Differential Diagnosis for Ongoing Pain

Given the limited information, we'll approach this with a broad perspective, considering various potential causes of ongoing pain that has lasted for 3 days. The differential diagnosis can be categorized as follows:

• Single Most Likely Diagnosis
  • Musculoskeletal strain or injury: This is a common cause of acute to subacute pain, especially if the onset is related to physical activity or trauma. The justification for this being the most likely diagnosis is based on the high prevalence of musculoskeletal issues in the general population and the typical time frame for the onset of pain after an injury.
• Other Likely Diagnoses
  • Viral gastroenteritis: If the pain is abdominal, viral gastroenteritis could be a likely cause, especially if accompanied by other symptoms like diarrhea, vomiting, or fever.
  • Urinary tract infection (UTI): UTIs can cause significant pain, especially if the infection involves the kidneys (pyelonephritis). Symptoms might include dysuria, frequent urination, and flank pain.
  • Respiratory infection: Pneumonia or other respiratory infections can cause chest pain or discomfort that persists.
• Do Not Miss Diagnoses
  • Appendicitis: Although less common, appendicitis is a critical diagnosis to consider, especially if the pain is localized to the right lower quadrant of the abdomen. Missing this diagnosis can lead to severe consequences, including perforation and peritonitis.
  • Myocardial infarction (MI) or cardiac ischemia: Chest pain that persists for days could be indicative of cardiac issues, including MI. This is particularly concerning in individuals with risk factors for cardiovascular disease.
  • Pulmonary embolism (PE): Sudden onset of chest pain, especially if accompanied by shortness of breath, could indicate a PE, which is life-threatening and requires immediate medical attention.
• Rare Diagnoses
  • Pancreatitis: Inflammation of the pancreas can cause severe, persistent abdominal pain, often radiating to the back. This condition is less common but serious and requires prompt medical evaluation.
  • Inflammatory bowel disease (IBD) flare: Conditions like Crohn's disease or ulcerative colitis can cause chronic or recurrent abdominal pain, though a new onset of severe pain could indicate a flare.
  • Malignancy: Although rare, persistent pain could be an early sign of cancer, depending on the location and type of cancer. This would be more concerning in individuals with risk factors or other symptoms suggestive of malignancy.

Each of these diagnoses requires careful consideration of the patient's history, physical examination, and potentially, diagnostic tests to determine the underlying cause of the pain.