Reorganization of thalamocortical connections in congenitally blind humans.

Cross-modal plasticity in blind individuals has been reported over the past decades showing that nonvisual information is carried and processed by "visual" brain structures. However, despite multiple efforts, the structural underpinnings of cross-modal plasticity in congenitally blind individuals remain unclear. We mapped thalamocortical connectivity and assessed the integrity of white matter of 10 congenitally blind individuals and 10 sighted controls. We hypothesized an aberrant thalamocortical pattern of connectivity taking place in the absence of visual stimuli from birth as a potential mechanism of cross-modal plasticity. In addition to the impaired microstructure of visual white matter bundles, we observed structural connectivity changes between the thalamus and occipital and temporal cortices. Specifically, the thalamic territory dedicated to connections with the occipital cortex was smaller and displayed weaker connectivity in congenitally blind individuals, whereas those connecting with the temporal cortex showed greater volume and increased connectivity. The abnormal pattern of thalamocortical connectivity included the lateral and medial geniculate nuclei and the pulvinar nucleus. For the first time in humans, a remapping of structural thalamocortical connections involving both unimodal and multimodal thalamic nuclei has been demonstrated, shedding light on the possible mechanisms of cross-modal plasticity in humans. The present findings may help understand the functional adaptations commonly observed in congenitally blind individuals.

Assessment of sleep in subjects with visual impairment: Comparison using subjective and objective methods.

The objective of the present study was to verify the agreement between objective and subjective measures of sleep in people with and without visual impairment. Thirty-seven subjects with visual impairment participated in the study (19 blind without light perception and 18 low-vision), as well as 34 subjects with normal vision, with paired age and gender characteristics. For the subjective sleep evaluation, we used the Sleep Quality Index-PSQI and for the objective evaluation we used the ActiGraph GT3X+. Among the three analyzed groups, the blind was the only ones who presented differences between subjective and objective sleep duration (p = 0.021). Furthermore, the concordance between subjective and objective sleep duration (ICC = 0.388; p = 0.108) was not observed in blind subjects, and a greater variability of differences in sleep duration between the two methods was observed by the Bland Altman scatter plot. We concluded that the sleep duration obtained by PSQI did not show agreement for the objective sleep duration in blind subjects without light perception.

[Tubulointerstitial nephritis syndrome and uveitis]. / Síndrome de nefritis túbulo-intersticial agudo asociado a uveítis.

Intermediate uveitis is described as inflammation in the anterior vitreous, ciliary body and the peripheral retina. It is a subset of uveitis where the vitreous is the major site of damage. It has been reported to be associated with many local and systemic inflammatory and infectious diseases. An infrequent cause is the tubulointerstitial nephritis and uveitis syndrome. We report a case of an acute visual acuity loss related with renal failure in a 64 years old woman with Hashimoto disease. It was an acute tubulointerstitial nephritis and uveitis syndrome case.

Síndrome de nefritis túbulo-intersticial agudo asociado a uveítis / Tubulointerstitial nephritis syndrome and uveitis

La uveítis intermedia es una enfermedad ocular caracterizada por la inflamación de la úvea, principalmente el vítreo anterior, la retina periférica y la pars plana. Diversas etiologías de carácter infeccioso, inflamatorio sistémico y local pueden asociarse a dicho fenómeno. Un cuadro infrecuente es el síndrome de nefritis túbulo-intersticial aguda asociado a uveítis. Presentamos el caso de una mujer de 64 años con antecedente de tiroiditis de Hashimoto, que desarrolló pérdida brusca de la agudeza visual en contexto de falla renal aguda. Se trata de una paciente con nefritis túbulo-intersticial aguda asociada a uveítis.

Intermediate uveitis is described as inflammation in the anterior vitreous, ciliary body and the peripheral retina. It is a subset of uveitis where the vitreous is the major site of damage. It has been reported to be associated with many local and systemic inflammatory and infectious diseases. An infrequent cause is the tubulointerstitial nephritis and uveitis syndrome. We report a case of an acute visual acuity loss related with renal failure in a 64 years old woman with Hashimoto disease. It was an acute tubulointerstitial nephritis and uveitis syndrome case.

Migration of tip knife blade through middle-third facial tissues.

PURPOSE: The aim of this paper is to report a case of knife aggression with a spontaneous migration of a tip blade lodged in deep tissues 6 months after trauma. PATIENT: An 18-year-old woman that was a victim of impalement injury with a knife by her boyfriend on the glabella region with a blade fracture and tip lodging into middle-third facial tissues. RESULTS: After conservative management of a knife tip, a spontaneous migration occurred with its exposition on the zygomatic area, possibly due to a functional treatment to improve mouth opening. CONCLUSION: Fracture of knife blade with a tip retained deeply into the tissues is considered foreign body, and its removal must be considered. Nevertheless, the basis for this removal takes account the cost-benefit ratio, and if a conservative management was chosen, the clinical and radiological accompanying is mandatory to prevent and to treat its possible complications.

Blinding orbital cellulitis: a complication of strabismus surgery.

A 56-year-old healthy man underwent left medial rectus recession and lateral rectus resection for esotropia. The next day he developed severe left periocular pain with decreased vision, an afferent pupillary defect, periorbital edema, limited ocular motility, and proptosis. Computed tomography showed fat stranding and less than 90 degrees of posterior globe tenting. Despite intravenous antibiotics to treat orbital cellulitis, and a lateral canthotomy and cantholysis to decompress the orbit, visual acuity worsened to no light perception. The patient underwent emergent orbital decompression including release of the superior and inferior septum and outfracturing of the orbital floor and medial wall; however, there was no recovery of vision. Blinding orbital cellulitis is a rare complication after strabismus surgery. Despite poor prognosis, prompt diagnosis and aggressive treatment may maximize visual potential.

Structural and functional analyses of the occipital cortex in visual impaired patients with visual loss before 14 years old.

Single photon emission tomography (SPECT) perfusion images of the brain of individuals with complete visual loss before the age of 14 were carried out and compared to those of visually normal subjects, in order to assess hypothetical differences in brain structural and metabolism between the two groups. Study group was comprised by 2 females and 3 males, aged 30 +/- 10 years. Controls were composed by 6 females and 5 males aged 41.5 +/- 3.8 years. All individuals were submitted to physical and neurological examinations, and to MRI and to SPECT. Blind subjects presented larger perfusion measurements bilaterally in their medial temporal lobes (p=0.030, right side; p=0.01, left side), but smaller perfusion measurements in their left frontotemporal area than controls (p=0.026). Intragroup analysis of the study group disclosed asymmetric perfusion, lesser in the left temporal and parietal areas (p=0.026 and p<0.0001, respectively) compared to the right side. In the healthy controls, reduced perfusion was also noted at the left parietal areas when compared to the right side (p=0.035). The study revealed that completely blind patients that became visually impaired before the age of 14 in spite of not having MRI detectable changes in their brain's anatomy do present increases in perfusion of their left and right medial temporal lobes, and a reduction in the perfusion of the left frontotemporal area, as compared to normal controls. While the increases in blood flow may reflect compensatory mechanisms for visual deprivation, the significance of the diminished perfusion in the left frontotemporal area remains elusive.