CHAPTER 10 Cough

Cough is one of the most common symptoms for which patients seek health care. Cough occurs when inspiration is followed by an explosive expiration. Coughing promotes clearance of secretions and foreign bodies from the airways. Cough is usually the result of a reflex initiated by stimulation of the sensory nerve endings beneath and between the epithelium of the larynx and tracheobronchial tree. A cough arises from the stimulation of the cough reflex in the upper respiratory tract by postnasal drip, clearing of the throat, or both. The reflex stimulation follows the vagus nerve to the “cough center,” which is located in the medulla oblongata of the brainstem. However, other anatomical locations can be stimulated and initiate the cough reflex, including the pleura, pericardium, ear canals, esophagus, and stomach. The cough reflex is absent in very young infants. Effective coughing can also be impossible in emaciated persons, in persons whose respiratory musculature is weak or paralyzed, and in those with massive ascites.

Although most coughs are a symptom of minor upper respiratory infections (URIs), such as the common cold, a persistent cough can greatly affect a patient’s quality of life and ability to sleep. Keep in mind, however, that a cough in a patient in acute distress can signal a life-threatening problem (such as foreign body aspiration with occlusion of airway), severe asthma, escalating heart failure, or pneumonia.

Diagnostic reasoning: focused history

What type of cough is this?

Key question

How long have you had a cough?

Duration

Cough can be characterized by the following three categories of duration: (1) acute, less than 3 weeks; (2) subacute, lasting 3 to 8 weeks; and (3) chronic, lasting more than 8 weeks. A cough of recent onset is most often the result of viral or bacterial infection in the respiratory system. Allergies can also precipitate acute onset of cough in both children and adults. Coughs of longer duration (>3 weeks) are more likely caused by chronic lung or heart disease, such as chronic obstructive pulmonary disease (COPD), cystic fibrosis, chronic bronchitis, asthma, postnasal drainage, heart failure, pertussis, and chronic sinusitis. Gastroesophageal reflux disease (GERD) and a foreign body in the ear canal should also be considered in both adults and children.

Is this cough related to a life-threatening condition?

Key questions

Are you short of breath?

Do you have a history of heart failure?

Do you have a history of asthma?

If a child: Have you noticed the child putting small objects in his or her mouth?

Shortness of breath

Cough associated with shortness of breath (SOB) usually suggests a physical obstruction of the airway caused by a foreign body or the effects of acute asthma. Persons with heart failure report orthopnea, paroxysmal nocturnal dyspnea (PND), cough with possible frothy sputum, possible weight gain with swollen feet and ankles, and often a history of heart disease. Cardiac failure of any kind results in decreased lung compliance and cough.

History of asthma

Acute exacerbation of asthma is characterized by an irritating nonproductive cough that can progress to tachypnea, dyspnea, wheezing, grunting, cyanosis, fatigue, and finally respiratory and cardiac failure. Viral infection, especially respiratory syncytial virus (RSV), parainfluenza viruses, and rhinoviruses, are the most important triggers of asthma in children.

Foreign body

Consider a foreign body aspiration in any child. A child who has aspirated a foreign body can have a varied presentation; generally, the onset of cough is sudden and unexpected. A brief period of severe coughing, gagging, and choking occurs; then a quiet period ensues of no coughing. This can last for hours, days, or even months. A foreign body in the lower airway can produce either emphysema caused by a ball-valve phenomenon or complete distal atelectasis because of absorption of the trapped gas. A mobile foreign body in the lower airway can also produce a paroxysmal cough, with cyanotic episodes and stridor as a result of proximal migration and subglottic impaction.

A foreign body in the esophagus can also produce airway obstruction and cough as well as dysphasia to solid foods because the posterior trachea is compliant and adjacent to the anterior esophagus. Coins are the most frequently found foreign bodies.

What do I need to know if the cough is acute (<3 weeks’ duration)?

Key questions

Do you have nasal congestion or a sore throat?

Do you have or have you had a fever? Do you have chills?

Do you have a headache?

Nasal congestion

Nasal congestion occurs as a result of a cascade of events. First, the offending organism invades the epithelial cells of the upper respiratory tract. Inflammatory mediators are released, resulting in altered vascular permeability, edema, and nasal stuffiness. Stimulation of cholinergic nerves in the nose and upper respiratory tract leads to increased mucus production (rhinorrhea) and occasionally to bronchoconstriction, which causes cough. It is hypothesized that cellular damage to the nasopharynx is probably what causes the sore and scratchy throat.

