Harry R. F. Powell

Nationwide study of haemolytic uraemic syndrome: clinical, microbiological, and epidemiological features

AIMS To establish the incidence and aetiology of haemolytic uraemic syndrome (HUS) in Australia and compare clinical and microbial characteristics of sporadic and outbreak cases. METHODS National active surveillance through the Australian Paediatric Surveillance Unit with monthly case notification from paediatricians, July 1994 to June 1998. Children under 15 years presenting with microangiopathic haemolytic anaemia, thrombocytopenia, and acute renal impairment were identified. RESULTS Ninety eight cases were identified (incidence 0.64 per 105 children <15 years/annum and 1.35 per 105 children <5 years/annum). Eighty four were associated with diarrhoea (64 sporadic, 20 constituting an outbreak) and 14 were atypical. Shiga toxin producingEscherichia coli (STEC) O111:H− was the most common isolate in sporadic HUS and caused the outbreak. However O111:H− isolates from outbreak and sporadic cases differed in phage type and subtyping by DNA electrophoresis. STEC isolates from sporadic cases included O26:H−, O113:H21, O130:H11, OR:H9, O157:H−, ONT:H7, and ONT:H−. STEC O157:H7 was not isolated from any case. Only O111:H− isolates produced both Shiga toxins 1 and 2 and possessed genes encoding E coli attaching and effacing gene (intimin) and enterohemolysin. Outbreak cases had worse gastrointestinal and renal disease at presentation and more extrarenal complications. CONCLUSIONS Linking national surveillance with a specialised laboratory service allowed estimation of HUS incidence and provided information on its aetiology. In contrast to North America, Japan, and the British Isles, STEC O157:H7 is rare in Australia; however, non-O157:H7 STEC cause severe disease including outbreaks. Disease severity in outbreak cases may relate to yet unidentified virulence factors of the O111:H− strain isolated.

A Comparative Study of Audiologic Outcomes for Two Transcutaneous Bone-Anchored Hearing Devices.

Objective: In 1977, Tjellstrom et al. used the concept of osseointegration and implanted patients with a titanium screw as part of the first bone-anchored hearing solution. Despite good hearing outcomes with the percutaneous device, there has been a drive for the development of transcutaneous bone conduction systems because of soft tissue complications, aesthetics, and loss or failure of the abutment. This study compares audiologic and quality of life questionnaire outcomes (author-designed questionnaire) for two transcutaneous bone conduction implants. Study Design: Cross-sectional cohort study. Setting: Tertiary referral hospital and national audiology service. Patients: Twelve patients, 10 children and two adults. Six recipients of each device. Main Outcome Measures: Pure-tone audiometry, aided thresholds, speech discrimination scores, and quality of life questionnaire results. Results: The unaided four-frequency average air conduction for affected ears was 60.8 dB HL for the Attract group and 57.8 dBHL for the Sophono group; these improved to mean aided thresholds of 30.6 dB HL and 29.8 dB HL, respectively. Therewas no statistical difference between the speech discrimination scores for the two devices in quiet at 55 dB SPL (p = 0.33) orin noise (p = 0.87). Conclusion: Both systems provide audiologic benefit compared with the unaided situation. Comparing small numbers of patients, there was no significant difference in aided thresholds or speech discrimination scores between these two transcutaneous bone-anchored implants. All Attract and Sophono users reported improvement in quality of life and would recommend their device to others in a similar situation.

Cochlear Implant Outcomes in Cochlea Nerve Aplasia and Hypoplasia.

Objective: To assess cochlear implant (CI) outcomes, and factors affecting outcomes, for children with aplasia/ hypoplasia of the cochlea nerve. We also developed a new grading system for the nerves of the internal auditory meatus (IAM) and cochlea nerve classification. Study Design: Retrospective patient review. Setting: Tertiary referral hospital and cochlear implant program. Patients: Children 0 to 16 years inclusive with a CI who had absent/hypoplastic cochlea nerve on magnetic resonance imaging (MRI). Intervention: Cochlear implant. Main Outcome Measures: MRI, trans-tympanic electrical auditory brainstem response, intraoperative electrical auditory brainstem response, Neural Response Telemetry, Categories of Auditory Perception score, Main mode of communication. Results: Fifty CI recipients (26 males and 24 females) were identified, 21 had bilateral CIs, 27 had developmental delay. MRI showed cochlea nerve aplasia in 64 ears, hypoplasia in 25 ears, and a normal nerve in 11 ears. Main mode of communication was analyzed for 41 children: 21 (51%) used verbal language (15 speech alone, 5 speech plus some sign, 1 bilingual in speech and sign), and 20 (49%) used sign language (10 sign alone, 9 sign plus some speech, 1 tactile sign). Seventy-three percent of children used some verbal language. Cochlea nerve aplasia/ hypoplasia and developmental delay were both significant factors affecting main mode of communication. Categories of Auditory Performance scores were available for 59 CI ears; 47% with CN Aplasia (IAM nerve grades 0–III) and 89% with CN hypoplasia (IAM nerve grade IV) achieved Categories of Auditory Performance scores of 5 to 7 (some verbal understanding) (p = 0.003). Conclusion: Our results are encouraging and useful when counselling families regarding the likelihood of language outcomes and auditory understanding.

