Dr. Pramod Singh1, Dr. Astha Mathur2, Dr. Junaid Ahmad3, Dr. Geeta Sharma4,
Cough is one of the most common symptoms that result in patients seeking advise from general physicians and pulmonologists accounting for close to 40% of their outpatient practice. Cough is an important defense mechanism that helps clear secretions and particulate matter from the airways and protects the lower airways from aspiration of foreign materials. It therefore plays an important role in protecting the airways and lung parenchyma under normal conditions, but sometime it may become excessive, troublesome and be indicative of an ongoing pathological process. The vicious cycle of perpetuating cough can be prevented by early diagnosis and treatment. Nearly all conditions affecting the respiratory system and some extrapulmonary conditions may cause cough and therefore, a stop wise symptom based approach to diagnosis is important.
Cough therefore, is a multifaceted symptom – a defense mechanism for the lungs, a cautionary sign of a disease and a damaging symptom when persistent. The exact pathophysiology of genesis of cough, however, is still incompletely understood. Understanding and treating cough efficiently remains a challenge from the investigational as well as clinical angle for the treating physician.
Respiratory system and its defense mechanisms:
Air enters the respiratory vi the nose or mouth, small hair (vibrissae) in the nose act as a filter removing any large particle in the inspired air. The air is warmed and humidified during its passage via the nasal turbinate bones in the nasal passage. Nasal turbinates causes the inspired airflow to become turbulent and mix more efficiently, allowing it to then pass into the pharynx. The pharynx is a part of both the digestive and respiratory tracts, food being channeled through the esophagus to the stomach and the air passing to and from the lungs. The vocal cords and several cartilages are found in the larynx. The respiratory system The respiratory system is structurally and functionally divided into 2 main zones: a conducting zone that comprises of the nasal cavity, nasopharynx, larynx, trachea, bronchi, and bronchioles, and a respiratory zone consisting of the terminal bronchial tree and the alveoli as shown in Fig. 1. The trachea enters the thorax and divides into left and right bronchi at the carina. The bronchi further divide into secondary bronchi, which pass into the lobes of the lung. In each lobe, the secondary bronchi divide into tertiary bronchi and further branch into a fine network of bronchioles, the terminal bronchioles, which end in the alveolar sac. Every division of the bronchial tree is referred to as a new generation and there are 23 such generations of airways. Gas exchange occurs in the last
8 generation of airways. The terminal bronchioles, alveolar ducts, alveoli and surrounding blood and lymphatic vessels are surrounded by sheets of elastic connective tissue, which divide the lobes of the lung into lobules. In the steady state, more than 10,000 liters of air is delivered daily by the conducting airways to the pulmonary parenchyma to ensure gas exchange, However, inhaled air contains a mix of harmful inorganic substances such as smoke and soot, as well as organic particles including pollen, fungi, viruses and and bacteria. Moreover, the lung is also exposed to endogenous factors such as toxins and immunocomplexes, reaching via the pulmonary circulation. Therefore, the respiratory tract has a significant number of protective and defense mechanisms to prevent and respond to its continuous invasion by harmful agents.
Defence mechanisms of the respiratory system
Vibrissae in the nostril filter particles greater than 10-15μ in diameter. The nasal turbinates force inspired air to pass in narrow streams so that solid particles pass close to either the nasal septum or mucosa of the turbinates and
impinge directly or settle due to gravity. Particles greater than 10 μ are almostcompletely removed in the nose. Particles between 2-10 μ usually settle on themucus-lined walls of the trachea, bronchi, and bronchioles whereas those between 0.3 and 2.0 μ and all foreign gases reach the alveolar ducts and alveoli. Particles less than 0. 3μ in diameter usually remain as aerosols and arealmost entirely expired.
Removal of filtered particles
Sneeze reflex, cough reflex, and reflex bronchospasm also help in expelling inhaled particles.
The pseudostratified columnar ciliated epithelium lining the major part of the upper respiratory tract ensures the removal of harmful agents towards pharynx by the co-ordinated movements of its cilia. Mucosal secretions line the posterior wall of the nasal cavity and the bronchial tree. Mucus is a mixture of macromolecular polysaccharides which traps foreign particles. Respiratory mucosal secretions contain a lysozyme called muramidase which cleaves the N-acetyl muramic acid (MurNac) bond frequently found in the bacterial cellwall, thus, preventing bacterial entry into tissues. The epithelial cilia beat 1000 times per minute and create an effective mucociliary escalator that moves trapped particles and mucus towards the pharynx for expulsion by swallowing or as phlegm. Epithelial cilia can be damaged due to infection, toxins or an inborn defect. Excess mucus production as evidenced in chronic bronchitis can lead to mucus stagnation and predispose to infection.
