Differential Diagnosis

The patient presents with a history of left upper quadrant (LUQ) pain that started in April, which feels tight and improves with bowel movements. Considering the patient's past medical history (PMH) of NSTEMI, atrial fibrillation, impaired left ventricular function, and acute kidney injury, the following differential diagnoses are proposed:

• Single Most Likely Diagnosis
  • Constipation-related abdominal pain: The patient's symptoms of LUQ pain that improves with bowel movements, and having bowel movements every couple of days, suggest that constipation could be a contributing factor. Although the patient denies needing medication for constipation, the pattern of pain relief after bowel movements is a strong indicator.
• Other Likely Diagnoses
  • Gastroesophageal reflux disease (GERD): Given the location of the pain in the LUQ, GERD is a possible cause, especially if the patient experiences symptoms like heartburn or regurgitation, which are not explicitly mentioned but could be related to the feeling of tightness.
  • Diverticulitis: Although less common on the left side, diverticulitis could cause LUQ pain, especially if the patient has a history of diverticula. The improvement with bowel movements might not be as directly related, but changes in bowel habits can occur.
  • Irritable bowel syndrome (IBS): The patient's bowel movements are regular for him, ranging from soft to normal, and he experiences relief from pain after bowel movements, which could align with IBS, particularly if other symptoms like bloating or changes in stool consistency are present.
• Do Not Miss Diagnoses
  • Mesenteric ischemia: Given the patient's history of atrial fibrillation and NSTEMI, there is an increased risk of embolic events, including mesenteric ischemia, which is a medical emergency. Although the patient's symptoms have been chronic rather than acute, any abdominal pain in a patient with cardiovascular risk factors warrants consideration of this diagnosis.
  • Pancreatitis: The LUQ location of the pain could suggest pancreatitis, especially if there are other symptoms like nausea, vomiting, or radiation of pain to the back. The patient's history of acute kidney injury might also be relevant if there were episodes of hypotension or dehydration.
• Rare Diagnoses
  • Splenic infarction or spleen-related issues: Given the LUQ location of the pain and the patient's history of atrial fibrillation, a splenic infarct could be considered, although it would typically present more acutely.
  • Gastric or intestinal obstruction: Although less likely given the chronic nature of the symptoms and the improvement with bowel movements, any cause of mechanical obstruction could potentially cause LUQ pain and alterations in bowel habits.

Each of these diagnoses should be considered in the context of the patient's full medical history, physical examination, and appropriate diagnostic testing to determine the most likely cause of the LUQ pain. The patient's financial constraints and access to care should also be taken into account when planning diagnostic and therapeutic interventions.