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Biomedical subjects

Lionel Kowal

Publications and source records attributed to Lionel Kowal.

15 recordsLinked to original sources
PubMed2006

Chiari 1 malformation presenting as strabismus.

INTRODUCTION: Strabismus has been previously reported as a rare presenting feature of the Type 1 Chiari malformation. CASE REPORTS: We report a case series of twelve patients with Chiari 1 malformations with either strabismus or diplopia as part of their initial presentation. Ten patients had diplopia at the time of presentation, while 2 young children (ages 2 and 6) presented with esotropia without complaints of diplopia. Of the 10 patients with diplopia, 7 were constantly or frequently tropic while 3 had symptomatic phorias. One or more unusual features of the strabismus led to further investigations and the diagnosis of Chiari in these patients. The most common oculomotor disturbance was a comitant esotropia. Most patients were managed with prism glasses. One patient had strabismus surgery as primary treatment with early orthotropia. Three patients underwent neurosurgical decompression, with minimal improvement of their strabismus; one of these underwent subsequent successful strabismus surgery. CONCLUSIONS: Chiari 1 malformation may present with strabismus or diplopia as the major finding. Associated neurological features may be nonspecific (e.g., headache), subtle (e.g., gaze-evoked nystagmus), or delayed. Although neurosurgery may be required in some cases, primary strabismus management (surgical or prismatic correction) can be successful, particularly when strabismus is the lone (or sole specific) finding.

Adolescent↗
PubMed2005

Refractive surgery and strabismus.

This review discusses the potential for strabismic complications after refractive surgery for hyperopia, myopia, anisomyopia, astigmatism and monovision, and how to avoid these complications. Guidelines are given for assessing patients with strabismus seeking refractive surgery. Screening tests are suggested that lead to stratification of refractive surgery patients into different risk groups each warranting a different intensity of evaluation.

Adult↗
PubMed2004

Anti-GM1 antibodies: the cause of otherwise unexplained ophthalmoplegias?

PURPOSE: To report four patients with otherwise unexplained ophthalmoplegia who were found to have elevated levels of anti-GM1 antibodies. METHODS: Retrospective chart evaluation of 50 consecutive patients with otherwise unexplained ophthalmoparesis. All patients were tested for anti-GM1 antibodies. RESULTS: Six out of 50 cases (12%) were found to have elevated anti-GM1 antibodies, far greater than the 2.7% found in the general population. Four of the subjects with elevated anti-GM1 antibodies are reported. CONCLUSION: Although the mechanism and relationship between the neural antibodies and ophthalmoparesis is not understood, it is proposed that the presence of anti-GM1 antibodies should be considered in cases of otherwise unexplained ophthalmoplegia.

Adolescent↗
PubMed2004

Clinical application of the multifocal visual evoked potential.

BACKGROUND: Measures of visual function thresholds such as visual acuity and visual fields are generally dependent on subjective responses and assume maintenance of fixation, attention and motivation. In the young, elderly, cognitively impaired or malingering populations, such measures may be inaccurate or difficult to obtain. The Visual Evoked Response Imaging System (VERIS) has been claimed to give more objective topographic recordings of retinal and cortical function. This paper aims to explore the adequacy of this technique in four unusual, unrelated, clinically difficult cases. METHODS: Multifocal visual evoked potentials (mfVEPs) recorded on the VERIS System 3.01 are used to assess visual function in four cases with contradictory clinical findings or unreliable subjective responses. RESULTS: Patient 1 had sustained a head injury and had normal ocular and pupil examination but light perception in the right eye and 6/5 acuity in the left. Multifocal VEPs showed a marked depression of the right visual field with little macular response. Patient 2 had sustained a head injury, had a left field hemianopia, possible macular sparing and loss of much of the right field, reduced but variable visual acuities, good near vision and normal ocular fundi. Multifocal VEPs showed a severe depression in both visual fields (L more than R) with little macular response. Patient 3 had a left optic nerve meningioma and experienced great difficulty with visual field assessment. mfVEPs showed a bilateral depression in the superior field particularly the left field, with a larger deficit in the left eye. Patient 4 had unexplained visual acuity and peripheral field deficits. mfVEP results were inconclusive in this case. DISCUSSION: Where there is difficulty performing traditional techniques or conflicting clinical findings, mfVEPs may provide additional objective information to aid in the assessment of patients.

Adult↗
PubMed2003

Heterozygous mutations of the kinesin KIF21A in congenital fibrosis of the extraocular muscles type 1 (CFEOM1).

Congenital fibrosis of the extraocular muscles type 1 (CFEOM1; OMIM #135700) is an autosomal dominant strabismus disorder associated with defects of the oculomotor nerve. We show that individuals with CFEOM1 harbor heterozygous missense mutations in a kinesin motor protein encoded by KIF21A. We identified six different mutations in 44 of 45 probands. The primary mutational hotspots are in the stalk domain, highlighting an important new role for KIF21A and its stalk in the formation of the oculomotor axis.

Amino Acid Sequence↗
PubMed2003

Hereditary hyperferritinemia-cataract syndrome: prevalence, lens morphology, spectrum of mutations, and clinical presentations.