Outcomes of Transmastoid Surgery for Superior Semicircular Canal Dehiscence Syndrome.

Objective: To present the management strategy and outcomes for our series of superior semicircular canal dehiscence syndrome (SSCDS) patients. Study Design: Retrospective cross-sectional study. Setting: Tertiary referral center. Patients: Thirty-seven consecutive patients referred from June 2011 to January 2015. Diagnosis of SSCDS based on presence of classical symptoms, computerized tomography, and concordant reduction in cervical vestibular evoked myogenic potentials. Interventions: Transmastoid resurfacing or plugging. Main Outcome Measures: Pre- and postoperative pure tone audiometry. Nine item questionnaire grading pre- and postoperative symptom severity. Results of a short semi-structured telephone survey. Results: Twenty surgical patients: 13 women and 7 men. Mean age 52 years 6 months. Eighteen patients underwent transmastoid resurfacing and two underwent transmastoid plugging. Three of those who initially had resurfacing but had ongoing SSCD symptoms, subsequently had transmastoid plugging with complete resolution of third window symptoms. From the questionnaire there was improvement in mean scores for 8 of 9 of the SSCD symptoms, with statistically significant improvement in 6 of 9. Conclusions: Management strategies and surgical techniques continue to evolve for SSCDS. We currently offer transmastoid resurfacing having informed patients of a 25% possibility of incomplete symptom resolution, and explain that plugging can be performed as a “second stage,” if necessary. However, as we accrue more experience and there is more evidence from the literature we are considering whether to offer transmastoid plugging as our primary surgical procedure. In our experience, patients with multiple vestibular pathologies or atypical vestibular symptoms are the ones for whom SSCD surgery has not been curative, although they do report improvement in their SSCD symptoms.

Mutations and altered expression of SERPINF1 in patients with familial otosclerosis

Otosclerosis is a relatively common heterogenous condition, characterized by abnormal bone remodelling in the otic capsule leading to fixation of the stapedial footplate and an associated conductive hearing loss. Although familial linkage and candidate gene association studies have been performed in recent years, little progress has been made in identifying disease-causing genes. Here, we used whole-exome sequencing in four families exhibiting dominantly inherited otosclerosis to identify 23 candidate variants (reduced to 9 after segregation analysis) for further investigation in a secondary cohort of 84 familial cases. Multiple mutations were found in the SERPINF1 (Serpin Peptidase Inhibitor, Clade F) gene which encodes PEDF (pigment epithelium-derived factor), a potent inhibitor of angiogenesis and known regulator of bone density. Six rare heterozygous SERPINF1 variants were found in seven patients in our familial otosclerosis cohort; three are missense mutations predicted to be deleterious to protein function. The other three variants are all located in the 5′-untranslated region (UTR) of an alternative spliced transcript SERPINF1-012. RNA-seq analysis demonstrated that this is the major SERPINF1 transcript in human stapes bone. Analysis of stapes from two patients with the 5′-UTR mutations showed that they had reduced expression of SERPINF1-012. All three 5′-UTR mutations are predicted to occur within transcription factor binding sites and reporter gene assays confirmed that they affect gene expression levels. Furthermore, RT-qPCR analysis of stapes bone cDNA showed that SERPINF1-012 expression is reduced in otosclerosis patients with and without SERPINF1 mutations, suggesting that it may be a common pathogenic pathway in the disease.

Post-Stapedectomy Granuloma: A Devastating Complication

Introduction: While the endoscope has long been used in surgery, its adoption has been slower in ear surgery due to the narrowness, relative inaccessibility and delicateness of the ear. However, we have successfully used the endoscope in transcanal endoscopic ear surgery (TEES) as well as a combined transcanal-transcortical endoscopic approach. TEES is a less invasive procedure used initially to remove primary cholesteatomas located in the antrum and/or attic through the ear canal without the need for a large, invasive retroauricular incision. Moreover TEES can also now be used to remove residual and recurrent cholesteatomas if they are located in the attic and/or antrum. The combined transcanal-transcortical endoscopic approach is also being used to successfully remove recurrent cholesteatomas extending into the mastoid even after removal of the primary cholesteatoma via a transcortical mastoidectomy. Therefore the endoscopic approach should be considered as an option in the removal of residual and recurrent cholesteatomas regardless of their location.