Humoral factors are biomolecules with bacteriocidal or antiviral properties that adhere to the harmful agent facilitating its recognition (opsonization) and Phagocytosis by phagocytes. These include muramidase, interferons (IFNs), antimicrobial peptides and lactoferrin, acute phase proteins, complementfactors, lipopolysaccharide (LPS)-binding protein (LBP), and collectins.
The cellular defense system of the respiratory tract include the following:
Airway epithelial cells: They are divided into the ciliated epithelial cells of the upper respiratory tracts, Clara cells of the small airways and type II epithelial cells of the alveoli forming the first line of defense in the respiratory system. They remove the harmful agents by co-ordinated movements of their cilia; recognize pathogenic agents via pattern recognition receptors (PRRs) and toll like receptors (TLRs); release small anionic and cationic antimicrobial peptides and antimicrobial proteins which act as “endogenous antibiotics” and release cytokines, chemokines and chemotactic factors that attract cells of specific and non-specific immunity,triggering local inflammatory reactions.
Polymorphonuclear leucocytes: The respiratory system has large numbers of polymorphonuclear leucocytes adhering to the vascular endothelium due to its rich vasculature. They phagocytose particles such as cocci, bacteria, fungi, molecular aggregates, carbon, and colloids. Their extravasation is enhanced by expression of adhesion molecules and chemotactic factors.
Polymorphonuclear eosinophils: They release toxic substances contained in their electron-dense granules against parasites; secrete histaminase to inactivate excess histamine released by basophils and mast cells; secrete aryl-sulfatase, an enzyme that inactivates slow reactive substance-A (SRS-A) produced by basophils and mast cells and phagocytose immune complexes. Other cellular defense mechanisms: Include alveolar macrophages, monocytes, natural killer (NK) cells, dendritic cells, B-lymphocytes and T-lymphocytes.
The defense mechanisims of the respiratory system are summarized below in table.
|Defense mechanisms of the respiratory system|
Cough can be broadly classified as follows
a) Acute cough : < 3 weeks in duration
b) Subacute cough : 3-8 weeks in duration
c) Chronic cough : 8 weeks in duration
Acute cough is the nomenclature used for cough lasting for a maximum of 3 weeks. It is commonly caused by upper respiratory tract infections (URTI), acute bronchitis or tracheo-bronchitis due to bacterial or viral infections. Acute cough due to such infections is usually self-limiting and subsides within 1-2 weeks as the infection clears.
Acute cough can be associated with life-threatening conditions such as pulmonary embolism, congestive heart failure, or pneumonia. The first step in the treatment of acute cough is to rule out underlying serious conditions or an acute URTI, lower respiratory tract infection (LRTI), or an exacerbation of a preexisting condition (e. g., asthma, bronchiectasis, chronic obstructive pulmonary disease [COPD], or upper airway cough syndrome [UACS].
It has been defined as a cough lasting for 3-8 weeks. Increase in bronchial hyper-responsiveness may persist following specific infections, which can perpetuate cough that can remain bothersome for weeks even after the initial infection has subsided. Respiratory causes include pneumonia (bacterial, viral, fungal) and Bordetella pertusis infection (whooping cough), bronchial asthma and non-infectious include GER, aspiration and rarely Tourette’s syndrome,
which can manifest itself solely as paroxysmal coughing episodes.
Cough lasting for more than 8 weeks is termed as chronic cough. Chronic cigarette smoking is the most common cause of chronic cough. Other than that, 3 dominant etiologies have emerged to explain the causes of chronic cough – UACS due to a variety of rhinosinus conditions, asthma, and GERD.
Upper respiratory tract causes include allergic or vasomotor rhinitis, Postnasal drip syndrome, post-infectious cough, sinusitis whereas lower respiratory causes may be abscess, allergic inflammation, aspiration, asthma,
bronchiectasis, bronchitis, COPD, CF, drugs (I.e., angiotensin-converting enzyme inhibitors), eosinophilic bronchitis, interstitial lung disease, pertussis, primary or metastatic lung tumors, sarcoidosis, or tuberculosis. Cardiovascular causes implicated include left ventricular failure and mitral stenosis. Psychological responses such as habit cough and psychogenic cough should
The medical history is important to rule out ACE inhibitor therapy, current as well as former smoking, or exposure to tuberculosis or certain endemic fungal diseases. In addition a previous history of cancer, tuberculosis, or AIDS, or other systemic symptoms of fever, sweats, or weight loss also needs to be taken into consideration.
