Cough

One of the most frequent causes for medical consultation.

Cough is a common medical problem, and cough is the single most common symptom for seeking medical consultation.

Chronic cough is also a globally prevalent problem, affecting ~10% of adults in the general population.

Cough can seriously impair quality of life, as it includes psychological, social, and physical consequences.

A survey among elderly individuals found that the impact of chronic persistent cough on mental health was comparable to that of stroke or Parkinson’s disease.

Cough results following stimulation of receptors in the respiratory tract with sudden inspiration occurring and then tightening of the chest and abdominal muscles against the closed glottis with a sharp rise in intrathoracic pressures of up to 300 mmHg.

The high intrathoracic pressures of up to 300 mmHg, a velocity of up to 28,000 cm/s or greater than 500 mph and chest energy of up to 25J produces vigorous coughing in healthy persons so that cough is an important defense mechanism that can help clear excessive secretions and foreign matter from airways and maintain consciousness during potentially lethal arrhythmias.

It is the same bio physical properties that can spread infections and lead to psychosocial, functional and emotional complications, including fear about personal safety as well as extreme physical symptoms that can involve any organ system, all of which can lead to deterioration in the quality of life and rarely to death.

Following this the glottis suddenly opens leading to the rapid expiratory flow and characteristic noisy expiration, termed cough.

Cough that occurs in a series is referred to as a cough bout.

A weak or ineffective cough is associated with serious pulmonary infections.

Viral infections of the upper respiratory tract are the most common cause of acute cough.

Acute cough, is associated with acute upper and lower viral and bacterial respiratory tract infections, predominately, but exacerbations of pre-existing conditions may occur.

Chronic cough is related to smoking, upper airway cough syndrome, bronchial asthma, non-asthmatic eosinophilic bronchitis and gastrointestinal reflux disease.

The prevalence of chronic cough in the general adult population is 2 to 5% with women out numbering men.

Most common causes of chronic cough are postnasal drip, asthma and gastroesophageal reflux.

Chronic cough defined as a cough of 3 weeks or more in duration.

Induced rib fractures occurs primarily in women and is associated with chronic rather than acute coughing.

In patients with chronic cough approximately one-half of patients have more than one cause for cough.

Longstanding process may indicate the presence of upper airway disease, gastroesophageal reflux disease and parenchymal lung disease.

Chronic cough was thought to be primarily a consequence of chronic disease conditions, such as reactive airways (asthma and eosinophilic bronchitis), rhinosinusitis, or reflux disease, the “three Rs.”

However, a large proportion of patients with these conditions do not complain of chronic cough.

Many patients with chronic cough did not fit into any disease category, resulting in common diagnoses of idiopathic, refractory, or unexplained cough.

It is suggested that cough is not always related to another disease condition but rather is a clinical entity with a distinct pathophysiology.

The cough reflex has its own neural pathways of regulation, and disease conditions, such as the 3Rs, could be associated with or act as triggers, rather than direct causes of cough.

The majority of cases of chronic cough in adults are caused by upper airway cough syndrome due to a variety of rhinosinus conditions: asthma, GERD, non-asthmatic eosinophilic bronchitis, or a combination of these disorders.

Less common causes of chronic cough include broncholithiasis, tracheobronchomalacia, heart failure, and ear problems.

Classification includes acute cough with duration of less than three weeks, subacute cough 3-8 weeks or chronic cough grade in eight weeks (Prather MR et al).

It may be a voluntary act or in unsuppressable reflex.

Cough is an essential protective reflex aimed at clearing the larynx, trachea, and bronchi of mucus, irritants, foreign particles, and micro organisms.

Call attempts to free the airways and preventing infection.

Most common cause of acute cough is a self limited process, a viral upper respiratory infection, although it may be caused by a serious condition such as congestive heart failure, lung cancer, pneumonia, or pulmonary embolism.

Subacute cough most frequently represents persistence of an acute respiratory infection involving either the upper or lower airways.

Associated with angiotensin-converting enzyme inhibitors.

Chronic cough most commonly caused by gastroesophageal reflux disease, asthma, and chronic sinusitis/post nasal drip.

Non-asthmatic eosinophilic bronchitis may be associated with chronic cough and is defined by cough, with eosinophils in the sputum, but not associated with dyspnea, wheezing, airflow obstruction or airway hyperactivity.

Pertussis can be associated with sub acute and chronic cough.

Severe cough may cause subconjunctival bleeding, rib fractures, incontinence of urine, hernias, syncope, intracranial hemorrhage and dissection of the vertebral artery and insomnia (Irwin RS).

Cough can be severe, violent and repetitive and can be associated with tissue injury which may aggravate an underlying process.

Cough induced complications include: involvement of the upper airways, chest wall and thorax, abdominal wall, heart and aorta, CNS, eye, gastrointestinal tract, stress incontinence, and emotional and psychological harm.

Cough complications include cartilage fracture intercostal lung herniation, diaphragmatic rupture, spontaneous pneumothorax or pneumomediastinum, hemothorax, and rupture of an intercostal artery.

