From the Guidelines
For this 44-year-old male with history of colon cancer, COPD, and morbid obesity (BMI 50) presenting with shortness of breath, tiredness, and cough, I recommend ordering several key tests, including a complete blood count (CBC), comprehensive metabolic panel (CMP), arterial blood gas (ABG) analysis, chest X-ray, pulmonary function tests (PFTs), D-dimer testing, and CT pulmonary angiogram if D-dimer is elevated, as well as sputum culture, pro-BNP and troponin levels, and an ECG. The patient's symptoms could represent COPD exacerbation, cancer progression with pulmonary metastases, pneumonia, heart failure, or pulmonary embolism, making this comprehensive workup necessary to determine the underlying cause and guide appropriate treatment 1. Given the patient's history of COPD, pulmonary function tests (PFTs) are essential to quantify COPD severity and assess for acute exacerbation 1. Additionally, chest X-ray is crucial to evaluate for pneumonia, pleural effusion, or metastatic disease, and CT scanning can help differentiate between structural abnormalities that cause airflow limitation and detect pulmonary comorbidities 1. The patient's cancer history and morbid obesity also increase the risk of pulmonary embolism, making D-dimer testing and CT pulmonary angiogram if elevated essential 1. Sputum culture should be collected if productive cough is present, and pro-BNP and troponin levels would help evaluate for heart failure or cardiac involvement 1. An ECG would assess for arrhythmias or ischemic changes, and comprehensive metabolic panel (CMP) would evaluate organ function and electrolyte balance 1. Arterial blood gas (ABG) analysis would help determine oxygenation status and acid-base balance, and complete blood count (CBC) would assess for anemia or infection 1. Overall, this comprehensive workup is necessary to determine the underlying cause of the patient's symptoms and guide appropriate treatment, prioritizing morbidity, mortality, and quality of life as the outcome.
From the Research
Laboratory Tests for Diagnosis
The patient's presentation with dyspnea, fatigue, and cough, along with a history of colon cancer, COPD, and a high BMI, requires a comprehensive diagnostic approach. The following laboratory tests may be ordered:
- Complete Blood Count (CBC) to evaluate the patient's hematologic status, as it is one of the most frequently ordered laboratory tests in medicine 2
- CBC components, such as white blood cell count, neutrophil-to-lymphocyte ratio, hemoglobin, mean corpuscular volume, red cell distribution width, platelet count, mean platelet volume, and platelet-to-lymphocyte ratio, may be useful in predicting cardiovascular and metabolic diseases 3
Diagnostic Approach
A systematic approach to differential diagnosis is necessary to identify the underlying condition. This involves:
- Evaluating patient history, physical examination, and laboratory data to determine the etiology of the disease or condition 4
- Recognizing specific chief complaints to narrow down the differential diagnosis 5
- Considering a multi-step diagnostic approach, prioritizing probabilities, and delaying antibiotic treatment until a correct diagnosis is made 5
Additional Considerations
The patient's history of colon cancer, COPD, and high BMI should be taken into account when interpreting laboratory results and developing a diagnostic plan. The clinical utility of tests and measures should be understood, and findings should be implemented in clinical practice to improve patient management 4