The commonest etiologies which include UACS, asthma and GERD deserve special mention and are discussed in detail. Others include conditions such as smoker’s cough and chronic cough due to conditions such as pulmonary tuberculosis.
Upper airway cough syndrome (UACS) or post nasal drip syndrome (PNDS):
One of the commonest causes of chronic cough that often occurs after viral URTIs are those caused by respiratory syncytial or parainfluenza viruses, Chlamydia pneumoniae (TWAR strain), Mycoplasma pneumoniae, or Bordetella pertussis. Other causes include perennial rhinitis ; rhinitis as a consequence of seasonal allergens, irritants, drugs, and vasomotor responses and chronic sinusitis. Chronic inflammation augments nasal and sinus secretions that continuously stimulate the cough reflex. Though some individuals may have no symptoms other than chronic cough most, however, present with sensation of tickling or a constant drip in the back of the throat. Throat clearing, nasal congestion, rhinorrhea, and hoarseness may also be present. The diagnosis cannot be made based on the history and physical examination alone. Radiography of the sinuses may be useful when rhinitis and asthma have been ruled out as causes of chronic cough. Treatment for post-infectious, perennial, and vasomotor rhinitis includes a first-generation antihistamine combined with a decongestant. Chronic sinusitis should be treated with a combination of antibiotic, anti-inflammatory, and decongestant followed by nasal steroids, if needed.
Chronic cough is often attributable to asthma and is usually associated with wheezing, dyspnea, and chest tightness. In approximately 57% asthmatic patients, cough may be the only presenting feature and this condition is knownas cough-variant asthma, cough-variant asthma should be considered when persistent cough is exacerbated by cold or exercise, or when cough worsens at night. Airway hyper-responsiveness may suggest the diagnosis of cough-variant asthma. Spirometry with a bronchodilator showing 12% improvement in FEV, suggests a diagnosis of asthma. Treatment consists of β-agonists andinhaled corticosteroids.
Gastroesophageal ref lux disease (GERD):
GERD is a common cause of chronic cough and is possibly due to transient loss of tone in the lower esophageal sphincter (LES). Loss of tone in the LES can be exacerbated by coughing induced by GERD and perpetuates the cycle of more reflux, irritation, inflammation, and coughing. Adults usually present with symptoms of microaspiration, symptoms of heartburn, regurgitation, sour taste, dysphonia, hoarseness, and throat pain preceding development of the cough. Management of GERD involves a trial of antireflux and proton pump inhibitor (PPI) therapy. Preventive measures include weight reduction, smoking cessation, and a diet low in foods that reduce lower esophageal sphincter tone.
Cough reflex sensitivity is significantly diminished in smokers due to long-term tobacco smoke-induced desensitization of the cough receptors within the airway epithelium. It has also been postulated that nicotine-induced inhibition of C-fibers, or the depletion of neuropeptides, within the airways may be the cause of diminished cough reflex sensitivity in smokers. Chronic bronchitis from exposure to cigarette smoke or other irritants is an important cause of
chronic cough. Patient presents with chronic cough usually worse in the mornings. A sputum eosinophil count to rule out eosinophilia and a chest X-ray along with spirometry need to be carried out. The initial treatment step is to eliminate tobacco smoke or other environmental irritants. In the absence of these irritants, sputum production and airway inflammation usually decrease. First-generation antihistamine combined with a decongestant may be required
in few cases.
Cough due to pulmonary tuberculosis:
Due to the contagious nature and significant morbidity, the diagnosis of pulmonary tuberculosis should be kept in mind while investigating chronic cough. Along with cough which often is blood tinged, patient may have fever with evening rise, anorexia, and loss of appetite. On examination, patient may have clubbing, lympadenopathy, and bronchial breathing. Investigations include CBC, ESR, Montoux test, sputum AFB stain and chest X-ray. Treatment of tuberculosis includes an intensive phase of 2 months of isoniazid (H), rifampicin (R), pyrazinamide (Z) and ethambutol (E) therapy followed by the continuation phase (CP) which consists of isoniazid and rifampicin given for 4 months.
