Anja M. Giesemann

Neurologic manifestations of E coli infection–induced hemolytic-uremic syndrome in adults

Objective: To describe the neurologic and neuroradiologic complications of Shiga toxin producing Escherichia coli infection (STEC)–associated hemolytic-uremic syndrome (HUS) in adults. Methods: All 52 adult patients with STEC O104:H4 infection cared for at Hannover Medical School during the outbreak in Germany through May–July 2011 are considered in this observational study. Forty-three of the 52 patients underwent a standard neurologic diagnostic procedure including clinical examination, Mini-Mental State Examination, and Glasgow Coma Scale Score. Thirty-six patients underwent EEG, and 26 had cerebral MRI, 9 of them repeatedly. Case records of 9 patients who had not been seen by a neurologist were analyzed retrospectively. Results: Forty-eight of the 52 patients had HUS. All but 1 of these showed neurologic symptoms. Focal neurologic signs like double vision, difficulties in finding words, or hyperreflexia were present in 23, additional deficits in orientation, attention, memory, or constructive abilities in 9, and marked impairment of consciousness in 15. MRI showed brainstem, midbrain, thalamus, corpus callosum, and white matter lesions in half of the patients, predominantly in diffusion-weighted images. The extent of MRI lesions did not correlate with clinical symptoms. General slowing but no focal alteration was found in half of the patients examined by EEG. Conclusion: Our findings suggest a toxic-metabolic pathology behind the neurologic impairment instead of multiple infarction due to microthrombosis. Future studies should aim to clarify if early antibiotic therapy or bowel cleansing might help to decrease the rate of neurologic complications in STEC-HUS.

The vestibulocochlear nerve: aplasia and hypoplasia in combination with inner ear malformations

AbstractObjectiveTo determine features of hypoplasia and aplasia of the vestibulocochlear nerve (VCN) in combination with inner ear malformations (IEMs).MethodsIndex cases were retrospectively selected from all IEMs collected since 1995. CT and MRI data were reviewed by two neuroradiologists. The number and thickness of visible nerves in the cerebellopontine angle cistern and inside the internal auditory canal (IAC) were analysed.ResultsMR images for 176 patients with IEMs were analysed. Labyrinthine aplasia and otocyst deformity showed 100% correlation, and IAC malformations exhibited 92% correlation with VCN aplasia. Cochlear aplasia, complete aplasia of the semicircular canals, severe cochlear hypoplasia, common cavity, incomplete partition type 1 and mild cochlear hypoplasia showed decreasing degrees of correlation with hypoplasia of the VCN. The remaining types of IEM did not demonstrate VCN hypoplasia.ConclusionsCertain forms of IEM show 100% correlation with hypoplasia or aplasia of the VCN, while others correlate less strongly and some do not usually exhibit VCN hypoplasia. MRI should always be carried out for those forms often correlated with VCN hypoplasia.Key Points• Vestibulocochlear nerve deficiency can be strongly suspected in certain inner ear malformations • Bony cochlear aplasia and cochlear nerve aplasia are strongly correlated • In semicircular canal aplasia, hypoplasia of the vestibular nerve can be found • Before cochlear implantation, the type of any IEM should be fully understood

Persistent Petrosquamosal Sinus: High Incidence in Cases of Complete Aplasia of the Semicircular Canals

PURPOSE To determine the frequency and to describe the morphologic characteristics and associated skull base anomalies of the petrosquamosal sinus (PSS) in cochlear implant candidates with complete aplasia of the semicircular canals (SCCs). MATERIALS AND METHODS Ethics committee approval was obtained. Index cases were retrospectively selected from an electronic database in which all inner ear malformations observed in patients presenting to a tertiary referral center between 1995 and 2010 were collected. Computed tomography (CT) data were reviewed by neuroradiologists. Clinical consequences of the neuroradiologic findings were analyzed. The Pearson χ(2) test and the Mann-Whitney U test were used to determine significant differences between the number of PSSs observed in cases of complete aplasia of the SCCs and the number observed in cases of other types of inner ear malformations. RESULTS Inner ear malformations were analyzed in 241 patients. Thirty-one patients (13%) with bilateral SCC aplasia were identified. Among 31 patients, a uni- or bilateral PSS was observed in 25 (81%). In the ears with SCC aplasia, a PSS was observed in 40 (65%) of 62. The three cases in which these PSS occupy the largest area correlate with bilateral absence of the jugular foramen. In seven of eight ears with a PSS, the PSS inhibited surgical exposure or resulted in accidental opening of the PSS during surgery. In all other patients with inner ear malformations, a PSS was observed in 39 (9%) of 412 ears only. CONCLUSION The PSS presents a risk for cochlear implant surgery that can be detected by the neuroradiologist in advance. Venous CT angiography is advisable in certain cases. The previous assumption that a persistent PSS is encountered more frequently in cases of skull base deformity can be affirmed in the special situation of complete aplasia of the SCCs.

