Cough PDF

# Cough ## Background * Coughing is the body's defense mechanism in an attempt to clear the airways of foreign bodies and particulate matter. * Cough is the most common respiratory symptom and one of the few ways whereby abnormalities of the respiratory tract manifest themselves. * Cough can be ve...

# Cough ## Background * Coughing is the body's defense mechanism in an attempt to clear the airways of foreign bodies and particulate matter. * Cough is the most common respiratory symptom and one of the few ways whereby abnormalities of the respiratory tract manifest themselves. * Cough can be very debilitating to the patient’s well-being and can also be disruptive to family, friends and work colleagues. * Coughs can be described as productive (chesty) or nonproductive (dry, tight, tickly). * However, many patients will say that they are not producing sputum, although they may go on to say that they 'can feel it on their chest'. * In these cases, the cough is probably productive in nature and should be treated as such. * The British Thoracic Society Guidelines (2019) state that: * cough is usually self-limiting and will resolve in 3 or 4 weeks without the need for antibiotics. * Coughs are classified as *acute* or *chronic* in nature. ## Guidance from current Clinical Knowledge Summaries define cough as follows: * **Acute** when present for less than 3 weeks * **Subacute** when present for 3 to 8 weeks * **Chronic** when present for more than 8 weeks * Although these times are only considered indicative, patients who present with cough, other than acute cough (not being systemically unwell), are usually best referred to a medical practitioner for further investigation. ## Prevalence and epidemiology * Acute cough is usually caused by a viral upper respiratory tract infection (URTI) and constitutes 20% of consultations. * Schoolchildren experience the greatest number of coughs, with an estimated 7 to 10 episodes per year (compared with adults, with two to five episodes per year). * Acute viral URTIs exhibit seasonality, with a higher incidence seen in the winter months. ## Aetiology * The vast majority (90%) of URTIs are caused by viruses. These include respiratory syncytial virus, rhinovirus and viral influenza. * The remaining 10% of infections involve bacteria and include *Streptococcus pneumoniae*, *Haemophilus influenzae*, *Staphylococcus aureus* and *Klebsiella pneumoniae*, although these infections often have a viral element. * A five-part cough reflex is responsible for cough production. ## Arriving at a differential diagnosis * As stated above, the most likely cause of acute cough in primary care for all ages is a viral infection. * Recurrent viral bronchitis is most prevalent in preschool and young school-aged children, and is the most common cause of persistent cough in children of all ages. * As viral infection is by far the most likely cause of cough in all age groups, it is logical to hypothesize that this will be the cause of the cough, and questions should be directed to help confirm or refute this assumption (using hypotheticodeductive reasoning). ## Asking symptom specific questions will help the pharmacist establish a differential diagnosis | Incidence | Cause | |---|---| | Most likely | Viral infection | | Likely | Upper airways cough syndrome (formerly known as postnasal drip; includes allergies), acute bronchitis | | Unlikely | Croup, chronic bronchitis, COPD, asthma, pneumonia, ACE inhibitor induced | | Very unlikely | Heart failure, bronchiectasis, tuberculosis, cancer, pneumothorax, lung abscess, nocardiosis, GORD, psychogenic cough | **ACE**, Angiotensin-converting enzyme; **COPD**, chronic obstructive pulmonary disease; **GORD**, gastro-oesophageal reflux disease. ## Specific questions to ask the patient: Cough | Question | Relevance | |---|---| | Sputum colour | Mucoid (clear and white) normally of little consequence, suggests that no infection is present; yellow, green or brown sputum normally indicates infection; mucopurulent sputum is generally caused by a viral infection and does not require automatic referral. Haemoptysis can be rust coloured (pneumonia), pink tinged (left ventricular failure), or dark red (carcinoma); occasionally, patients can produce sputum with bright red blood as a single event due to the force of coughing, causing a blood vessel to rupture. This is not serious and does not require automatic referral. | | Nature of sputum | Thin and frothy suggests left ventricular failure; thick, mucoid to yellow, can suggest asthma. Offensive foul-smelling sputum suggests bronchiectasis or lung abscess. | | Onset of cough | Cough worse in the morning - may suggest upper airways cough syndrome, bronchiectasis or chronic bronchitis. | | Duration of cough | Acute cough can sometimes take 4 weeks or more to resolve (British Thoracic Society Guidelines Guidelines, 2019). However, coughs lasting longer than 3 weeks should be viewed with caution - the longer the cough is present, the more likely serious pathology is responsible. For example, the likely diagnosis at 3 days will be upper respiratory tract infection (URTI); at 3 weeks acute, or chronic bronchitis; and at 3 months, conditions such as chronic bronchitis, gastro-oesophageal reflux disease (GORD), and carcinoma. | | Periodicity | Adult patients with recurrent cough might have chronic bronchitis, especially if they smoke. Care should be exercised in children who present with recurrent cough and have a family history of eczema, asthma or hay fever. This might suggest asthma and referral would be required for further investigation. | | Age of the patient | Children will most likely be suffering from a URTI but asthma and croup should be considered; with increasing age, conditions such as bronchitis, pneumonia and carcinoma become more prevalent | | Smoking history | Patients who smoke are more prone to chronic and recurrent cough. Over time, this might develop into chronic bronchitis and chronic obstructive pulmonary disease (COPD). | ## Clinical features of acute viral cough * Viral coughs typically present with sudden onset and associated fever. Sputum production is minimal, and symptoms are often worse in the evening. Associated cold symptoms are also often present; these usually last between 7 and 10 days. * A duration of longer than 14 days might suggest postviral cough or possibly indicate a bacterial secondary infection, but this is clinically difficult to establish without sputum samples being analysed. * A common misconception is that cough with mucopurulent sputum is bacterial in cause and requires referral. This is almost never the case, and people should not be routinely referred to the GP for cough associated with mucopurulent sputum.