Cough in pediatric population and elderly:
Cough in children:
Cough in children is mostly related to viral respiratory tract infections andusually resolves spontaneously. External factors such as pollution, particulate matter, irritant gases, environmental tobacco smoke exposure also play an important role in the etiology of cough among children. Cough in children can be classified as normal or abnormal. Children experience 10-11 normal cough episodes/day. Abnormal cough in children can be due to an underlying condition, neuromuscular weakness or structural airway abnormality. It can be further classified as acute or chronic based on duration dry or wet daytime or nocturnal and specific or non-specific based on etiology. Most acute and subacute coughs in children are associated with viral URTI. In children, as opposed to adults, the character and quality of cough may point to a specific diagnosis as shown in Table 2. Cough is subject to more psychological influences in children as seen with habit cough. Habit cough is a harsh, dry, often honking repetitive cough occurring throughout the day which improves with distraction and during sleep. Foreign body aspiration (FBA) is most commonly seen in children below 24 months. The diagnosis should be suspected if there is a history of choking followed by prolonged cough and non-resolving pneumonia.
|Table 2 : Cough characteristic and possible etiologies in children at various ages|
|Cough Charectristic||Possible etiology|
|Barking or brassy||Croup, tracheomalacia/other anatomic
abnormalities of respiratory or GI tract
|Barking or brassy||Croup|
|Spasmodic/paroxysmal (with or without
|Wet (with or without produced sputum)||PBB/sinusitis|
|Spasmodic/paroxysomal (with or without whoop)||Pertussis-like syndrome|
|Wet (with or without produced sputum)||Pneumonia/PBB/sinusitis|
PBB : Protracted bacterial bronchitis
Chronic cough with purulent sputum in children is always pathological, and indicative of conditions such as CF, non-CF bronchiectasis, ciliary dysmotility syndromes or immune deficiency and, therefore, needs thorough assessment. A chest X-ray and spirometry (if possible) should be obtained in all children with chronic cough and computed tomography (CT) scan is a requisite to support a diagnosis of bronchiectasis or interstitial lung disease. Spirometry is possible in most children more than 6 years of age. Spirometry with a bronchodilator showing 12% improvement in FEV, suggests a diagnosis of asthma. A limited CT scan of the sinuses may help rule out intrinsic sinus disease. Cough in children should be treated as per etiology, however, for chronic non-specific cough, empiric trials of therapy are often needed such as a short trial(2-4 weeks) of beclomethasone ; 400 μg/d or an equivalent dosage of budesonide may be warranted. Use of medication for symptomatic relief in acute cough is not recommended. In children who have started therapy with a medication, if cough does not resolve within an expected response time, the medication should be withdrawn and other diagnoses should be considered.
Cough in the elderly:
Elderly people are a unique group with unique management challenges due toco-morbid conditions. Coughing in the elderly may be due to an underlying cause and, therefore, a thorough assessment must be carried out. Acute cough in the elderly most commonly can be attributed to respiratory tract infections in nose, larynx and/or bronchi, either viral or bacterial, of both. These are especially frequent and dangerous in the elderly. A number of viruses and bacteria have been implicated, such as rhinovirus, influenza and respiratory syncytial viruses, Streptococcus pneumoniae, Haemophilus influenza and Bordetella pertussis. Viral infections can predispose to community-acquired pneumonia.
Although asthma, post-nasal drip and GERD are said to be responsible for 90% cases of chronic cough in adults, in older patients, the causes of chronic coughmay be more complicated. Age related changes in cough reflex may affect the causes and treatment efficacy of chronic cough. In addition, sensitivity of the cough reflex appears to be significantly reduced in elderly subjects. This may increase the risk of aspiration and bronchopulmonary infection in old age, even in the absence of respiratory disease. In diabetic patients, autonomic dysfunction may result in an altered cough reflex as well as impaired autonomic reflexes which can lead to increased cough threshold and reduced cough frequency in the elderly age group. An elderly patient with persistent symptoms despite having normal chest radiography and a negative evaluation for common causes of cough should also be evaluated with computed tomography or bronchoscopy to rule out malignancy.
RARELY USED REMEDIES FOR COUGH:
Hawking of profuse mucus. Throat very sensitive, especially to air. Profuse, nasal catarrh. Inspired air feels cold (Cistus). Profuse secretion of mucus dropping through posterior nares. Dry, spasmodic, suffocative cough; very rapid cough, short, barking. Cough with great sensitiveness of air-passages; feel cold on deep inspiration. Continuous hysterical cough. Feels suffocated and greatly exhausted after whooping-cough.
