Lung Diseases

Overview
Diseases
Tests
Treatment
Sources

Signs and Symptoms

Signs and symptoms associated with lung disease will vary from person to person and change over time. With chronic conditions, symptoms often emerge gradually and grow progressively worse. With acute conditions, symptoms may be mild to severe. Some may be life-threatening without prompt medical attention. While each disease will have its own characteristics, there are common signs and symptoms that are seen with many lung disorders. These include a persistent cough and dyspnea. People may wheeze, gasp, cough up blood or sputum, and may experience chest pain. Those with obstructive lung conditions such as COPD may have trouble exhaling – some describe it as “like trying to breathe through a straw.” Lack of oxygen may cause an affected person’s skin to have a bluish tint. Over time, oxygen deficiency may lead to clubbing in some people – an enlargement of the fingertips and abnormal fingernail growth.

Tests
The goals with testing are to diagnose lung diseases, determine their causes where possible, and evaluate their severity. Many doctors will order blood gasses to evaluate oxygen and carbon dioxide levels, lung or pulmonary function tests (PFTs) to help diagnose and monitor lung function, and chest x-rays and or CT (computed tomography) scans to look at lung structure. Other testing is performed to help diagnose specific conditions.

Laboratory Tests

Blood gases – an arterial blood sample is collected to evaluate blood pH, oxygen and carbon dioxide

Complete Blood Count (CBC) – to look for anemia

Cystic Fibrosis Tests (CF Gene Mutation Testing, Sweat chloride, Immunoreactive trypsin (IRT), Stool trypsin) – to look for the genetic mutations causing cystic fibrosis and to diagnose the condition

Alpha-1 antitrypsin – to determine if patient has AAT deficiency

Sputum culture – to diagnose lung infections caused by bacteria

AFB smear and culture – to diagnose tuberculosis and nontuberculous mycobacteria (NTM)

Blood cultures – to diagnose bacteria and sometimes yeast infections that have spread into the blood

Influenza tests – to diagnose influenza

Lung Biopsy – to evaluate lung tissue for damage and for cancer

Sputum cytology – to evaluate lung cells for abnormal changes and for cancer

Fetal Lung Maturity (FLM) tests - used to evaluate the lung maturity of a fetus and may include tests for lecithin/sphingomyelin (L/S) ratio, phosphatidylglycerol (PG), foam stability index (FSI), or lamellar body counts (LBC). May be used to determine age of gestation before cesarean delivery or when a preganant woman is having symptoms of premature labor.

Drug sceen - to detect drugs in overdoses that lead to decreased respiration or acute respiratory distress

Lung Function Tests (Pulmonary Function Tests, PFT)
A few of the more common tests are listed below. For more complete information visit the website for John Hopkins Medicine: Pulmonary Function Laboratory.

Spirometry – measures the amount and rate of air exhalation as a patient blows out through a tube. It is performed to evaluate narrowed or obstructed airways.

Air flow with a Peak Flow Meter – measures the rate of exhalation. It can be used at home by patients with asthma to help monitor their condition.

Lung Volume – the quantity of air a person takes into their lungs and how much is left in the lungs after exhalation. Helps evaluate the elasticity of the lungs, the movement of the rib cage, and the strength of the muscles associated with respiration.

Diffusing Capacity Measurement – assesses the transfer of oxygen from the lung air sacs to the bloodstream by evaluating how much carbon monoxide is absorbed when a small quantity is inhaled (not enough to harm).

Imaging studies

Chest x-ray – to look at lung structure and chest cavity

CT (computed tomography) scan – a more detailed evaluation of lung structure

MRI (Magnetic resonance imaging) – detailed pictures of organs and vessels in the chest

Ultrasound – used to detect fluid between the pleural membranes

Nuclear lung scanning – used to help detect pulmonary embolism and rarely, to evaluate the effectiveness of lung cancer treatment

Positron emission tomography (PET) scans – used to help diagnose lung cancer

Other tests

Electrocardiogram (EKG, ECG) – to look at heart rhythm, to determine if heart disease may be affecting breathing

Sleep studies – usually performed at special sleep centers to help determine whether a person is breathing normally during sleep