Increase in intraabdominal pressure during coughing can worsen inguinal, umbilical, and abdominal hernias.

Rupture of a normal spleen can occur spontaneously from severe cough.

Cough syncope has been reported with the loss of consciousness occurring immediately after cough, especially after prolonged bouts of violent coughing.

Cough syncope is more common in males who are middle-age, obese, with COPD and who smoke.

Cough or sneeze syncope is classified as situational syncope along with syncope following G.I. stimulation or micturition as a form of reflex syncope similar to vasovagal faint.

Cough is mediated by the vagus nerve innervating the lungs and may be modulated by input from vagal afferents innervating other visceral organs and possibly from trigeminal afferents innervating the nasal mucosa.

Vagal afferent mediating the cough reflex terminate in the medulla oblongata.

Cough evoked by stimulus is not a sole brain stem media reflex response.

Projections from brainstem regions, are modulated by subcortical and cortical brain activities.

Coughing acutely increases intrathoracic pressure, lowers  venous return and cardiac output.

With coughing patient’s blood pressure drops excessively where is expected heart rate compensatory  acceleration does not occur.

Rib fractures due to severe cough can be diagnosed by the presence of chest pain occurring after the onset of coughing, x-ray changes of rib fracture, absence of trauma, metastatic disease or other obvious explanation for a fracture.

Patients with rib fractures  may have pleuritic chest pain or chest wall tenderness on palpation.

Cough can be associated with poorly localized muscle pain, especially chest pain.

Women predominate in cough induced rib fractures.

Cough induced fractures are very uncommon.

Bruising or puncture of long but I really is could cause pleural effusion, pneumothorax, hemothorax, and even lung herniation.

Rapid increase in intrathoracic an intra-abdominal pressure during coughing increases central venous and intracranial pressure and triggers a sudden, sharp, stabbing, moderate to severe headache of short duration from one second to 30 minutes.

Unilateral headache is not uncommon.

Most patients with cough induced headache are in their 40s or 50s amd the prevalence is up to 1.2% in headache clinics.

Primary cough headache must be ascertained by neuroimaging because 40% of these patients have an underlying structure etiology, most located in the posterior fossa.

Such headaches are often due to Chiari type 1 malformation, a herniation of the cerebellar tonsils through the foraminal magnum.

Cough induced headache is mediated by transient increase in intracranial CSF pressure as a result of obstruction and the symptom can be reproduce by a modified Valsalva test.

Chronic cough is associated with subsequent myocardial infarction.

Chronic cough is an independent predictor of MI with significant odds ratio of 1.6-1.8, respectively.

A focal neurological deficit induced by coughing is rare but is well-established: cervical artery dissection is the most common reason, when arterial wall layers becomes separate and blood connects between them.

Chronic cough is the leading symptom of gastrointestinal reflux disease and can occur even without concomitant gastrointestinal symptoms.

GERD is one of the major causes of chronic cough.

Cough leading to secondary GERD is also well-established.

In patients with asthma, nearly half of all coughs are associated with a reflux episode, seven times more often than the opposite.

Rapidly increasing abdominal pressure associated with coughing, sneezing, laughing or exertion can cause involuntary leakage from the urethra and signifies stress urinary incontinence.

Stress urinary incontinence affects 3.5% of women and in 24-54% of affected women chronic cough is a risk factor.

Women more frequently seek medical attention for chronic cough than, which  men which may be related to the fact that women have more pronounced cough reflex sensitivity to inhaled capsaicin and citric acid than men, and a greater degree of health related quality of life factors being adversely affected with increased physical symptoms such as stress urinary incontinence.

Chronic cough can lead to impaired quality of life with depression, anxiety, insomnia and frustration.

All  patients with chronic cough are at risk for multiple psychological symptoms: depression, anxiety.

The eight week duration for chronic cough suggest that post infectious coughs due to viral, mycoplasma, or chlamydophila infections should not last longer.

A history that includes the character of the chronic cough-dry or productive, honking, or barking, paroxysmal, brassy, self propagating, loose, nocturnal, with meals, postprandial, with milk, products, on awakening and associated complications of syncope or hypothesis are not helpful in diagnosing the underlying cause of chronic cough and adults.

Additionally, anti-tussive medicines with proven efficacy and safety are nearly lacking.

A European study most subjects with chronic cough responded that their cough medication had limited or no effectiveness (57% and 36%, respectively).

The absence or near absence of cough during sleep is a nonspecific finding and may be seen in a variety of common disease diseases, such as GERD or chronic bronchitis and tends to be suppressed during sleep.

Patients with chronic cough frequently report fits of coughing provoked by low levels of triggers, and proceeded by sensations in the pharynx and larynx such as a tickle or itch with an uncontrollable urge to cough, consistent with a cough hypersensitivity syndrome, but is a limited value in diagnosing and predicting the outcomes of chronic cough.

Some adults with chronic cough feign cough associated illness for secondary gain as part of Munchhausen syndrome, have recurrences in adulthood tics due to Tourette’s syndrome or have a primary motor or a phonic tic disorder that develops in adulthood with a somatic cough syndrome, a psychiatric disorder.