Differential Diagnosis for Right Side Abdominal Pain Radiating to Right Back Shoulder

Single Most Likely Diagnosis

• Musculoskeletal strain or costochondritis: Given the patient's history of severe coughing due to bronchitis, which can lead to strain on the chest wall and abdominal muscles, and the radiation of pain from the right abdomen to the right shoulder, this diagnosis is plausible. The fact that the pain starts in the right abdomen and then radiates to the right shoulder upon coughing supports this, as it suggests referred pain from the musculoskeletal structures.

Other Likely Diagnoses

• Pulmonary causes (e.g., pneumonia, pleurisy): Although the patient was diagnosed with bronchitis, the persistence of symptoms and the nature of the pain could suggest complications or other pulmonary issues that are causing referred pain to the abdomen and shoulder.
• Gastrointestinal issues (e.g., gallbladder disease, peptic ulcer disease): These conditions can cause abdominal pain that radiates to the shoulder due to shared nerve roots. The patient's symptoms could be indicative of a gastrointestinal issue, especially if the pain is related to eating or has other gastrointestinal symptoms.
• Intercostal muscle strain: The patient's reported separation of chest walls could imply strain on the intercostal muscles, which could cause pain radiating to the shoulder.

Do Not Miss Diagnoses

• Pneumothorax: Although less likely given the patient's presentation, a pneumothorax could cause sudden onset of chest pain that radiates to the shoulder and could be life-threatening if not promptly diagnosed and treated.
• Myocardial infarction: Chest pain radiating to the shoulder could also be indicative of cardiac issues, including myocardial infarction, especially in a 54-year-old patient.
• Cholecystitis or pancreatitis: These conditions can cause severe abdominal pain that radiates to the shoulder and back and are medical emergencies.

Rare Diagnoses

• Diaphragmatic rupture: This is a rare condition that could result from severe coughing or trauma, leading to abdominal contents herniating into the thoracic cavity and causing severe pain.
• Splenic rupture or infarct: Although rare, these conditions could cause left upper quadrant abdominal pain radiating to the shoulder, but given the patient's right-sided pain, this is less likely unless there's an unusual anatomical variation or other rare conditions.

History of Present Illness (HPI)

The patient is a 54-year-old male presenting with right-sided abdominal pain that radiates to the right back shoulder. The pain started after a bout of severe coughing due to bronchitis, for which he was treated with Cephalexin and Cyclobenzaprine, with minimal relief. He was seen at the ER and given Tessalon pearls for his cough, which did not provide relief. The patient reports that the pain begins in the right abdomen and then radiates to the right shoulder upon coughing. He has been told he may have separated his chest walls, which he believes could be the cause of his pain. The patient continues to cough up thick phlegm and is concerned about the possibility of an abdominal tear.