Naidoo, KT

Wilson, D

English

AJOL - African Journals Online

Respiratory tract infections are one of the commonest reasons fora visit to a family physician, and given time constraints and per-ceived patient expectations many consultations will end with anantibiotic prescription. Antibiotic resistance among the respirato-ry tract pathogens is clinically significant and increasing rapidly,and clinicians treating outpatients with respiratory tract infectionsneed to grapple with the issue of whether or not an antibioticshould be prescribed (Fig. 1). A recent study from the UnitedStates1 gives insight into the manner in which clinicians respondto these issues. The study reviewed the treatment of more than24 000 adults presenting with nonspecific respiratory tract infec-tions and revealed that 63% received a prescription for an oralantibiotic. Importantly, the study excluded patients with chronicbronchitis, asthma or chronic obstructive pulmonary disease(COPD), and concluded that interventions are needed to reduceantibiotic prescribing to limit the progression of antibiotic resist-ance. How should clinicians responsibly approach the management ofviral upper respiratory tract infections (URTIs), sinusitis and bron-chitis? Guidelines were developed in the 1980s and 1990s, butwere difficult to use in individual cases and did not take intoaccount varying antibiotic resistance in different regions. Analternative approach is to consider each case on merit and,when an antibiotic is necessary, to prescribe effectively.The following three clinical scenarios will be discussed: • acute bronchitis• acute sinusitis• infective exacerbation of chronic bronchitis, COPD orbronchiectasis.ACUTE BRONCHITISAcute bronchitis is often preceded by a viral URTI. Symptomsprogress to include general malaise, retrosternal pain, dry ‘tickly’cough and sputum production that is initially mucoid and maylater become mucopurulent because of secondary bacterial infec-tion. The microbiological causes of acute bronchitis are shown inTable I. Management should be based on the following princi-ples:• assessment of the severity of the symptoms, and colour andquantity of the sputumK T NAIDOOBSc, MB ChB, FCP(SA),Certificate in PulmonologySpecialistPhysician/LecturerNelson Mandela School ofMedicineUniversity of KwaZulu-NatalPulmonologistRespiratory UnitInkosi Albert Luthuli CentralHospitalDr Naidoo obtained hisPulmonology Certificationin September 2003. Hiscurrent interests includecritical care medicine, dif-fuse pulmonary disease andpulmonary vascular dis-ease.THE RESPIRATORY TRACT200 CME April  2004  Vol.22  No.4TREATMENT OF COMMONRESPIRATORY INFECTIONS: THEANTIBIOTIC DILEMMAAntibiotics — to use or not to use, a common question.DOUGLAS WILSONMB ChB, FCP (SA)Principal SpecialistPietermaritzburg HospitalComplexHonorary LecturerUniversity of KwaZulu-NatalDouglas Wilson trained ininternal medicine, and from1999 to 2002 in infectiousdiseases and as an HIV cli-nician at Somerset Hospitaland Groote SchuurHospital. He started an anti-retroviral clinic at SomersetHospital in 2001, and inApril 2003 moved to Grey’sHospital inPietermaritzburg.• evaluation for underlying co-mor-bidity (Table II)• exclusion of acute bacterial tonsilli-tis by looking for purulent tonsillarexudates• clinical exclusion of pneumonia achest radiograph (CXR)• assessment of the clinical severityand access to medical care• informing the patient that the infec-tion will probably resolve sponta-neously and about problems associ-ated with antibiotic over-use andresistance• antibiotic allergies.Crucially, patient satisfaction has beenshown to relate to the quality of thedoctor-patient interaction rather thanthe prescription of an antibiotic. Theuse of an antibiotic for acute bronchi-tis is widely discouraged.If the assessment justifies the adminis-tration of an antibiotic, either amoxy-cillin or doxycycline should be pre-scribed for 5 days. In order to achievethe concentration of amoxicillin in thebronchial secretions above the mini-mum inhibitory concentration (MIC)(for pneumococcus), the adult doseshould be 500 mg 3 times daily.Erythromycin can be prescribed withamoxicillin if there is an outbreak ofmycoplasma or chlamydia infection inthe community. Doxycycline will coverboth the typical respiratory tractpathogens and the mycoplasma/chlamydia.  