Pleurisy: A Nutrition and Natural-Health Reference
Definition and Overview
Pleurisy, or pleuritis, is an inflammation of the parietal pleura that causes sharp, localized chest pain, typically worsening with breathing, coughing, or sneezing. The pleura is a large, thin sheet of tissue that wraps around the outside of the lungs and lines the inside of the chest cavity. Between the layer that wraps around the lungs and the layer that lines the chest cavity is a very thin space called the pleural space, normally filled with a small amount of fluid that helps the two layers of the pleura glide smoothly past each other as the lungs breathe air in and out.
Pleurisy may be characterized as dry or wet. In dry pleurisy, little or no abnormal fluid accumulates in the pleural cavity, and the inflamed surfaces produce a pleural friction rub when they rub against each other during respiration. In wet pleurisy, fluids produced by the inflamed tissues accumulate within the pleural cavity, sometimes in quantities sufficient to compress the underlying lung and cause shortness of breath.
Body Systems Involved
Inflammation of the pleural membranes is usually a consequence of diseases elsewhere in the body and rarely of disturbances residing primarily in the pleura. The inciting process may be infection, neoplasm, trauma, pulmonary vascular obstruction, systemic granulomatous disease, or a generalized inflammatory disorder affecting the serous membranes.
The primary systems involved are:
- Respiratory system: The thin layers of membrane that surround the lungs (visceral pleura) and the internal chest cavity (parietal pleura) become inflamed.
- Nervous system: The parietal pleura is innervated by somatic nerves that sense pain when inflamed. Inflammation that occurs at the periphery of the lung parenchyma can extend into the pleural space and involve the parietal pleura, thereby activating the somatic pain receptors and resulting in pleuritic pain. The phrenic nerve supplies innervation to the central part of each hemidiaphragm; when these fibers are activated, the sensation of pain is referred to the ipsilateral neck or shoulder.
- Immune system: Studies suggest that the NLRP3 inflammasome plays a role in regulating the innate immune system and inflammatory response in pleurisy. Oxidant-mediated injury involves an increase in the production of free radicals that overwhelm the body's natural antioxidant defenses; this accumulation of oxygen-free radicals triggers an inflammatory response. Drugs or antigens can also trigger immune-mediated lung toxicity, where the formation of antigen-antibody complexes initiates an inflammatory cascade.
- Cardiovascular system: In post-cardiac injury syndromes, initial cardiac injury triggers an immune response. Studies suggest that the NLRP3 inflammasome plays a role, and other theories propose that cardiac injury releases antigens that stimulate antibody formation, with antibody-antigen complexes depositing in the lungs, pericardium, and pleurae, triggering inflammation.
- Musculoskeletal and autoimmune systems: Researchers believe impaired fluid resorption in inflamed pleurae, necrosis of subpleural rheumatoid nodules, and endothelial injury and capillary permeability due to local cytokine and immune complex production contribute to pulmonary effusions and pleural disease in rheumatoid arthritis patients. Long-term pleural inflammation in patients with rheumatoid arthritis can cause the lungs to become "non-expandable" due to restriction of the visceral pleura.
- Renal system: Pulmonary effusions and pleurisy are common in patients with chronic kidney disease (CKD).
Symptoms and Clinical Presentation
Pleurisy typically presents with sharp chest pain that worsens with breathing, coughing, or sneezing. Other symptoms may include shortness of breath, cough, fever, and chills. Other symptoms such as malaise, weight loss, night sweats, and joint pains may indicate one of the less-common causes of pleurisy.
When the space between the pleurae starts to fill with fluid, as in pleural effusion, the chest pain can be eased but shortness of breath can result, since the lungs need room to expand.
Contributing and Associated Factors
Infectious Causes
Although viral infections are the most common cause of pleurisy, idiopathic cases may occur. Infections caused by viruses such as the influenza virus can result in infections of the lungs and ultimately pleurisy. Other viruses that may lead to development of pleurisy include adenovirus, coxsackieviruses, cytomegalovirus, Epstein-Barr virus, parainfluenza virus, and respiratory syncytial virus.
More specifically, bacterial pneumonia, a respiratory infection that can result in inflammation of the air sacs in the lungs, and tuberculosis, a serious bacterial disease that typically infects the lungs, can prompt pleurisy. In industrialized nations, bacterial pneumonia resulting from staphylococci, pneumococci, Haemophilus influenzae or other organisms is a frequent cause of pleurisy.
