Diagnostic Priorities for Chronic Cough with Constitutional Symptoms

Tuberculosis Evaluation

A chest radiograph is the mandatory first‑line imaging study for any adult with chronic productive cough, fever and weight loss who works in a healthcare setting. 1
Sputum testing should incorporate the Xpert MTB/RIF assay; this molecular test improves pulmonary TB detection by 23 % over smear microscopy, with a pooled sensitivity of 89 % and specificity of 99 %. 1
When Xpert MTB/RIF is unavailable, sputum should be sent for acid‑fast bacilli smear and mycobacterial culture with drug‑susceptibility testing. 1
Occupational exposure as a healthcare worker markedly raises TB risk, justifying evaluation even if cough duration is short (as brief as 1 week). 1

In a smoker with a ≥30 pack‑year history and persistent cough, bronchoscopy is recommended even if the chest radiograph appears normal, because ≈16 % of centrally obstructing airway cancers are radiographically occult. 2
A chest CT should be performed when the radiograph shows any abnormality or to further delineate central airway lesions that are not visible on plain films. 2
The combination of chronic cough, hemoptysis risk, and unintentional weight loss yields a high pre‑test probability for lung cancer. 2

If a fasting sample cannot be obtained promptly, a random blood glucose measurement may be collected immediately to screen for diabetes. 2

A complete blood count with differential assists in detecting infection, anemia of chronic disease, or possible hematologic malignancy. 2
A comprehensive metabolic panel (electrolytes, renal and liver function) establishes baseline organ status and evaluates for systemic disease. 1
Erythrocyte sedimentation rate and C‑reactive protein provide nonspecific inflammatory markers that can support a diagnosis of TB or malignancy. 1

Hypertension should be confirmed with repeat blood‑pressure measurements before initiating therapy, as a single reading of 150/100 mmHg is insufficient for diagnosis. 2

Pulmonary tuberculosis is the highest‑priority diagnosis in a healthcare worker presenting with constitutional symptoms, productive cough and weight loss. 1
Lung cancer ranks second in priority given the heavy smoking history and similar symptom profile. 2
Community‑acquired pneumonia is less likely to be the sole explanation for a month‑long productive cough with systemic signs. 2

Do not postpone TB workup while awaiting other test results, as active pulmonary TB has critical individual and public‑health implications. 1
Do not rely on a normal chest radiograph to exclude lung cancer in a high‑risk smoker; bronchoscopy remains indicated. 2
Severe underweight status (BMI ≈ 18 kg/m²) in the setting of recent weight loss signals serious underlying pathology and warrants urgent investigation. 2

Sputum collection and chest radiography should be completed within 24 hours of presentation. 1
Bronchoscopy should be scheduled urgently (within 1–2 weeks) when imaging suggests airway involvement or when clinical suspicion remains high despite a normal radiograph. 2
Diabetes screening can be performed concurrently with other laboratory tests and should not delay infectious or oncologic investigations. 2