PBL 14 A Persistent Cough
Rick Allen
Common viral infections. Cold and flu, croup, bronchiolitis. Managing Pt treatment
expectations in cold & flu presentations
Croup
laryngotracheobronchitits – inflammatory narrowing of the airway  inspiratory stridor.
Parainfluenza virus. Fever, coryza (head cold symptoms), sore throat, hoarseness, cough.
Laryngoepiglottis
Caused by RSV (respiratory syncitial virus), haemophilus influenzae or β-haemolytic
streptococci  sudden swelling of epiglottis and vocal cords are potentially leathal in young
kids…not in adults due to larger airways.
Bronchiolitis
(laryngotracheobronchitis) – vocal cord swelling and abundant mucus exudate. Impaired
bronchociliary function  secondary bacterial infection  increase of symptoms. Can block
smaller airways and lead to atelectasis (incomplete expansion or collapse of a portion of a
lung)
Pertussis
Bordetella pertussis, pertussis = “violent cough”. Gram neg aerobic bacilli.
Spread = unimmunized house – 80-100%. Immunized = 20%
Pathogenesis = attaches to nasopharynx epithelium (adhesins), replicates, releases toxin,
which causes local mucosal damage along with other stuff. Incubation 7-10 days.
Symptoms – Whooping cough, prolonged/paroxysmal/sleep-disturbing cough, Can cause
vomiting. Fatigue evident. Cough can become less frequent and severe after 2-4 weeks,
lasting 1-3 months.
Complications = ↑ intrathoracic pressure  petechiae haemorrhages on face and trunk,
Hernias, wt. loss (↓ intake), pneumothorax.
Dx. nasopharyngeal swab/aspirate then culture.
Tx. macrolide Ab. Azithromycin/clarithromycin/erythromycin
Prevention: chemoprophylaxis (wow!) and immunisation.
Common Cold
Generally speaking are inflammatory diseases of the upper airways. Origin = viral 
bacterial (greater symptoms)
-Infectious rhinitis –aetiology: adenovirus, echovirus, rhinovirus
pathogenesis: evoke profuse catarrhal discharge. Initial acute stage,
nasal mucosa is thickened, red and oedematous, nasal cavaties narrowed, turbinates
enlarged. Can extend  pharyngotonsilitis. Secondary bacterial infection enhances the
inflam. reactionmucopurulent/suppuratives exudate. Symptoms approx. 10 days, + 3 in
smokers, resolve without sequlae. Incubation 1-2 days.
PBL 14 A Persistent Cough
Rick Allen
Symptoms: rhinorrhoea, sneezing, nasal congestion, sore throat, systemic – malaise,
headache. Can exacerbate asthma and chronic pulmonary issues, blockage of
pharyngotympanic tube/sinus drainage  otitis media/acute sinusitis. Immunosuppressed 
pneumonia
Tx. – Symptomatic.
Sinusitis
Acute is generally preceded by acute/chronic rhinitis. Maxillary sinusitis can arise from a
periapical infection through the bony floor of the sinus.
Aetiology: many common nasal flora. Inflam. is nonspecific (oedema)  blockage of sinus
drainage  suppuratives exudates (sinus empyema)
Tonsilitis
Enlargement of lymphoid tissue (hyperplasia) within Waldeyers ring.
Influenza
Aetiology: A, B or C based on nucleoprotein surrounding single-strand RNA. Lipid bilayer
round the outside with viral hemagglutinin and neuraminidase (H1N1). This is what Ab’s are
created against.
Type A – infects humans, pigs, birds, horses. Major pandemic and epidemic cause.
Antigenic drift = Mutations of H and N causes repeated infections by avoiding host Ab’s.
Antigenic shift = H and N are replaced with those of animal varients, leading to all people
being susceptible.
Type B and C do not undergo shift or drift and therefore only affect kids.
Symptoms: abrupt onset, fever, cough, myalgia (muscle pain), malaiseUsually self resolves
in 2-5 days, with a cough lasting for approx. 1-2 weeks after.
Complications: . Complications are usually due to exacerbation of pulmonary complications.
>64, <2, pregnant in 2nd/3rd trimester. Pneumonia
Clearance: cytotoxic T cells kill infected cells, and intracellular anti-influenza protein (Mx1) is
induced in macrophages by cytokines (IFN-α and β)
Pathogenesis – spread most efficiently via airborne droplets, though contact and fomite
transfer may also be to blame. Virus invades URT epithelium, replicates within cells and then
spreads rapidly. Causes necrosis, can cause metaplasia. Unlikely to be found outside
pulmonary system despite systemic symptoms.
Morphology: mucosal hyperaemia, and swelling, with primarily lymphomonocytic and
plasmacytic infiltration of submucosa plus mucous oversecretion  can plug sinuses,
pharyngotympanic tube or nasal channels  secondary bacterial infection.
PBL 14 A Persistent Cough
Rick Allen
2008 NICE (National Institute for Health and Clinical Excellence) guidelines from the UK
recommend that patients seeking medical evaluation for cold symptoms should [5,6]:






Be advised that the usual course and duration of illness is up to one and a half weeks
for patients with a cold; symptoms persist an additional three days on average in
smokers [7]
Be informed regarding the risks and benefits of symptomatic management, including
analgesics and antipyretics
Be informed and reassured that antibiotics are not needed and may have side effects
Have their concerns and expectations discussed
Be advised to return for review if their condition worsens or exceeds the expected
time for recovery.
We suggest prophylaxis with vitamin C (200 to 500 mg daily) for prevention of upper
respiratory infection for people exposed to vigorous activity in extreme cold
conditions (Grade 2B) (does not change severity). We suggest not using echinacea or
vitamin E for prophylaxis of colds (Grade 2B). (See 'Prevention' above.)