Differential Diagnosis
The patient's presentation of coughing up small amounts of blood (hemoptysis), a history of lung cancer, elevated INR (16.29), and a temperature of 100°F suggests a complex clinical picture. Here's a categorized differential diagnosis:
Single Most Likely Diagnosis
- Bleeding complication from lung cancer: Given the patient's history of lung cancer and the presence of hemoptysis, a bleeding complication from the tumor itself is highly plausible. The elevated INR could be due to metastasis affecting the liver or a side effect of chemotherapy, further increasing the risk of bleeding.
Other Likely Diagnoses
- Pulmonary embolism: Although less directly linked to the symptoms, pulmonary embolism can occur in cancer patients due to hypercoagulability (Trousseau’s syndrome) and could potentially cause hemoptysis, though it's less common.
- Infection: The fever (temperature of 100°F) could indicate an infectious process, possibly pneumonia, which is common in patients with lung cancer, especially if they have undergone treatments that compromise lung function or immune status.
- Anticoagulant toxicity: The significantly elevated INR suggests anticoagulant therapy, which, if not properly managed, could lead to bleeding complications, including hemoptysis.
Do Not Miss Diagnoses
- Pulmonary artery rupture or pseudoaneurysm: Though rare, these conditions can be fatal and are associated with lung cancer, especially if there's tumor invasion into the pulmonary arteries. The presence of hemoptysis and a history of lung cancer makes this a critical diagnosis not to miss.
- Sepsis: Given the fever and potential for infection, sepsis is a condition that must be considered and promptly treated if present, as it can rapidly progress to a life-threatening state.
Rare Diagnoses
- Goodpasture syndrome: An autoimmune disease that can cause hemoptysis due to anti-GBM antibodies affecting the lungs and kidneys. It's rare but could be considered in a differential diagnosis, especially if other causes are ruled out.
- Wegener's granulomatosis (Granulomatosis with Polyangiitis, GPA): A form of vasculitis that can affect the lungs and kidneys, causing symptoms like hemoptysis. It's less common but should be considered if the patient's presentation doesn't fit more typical diagnoses.