Code R05, Cough, has been expanded and new codes created to identify specific types of cough as noted below:
- R05.1, Acute cough
- R05.2, Subacute cough
- R05.3, Chronic cough
- R05.4, Cough syncope
- R05.8, Other specified cough
- R05.9, Cough, unspecified
An acute cough is defined as a cough of less than three weeks duration in an adult. An acute cough may be a sign of a life-threatening condition or an exacerbation of a pre-existing respiratory condition, but most acute coughs are associated with respiratory tract infections (RTIs) and acute bronchitis is the most common cause of cough. A cough associated with a RTI usually resolves after the infection clears.
A subacute cough is very similar to an acute cough in that both may be related to RTIs and typically resolves after the infection clears. However, a subacute cough may be caused by conditions such as pertussis, infection with Mycoplasma or Chlamydia, exacerbations of other disease (asthma or COPD), or post-infectious cough. The difference between acute and subacute cough is the duration of the cough, with subacute lasting longer—from three to eight weeks.
A cough that persists despite treatment of underlying etiologies is a chronic cough. This type of cough occurs in a small number of patients and is defined as one that persists after extensive medical investigation. It is considered a diagnosis of exclusion. The American Thoracic Society (ATS) and the American College of Chest Physicians (CHEST) guidelines define an unexplained chronic cough (UCC) as a cough that occurs as follows: (1) one with no diagnosable cause, (2) explained but refractory chronic cough, and (3) unexplained and refractory chronic cough. Some of the more severe symptoms of chronic cough include incontinence, vomiting and sleep deprivation.
Cough syncope, also called “laryngeal ictus” results in loss of consciousness after prolonged bouts of cough. This rare phenomenon can result from transient increases in intracranial pressure and consequent reduction in cerebral blood flow due to abnormally high internal jugular vein pressures. Management of cough syncope focuses on treatment of the underlying condition. There is a “Code first syncope and collapse (R55)” note at code R05.4, Cough syncope.