An immunocompetent patient presenting with severe nasal herpes simplex: a case report

BackgroundCutaneous manifestations of common viral pathogens or disease processes more common in immunocompromised individuals need to be considered when assessing patients with unusual clinical presentations. To our knowledge this is the first published case of severe nasal herpes simplex infection in an immunocompetent individual.Case PresentationA 27-year-old Burmese woman presented to the Accident and Emergency department with increasing facial pain and fever having sustained local trauma to her nose 7 days prior. Despite 5 days of treatment with oral Amoxicillin 500 mg TDS and topical Neomycin sulphate cream the patient developed blistering followed by de-epithelialisation of the nasal skin.ConclusionHerpes simplex virus is very common, occasionally patients present with severe and potentially disfiguring lesions. This case is important for any sub specialists dealing with facial lesions. Early accurate diagnosis can improve outcome and reduce long-term morbidity.

Cochlear implantation in X-linked deafness – How to manage the surgical challenges

Objective and importance: In children with X-linked deafness, cochlear malformations challenge the implant surgeon to avoid electrode insertion into the internal auditory meatus and prevent a continuous cerebrospinal fluid (CSF) leak. We describe our experience of cochlear implantation (CI) in two children with profound hearing loss secondary to X-linked deafness, highlighting safer operative techniques to avoid potential complications. Clinical presentation: Descriptive cases of two children with X-linked deafness (patient 1 and patient 2) undergoing CI. Peri-operative imaging and work-up to surgery are discussed. Specific operative considerations, post-operative complications and subsequent audiological performance are highlighted. Technique: In each case, intra-operative fluoroscopic imaging ensured intra-cochlear insertion of electrodes. Expected CSF gusher was seen in each case which was initially controlled by packing around the cochleostomy and array with temporalis muscle and fascia. Patient 1 developed post-operative meningitis secondary to continuous CSF leak. We avoided further significant CSF leak by planning staged procedures for patient 2, with obliteration of the middle ear cleft and external ear canal (EAC) at the time of implantation. In both patients, bilateral implantation successfully provided hearing thresholds of less than 35 dB in both ears at routine follow up. Conclusions: When planning for CI in children with radiological features of X-linked deafness, intra-operative imaging should be utilized to ensure correct electrode positioning. Traditional methods of stopping a CSF gusher may not suffice. We therefore encourage additional surgical obliteration of the middle ear space and EAC to avoid persistent CSF leak and its associated complications.

Novel surgical management of a laryngeal granular cell tumour

Granular cell tumour (GCT) is a rare benign tumour occurring, most commonly, in the head and neck. Multiple tumours occur in 5–16% of patients. These tumours are chemo-radio-resistant and have high recurrence rates despite their benign histopathological features. Traditional management, depending on access, involves total tumour resection with wide margins due to the high rates of recurrence with incomplete resection. We present a patient with two synchronous GCTs of their upper airway: in the larynx and the trachea. Complete excision of the supraglottic lesion would have rendered the patients larynx incompetent. Therefore, after multidisciplinary team (MDT) discussion, and following a discussion with the patient regarding the risks and benefits, a novel surgical management approach was agreed. Subtotal CO2 laser excision of the upper GCT was performed enabling functional organ preservation. A subsequent procedure was required when the patient became symptomatic due to tumour recurrence.

Sensorineural Hearing Loss in Hajdu-Cheney Syndrome

Hajdu-Cheney Syndrome (HCS) is a rare connective tissue disorder which was first described in 1948 [1]. Less than 50 cases have been reported in the medical literature. The majority of cases are sporadic however an autosomal dominant inheritance pattern has been recognized [2-4]. The main characteristics of HCS include acroosteolysis, shortened terminal phalanges, short stature, joint hypermobility, as well as micrognathia. Cranial findings include open cranial suture lines, basilar invagination, posterior fossa abnormalities and hydrocephalus [2,4]. Conductive hearing loss has been reported in association with HCS [2,4,5], however sensorineural hearing loss has never been described in the literature. In particular the correlation between the course of the eighth cranial nerve and its mechanical stretching as a possible cause of sensorineural hearing loss remains unclear.