ACUTE SINUSITIS Purulent Sinusitis can be caused

ACUTE SINUSITIS

Purulent Sinusitis can be caused when the ciliary clearance
mechanism of the sinus is decreased, or by means of an obstructed ostium. As a
result, secretions are retained, sinus pressure is reduced to negative, along
with a decrease in oxygen partial pressure as well. Sinus blockage and ciliary
dysfunction are aggravated by allergic, non-allergic and/or viral attacks that
produce an inflammatory response in the mucosa of the nasal- and sinus
cavities, which produces an environment suitable for the growth of pathogens.

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Predisposing conditions such as cystic fibrosis, ciliary
dyskinesia, allergic inflammation, immuno-compromisation and ostiomeatal
obstruction (due to drug addiction and nasal polyps) should be seriously
considered in those patients suffering from persistent or recurrent sinusitis.
1

 

Acute viral rhinosinusitis

The majority of rhinosinusitis cases/episodes are caused by
viral pathogens, the most common being Rhinovirus, along with Influenza and
Parainfluenza viruses, presenting in 3-15% of acute sinusitis cases. Other
viruses include Corona virus, Respiratory Syncytial virus, Adenovirus and
enterovirus of which 0.5-2% can progress to acute bacterial sinusitis 2,3.

Of all other risk factors, Viral infections of the upper
airway appear to be the most prevailing factor predisposing individuals to acute
bacterial sinusitis. Of these patients, approximately 90% will present with
sinus involvement, but a mere 5-10% of these individuals will have a bacterial superinfection.
(4,5)

 

Acute bacterial rhinosinusitis

There is a strong correlation between acute bacterial
rhinosinusitis and upper respiratory tract infection. The following factors
contribute to impaired mucocilliary clearance and bacterial infection:

·        
Allergy

·        
Trauma

·        
Neoplasms

·        
Granulomatous and inflammatory diseases

·        
Midline destructive disease

·        
Environmental factors

·        
Dental infection

·        
Anatomic variation

S aureus, S Pneumonia
and H Influenza are the most common
pathogens contributing to sinusitis. Administration of the 7-valent
pneumococcal vaccine in Paediatric cases of S Pneumonia, resulted in a
decreased rate of recovery for S Pneumonia, but an increased recovery rate for
H Influenza cases. Vaccination also altered the rate of recovery of S
pneumoniae penicillin-resistant strains6,7.

P aeruginosa(amongst other gram-negative rods) have been observed
in acute sinusitis of nosocomial origin. Patients with nasogastric- and/or
catheters in situ; immunocompromised persons; patients with HIV infection, and
those with cystic fibrosis were all frequent hosts of P aeruginosa.

66% patients suffering from acute sinusitis are infected
with at least one pathogenic bacterial species, while up to 30% show infection
with multiple predominant bacterial species . Normal flora are the bacteria
most commonly involved in acute sinusitis and can become sinus pathogens when sneezing,
coughing and/or direct invasion deposit these pathogens into the sinuses, if
conditions optimize their growth.

 

Most Maxillary Sinusitis episodes are mostly caused by Streptococcus pneumoniae, Haemophilus influenzae
and Moraxella catarrhalis.  Streptococcus
pyogenes, Staphylococcus aureus and anaerobes cause less than 10% of cases
with acute bacterial sinusitis, despite the environment providing sufficient
means for their growth. In Chronic Sinusitis, and sinusitis resulting from
dental sources, anaerobic organisms were frequently isolated.

 

S Pneumonia is a gram-positive, catalase-negative,
facultative anaerobic cocci. Almost to 20- 43 % of acute bacterial
rhinosinusitis episodes in adults result from this pathogen which is proving to
become increasingly resistant to various antibiotics including penicillin. Intermediate
penicillin-resistance to Macrolides, Clindamycin, Trimethoprim-Sulfamethoxazole
and Doxycycline, than the complete penicillin resistant counter-part 8.

 

In the past, H Influenza type B(gram-negative facultative
anaerobic bacilli ) was one of the leading causes of meningitis, but this all
changed after the vaccine became extensively administered. Non-typeable strains
of H influenzae develop antimicrobial resistance by means of Beta-lactamase
production and have found to cause 22-35% of acute bacterial rhinosinusitis
cases amongst adults. 32.7%-44% of these patients were infected with
beta-lactamase–positive H influenza.

 

M catarrhalis(gram-negative,
oxidase-positive, aerobic diplococci) causes up to 10% of acute bacterial
rhinosinusitis cases in adults and its resistance to antimicrobials is
increasing with aspirates from the paranasal sinus showing 98%
beta-lactamase–positive M catarrhalis.

