Conditions that have symptoms similar to pneumonia include:

• Pleurisy, an inflammation of the membrane (pleura) covering the lungs and lining the chest cavity. Symptoms include chest pain, coughing, and fever.
• Influenza, a viral infection affecting the respiratory system. Symptoms include fever and fatigue.
• Bronchitis, which is inflammation of the breathing tubes that lead to the lungs (bronchial tubes). Symptoms include coughing, chest pain, and wheezing.
• Chronic obstructive pulmonary disease (COPD), which is difficulty breathing caused by chronic bronchitis or emphysema.
• Pulmonary embolus, a sudden blockage of blood flow within the lung. Symptoms include shortness of breath, chest pain, and a rapid heartbeat.
• Tuberculosis, a bacterial infection that usually affects the lungs. It can cause fatigue and a cough.
• Hantavirus pulmonary syndrome, an illness caused by a virus found in the saliva, urine, and droppings of some rodents. Symptoms include fever and fatigue.
• Lung cancer, especially in someone with a history of smoking. Symptoms include cough, chest pain, and shortness of breath.
• Heart failure, which is the heart not pumping like it should. Symptoms include shortness of breath and fatigue.
• Severe acute respiratory syndrome (SARS), a virus that causes symptoms of cough, shortness of breath, and difficulty breathing.