Importantly, treatment forthe ‘atypical’ pathogens should becontinued for 14 days.ACUTE SINUSITISMucoid nasal discharge with post-nasal drip and nasal congestion is aprominent feature of the common cold,and is not an indication for antibiotictreatment. Patients should be informedthat these symptoms should resolvespontaneously within 3 - 4 days.Persisting symptoms for more than 1week and a purulent nasal dischargesuggest that acute bacterial sinusitishas developed. Facial pain, which isexacerbated by bending forward, orby direct pressure over the sinuses, isalso highly suggestive of this condi-tion. THE RESPIRATORY TRACTApril 2004  Vol.22  No.4   CME 201Fig. 1. The clinical dilemma of acute bronchitis.Not giving an antibiotic• Risk of clinical deterioration• Perception of poor patientsatisfactionGiving an antibiotic• Creating bacterial resistance• Unnecessary side-effects• CostTable I. Causes of acute bronchitisPrimary infection Secondary infectionAdenovirus Streptococcus pneumoniae (pneumococcus)    Rhinovirus Haemophilus influenzaeInfluenzaMycoplasmaChlamydia In the elderlyRespiratory syncytial virus Para-influenza virusTable II. Conditions associated with increased risk of progression to severe lower respiratory tract infection Immunocompetent Immunocompromised individuals individualsPersons > 65yrs HIV infectionChronic cardiovascular disease Leukaemia/lymphomaChronic respiratory disease MyelomaOther chronic medical conditions Other malignanciesDiabetes mellitus Chronic renal failureCirrhosis Nephrotic syndromeAlcoholism Organ transplantsSpecial environments Immunosuppressive medicationNursing homesMinesHostelsPrisonsCertain patients develop sinusitis morereadily; the threshold for using anantibiotic should be lower if thepatient has a history of:• sinus surgery• sinus polyps• bloodstained nasal discharge dur-ing the current URTI• mucociliary disorders (rare). If acute sinusitis is diagnosed, antibiot-ic treatment is indicated using amoxi-cillin (at least 500 mg 3 times daily),co-amoxiclav (with 500 mg of theamoxicillin component) or cefuroxime. INFECTIVE EXACERBATIONSOF UNDERLYING LUNGDISEASEPatients with underlying lung diseaseexperiencing an infective exacerbationare more likely to need an antibiotic.The following points should raise thesuspicion of underlying chronic lungdisease:• smoking• daily sputum production for > 3months yearly for the last 2 years• gradually increasing effort intoler-ance  • previous pulmonary tuberculosis• history of working underground inthe mines.Clinical features suggesting chroniclung disease include:• prolonged expiration, hyperinflatedchest and wheezing• fixed coarse inspiratory crackles(also heard at the mouth) and fin-ger clubbing.Symptoms suggesting an infectiveexacerbation include increasingbreathlessness, increased volume ofsputum production and more purulentsputum.  Patients with the followingclinical features should be treated withan antibiotic:• severe underlying COPD• markedly purulent sputum• evidence of systemic infection(fever, raised white cell count,raised erythrocyte sedimentationrate (ESR) or C-reactive protein(CRP)• new infiltrate on chest radiograph• co-morbidity or an increased risk ofdeveloping pneumonia.The use of an antibiotic is associatedwith the following benefits:• more rapid improvement in peakexpiratory flow rate• lower risk of clinical failure andprogression to pneumonia• two-day reduction in duration of ill-ness• lower relapse rate.An appropriate antibiotic will alsoeradicate infections that acceleratelung destruction and chronic airwayobstruction. Importantly, treatmentshould also include inhaled/nebulisedbeta2-agonists with ipratropium, pred-nisone 40 mg daily for 14 days, andinhaled oxygen if the patient is severe-ly hypoxaemic. (Note that oxygen sup-plementation should be used cautious-ly if hypercarbia is present.) The appropriate choice of antibiotic isdetailed in Table III. Intravenous antibi-otics may be required in severe cases,but can be ‘switched’ to oral therapywhen clinical improvement occurs.Moxifloxacin (400 mg daily) and gati-floxacin (400 mg daily) have excellentabsorption from the gastrointestinaltract, but are very expensive andresistance develops rapidly; hencetheir use should be restricted topatients who are allergic to beta-lac-tam antibiotics. If co-amoxiclav is useda minimum of 500 mg of the amoxi-cillin component should be given.Duration of therapy for severe diseaseshould be 10 - 14 days.PreventionPreventing influenza and severe bacte-rial infections is a crucial componentof the management of patients withunderlying lung disease. The influenzavaccine should be given yearly at thestart of the influenza season to allhigh-risk patients. The 23 serotypepneumococcal vaccine (Pneumovax23 or Imovax Pneumo 23) should alsobe given every 5 years to high-riskpatients. The role of the new heptava-lent pneumococcal vaccine in adults isstill unclear. Long-term physiotherapyand postural drainage are importantin patients with bronchiectasis.Clinical exampleA 45-year-old woman has bilateralbronchiectasis diagnosed in child-hood. Extensive, bilateral lower lobedisease was seen on a recent high-res-olution CT scan of the lungs. Her cur-202 CME April  2004  Vol.22  No.4THE