Autoimmune and Inflammatory Conditions
Inflammatory conditions that can bring about pleurisy include systemic lupus erythematosus (SLE), rheumatoid arthritis, and Sjögren syndrome. SLE is a multisystem inflammatory disease that can lead to chronic inflammation of many organs, including the kidneys, joints, and lungs.
Pleurisy often signals an underlying condition, necessitating the exclusion of life-threatening causes such as pulmonary embolism, myocardial infarction, and aortic dissection before considering other diagnoses, such as systemic lupus erythematosus (SLE) or malignancy.
Pulmonary and Vascular Causes
Various pulmonary conditions may also cause pleurisy. These include pneumothorax, which is marked by a collapsed lung; asbestosis, a lung disease resulting from long-term inhalation of asbestos; mesothelioma, a malignancy that may also occur as a result of asbestos exposure; and pulmonary embolism, which occurs when there are blood clots or an obstruction in the artery that supplies blood to the lungs.
Other causes include bacterial infection, pneumonia, pulmonary embolism, autoimmune disorders, lung cancer, following heart surgery, pancreatitis, and asbestosis.
Drug-Induced and Genetic Factors
Nitrofurantoin and certain chemotherapy drugs increase the production of free radicals, overwhelming the body's natural antioxidant defenses such as superoxide dismutase, glutathione peroxidase, and alpha-tocopherol. This accumulation of oxygen-free radicals triggers an inflammatory response. Potential genetic factors include specific human leukocyte antigens (HLA) such as HLA-DR4, HLA-DR0*301, and HLA-DR2, as well as the complement C4 null allele.
COVID-19
A few research papers and case reports have reported that pleuritic pain can be a symptom of COVID-19, the infection caused by the coronavirus.
Nutrients Studied or Traditionally Used in Relation to Pleurisy
Omega-3 Fatty Acids
Traditional and General Nutritional Use
Dietary recommendations related to pleurisy have included omega-3 fatty acids, which are fats with anti-inflammatory activity found in salmon, mackerel, herring, and flaxseed oil.
Scientific Evidence
Omega-3 fatty acids have been described since the 1980s as promising anti-inflammatory substances, with prostaglandin and leukotriene modulation exhaustively explored as the main reason for their beneficial outcomes. Omega-3 polyunsaturated fatty acids (PUFAs), mainly represented by eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are able to inhibit different pathways including leukocyte chemotaxis, adhesion molecule expression and interactions, and production of inflammatory cytokines, through the action of specialized proresolving mediators (SPMs).
A new class of omega-3-derived substances, such as maresins, resolvins, and protectins, increases omega-3 actions. Inflammasome disruption, the presence of GPR120 on immune cell surfaces, and intracellular crosstalk signaling mediated by PPARγ compose the last discoveries regarding the multipoint anti-inflammatory targets for this nutrient.
Clinically important anti-inflammatory effects in humans are further suggested by trials demonstrating benefits of omega-3 fatty acids in rheumatoid arthritis, psoriasis, asthma, and inflammatory bowel disorders. These findings are relevant to pleurisy insofar as autoimmune and inflammatory conditions (including rheumatoid arthritis and lupus) are recognized contributors to the condition. Evidence strength: The anti-inflammatory mechanisms of omega-3 fatty acids are well-established; however, no clinical trials have specifically studied omega-3 supplementation for pleurisy itself. Benefits in related inflammatory conditions are moderate to strong, supported by randomized controlled trials (RCTs) and meta-analyses.
Vitamin C
Scientific Evidence
Supplementation with vitamin C appears to be able to both prevent and treat respiratory and systemic infections. Prophylactic prevention of infection requires dietary vitamin C intakes that provide at least adequate, if not saturating plasma levels (i.e., 100–200 mg/day), which optimize cell and tissue levels. Treatment of established infections requires significantly higher (gram) doses of the vitamin to compensate for the increased inflammatory response and metabolic demand.
As a major physiological antioxidant, vitamin C may have nonspecific protective effects on diverse parts of the immune system. During infections, phagocytes generate a set of oxidizing agents that have antimicrobial effects but, if released into the extracellular medium, the oxidants can be harmful to the host.
The preventive effects of vitamin C are mediated by antioxidant, immunomodulatory, and anti-inflammatory mechanisms in experimental animal models of different respiratory diseases. Vitamin C is used in modern medicine supplements for treatment of various disorders associated with oxidative stress, inflammation, and immune dysregulation.