Appearance of hypoplastic cochleae in CT and MRI: a new subclassification

IntroductionHypoplastic cochleae are among the inner ear malformations more frequently encountered by radiologists; little detailed information is available on these, however. We present the first large series of hypoplastic cochleae and document imaging findings to better characterize this anomaly radiologically.MethodsWe used our electronic database to search for inner ear malformations described between 1995 and 2009 and extracted 81 ears (of 47 patients) with hypoplastic cochleae out of 289 patients with inner ear malformations. Two neuroradiologists evaluated the available CT and MRI data. Measurements of all inner ear structures were performed. Accompanying findings were listed.ResultsCochlear hypoplasia (58 ears, 32 patients) often involves not only the apical turn being reduced in size but also the basal turn being smaller in length. Additionally, 11 ears (eight patients) of hypoplastic cochleae with only a basal turn and five ears (four patients) of cochleae with only a small bud were identified. Non-classifiable hypoplastic cochleae (seven ears, five patients) were those with either a rudimentary or an absent basal turn or a “dwarf appearance” with no further partition.ConclusionsThe term “hypoplastic cochlea” is very general; a further division into severe and less severe forms based on the length and existence of cochlea turns is possible and can help enhance the comparison of CI outcome data. Measurements can help the less experienced radiologist to detect them more easily.

Improved imaging of Cochlear nerve hypoplasia using a 3-tesla variable flip-angle turbo spin-echo sequence and a 7-cm surface coil

Magnetic resonance imaging of the temporal bone has an important role in decision making with regard to cochlea implantation, especially in children with cochlear nerve deficiency. The purpose of this study was to evaluate the usefulness of the combination of an advanced high‐resolution T2‐weighted sequence with a surface coil in a 3‐Tesla magnetic resonance imaging scanner in cases of suspected cochlear nerve aplasia.

Radiological diagnosis of incomplete partition type I versus type II: significance for cochlear implantation

AbstractObjectivesTo investigate an extended cohort of patients with incomplete partition (IP) and examine the adequacy of the existing classifications based on radiological criteria and on their implications for cochlear implantation.MethodsPatients with IP admitted to a tertiary referral centre during the period 2000–2010 were retrospectively examined. The subjects were initially classified into IP-I, IP-II and atypical cases. For cochlear implant recipients relevant aspects were analysed.ResultsEighty-three ears (49 patients) with IP were found, 19 with IP-I, 54 with IP-II and 10 atypical. Thirty-three patients received a cochlear implant (11 with IP-I, 19 with IP-II and three atypical) achieving heterogeneous though mostly promising results. Cerebrospinal fluid gushing was the commonest surgical complication, particularly in cases of IP-I. In general, patients with IP-II performed better than those with IP-I.ConclusionsCochlear implantation promises adequate hearing rehabilitation for most patients with IP. As we move from IP-I to IP-II better results and lower risk for gushing shall be expected. Based on radiological findings we suggest a modified classification into IP-I, atypical IP-I (with large vestibular aqueduct (LVA) and better partition), IP-II (Mondini deformity) and atypical IP-IIa (without LVA) and b (without LVA but with semicircular canal dysplasia).Key Points• Radiological (CT and MR) features are of crucial importance for cochlear implantation • Imaging can identify two types of incomplete cochlear partition and atypical cases • Detailed pre-operative radiological assessment can help predict complications and outcome • A more comprehensive radiological classification of these anomalies is proposed

Quantitative MRI shows cerebral microstructural damage in hemolytic–uremic syndrome patients with severe neurological symptoms but no changes in conventional MRI

IntroductionSevere neurological symptoms in Shiga toxin-producing Escherichia coli infection associated hemolytic–uremic syndrome (STEC–HUS) are often accompanied by none or only mild alterations of cerebral magnetic resonance imaging (MRI). This study aims to analyze if quantitative MRI is able to reveal cerebral pathological alterations invisible for conventional MRI.MethodsIn nine patients with STEC–HUS associated severe neurological symptoms but inconspicuous cerebral MRI findings maps of the parameters T2 relaxation time, relative proton density (PD), apparent diffusion coefficient (ADC), and fractional anisotropy (FA) were generated. Quantitative values of these parameters were measured at the basal ganglia, thalamus, and white matter of the frontal and parietal lobe and compared to those of nine age- and sex-matched controls.ResultsSignificant T2 prolongation (p < 0.01) was found in the basal ganglia of all patients compared to controls. PD and ADC were not significantly altered. A significant reduction of FA in patients was seen at caput nuclei caudati (p < 0.01).ConclusionProlonged T2 relaxation time indicates cerebral microstructural damages in these patients despite their inconspicuous MRI findings. T2 relaxometry could be used as a complementary tool for the assessment of metabolic–toxic brain syndromes.

