A blood clotting disorder

Use of anticoagulants (as used to treat pulmonary embolism, blood clots in the legs, or atrial fibrillation or to reduce the risk of clots after certain heart procedures)

Use of medications that dissolve clots (thrombolytic medications, as used to treat a heart attack or stroke)

Sometimes bleeding from other sites, such as the nose or digestive tract (seen in stool)

In people taking anticoagulants or thrombolytic agents

Sometimes a family history of a blood clotting disorder

Blood tests that assess the blood's ability to clot

Bronchiectasis

A chronic cough and mucus production in people with a history of recurring infections

High-resolution CT of the chest

Sometimes bronchoscopy

Bronchitis

• Acute bronchitis

• Chronic bronchitis

Acute: A cough that may or may not produce sputum (productive or nonproductive) and sometimes symptoms of an upper respiratory infection (such as a stuffy nose)

Chronic: A productive cough on most days of the month or for 3 months of the year for 2 successive years in people who smoke or in people known to have chronic obstructive pulmonary disease

Acute: A doctor's examination

Chronic: A chest x-ray

Certain long-lasting lung infections (tuberculosis, fungal infections, parasitic infections, or syphilis that affects the lungs)

Fever, cough, night sweats, and weight loss in people known to be exposed to the infection

Often a history of a weakened immune system (immunosuppression) due to a disorder or medication

A chest x-ray

CT of the chest

Testing of sputum samples or samples of fluid from the lungs obtained with a bronchoscope

A foreign object that has been present a long time and has not been identified

A chronic cough (typically in infants or young children) without symptoms of an upper respiratory infection

Sometimes a fever

A chest x-ray

Sometimes bronchoscopy

Heart failure

Frothy, pink sputum, sometimes with blood streaks

Shortness of breath that worsens while lying flat or that appears 1–2 hours after falling asleep

Sounds suggesting fluid in the lungs, heard through a stethoscope

Usually swelling (edema) of the legs

A chest x-ray

Sometimes a blood test to measure a substance that is produced when the heart is strained (called brain natriuretic peptide, or BNP)

Sometimes echocardiography

Lung abscess

Fever, usually for one or more weeks

A cough, night sweats, loss of appetite, and weight loss

Poor dentition

A chest x-ray

Sometimes CT or bronchoscopy

Lung cancer

Night sweats and weight loss

Usually in middle-aged or older adults with a history of heavy smoking

A chest x-ray

CT

Bronchoscopy

Pneumonia

Fever, a feeling of illness, a productive cough, and shortness of breath

Sudden appearance of chest pain when taking deep breaths

Certain abnormal breath sounds, heard through a stethoscope

A chest x-ray

Pulmonary embolism (sudden blockage of an artery in a lung, usually by a blood clot)

Sudden appearance of sharp chest pain that usually worsens when inhaling

Shortness of breath

A rapid heart rate and a rapid breathing rate

Often risk factors for pulmonary embolism, such as cancer, immobility (as results from being bedbound), blood clots in the legs, pregnancy, use of birth control pills (oral contraceptives) or other medications that contain estrogen, recent surgery or hospitalization, or a family history of the disorder

Specialized lung imaging tests, such as CT angiography or ventilation/perfusion (V/Q) scanning

Pulmonary vasculitis (such as Goodpasture syndrome or granulomatosis with polyangiitis)

Fatigue and weight loss

Sometimes blood in the urine

Sometimes shortness of breath

Sometimes swelling (edema) of the legs

A biopsy of kidney or lung tissue

Blood tests to check for antibodies characteristic of the disorder (antiglomerular basement membrane antibodies, antineutrophil cytoplasmic antibodies)