What is Pleural Friction Rub?
A pleural friction rub is a certain sound your doctor might hear while listening to your lungs with a stethoscope. This sound results from inflamed and rough lung lining surfaces rubbing against each other as you breathe in and out.
The sound doesn’t have musical tone and is often described as “grating,” “creaky,” or “the sound made by walking on fresh snow.” It is usually heard in the upper parts of your lungs. Any condition that causes fluid build-up in your lungs, inflammation of the lung lining, or inflammation of the linings of your chest can result in a pleural friction rub.
Patients sometimes could indicate where they feel the pain, which helps them pinpoint the location of the friction rub. The presence of a pleural friction rub suggests that there’s a disease affecting the lining of the lungs. However, not having this sound doesn’t mean there’s no disease. If this type of sound is detected during a lung check-up, it’s crucial for doctors to quickly recognize and act upon it.
What Causes Pleural Friction Rub?
When your doctor listens to your chest with a stethoscope, they may hear a sound called a pleural friction rub. This happens when the normally smooth lining of your lungs, the pleura, gets inflamed and rough. Pleurisy, which is inflammation of this lining, can cause this sound. Other conditions affecting the chest cavity can cause a pleural friction rub too.
It’s not uncommon to hear a pleural friction rub in patients who have pneumonia, a pulmonary embolism (blood clot in the lungs), malignant pleural disease (a serious lung condition), pleurisy due to a viral infection, pancreatitis (inflammation of the pancreas), or other causes.
However, not all friction rub sounds are the same. Your doctor is trained to tell the difference between the pleural friction rub we’ve been talking about and a pericardial friction rub, which is a sound made by inflammation of the sac around the heart, known as pericarditis.
Risk Factors and Frequency for Pleural Friction Rub
Current medical research does not provide information on how often a condition called pleural friction rub occurs in patients who have diseases in the pleura or other parts of the chest cavity.
Signs and Symptoms of Pleural Friction Rub
If someone is experiencing a pleural friction rub, a common symptom is sudden, intense chest pain that worsens with actions like breathing. This pain often feels better when the person leans forward and supports their upper body, such as resting their hands on their knees. A healthcare provider may feel a sensation similar to sandpaper rubbing together when they press on the person’s chest, which is characteristic of a pleural friction rub. Depending on what is causing the rub, the person might also experience tenderness in the local area.
Pleural friction rub produces a distinctive sound when listened to with a stethoscope. This sound is brief and explosive, often compared to the sound made when stepping on fresh snow. The sound might be intermittent or ongoing and is usually heard during both inhalation and exhalation. It’s localized to a small area of the chest and can be made louder by applying more pressure with the stethoscope. Coughing usually doesn’t change the sound.
The cause of the pleural friction rub can often be determined by other findings in the person’s medical history and physical examination. Key factors include accompanying symptoms, previous infections, and professional background. For example, if a person has decreased breath sounds, increased tactile fremitus (vibrations felt on the chest), and a history of infective symptoms, it could suggest that they have pneumonia.
Testing for Pleural Friction Rub
If a doctor hears a rubbing sound when listening to your chest, this warrants further examination to determine the cause. Your doctor may order certain blood tests, such as Erythrocyte Sedimentation Rate (ESR), C-reactive Protein (CRP), and White Blood Cell count (WBC). These tests can help your doctor figure out what might be causing your symptoms.
In addition to blood tests, a chest X-ray can be very helpful. This scan can detect if there is air or fluid that shouldn’t be there in the space around your lungs – a condition termed pneumothorax and pleural effusion respectively. In some cases, analyzing the fluid found around the lungs (pleural fluid) could also be beneficial.
Your doctor might use a tool called the Wells Score which helps to figure out the likelihood of you having a pulmonary embolism, a serious condition where a blood clot gets lodged in the arteries of the lungs. In situations where there is a suspected heart attack or inflammation of the sac around the heart (called pericarditis), an Electrocardiogram (ECG) may be suggested. This simple and painless test records the electrical signals in your heart.
Furthermore, based on what your doctor thinks might be going on, additional tests could be recommended. This could include a D-dimer test (which looks for signs of blood clots), an arterial blood gas test (which measures oxygen and carbon dioxide levels in your blood), a ventilation-perfusion scan (a type of lung imaging test), or a CT scan of the pulmonary arteries (this gives a detailed view of the blood vessels in your lungs).
Treatment Options for Pleural Friction Rub
The rubbing sound from your chest area, known as pleural friction rub, should clear up once the underlying cause is treated. The treatment should center around managing chest pain (if you are experiencing it) and handling the original health problem that caused this condition.
For immediate relief from the symptoms, medications such as aspirin or ibuprofen, which are part of a group of drugs called nonsteroidal anti-inflammatory drugs, may be used. If your condition is caused by a bacterial infection, antibiotics can be effective in treating it.
What else can Pleural Friction Rub be?
It’s important to differentiate between the sounds made by a pleural friction rub and a pericardial rub, as these are distinct medical conditions. If someone has pericarditis, which means inflammation of the sac around the heart (the pericardium), doctors may hear a rough, scraping sound as inflamed layers of the pericardium rub against each other. The key difference from a pleural friction rub is that the sound from a pericardial rub can still be heard even when the patient is holding their breath – this is because the movements of the pericardium aren’t linked to the movements of the chest wall. Additionally, when listening carefully, the doctor will hear three separate sounds from a pericardial rub – one during the squeezing phase of the heartbeat (systolic) and two during the relaxing phase (diastolic).
In contrast, a pleural friction rub, which indicates friction between the two layers of the pleura in the lungs, typically produces two distinct sounds: one during inhaling (inspiration) and the other during exhaling (expiration). Other lung sounds, like coarse crackles and rhonchi, could be confused with a pleural friction rub, but these sounds change when a patient coughs, helping differentiate them from a pleural friction rub which remains consistent.
It should be noted that in about 4% of cases of lung blood clots (pulmonary embolism) or pneumonia, a pleural friction rub may be a clinical symptom.
What to expect with Pleural Friction Rub
The outlook of the condition depends on what’s causing the pleural rub, a grating sound heard when the two layers of tissue lining your lungs rub against each other.