From labyrinthine aplasia to otocyst deformity.

IntroductionInner ear malformations (IEMs) are rare and it is unusual to encounter the rarest of them, namely labyrinthine aplasia (LA) and otocyst deformity. They do, however, provide useful pointers as to the early embryonic development of the ear. LA is characterised as a complete absence of inner ear structures. While some common findings do emerge, a clear definition of the otocyst deformity does not exist. It is often confused with the common cavity first described by Edward Cock. Our purpose was to radiologically characterise LA and otocyst deformity.MethodsRetrospective analysis of CT and MRI data from four patients with LA or otocyst deformity. Middle and inner ear findings were categorised by two neuroradiologists.ResultsThe bony carotid canal was found to be absent in all patients. Posterior located cystic structures were found in association with LA and otocyst deformity. In the most severe cases, only soft tissue was present at the medial border of the middle ear cavity. The individuals with otocyst deformity also had hypoplasia of the petrous apex bone.ConclusionsThese cases demonstrate gradual changes in the two most severe IEMs. Clarification of terms was necessary and, based on these findings, we propose defining otocyst deformity as a cystic structure in place of the inner ear, with the cochlea, IAC and carotid canal absent. This condition needs to be differentiated from the common cavity described by Edward Cook. A clear definition of inner ear malformations is essential if outcomes following cochlear implantation are to be compared.

Neurological Sequelae in Adults After E coli O104: H4 Infection-Induced Hemolytic-Uremic Syndrome.

AbstractIn an outbreak of shiga toxin-producing Escherichia coli infections and associated hemolytic-uremic syndrome (STEC O104:H4) in Germany in the year 2011 neurological complications in adult patients occurred unexpectedly frequent, ranging between 48% and 100% in different patient groups. Few is known about the long-term effects of such complications and so we performed follow-up exams on 44 of the patients treated for STEC-HUS at Hannover Medical Scool in this observational study. Standardized follow-up exams including neurological and neuropsychological assessments, laboratory testing, magnetic resonance imaging (MRI), and EEG were carried out. Subgroups were examined 2 (n = 34), 7 (n = 22), and 19 (n = 23) months after disease onset. Additionally, at the 19-month follow-up, quality of life, sleep quality, and possible fatigue were assessed.Nineteen months after disease onset 31 patients were reassessed, 22 of whom still suffered from symptoms such as fatigue, headache, and attention deficits. In the neuropsychological assessments only 39% of the patients performed normal, whereas 61% scored borderline pathological or lower. Upon reviewal, the follow-up data most prominently showed a secondary decline of cognitive function in about one-quarter of the patients. Outcome was not related to treatment or laboratory data in the acute phase of the disease nor length of hospitalization. Prognosis of STEC-HUS associated brain dysfunction in adults with regard to severity of symptoms is mostly good; some patients however still have not made a full recovery. Patients’ caretakers have to be aware of possible secondary decline of brain function as was observed in this study.

Inner ear anatomy in Waardenburg syndrome: radiological assessment and comparison with normative data.

OBJECTIVE As patients with Waardenburg syndrome (WS) represent potential candidates for cochlear implantation, their inner ear anatomy is of high significance. There is an ongoing debate whether WS is related to any inner ear dysplasias. Our objective was to evaluate radiologically the inner ear anatomy in patients with WS and identify any temporal bone malformations. METHODS A retrospective case review was carried out in a tertiary, referral center. The high resolution computed tomography (HRCT) scans of the temporal bone from 20 patients (40 ears) with WS who were managed for deafness in a tertiary referral center from 1995 to 2012 were retrospectively examined. Measurements of 15 different inner ear dimensions, involving the cochlea, the vestibule, the semicircular canals and the internal auditory meatus, as well as measurements of the vestibular aqueduct, were performed independently by two neuroradiologists. Finally, we compared the results from the WS group with a control group consisting of 50 normal hearing subjects (100 ears) and with previously reported normative values. RESULTS Inner ear malformations were not found in any of the patients with WS. All measured inner ear dimensions were within the normative values compiled by our study group as well as by others. CONCLUSIONS Inner ear malformations are not characteristic for all types of WS; however, certain rare subtypes might be related to inner ear deformities. Normative cochleovestibular dimensions that can help in assessing the temporal bone anatomy are provided.