RESPIRATORY TRACTTable III. Antibiotic therapy recommended for patients with infective exacerbations of COPDCondition Patient profile Pathogens Appropriate antibiotic therapySimple chronic Younger patient, Streptococcus pneumoniae High-dose amoxicillin or amoxicillin/bronchitis near normal lung function, Haemophilus influenzae clavulanic acid or macrolide/azalidefew exacerbations Moraxella catarrhalisComplicated Older patient, impaired As above, but antibiotic Amoxicillin/clavulanic acid, or 2nd chronic lung function, frequent resistance more common or 3rd generation cephalosporin,bronchitis exacerbations > 4/year or new respiratory fluoroquinoloneBronchiectasis As above, plus continuous As above, plus Gram-nega- Ciprofloxacin or new fluoro-purulent sputum tive organisms, including   quinolone, or other agentproduction, possible Enterobacteriaceae and according to sputum culturestructural damage/ Pseudomonas aeruginosabronchiectasis THE RESPIRATORY TRACTApril 2004  Vol.22  No.4   CME 203Antibiotic resistance amongthe respiratory tractpathogens is clinically sig-nificant and increasing rap-idly, and clinicians treatingoutpatients with respiratorytract infections need tograpple with the issue ofwhether or not an antibiot-ic should be prescribed.Acute bronchitis is oftenpreceded by a viral URTI.Symptoms progress toinclude general malaise,retrosternal pain, dry ‘tick-ly’ cough and sputum pro-duction that is initiallymucoid and may laterbecome mucopurulentbecause of secondary bacterial infection.Crucially, patient satisfac-tion has been shown torelate to the quality of thedoctor-patient interactionrather than the prescriptionof an antibiotic. The use ofan antibiotic for acutebronchitis is widely discouraged.rent effort tolerance is good and shedescribes grade 2 exertional dysp-noea. Over the years she has hadmany courses of antibiotics as an out-patient and inpatient, and a recentsputum culture grew Pseudomonasaeruginosa resistant to amoxicillin, co-trimoxazole, doxycycline, co-amoxi-clav, cefuroxime, and sensitive toofloxacin, ceftriaxone, gentamicin,amikacin and piptazobactam.CommentThis patient has been colonised bypseudomonas resistant to multipleantibiotics. This organism would haveacquired the antibiotic resistancegenes (which it does with notoriousease) during previous courses of treat-ment. During this patient’s next infec-tive exacerbation another sputum cul-ture will have to be taken and anurgent Gram stain done. If the staindoes not clearly show another organ-ism (e.g. Gram-positive pneumococ-cus) the clinician will have to presumethat the infecting organism is thepseudomonas and treat accordingly. Outpatient treatment can be givenwith ofloxacin, but both the clinicianand the patient need to understandthat in time the organism will becomeresistant to this drug. Inpatient treat-ment should be with intravenous ceftri-axone and gentamicin: both are givenin an attempt to prevent the organismacquiring resistance to these valuabledrugs. The amikacin and piptazobac-tam can be kept in reserve. ‘Surveillance’ sputum culture and sen-sitivity testing should be done twiceyearly. Treatment should also includechest physiotherapy and appropriatevaccination. The ultimate goal of treat-ment is to slow the progression of thebronchiectasis and to preserve asmuch healthy lung tissue as possible.Reference available on request.Antibiotic over-prescribing for acuteupper respiratory tract infections(URTIs) is common and promotesantibiotic resistance.In patients without underlying co-morbidity the majority of URTIs willresolve spontaneously. Patient satis-faction is related to the quality ofthe doctor-patient interaction ratherthan to receiving an antibiotic pre-scription.Mucoid sputum or nasal dischargein itself is not an indication for anantibiotic.Acute bacterial sinusitis can bediagnosed 7 - 10 days after anURTI, when nasal dischargebecomes purulent and congestionpersists, and is associated withfacial pain worsened by bendingforward. A history of sinus surgeryor nasal polyps suggests that thepatient may develop sinusitis morereadily, especially if the dischargeis bloodstained.Patients with acute bronchitis andsevere underlying lung disease orco-morbidity may benefit frombeing treated early with an antibiot-ic to prevent pneumonia or to limitongoing lung damage.Sputum culture and sensitivity test-ing allow rational antibiotic selec-tion for patients with structural lungdisease (chronic bronchitis, emphy-sema and bronchiectasis) andrecurrent respiratory tract infec-tions.IN A NUTSHELL

Treatment of common respiratory infections: The antibiotic dilemma

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Treatment of common respiratory infections: The antibiotic dilemma

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