The efficacy of vitamin C for respiratory tract infection and sepsis is disputed. Vitamin C has anti-inflammatory, immune-boosting, and pathogen-clearing effects, but though some studies and case series have suggested potential benefits in preventing and/or treating respiratory tract infections and sepsis, the evidence remains controversial. Current data is insufficient to support the routine clinical use of vitamin C in managing these diseases and requires further rigorous evaluation. Evidence strength: Mechanistic and preclinical evidence is strong; however, clinical evidence for its specific application in pleurisy is absent. Evidence for reducing duration of general respiratory illness is moderate.
Vitamin D
Scientific Evidence
Vitamin D appears capable of inhibiting pulmonary inflammatory responses while enhancing innate defence mechanisms against respiratory pathogens. Population-based studies show an association between circulating vitamin D levels and lung function.
Meta-analyses of observational studies have demonstrated a link between low vitamin D status and risk of acute respiratory infections, COVID-19 disorders, multiple sclerosis, type 1 diabetes, inflammatory bowel disease, systemic lupus erythematosus, and other autoimmune disorders. Since several autoimmune disorders (SLE, rheumatoid arthritis) are recognized contributors to pleurisy, the relevance of vitamin D status to pleurisy risk is biologically plausible.
Vitamin D can regulate the antiviral immune response in the respiratory tract in order to provide an effective defense against respiratory viral infections and prevention from excessive inflammatory response and tissue damage.
Observational studies suggest that vitamin D supplementation may protect against several infectious and autoimmune conditions. Meta-analyses of RCTs had mixed results, demonstrating a small protective role for vitamin D supplementation against acute respiratory infections, especially in those with vitamin D deficiency and children, and providing modest benefits for the management of type 1 diabetes and IBD. Evidence strength: Observational evidence is consistent but RCT evidence is mixed. No clinical trials have specifically addressed vitamin D and pleurisy.
Antioxidant Vitamins (Vitamins A and E)
Scientific Evidence
Lungs are particularly vulnerable to the effects of oxidative stress because of their exposure to high levels of oxygen, large surface area, and abundant vascularization. Inhalation of toxicants or pathogens and activation of resident or inflammatory cells in response to injury can contribute to the depletion of antioxidant capacities. Oxidative stress is well-documented to play a role in the pathogenesis of respiratory diseases.
Oxidative stress can enhance cell injury and increase disease severity in influenza A infection, which is a major cause of pneumonia-related death. Several studies have investigated the role of antioxidant vitamins in the pathogenesis of respiratory disease, but findings have been inconsistent. Evidence strength: Preclinical and mechanistic data support a role for antioxidants in protecting lung tissue, but clinical evidence specific to pleurisy is lacking.
Herbs and Natural Ingredients: Traditional Use and Scientific Evidence
Pleurisy Root (Asclepias tuberosa)
Traditional Use
Pleurisy root was used by Native American tribes both internally as a remedy for pulmonary infections and topically to treat wounds. The Eclectic physicians seized upon these ideas and continued to use the plant primarily for lung problems such as pleurisy and pneumonia. It was also used as a diaphoretic (a substance that causes sweating) for all manner of infections. Pleurisy root was an official medicine in the United States Pharmacopoeia from 1820 to 1905.
Traditionally, pleurisy root has been used to help loosen bronchial secretions and support movement within the air sacs of the lungs. Herbalists describe its action as encouraging flow rather than force, particularly when bronchial secretions feel thick or slow to move. Pleurisy root has also been used in practices intended to promote sweating. In traditional systems, promoting sweating was associated with the body's natural response during times of physical stress or acute discomfort.
Scientific Evidence
Pleurisy root is used for coughs, swelling of the lining of the lungs (pleuritis), swelling of the air sacs in the lungs (pneumonitis), swelling of the airways (bronchitis), influenza, and many other conditions, but there is no good scientific evidence to support these uses. There is a lack of clinical research exploring the effects of pleurisy root in human trials. Pleurisy root was one of the most important traditional medicines for both physicians and home remedies; however, it is less often used in modern herbal medicine. Much of the evidence for use has roots in indigenous practices and comes from early pharmacopoeias, as opposed to modern-day research. Evidence strength: Traditional use only; clinical evidence is absent.
Echinacea (Echinacea spp.)
Traditional Use
Herbs thought to combat infection, such as echinacea, are included in herbal pleurisy remedies within traditional naturopathic and eclectic herbal traditions. Echinacea has a long history of use among Native American peoples for managing infections and wound healing, and it was subsequently adopted into 19th-century eclectic medicine.