OBJECTIVES: To provide a comprehensive description of the clinical presentations, cataract morphology, and molecular basis of hereditary hyperferritinemia-cataract syndrome (HHCS) in 4 Australian pedigrees and to estimate its prevalence. METHODS: All known cases of HHCS in southeastern Australia were ascertained. Family members provided a medical history and underwent physical examination, lens photography, and venipuncture for measurement of serum ferritin levels and DNA extraction. Sequence analysis of the iron-responsive element of the ferritin light chain on chromosome 19q13.3-qter was performed. RESULTS: We investigated 26 affected individuals from 5 Australian pedigrees. Two pedigrees with HHCS ascertained independently were subsequently found to form 1 large kindred carrying the mutation A40G. The minimum estimated prevalence of HHCS is 1/200000. One pedigree had the mutation G32C. Among 2 smaller pedigrees studied, one carried a novel mutation (C39A), and the other was identified through the 2-year-old propositus with cataract but no positive family history. The latter case was shown to be due to a de novo mutation (G32U). All cataracts were highly distinctive in morphology, consisting of slowly progressive flecks, vacuoles, and distinctive crystalline deposits scattered predominantly in the lens cortex but also in the nucleus. Eight of 18 affected individuals examined have required cataract extraction to date. No other identified clinical manifestations of HHCS were delineated. CONCLUSIONS: Cataract morphology in HHCS is highly distinctive. Longitudinal observation demonstrated slow progression of the cataracts. This study highlights that, although HHCS is an autosomal dominant condition, the diagnosis should be considered even in sporadic cataract of typical morphology. Furthermore, individuals with unexplained hyperferritinemia should be referred for ophthalmological assessment, as the cataract may be asymptomatic but lead to a correct diagnosis of HHCS. Clinical Relevance Progressive cataracts of highly distinctive morphology are an important feature of HHCS. Evaluation for this type of cataract may be of diagnostic value in patients with unexplained hyperferritinemia. Hereditary hyperferritinemia-cataract syndrome can be a cause of cataracts in pediatric patients even in the absence of any positive family history.

Adolescent↗
PubMed2003

Diplopia after refractive surgery: occurrence and prevention.

OBJECTIVES: To report the occurrence of persistent diplopia manifesting after refractive surgery, to describe the different causes of this complication, to provide risk stratification for its occurrence, and to outline minimal screening techniques for its prevention. METHODS: A retrospective medical record review of patients seen in 2 private strabismus practices who experienced persistent diplopia after refractive surgery. RESULTS: A total of 28 patients were identified who met the inclusion criteria. The causes of postoperative diplopia could be traced to 1 of 5 mechanisms. These included technical problems, prior need of prisms, aniseikonia, iatrogenic monovision, and improper control of accommodation in patients with strabismus. The recommended screening techniques would have identified all patients in this series as being at risk for postoperative diplopia with the exception of those in whom technical problems were responsible. CONCLUSIONS: Diplopia can become manifest after refractive surgery. With proper attention paid to risk stratification and recommended screening criteria, the incidence of this complication can be minimized.

Adult↗
PubMed2003

Central and peripheral vision loss associated with nefazodone usage.

A 35-year-old woman who reported persistent significant vision loss for 3 years after taking the antidepressant nefazodone was referred for electrophysiological assessment of vision. The vision changes included reduced acuities, reduced colour vision and visual field constriction in both eyes and were thought to be associated with the use of nefazodone for 6 - 8 weeks, 3 years earlier. Multifocal electroretinograms and visual evoked potentials were recorded using the Visual Evoked Response Imaging System (VERIS) to investigate the nature and site of the neural deficit. The summed retinal response showed a normal a- and b-wave latency and amplitude, however, the retinal topographic mfERGs showed a severe depression of the macular response in both eyes. The cortical topographic multifocal VEP mapping also showed a central depression in the right eye compared with the left. Two-frame motion and pattern custom mfVEP were also measured to assess different forms of cortical processing and especially of motion as nefazodone has previously been associated with image persistence with moving stimuli. The responses to two frame-motion showed signs of abnormality. Thus these results suggest that the primary locus of neural damage is retinal and is likely to have resulted from neurotoxicity. Other competing hypotheses such as hysterical blindness must be ruled out.

Adult↗
PubMed2003

Spontaneous recovery from inferior rectus contracture (consecutive hypotropia) following local anesthetic injury.

We present yet another case of apparent inferior rectus paralysis following retrobulbar anesthesia for cataract surgery. He initially had a typical course but, unusually, after developing hypotropia and presumed contracture, went on to spontaneously recover. We are unaware of any other such case described in the literature. Methods to enhance this more desirable course are considered.

Anesthetics, Combined↗
PubMed2003

Acute esotropia in heroin withdrawal: a case series.

BACKGROUND: Esotropia during opiate withdrawal is a new clinical syndrome that has only recently been reported in the literature. METHODS: Clinical case series. RESULTS: Five patients with acute esotropia during opiate withdrawal are presented. In four there was evidence of underlying hyperopia and/or other strabismogenic features. CONCLUSIONS: The precise cause of esotropia with heroin withdrawal is uncertain. Most (and possibly all) of these patients have one or more objective strabismogenic features, and these are probably a large factor in the causation.

Acute Disease↗