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Magnetic resonance imaging (MRI) was used in 52.6%
(n = 10) to delineate soft tissue involvement or intracranial
extension. Common areas of involvement were the masti-
cator space in 50% (n = 5), condylar bone marrow in 30%
(n = 3), parapharyngeal space in 40% (n = 4), nasopharynx
in 60% (n = 6), clivus in 50% (n = 5), and dural enhance-
ment in 40% (n = 4).
A subset of our patients had clival involvement, either as
contiguous spread or direct involvement. This subset was
noted to have poorer prognosis and required lengthier anti-
biotic therapy. Five patients had clival involvement on CT
or MRI. All patients with clival involvement had disease
that persisted after 6 weeks of antibiotics compared with
14.3% (n = 2) in those without (
P
= .002). Clival involve-
ment was also strongly associated with mortality and was
seen in 75% (n = 3) of mortalities.
Microbiology and Antibiotic Therapy
Ear swabs were routinely performed. Organisms were identi-
fied in only 63.2% (n = 12). The results of those with posi-
tive cultures are represented in
Figure 2
.
Pseudomonas
aeruginosa
was the main organism and was present in 75.0%
(n = 9). Multidrug-resistant
Pseudomonas
contributed to
33.3% (n = 3) of
P aeruginosa
isolates. Two patients with
positive cultures had light growth of
Staphylococcus epider-
midis
that were deemed as contaminants. There was no par-
ticular organism that occurred more often in the 3 patients
Table 1.
Inflammatory marker level comparison between disease progression and disease resolution groups.
Disease Resolved
Disease Progressed
P
Value
At diagnosis
TWC, mean,
3
10
9
/L
8.81
12.02
.118
CRP, mean, mg/L
41.60
34.00
.759
ESR, mean, mm/h
58.11
75.00
.357
2 weeks after antibiotics
TWC, mean,
3
10
9
/L
7.68
9.14
.300
CRP, mean, mg/L
13.80
29.57
.209
ESR, mean, mm/h
51.20
58.71
.669
6 weeks after antibiotics
TWC, mean,
3
10
9
/L
7.09
10.72
.014
CRP, mean, mg/L
17.89
27.00
.491
ESR, mean, mm/h
49.00
74.67
.120
Abbreviations: CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; TWC, total white cell count.
30
40
50
60
70
80
ESR
CRP
TWC
- - -
Progressed
___
Resolved
[mg/L]
[x10
9
/L]
[mm/hr]
0
10
20
Diagnosis
2 weeks
6 weeks
Figure 1.
Inflammatory marker trends during a period of antibiotic
treatment in the group in which disease resolved compared with
the group in which disease progressed. CRP, C-reactive protein;
ESR, erythrocyte sedimentation rate; TWC, total white cell count.
Table 2.
Frequency of minor and major CT scan findings.
No. (%)
Minor findings
EAC tissue swelling
16 (94.1)
EAC bony erosion
15 (88.2)
Mastoid involvement
16 (94.1)
Major findings
Infratemporal fossa
4 (23.5)
Temporomandibular joint
4 (23.5)
Parapharyngeal involvement
3 (17.6)
Nasopharyngeal involvement
1 (5.9)
Abbreviation: EAC, external auditory canal.
Pan-sensitive
66 7%
Pseudomonas
aeruginosa
(n=9)
.
Multi-drug resistant
Positive culture
(n=12)
33.3%
Klebsiella
pneumoniae
(n=1)
Contaminants
(n=2)
Figure 2.
Breakdown of positive ear swab culture results.
Loh and Loh
90