 

At present, S aureus
accounts for 10% of episodes of acute bacterial rhinosinusitis, but its
starting to be seen in more and more patients, rapidly becoming a common
pathogen in acute bacterial rhinosinusitis. 9 Methicillin-resistant S aureus
(MRSA) is still only responsible for a fraction of episodes rhinosinusitis,
increasing occurrences drug-resistant S
aureus will require revision of pharmacological treatment. 10

 

Gram-negative organisms are the leading cause in nosocomial
sinusitis, including:

·        
Pseudomonas
aeruginosa (15.9%)

·        
Escherichia
coli (7.6%)

·        
Proteus
mirabilis (7.2%)

·        
Klebsiella
pneumoniae

·        
Enterobacter
species

They account for 60% of cases. Polymicrobial infection is cultured
in 25-100% of aspirates. Gram-positive organisms and fungi contribute to 31%
and 8.5% of nosocomial sinusitis infections respectively. 10

Acute invasive fungal rhinosinusitis

On rare occasions, sinusitis is caused by fungal infections.
Fungal sinusitis (eg, allergic fungal sinusitis) may appear like a lower airway
disorder and allergic bronchopulmonary aspergillosis.

Aspergillus, Alternaria, Bipolaris and Curvularia species are the most common
fungi seen in allergic fungal sinusitis, the last two accounting for 60% and
20% of infections respectively.

 

CHRONIC
SINUSITIS(CRS)

The etiological studies of sinusitis are gradually moving
towards focussing on ostiomeatal obstruction; allergies, polyps; occult- and
subtle immunodeficiency states; as well as dental diseases. Microorganisms are
more often recognized as secondary invaders during Chronic Rhinosinutitus

Bacterial involvement

Bacterial involvement

The bacteria involved in CRS are not the same as those
involved in acute rhinosinusitis. The following bacteria have been observed in
samples obtained via endoscopy and/or sinus puncture in those individuals with
chronic sinusitis:

•    Staphylococcus
aureus (both methicillin-susceptible S aureus MSSA and methicillin-

resistant S
aureus MRSA strains) 11

•       Coagulase-negative
staphylococci

•       H
influenzae

•       M
catarrhalis

•       S
pneumoniae

•       Streptococcus
intermedius

•       Pseudomonas
aeruginosa

•       Nocardia
species

•       Anaerobic
bacteria ( Peptostreptococcus, Prevotella, Porphyromonas, Bacteroides, 

Fusobacterium species 12 )

The exact roles of these microbes in the aetiology of
chronic sinusitis is uncertain, as opposed to their well-defined role in Acute
Rhinosinusitis.  Various researchers
disagree on the microbial etiology of chronic sinusitis and much of the debate
has to do with varying research methodology. Studies that have used appropriate
methods for recovery of anaerobes have demonstrated their prominence in chronic
sinusitis (50-70%), while many studies that utilised other techniques, failed
to isolate them. 13 The variety growth of microbes in samples can also be
attributed to patients’ previous exposure to various broad-spectrum
antibiotics.

 

During a study,
Jyonouchi et al inoculated Bacteriodes
Fragilis in rabbits by means of intra-sinus inoculation, thereby
successfully inducing Chronic sinusitis. Following the experiment,
Immunoglobulin (IgG)was then identified against B.Fragilis organism in the infected animals. 14 IgG antibodies
to other anaerobic organisms have been isolated in human cases of chronic
sinusitis as well15, thereby reinforcing the suspected role of anaerobes in
chronic sinusitis.

 

In most cases, CRS patients present with 1-6 different
pathogens per specimen, thereby confirming the condition as a result of mostly
polymicrobial infection12. Antibiotic administration; past vaccinations; and
normal flora suppressing the emergence of pathogenic species all influence the pathogens
found during isolates of chronic sinusitis.

 

In some cases, acute exacerbation of chronic sinusitis is
often caused by polymicrobial infections, with the predominant pathogens being
anaerobic bacteria. Aerobic bacteria usually associated with acute sinusitis (S
pneumoniae, H influenzae, M catarrhalis) may still emerge at a later stage of
the condition. 16

Gram-negative facultative and aerobic bacteria, such as P
aeruginosa, are mostly found in isolated post-endoscopic sinus surgery. 17

Fungal involvement

Endoscopic and/or sinus punctures of individuals suffering
from chronic sinusitis, have shown the following fungal pathogens as cause of
infection 18:

·        
Aspergillus
species

·        
Cryptococcus
neoformans

·        
Candida
species

·        
Sporothrix
schenckii

·        
Alternaria
species

 

Risk factors

The following conditions and risk factors are predisposing
elements in the development of chronic sinusitis:

·        
Anatomic abnormalities of the ostiomeatal
complex (septal deviation, concha bullosa, deviation of uncinate process,
Haller cells)

·        
Allergic rhinitis

·        
Aspirin sensitivity

·        
Asthma

·        
Nasal polyps

·        
Nonallergic rhinitis (eg, vasomotor rhinitis,
rhinitis medicamentosa, cocaine abuse)

·        
Defects in mucociliary clearance

·        
Nasotracheal intubation

·        
Nasogastric intubation

·        
Hormonal (eg, puberty, pregnancy, oral
contraception)

·        
Obstruction by tumor

·        
Immunologic disorders (eg, common variable
immunodeficiency, immunoglobulin A IgA deficiency, IgG subclass deficiency,
AIDS)

