Pseudomonas aeruginosa meningitis following head injury after cochlear implantation: A case report

History and examination

A 7-year-old boy from China was admitted to our hospital with the chief complaint of intermittent fever and headache for 6 months. Six years ago, the child underwent CI for the right ear due to severe binaural sensorineural deafness and incomplete partition type I (IP-I) malformation. On the third day after the operation, he fell down from the bed and cerebrospinal fluid (CSF) otorrhea in the right ear occurred, so a repair of cerebrospinal otorrhea for the right ear was performed, and meanwhile positive measures for the CSF leak, such as packing with muscle and fascia, were also taken during the operation. One month after the operation, the cochlear implant was started up and its effect of assisting hearing was very good. After that, he had never suffered from any discomforts.

Six months ago, the child began to have fever and headache under no circumstances of conspicuous precipitating factors, accompanied by abdominal pain. The highest body temperature had exceeded 39°C. He had no symptoms of nausea, vomiting, convulsion, insomnia, otorrhea, retroauricular swelling and pain, dizziness, rotary vision, deviated mouth and abnormal facial sensation. After systematic examination in local hospital, Pseudomonas aeruginosa was found in CSF and shown sensitivity to meropenem. The above-mentioned symptoms got remission after intravenous injection of meropenem for about 2 weeks but reappeared within 2 weeks after stopping the drug. Such a condition lasted about half a year.

For the complete rehabilitation, the child came to our hospital. The physical examination showed positive meningeal irritation sign, negative Hoffmann sign and negative Babinski sign. The results of blood routine tests (Table 1), CSF examination (Table 2) and different-layer CT images (Figure 1(a)–(e)) supported Pseudomonas aeruginosa infection. The cochlear implant infection was suspected. The right cochlear implant removal and middle ear exploration were thus performed under general anesthesia on April 7, 2017 after the indicators of blood routine test and body temperature returned to normal.

OPEN IN VIEWER

Table 1.

The results of blood routine tests at different time points before operation.

Items	Reference range	Date
		March 17	March 18	March 22	March 23	March 30	April 6
White blood cell (WBC, ×109/L)	3.5–9.5	13.76	8.55	25.44	7.86	7.14	7.22
Neutrophil % (NE%)	40–75	81.1	67.5	93.5	61.9	49.2	49.2
Lymphocyte % (LY%)	20–50	13.7	20.1	4.0	23.5	34.5	34.5
Neutrophils (NE, ×109/L)	1.8–6.3	11.17	5.78	23.80	4.86	3.52	3.55
Platelets (PLT, ×109/L)	100–300	566	489	575	458	683	640
Temperature (T, °C)	–	38.7	38.6	38.9	37.5	36.6	36.5

OPEN IN VIEWER

Table 2.

The testing results of CSF samples obtained by lumbar puncture.

Items	Reference range	March 24	April 7
Appearance	–	Colorless, transparent	Colorless, transparent
Pandy test	Negative	Positive	Negative
Total number of cells (µL)	–	1272.00	22.00
WBC (µL)	0–15	1272	22
Classified mononuclear cells (%)	–	13.00	82.00
Classified multiple nuclear cells (%)	–	87.00	18.00
Chlorine (mmol/L)	120–132	123.4	120.9
Glucose (mmol/L)	2.50–4.50	0.87	2.48
Micro total protein (mg/dL)	15–45	115	25

OPEN IN VIEWER

Figure 1.

Different-layer CT images of the temporal bone in the child before the operation. (a) Bilateral IP-I malformations (the arrow represents the enlarged internal auditory canal); (b) CI in the right ear (the arrow represents the vestibular aqueduct); (c) presence of soft tissue density shadows in the middle ear tympanum and mastoid; (d) the electrode of electrical cochlea in the right cochlea; (e) presence of soft tissue shadows around the electrode.

Operation procedures

The mastoid was opened intraoperatively along the previous incision. It could be seen that the formation of mastoid new bones covered the original mastoid cavity. The mastoid new bones were partly grinded to make the mastoid cavity exposed, and the cochlear electrode wire was seen in the operative cavity. The implant was positioned along the electrode wire, and then the cochlear electrode wire was cut off near the facial nerve recess. The facial nerve recess was opened to expose the round window after implantation, reference electrode and gelatin sponge in the facial nerve recess were taken out. Finally, the connective tissue around the round window was removed, the inserting electrode was taken out, and the round window and mastoid were closed. The CSF obtained by lumbar puncture was colorless and transparent, and 5 mL was used for biochemical test and bacterial culture. Additionally, the cochlear implant and the inserting electrode were used for bacterial culture.

Postoperative condition

Postoperatively, the bacterial cultures of CSF, cochlear implant and inserting electrodes all suggested Pseudomonas aeruginosa. Cefepime and mannitol were used to control the symptoms. The body temperature of the child was decreased below 37.5°C within 2 weeks after the operation, and the symptoms, such as headache and abdominal pain, disappeared. CSF routine and biochemistry indicators returned to normal. During 20-month follow-up visit, the child did not suffer any discomforts, such as pain, swelling, rupture and purulence in the local skin, earache, headache, tinnitus, dizziness, facial paralysis, otorrhea, etc.

Regarding the future hearing reconstruction, it is almost impossible to successfully implant the cochlea on the same side to achieve the good hearing effect under the circumstances of no severe complications, thus the contralateral cochlear implantation will be taken into more consideration. If this method is not applicable, we will consider the auditory brainstem implant or updated techniques to reconstruct the hearing.