Scientific Evidence
Echinacea purpurea has clinical antiviral activity against respiratory viruses and modulates immune functions. A meta-analysis including six clinical studies with a total of 2,458 participants found that use of echinacea extracts was associated with reduced risk of recurrent respiratory infections (RR 0.649, 95% CI 0.545–0.774; P < 0.0001). Three independent studies found that in individuals with higher susceptibility, stress, or a state of immunological weakness, echinacea halved the risk of recurrent respiratory infections (RR 0.501, 95% CI 0.380–0.661; P < 0.0001).
The antibacterial activity of echinacea against respiratory pathogens including Streptococcus pneumoniae, Haemophilus influenzae, and Legionella pneumophila, as well as its antiviral efficacy against herpes simplex, influenza, and rhinovirus, has been reviewed. Since bacterial pneumonia and viral respiratory infections are the most common precipitants of pleurisy, echinacea's role in reducing the frequency and severity of these infections is relevant. Evidence strength: Moderate evidence from multiple RCTs and meta-analyses supports echinacea in preventing and shortening respiratory tract infections. No clinical data exist specifically for pleurisy.
Turmeric / Curcumin (Curcuma longa)
Traditional Use
Turmeric has been used for centuries in Ayurvedic and traditional Chinese medicine for inflammatory and respiratory conditions. Turmeric is considered to work as an analgesic and may help ease chest pain caused by pleurisy. Research also indicates that it can act against bacteria which can lead to lung infection.
Scientific Evidence
Curcumin, the principal curcuminoid of the popular Indian spice turmeric, has been demonstrated as an antioxidant and anti-inflammatory agent in a broad spectrum of diseases. Using a model of reovirus 1/L-induced acute viral pneumonia, which displays many characteristics of human acute lung injury (ALI)/ARDS, researchers evaluated the anti-inflammatory and anti-fibrotic effects of curcumin. Female mice were treated with curcumin (50 mg/kg) 5 days prior to inoculation and daily thereafter. Administration of curcumin significantly modulated inflammation and fibrosis, as revealed by histological and biochemical analysis.
Curcumin, extracted from turmeric, exhibits broad anti-inflammatory properties through down-regulating inflammatory cytokines. However, the instability of curcumin limits its clinical application. Over the years, there has been increasing evidence that curcumin has a wide spectrum of therapeutic properties and a remarkable range of protective effects in various diseases. Evidence strength: Preclinical (in vitro and animal model) evidence for curcumin's anti-inflammatory effects in lung injury is consistent. Human clinical trial data specifically for pleurisy are absent. Poor bioavailability is a recognized limitation.
Traditional Chinese Medicine: Ephedra (Ephedra sinica)
Traditional Use
Traditional Chinese medicine uses the herb ephedra (Ephedra sinica), which acts to open air passages and alleviate respiratory difficulties in pleurisy patients. It has been used within TCM frameworks as part of compound formulas for chest conditions including pleurisy, typically with other herbs in decoction form.
Scientific Evidence
No peer-reviewed clinical trials specifically studying ephedra in pleurisy were identified. Its active alkaloid, ephedrine, has established bronchodilatory effects that account for its traditional respiratory applications, though modern use is substantially limited by safety concerns. Evidence strength: Traditional use only; no clinical evidence for pleurisy specifically.
Mullein (Verbascum thapsus) and Elecampane (Inula helenium)
Traditional Use
These herbs are often used in conjunction with pleurisy root remedies, serving as expectorants to clear excess mucus from the lungs. There are many other respiratory herbs used as expectorants or for other actions on the respiratory system.
Scientific Evidence
Peer-reviewed clinical trial data for mullein or elecampane specifically in pleurisy were not identified in the available literature. Preclinical and ethnobotanical reviews support antimicrobial and expectorant properties for elecampane. Evidence strength: Traditional use only for the pleurisy-specific context; preclinical data are limited.
Antiviral Herbs: Lomatium dissectum and Ligusticum porteri
Traditional Use
Antiviral herbs such as Lomatium dissectum and Ligusticum porteri (osha root) have been used in traditional herbalism if the pleurisy is of viral origin. Both plants are indigenous to North America and have long histories of use by Native American peoples for respiratory illnesses and infections.
Scientific Evidence
No peer-reviewed human clinical trials on these two plants specifically for pleurisy were identified. Evidence strength: Traditional use only; formal clinical trial data are absent.