·        
Cystic fibrosis

·        
Primary ciliary dyskinesia, Kartagener syndrome

·        
Wegener granulomatosis

·        
Repeated viral upper respiratory tract
infections

·        
Smoking

·        
Environmental irritants and pollutants

·        
Gastroesophageal reflux disease (GERD). The
reflux of gastric contents may play a contributing role in some cases of CRS;
this relationship still needs to be better defined

·        
Periodontitis/significant dental disease

·        
Systemic diseases (ie, granulomatosis with
polyangiitis (Wegener granulomatosis), Churg-Strauss vasculitis, sarcoidosis)

·        
Yellow nail syndrome

REFERENCES

1.      
Slavin RG, Spector SL, Bernstein IL, Kaliner MA,
Kennedy DW, Virant FS, et al. The diagnosis and management of sinusitis: a
practice parameter update. J Allergy Clin Immunol. 2005 Dec. 116(6
Suppl):S13-47. Medline. Full Text.

2.      
Ah-See K. Sinusitis (acute). Clin Evid (Online).
2008 Mar 10. 2008:Medline.

3.      
Hwang PH, Getz A. Acute sinusitis and
rhinosinusitis in adults. UpToDate. Available at http://www.uptodate.com.
Accessed: June 7th, 2009.

4.      
Revai K, Dobbs LA, Nair S, Patel JA, Grady JJ,
Chonmaitree T. Incidence of acute otitis media and sinusitis complicating upper
respiratory tract infection: the effect of age. Pediatrics. 2007 Jun.
119(6):e1408-12. Medline.

5.      
Gwaltney JM Jr. Acute community-acquired
sinusitis. Clin Infect Dis. 1996 Dec. 23(6):1209-23; quiz 1224-5. Medline.

6.      
Brook I, Foote PA, Hausfeld JN. Frequency of
recovery of pathogens causing acute maxillary sinusitis in adults before and
after introduction of vaccination of children with the 7-valent pneumococcal
vaccine. J Med Microbiol. 2006 Jul. 55:943-6. Medline.

7.      
Brook I, Gober AE. Frequency of recovery of
pathogens from the nasopharynx of children with acute maxillary sinusitis
before and after the introduction of vaccination with the 7-valent pneumococcal
vaccine. Int J Pediatr Otorhinolaryngol. 2007 Apr. 71(4):575-9. Medline.

8.      
Jacobs MR, Bajaksouzian S, Windau A, Good CE,
Lin G, Pankuch GA, et al. Susceptibility of Streptococcus pneumoniae,
Haemophilus influenzae, and Moraxella catarrhalis to 17 oral antimicrobial
agents based on pharmacodynamic parameters: 1998-2001 U S Surveillance Study. Clin
Lab Med. 2004 Jun. 24(2):503-30. Medline.

9.      
Payne SC, Benninger MS. Staphylococcus aureus is
a major pathogen in acute bacterial rhinosinusitis: a meta-analysis. Clin
Infect Dis. 2007 Nov 15. 45(10):e121-7. Medline.

10.  
Brook I, Foote PA, Hausfeld JN. Increase in the
frequency of recovery of meticillin-resistant Staphylococcus aureus in acute
and chronic maxillary sinusitis. J Med Microbiol. 2008 Aug. 57:1015-7.
Medline.

11.  
Brook I, Foote PA, Hausfeld JN. Increase in the
frequency of recovery of meticillin-resistant Staphylococcus aureus in acute
and chronic maxillary sinusitis. J Med Microbiol. 2008 Aug. 57:1015-7.
Medline.

12.  
Brook I. Acute and chronic bacterial sinusitis.
Infect Dis Clin North Am. 2007 Jun. 21(2):427-48, vii. Medline.

13.  
Brook I. Bacteriology of chronic maxillary
sinusitis in adults. Ann Otol Rhinol Laryngol. 1989 Jun. 98(6):426-8.
Medline.

14.  
Incorvaia C, Leo G. Treatment of rhinosinusitis:
other medical options. Int J Immunopathol Pharmacol. 2010 Jan-Mar. 23(1
Suppl):70-3. Medline.

15.  
Brook I, Yocum P. Immune response to
Fusobacterium nucleatum and Prevotella intermedia in patients with chronic
maxillary sinusitis. Ann Otol Rhinol Laryngol. 1999 Mar. 108(3):293-5.
Medline.

16.  
Brook I, Foote PA, Frazier EH. Microbiology of
acute exacerbation of chronic sinusitis. Laryngoscope. 2004. 114:129-31.

17.  
Nadel DM, Lanza DC, Kennedy DW. Endoscopically
guided cultures in chronic sinusitis. Am J Rhinol. 1998 Jul-Aug. 12(4):233-41.
Medline.

18.  
Ferguson BJ. Definitions of fungal
rhinosinusitis. Otolaryngol Clin North Am. 2000 Apr. 33(2):227-35. Medline.

 

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