Renzo A. Zaldivar

Acute intermittent porphyria presenting as a diffuse encephalopathy.

Although acute intermittent porphyria presents with dramatic neurological findings, the diagnosis is difficult. An 18‐year‐old woman had a clinical picture of porphyric encephalopathy. Magnetic resonance (MR) imaging demonstrated multiple large contrast‐enhancing subcortical white matter lesions, which regressed with glucose and hematin infusions. Diffusion‐weighted MR imaging was normal, and MR spectroscopy excluded acute demyelination or tissue necrosis. MR findings of acute intermittent porphyria can differ from those in posterior reversible encephalopathy syndrome by virtue of intense contrast enhancement. Because diffusion‐weighted MR imaging and spectroscopy were normal, the lesions are likely caused by reversible vasogenic edema and transient breakdown of the blood–brain barrier. Ann Neurol 2005;57:581–584

Modulating Neuromuscular Junction Density Changes in Botulinum Toxin–Treated Orbicularis Oculi Muscle

PURPOSE Botulinum toxin A is the most commonly used treatment for blepharospasm, hemifacial spasm, and other focal dystonias. Its main drawback is its relatively short duration of effect. The goal of this study was to examine the ability of corticotropin releasing factor (CRF) or antibody to insulin growth factor I-receptor (anti-IGFIR) to reduce the up-regulation of neuromuscular junctions that are associated with return of muscle function after botulinum toxin treatment. METHODS Eyelids of adult rabbits were locally injected with either botulinum toxin alone or botulinum toxin treatment followed by injection of either CRF or anti-IGFIR. After one, two, or four weeks, the orbicularis oculi muscles within the treated eyelids were examined for density of neuromuscular junctions histologically. RESULTS Injection of botulinum toxin into rabbit eyelids resulted in a significant increase in the density of neuromuscular junctions at one and two weeks, and an even greater increase in neuromuscular junction density by four weeks after treatment. Treatment with either CRF or anti-IGFIR completely prevented this increase in neuromuscular junction density. CONCLUSIONS The return of function after botulinum toxin-induced muscle paralysis is due to terminal sprouting and formation of new neuromuscular junctions within the paralyzed muscles. Injection with CRF or anti-IGFIR after botulinum toxin treatment prevents this sprouting, which in turn should increase the duration of effectiveness of single botulinum toxin treatments. Future physiology studies will address this. Prolonging botulinum toxins clinical efficacy should decrease the number of injections needed for patient muscle spasm relief, decreasing the risk of negative side effects and changes in drug effectiveness that often occurs over a lifetime of botulinum toxin exposure.

Intravascular Lymphoma Presenting as an Orbital Mass Lesion: A Case Report

We describe a case of intravascular lymphoma that presented as an orbital mass lesion. A 77-year-old female presented with longstanding fatigue and one-month of diplopia. Magnetic resonance imaging (MRI) revealed a frontal lobe brain lesion and a right orbital mass. Brain biopsy was interpreted as anaplastic oligodendroglioma. Orbital biopsy revealed intravascular lymphoma. On review of brain histopathology, the diagnosis was revised to CNS intravascular lymphoma. To the best of our knowledge, this case represents the first report of intravascular lymphoma presenting as an orbital mass lesion.

Orbital Bony Anatomy and Orbital Fractures

The bony orbit surrounds and protects the globe. Orbital fractures are common and may involve one or all of the walls. This article reviews the orbital bony anatomy as well as blowout, medial wall, and tripod fractures.

A rabbit model of lower eyelid fibrosis

Purpose: To create and validate a new model of lower eyelid fibrosis in Dutch-belted rabbits. Methods: Five Dutch-belted rabbits were injected with a transcutaneous 1-ml injection of standard 95% ethanol alcohol just inferior to the eyelid margin of one lower eyelid. A control injection of 1 ml of balanced saline solution was given to the opposite eyelid. A small tattoo was placed on the skin overlying the inferior orbital rim and used as a measuring point of reference in relation to the lower eyelid margin. Analysis was twofold: eyelid measurements were made over 8 weeks to determine the presence of eyelid shortening, and a histopathologic analysis was performed. Results: Mean lower eyelid shortening was greater in the ethanol alcohol intervention eyelids than the control group (−3.4 mm ± 1.67 mm vs. 0.5 mm ± 0.71 mm, p = 0.01). Histopathologic analysis revealed extensive fibrosis in the ethanol alcohol invention eyelids compared with the control group. Conclusions: Ethanol alcohol induces eyelid fibrosis and lower eyelid shortening. This may be a useful model in the future testing of novel surgical or pharmacologic treatments.

Asymptomatic Renal Cell Carcinoma as a Finding of Bardet Biedl Syndrome

Retinitis pigmentosa represents a class of disorders that exhibit dystrophy of the photoreceptors, pigment epithelium, and often systemic abnormalities, Bardet-Biedl syndrome is a form of retinitis pigmentosa that has characteristic non-ocular findings including polydactyly, obesity, learning difficulties, male hypogonadism, and renal anomalies. Though none of these renal anomalies are neoplastic, there is a 17 fold increased risk for renal cell carcinoma in obligate carriers of Bardet-Biedl syndrome. Herein, we describe a case of metastatic renal cell carcinoma discovered in a patient with Bardet-Biedl syndrome.

Rhino-orbital-cerebral mucormycosis: a lethal complication of body dysmorphic disorder.

Young diabetics can sometimes have difficulty with insulin compliance for various reasons. This can be exacerbated if associated with body dysmorphic disorder or other eating disorders. The manipulation of insulin to lose weight can have devastating consequences. The authors describe a fatal case of rhino-orbital-cerebral mucormycosis secondary to insulin manipulation for the purpose of weight loss.

Imaging of the Orbit

Modern imaging techniques are discussed. These imaging modalities, including computed tomography and magnetic resonance imaging, have dramatically improved our ability to assess orbital soft tissues. This has resulted in an increased ability for the physician to assess orbital health, as well as more effectively plan surgical intervention when it is needed due to injury or disease.

Sulcus-based 25-gauge vitrectomy with transscleral intraocular lens fixation

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