Runny nose with cough and mild fever followed by a persistent cough for more than 1 week with clear to off-white mucus greater in the morning suggests bronchitis.

Nasal congestion or a sensation of postnasal discharge, especially associated with facial pain or pressure, suggests sinusitis. A history of bloody nasal discharge can also be present.

Infants with nasal congestion 3 days to 8 weeks after birth who have a cough but are afebrile could have Chlamydia trachomatis, contracted from the mother during childbirth. Older children, adolescents, and adults with a sore throat, fever, headache, and malaise progressing to a cough could have mycoplasmal pneumonia.

Fever

In adults, a temperature that is less than 38.3° C (101° F), small amounts of clear to yellow sputum production, nasal congestion, sore throat, and generalized malaise most frequently accompany acute cough with a viral etiology. Acute cough of a more serious nature (e.g., bacterial pneumonia) is usually accompanied by a temperature of greater than 38.3° C (101° F), chest pain, SOB, and purulent or dark sputum. Acute cough resulting from noninfectious processes (heart failure or pulmonary embolism) lacks the signs of infectious disease, such as fever, chills, and purulent sputum.

Viral infection is the most common cause of a low-grade fever in a child who has nasal congestion and little interruption of appetite and activity. An acute cough associated with a persistent fever, loss of appetite, and ill appearance indicates a more serious illness, such as bacterial pneumonia.

Headache

Headache pain can signal sinusitis as the cause of the cough (see Chapter 14).

What does the nature of the sputum tell me?

Key questions

Do you cough up sputum?

Does it have an odor?

How much have you coughed up?

What color is the sputum?

Malodorous sputum suggests anaerobic infection of the lungs and sinuses. Very thick, tenacious, dark sputum is characteristic of bronchiectasis. Cloudy, thick sputum suggests lower respiratory tract infection but can also reflect an increase in the number of eosinophils from an asthmatic process. Viral bronchitis rarely causes more than 2 tablespoons of mucopurulent sputum per day. Bacterial bronchitis, however, is frequently associated with purulent sputum, often more than 2 tablespoons per day. Clear, mucoid sputum indicates allergic disorder. Hemoptysis, uncommon in children, usually indicates a more serious disease, such as bacterial pneumonia, an acute inflammatory bronchitis, cystic fibrosis, tumor, or a foreign body.

Children tend to swallow rather than expectorate sputum. Occasionally emesis will have mucus in it and can be used to identify the sputum. A child with a persistent cough and purulent sputum is likely to have an infectious lung disease.

What does the nature of the cough tell me?

Key questions

Is the cough getting worse or more frequent?

What time of day is the cough most bothersome?

If a child: Did the child have an episode of severe cough, gagging, and choking a few weeks ago?

What type of work do you do?

What does the cough sound like?

Severity and progression of cough

A cough in children or adults that becomes progressively worse can indicate pertussis. Pertussis has three stages. The first stage presents with a mild cough, rhinorrhea, conjunctivitis, and low-grade fever for 1 to 2 weeks. In the next stage, the cough becomes severe and comes in short paroxysms. There is a “whoop” on the inspiration effort at the end of the paroxysm. In the convalescent stage, the coughing and paroxysmal whooping decrease, but the cough can persist in a milder form for 3 months.

Young infants and older adults with pertussis do not “whoop.”

A cough in children that begins with a history of mild URI followed in 2 to 3 days with a cough that is brassy in sound can indicate croup. The cough is usually worse at night. Symptoms escalate as compromise of the upper airway continues from the viral agent (usually parainfluenza). Obstruction increases, stridor becomes continuous, and there is nasal flaring and suprasternal, infrasternal, and intracostal retraction. The child is agitated and sits up. In most children recovery occurs within a few hours. However, any intensification of symptoms of respiratory obstruction requires hospitalization.

Persistent paroxysmal coughing is often associated with asthma.

