Back pain can occur with pneumonia, a lung infection that inflames the air sacs in one or both lungs, often causing them to fill with fluid or pus. Although pneumonia primarily affects the respiratory system, its effects can extend to other parts of the body, including the back. Back pain is a recognized symptom that may accompany the fever, cough, and shortness of breath typical of pneumonia. This discomfort arises from several distinct mechanisms, including direct inflammation and indirect muscle effects.
The Direct Link: Pleuritic Pain
The most specific cause of sharp back pain in pneumonia is pleurisy, the inflammation of the pleura. The pleura is a double-layered membrane surrounding the lungs and lining the inner chest wall. Infection causes these layers to become inflamed and rub together, rather than gliding smoothly during breathing.
This irritation triggers a sharp, stabbing sensation, often felt in the chest. Due to shared nerve pathways, this pain is frequently “referred” to the back, typically localizing in the mid-back or around the shoulder blade on the same side as the infected lung.
Pleuritic pain intensifies with movements that expand the lungs, such as taking a deep breath, coughing, or sneezing. The pain may also worsen with upper body movement or spread to the shoulders.
Indirect Causes of Back Discomfort
Back discomfort can result from indirect effects of the illness, not solely due to inflammation of the lung lining. One common indirect cause is muscle strain resulting from a persistent, forceful cough.
The repetitive action of coughing stresses the back and chest muscles, leading to soreness, stiffness, and aching pain. This discomfort is essentially a musculoskeletal injury, which manifests as a dull, persistent ache.
The body’s systemic response to infection also causes generalized body aches, known as myalgia. The fever and inflammatory response cause widespread muscle weakness and pain throughout the body, including the back.
Identifying Pneumonia-Related Back Pain
Distinguishing pneumonia-related back pain involves looking for specific accompanying symptoms. This pain almost always occurs alongside other signs of a respiratory infection, such as a productive cough, fever, chills, and shortness of breath. The presence of these symptoms indicates the discomfort is linked to the lung infection.
The quality of the pain offers clues: pleuritic pain is sharp and stabbing, worsening when breathing deeply, while strain-related pain is often a duller, more constant ache. If the pain is sharp and worsens only with deep inhalation or coughing, it points toward pleuritic irritation. Conversely, if the back pain is a constant, generalized soreness that feels muscular, it is more likely due to coughing strain or systemic inflammation.
A person experiencing back pain along with a high fever, difficulty breathing, or severe chest pain should seek immediate medical attention. Other concerning signs include coughing up blood, a rapid heartbeat, or the blue discoloration of the lips or fingernails, which indicates low oxygen levels. Prompt medical evaluation is necessary for accurate diagnosis and appropriate treatment.