Cyanosis and dyspnśa; worse, sitting up. Patient puts hands on heart. Cough, with valvular disease. Exercise causes pain around heart. Tickling, dry cough. Dyspnśa. Constriction of chest. Cough, with copious, jelly-like, or bloody expectoration. Small and feeble pulse. Threatening paralysis of lungs. Gasping for breath; clutches at heart.
Sudden contraction of glottis, when drinking or talking. Food goes down wrong way. False croup; cannot exhale. Spasmodic and whooping-cough. Few paroxysms in day-time, but many at night; with vomiting after eating. Asthma, as if inhaling sulphur; cough from talking; hollow, deep, with rawness, hoarseness, and pains through chest. Violent spasmodic cough; worse at night.
Voice husky. Tip of nose to touch. Throat dry and sore, as if pin crosswise in it. Dry cough, worse from air into larynx, tobacco smoke, fog, talking; with irritation in suprasternal fossa (Rumex). Trachea painful to touch.
Sticking pain through right breast near sternum, extending to back near shoulders. Dyspnœa, and continuous cough, early in morning. Cough, with profuse and fetid expectoration; compels him to sit up. Hoarseness.
Chest oppressed with pressure in stomach, and nausea Hoarseness with tenacious mucus in larynx. Paroxysmal, suffocative cough, coming on about midnight, with crying and dyspnśa. Spasmodic croup. Dry coryza. Sniffles of infants; nose dry and obstructed. Loose choking cough. When nursing child must let go of nipple, nose blocked up, cannot breathe. Child awakes suddenly, nearly suffocating, sits up, turns blue. Cannot expire (Meph). Millar’s asthma.
Fluent coryza; margins of nostrils feel sore. Sneezing; throat irritated; short, dry cough; must take a deep breath. Dyspnśa and stitches in chest, and painful contraction of abdominal muscles. Violent, furious, exhausting cough, with much mucus; profuse, salty, slimy expectoration, and with involuntary spurting of urine and sneezing. Child rubs face with fist during cough (Caust; Puls). Cough provoked by taking a deep breath or cold drinks, from exertion, change from warm to cold air. Cough of measles. Frequent calls to urinate at night, passing large quantities (Phos ac). Sneezing with coughing.
Throat raw; dropping of mucus posteriorly. Dry, hacking cough during night; worse, inspiration. Tracheitis, facilitates expectoration. Loose cough in morning. Pain through chest from sternum to spiral column. Cough after measles (Sang); worse towards evening and when tired. Pulsation from right side of sternum down to abdomen.
Hoarseness. Hurts to talk. Bursting pain in back on coughing. Catarrh of larynx. Loss of voice. Hacking cough. Thorax feels too narrow. Cough often ends in a sneeze. Rattling in chest (Tart emet). Chest oppressed on ascending. Bronchial catarrh, with sore chest walls; much mucus; sensation of oppression and weight of chest. Difficult raising of tough, profuse mucus, in the aged. Asthenic bronchitis of old people with chronic interstitial nephritis or chronic emphysema. Old asthmatics with congestive attacks. Exudations in Pleura. Hydrothorax (Merc sulph). Pressure on chest as though lungs were forced back to spine. Voice unsteady, vocal cords partially paralyzed.
Hoarse; voice deep, harsh; sounds like a trumpet; “basso profundo”. Cough; worse at night. Asthma. Soreness in pharynx, cough during sleep.
DISCUSSION AND CONCLUSION:
In homoeopathy, medicines are prescribed on the basis of totality of the patient’s symptoms but in many cases there is possibility of paucity of symptoms with the peculiar presentation of Cough with its peculiar modality, in those type of cases these rarely used medicines show significant role in treatment of Cough. These medicines are listed in rare medicine because not used in day to day clinical practices but have been well proved in cases of Cough.
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Dr. Pramod Singh1, Dr. Astha Mathur2, Dr. Junaid Ahmad3, Dr. Geeta Sharma4,
- Head of Department, Department of Homoeopathic pharmacy, Dr. M.P.K. Homoeopathic Medical College, Hospital & Research Centre, Saipura, Jaipur.
- Assistant Professor Department of Homoeopathic pharmacy, Dr. M.P.K. Homoeopathic Medical College, Hospital & Research Centre, Saipura, Jaipur
- MD scholar, Department of Homoeopathic pharmacy, HOMOEOPATHIC UNIVERSITY, JAIPUR.
- MD scholar, Department of Homoeopathic pharmacy, HOMOEOPATHIC UNIVERSITY, JAIPUR.