Diagnosing lung infections may require testing such as blood tests, bronchoscopy, lung biopsy or a CT scan, according to WebMD. Blood cultures may determine the presence of bacteria that causes pneumonia or influenza. Additional tests can show the amount of oxygen in the blood and sample mucus from the windpipe.
Symptoms of upper respiratory tract infections include coughing, sore throat, runny nose, sneezing and nasal congestion, according to MedicineNet.com. Less common symptoms include headaches, vomiting, shortness of breath, nausea and body aches. Infections of the upper respiratory tract affect the sinuses, pharynx, nasal passages and larynx, and include common cold, sinusitis and laryngitis. Most symptoms last anywhere from three days to two weeks, however if symptoms persist longer, the condition may be related to more serious infections such as bronchitis or pneumonia.
Pneumonia may be caused by bacteria, viruses or fungii, and produces symptoms such as fever, chills and fatigue, explains MedicineNet.com. Although most cases can be treated effectively without hospital care, pneumonia can be fatal. Risk is greater in patients under the age of two and over the age of 65, as well as in those with other chronic medical conditions.
Bronchitis is an inflammation of the bronchial tubes which causes thickened, discolored mucus, according to Mayo Clinic. It is categorized as either acute, which is very common, or chronic, which is considered to be more severe. Mucus may appear as grayish-yellow, green, white or clear. Chronic bronchitis may cause a persistent cough for an elongated period that can last from three months to two years.