Timing of cough

Coughs that awaken persons at night are frequently associated with respiratory problems in which bronchial irritation is a factor, such as asthma or chronic bronchitis, or with nonrespiratory conditions, such as GERD or heart failure. A hallmark of asthma is coughing at night, usually between midnight and 2:00 am. This is because of the low level of glucocortisol in the body at this time. A severe cough in the early morning indicates postnasal drip, cystic fibrosis, or bronchiectasis. Secretions accumulate through the night, and fits of coughing are followed by bronchorrhea. Cough that is worse at night indicates croup, postnasal drip, lower respiratory tract infection, and allergic reaction. A cough that disappears with sleep is a habit cough.

History of choking episode

Consider foreign body aspiration in any child with a cough lasting longer than 3 weeks. Frequently the caregivers report an episode of severe coughing and choking occurring 1 to 3 weeks before with a period of absence of cough (because the level of obstruction is in a lobar or segmental bronchus) and then sudden recurrence of coughing. This period of absence can last for hours, days, or even months. The cough can reappear when irritation of the foreign body or reaction to the foreign body occurs.

Occupation

An occupational and hobby review is warranted. Asbestos or coal dust exposure increases a person’s risk of lung disease, including lung cancer. Aerosol sprays, insecticides, chemical exposures, and sawdust can cause cough.

Nature of the cough

A throat-clearing cough is indicative of postnasal drip caused by irritation of the cough receptors in the pharynx, which are sensitive to mechanical stimulation, such as secretions. A dry, brassy cough indicates pharyngeal or tracheal irritation, allergy, or habit. A loose or moist cough can indicate lung disease, such as cystic fibrosis or asthma.

A paroxysmal cough is seen with asthma, pertussis, and cystic fibrosis and occasionally after inhalation of a foreign body. A barking, croupy cough indicates an irritation in the glottic and subglottic area. A sudden short burst of a cough in infants, called a staccato cough, is indicative of Chlamydia trachomatis. A harsh, dry cough caused by airway compression from enlarged nodes in the perihilar or paratracheal region seems to occur with tuberculosis (TB) or fungal infection.

A loud, bizarre cough that seems to be attention seeking can have a psychogenic origin. The cough usually is vibrating, throaty, and dry. The severity can range from occasional clearing of the throat to spells lasting several minutes. The cough usually follows a respiratory tract infection. The cough disappears with sleep or when the child is distracted. School absences are common.

Is the cough related to any event that would help me narrow down the cause?

Key questions

Does eating affect your cough?

Does your cough get worse during certain times of the year?

Does exercise affect your cough?

Eating

Inhalation into the tracheobronchial tree can occur as a result of lack of esophageal motility, GERD with regurgitation into the pharynx, or central nervous system and neuromuscular disorders. Difficulty with sucking and swallowing or coughing and choking during eating are highly suggestive of an underlying disorder, such as congenital malformations, congenital heart disease, or pneumonia.

In the adult, GERD probably causes cough through direct stimulation of cough receptors with acid or through inflammation from aspiration of stomach contents into the airway.

Season

Chronic cough during winter months suggests viral infections. Exacerbation of cough during spring, summer, and fall is suggestive of allergic disease with increased pollen counts. Croup occurs most commonly in the fall from the parainfluenza virus type 1. Smaller peaks of croup are seen with influenza B outbreaks in the winter months. RSV is common in infants during the winter months. In the warmer months, parainfluenza type 3 is the agent frequently isolated.

Exercise

The hyperpnea of exercise causes bronchospasm because of heat loss from the airway surface and is more pronounced in cold dry air. Asthma attacks are frequently exercise related, as is cough resulting from heart disease or airway compression.

Is this something that is going around?

Key questions

Is anyone else at home ill?

Is anyone else ill in day care, school, or the workplace?

Exposure to respiratory viruses is very common in day care, school, and the workplace. Viruses that cause the common cold are shed in nasal secretions. Contacts acquire the virus by being sneezed on or by touching a sneezed-on object and then touching their own nose or conjunctivae. The incubation period is 2 to 5 days. Mycoplasma pneumoniae tends to spread through school/households slowly as the incubation period is 21 days.

Is there anything that would lead me to suspect allergies or reactive airway disease?

Key questions

Does anyone in your family have allergies or asthma?

Is there anything you do or take that stops the cough?

Do you have pets?

Family history

Allergy-prone individuals are at increased risk for coughs associated with postnasal drip and asthma. Allergy-prone adults and children are those persons with personal or family history of atopic dermatitis, asthma, and allergic rhinitis. Pets residing in the household are frequently the source of the allergen, especially cats and dogs.

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