right abdomen, which may be accompanied by fever, nausea, and vomiting.
  • Pancreatitis: Inflammation of the pancreas can cause severe, persistent abdominal pain that radiates to the back, often accompanied by nausea and vomiting.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Myocardial infarction (heart attack): While chest pain is the most common symptom, some patients may present with severe pain in other areas, such as the arm, back, or jaw, and it is crucial to consider this diagnosis to prevent mortality.
  • Pulmonary embolism: Sudden onset of severe chest pain and shortness of breath could indicate a pulmonary embolism, which is life-threatening and requires immediate medical attention.
  • Aortic dissection: Severe, tearing chest pain that radiates to the back can be a sign of an aortic dissection, a medical emergency that requires immediate intervention.
  • Ectopic pregnancy: Severe abdominal pain in a woman of childbearing age, especially if accompanied by vaginal bleeding or missed periods, should prompt consideration of an ectopic pregnancy, which is life-threatening if not treated promptly.
• Rare diagnoses
  • Complex regional pain syndrome (CRPS): A chronic pain condition characterized by severe, burning pain and sensitivity, usually in an arm or leg, after an injury or trauma.
  • Herpes zoster (shingles): Can cause severe pain, usually on one side of the body, which may be accompanied by a rash.
  • Temporomandibular joint (TMJ) disorder: While more commonly associated with mild pain, severe cases can cause significant discomfort and dysfunction in the jaw area.