Differential Diagnosis

The patient presents with sharp chest pain, palpitations, and left arm heaviness. Considering the history, physical examination, and investigations, the differential diagnoses can be categorized as follows:

• Single Most Likely Diagnosis

  • Musculoskeletal Chest Pain: The patient's symptoms of sharp chest pain, chest wall tenderness on palpation, and the absence of significant cardiovascular findings on examination and investigations (normal ECG, previous normal treadmill test and CTCA) suggest musculoskeletal chest pain as a likely diagnosis. The pain's characteristics, such as being sharp, lasting 5-15 seconds, and occasionally up to 5 minutes, with random onset and a dull ache at night, along with left arm heaviness, could be related to musculoskeletal issues rather than cardiac.

• Other Likely Diagnoses

  • Anxiety or Stress-Related Symptoms: Given the patient's history of unemployment, caring for family members, and the presence of palpitations, it's possible that anxiety or stress could be contributing to the symptoms. The normal ECG and previous cardiac investigations reduce the likelihood of a primary cardiac cause but do not rule out the impact of stress on the cardiovascular system.
  • Gastroesophageal Reflux Disease (GERD): Although not directly mentioned, GERD can cause chest pain that might be sharp and could be considered, especially with the patient's lactose intolerance, which might suggest some gastrointestinal sensitivity.

• Do Not Miss Diagnoses

  • Acute Coronary Syndrome (ACS): Despite the normal ECG and previous investigations, ACS (including myocardial infarction) must be considered due to the patient's symptoms of chest pain and family history of early myocardial infarction. The fact that the pain is sharp and not typically exertional does not rule out ACS, as atypical presentations can occur.
  • Pulmonary Embolism (PE): Although the patient has no clear risk factors for PE (e.g., recent travel, immobilization) and the respiratory examination is normal, PE is a condition that can present with sudden onset of chest pain and must be considered due to its potential severity.
  • Aortic Dissection: This is a less likely but critical diagnosis to consider, given the severity of the condition. The absence of a typical tearing chest pain and significant blood pressure differences between arms makes this less likely, but it cannot be entirely ruled out without further investigation if suspicion arises.

• Rare Diagnoses

  • Pericarditis: This condition can cause sharp chest pain that may improve with sitting up and leaning forward. Although less likely, it should be considered, especially if there's any suggestion of pericardial friction rub on examination, which was not mentioned.
  • Pneumothorax: The patient's symptoms and examination findings do not strongly suggest pneumothorax, but it's a rare cause of sharp chest pain and must be considered if there are any respiratory symptoms or signs, particularly if the patient's condition changes.