Garlic (Allium sativum)
Traditional Use and Scientific Context
Certain medicinal plants such as garlic (Allium sativum) may help manage lung diseases. Garlic has millennia of cross-cultural traditional use as an antimicrobial and immune-supportive remedy, including for respiratory infections across Ayurvedic, Traditional Chinese, and European herbal traditions. Its relevance to pleurisy lies primarily in its established antimicrobial and anti-inflammatory properties in the context of infectious causes of pleurisy. Evidence strength: Some human trial evidence exists for garlic in reducing frequency or severity of common cold; specific evidence for pleurisy is absent.
Dietary and Lifestyle Factors
General Dietary Considerations
Dietary recommendations in relation to pleurisy have historically included eating fresh fruits and vegetables, adequate protein, and omega-3 fatty acids found in salmon, mackerel, herring, and flaxseed oil.
A healthy, balanced diet with plenty of vegetables, fruit, and lean protein, while limiting sugar, fat, and alcohol and maintaining a healthy weight, is considered important during and after treatment for pleural conditions.
A diet low in antioxidants and high in processed foods may negatively impact immune function, which is relevant given that immune function mediates the body's ability to respond to the infections and inflammatory processes most commonly responsible for pleurisy.
Hydration and Rest
Adequate rest and hydration are essential for recovery, especially if pleurisy is caused by an infection. Healthy lifestyle practices that can reduce the risk of lung infection for people with pleurisy include drinking plenty of fluids, eating a well-balanced diet, getting plenty of rest, and refraining from smoking.
Smoking
Smoking is a significant risk factor for respiratory infections and chronic lung diseases. Smoking causes a state of chronic low-level inflammation throughout the respiratory tract. When the immune system is already preoccupied with this chronic irritation, it reacts more slowly and less effectively to a new infectious threat. This delayed response allows pneumonia to settle deeper into the lung tissue before the body starts to fight back, leading to a much higher risk of the infection spreading to the pleural membranes. Because smokers have higher baseline levels of inflammation, their pleural membranes are more reactive and prone to swelling when an infection occurs. Smokers who contract pneumonia are significantly more likely to experience the sharp, stabbing chest pain of pleurisy than non-smokers.
For patients who smoke, quitting smoking is considered crucial to reduce lung irritation and promote healing.
Stress Management and Sleep
Finding healthy ways to manage stress and aiming for 7–8 hours of sleep per night are recommended as supportive lifestyle measures for individuals with pleural conditions. This recommendation is consistent with the well-established relationship between psychological stress, sleep deprivation, and immune suppression, which could worsen susceptibility to the respiratory infections most commonly responsible for pleurisy.
Breathing Exercises
Breathing exercise techniques such as shallow breathing can help reduce pain while allowing the lungs to function adequately during active pleurisy.
Environmental and Occupational Exposures
Risk factors for pleurisy include smoking, recent respiratory infections, autoimmune disorders, and exposure to asbestos or other lung irritants. Exposure to certain environmental toxins or pollutants may also increase the risk of pleurisy.
Vaccination and Infection Prevention
Staying up-to-date with vaccinations such as the flu and pneumonia vaccines can reduce the risk of infections that may lead to pleurisy. Regular handwashing and avoiding close contact with sick individuals can also help prevent respiratory infections.
Summary of Evidence Strength
- Omega-3 fatty acids (anti-inflammatory): Moderate-to-strong evidence in related inflammatory and autoimmune conditions from RCTs and meta-analyses; no pleurisy-specific trials.
- Vitamin D (immune modulation and respiratory infection): Consistent observational evidence; mixed RCT evidence; no pleurisy-specific trials.
- Vitamin C (antioxidant, immune support): Mechanistic and animal evidence is strong; clinical evidence in respiratory illness is moderate but specifically for pleurisy is absent. Results remain disputed at the RCT level.
- Antioxidant vitamins A and E: Mechanistic evidence supports lung protection; clinical findings inconsistent; no pleurisy-specific trials.
- Echinacea: Moderate clinical evidence from multiple RCTs and meta-analyses for reducing respiratory tract infections; no pleurisy-specific trials.
- Curcumin/turmeric: Strong preclinical evidence for anti-inflammatory effects in lung injury; limited human clinical trial data; poor bioavailability is a barrier; no pleurisy-specific trials.
- Pleurisy root (Asclepias tuberosa): Traditional use only; absent clinical evidence; officially removed from the United States Pharmacopoeia in 1905.
- Mullein, elecampane, lomatium, osha, ephedra: Traditional use only; no clinical trial evidence for pleurisy.
References
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