Challenges in posterior uveitis-tips and tricks for the retina specialist.

PURPOSE: Posterior uveitis is a common chorioretinal pathology affecting all ages worldwide and is a frequent reason for referral to the retina clinic. The spectrum of etiologies for uveitis is very broad and includes infectious and auto-immune diseases. Inflammation can be confined to the eye or may be a part of systemic disease. A useful outline is therefore proposed to aid in the correct diagnosis of these challenging entities. The situation is further complicated by the fact that many neoplastic conditions resemble features of posterior uveitis; they are known as "masqueraders of uveitis". Here, we summarize different posterior uveitides that present with rare findings, along with masqueraders that can be difficult to distinguish. These conditions pose a diagnostic dilemma resulting in delay in treatment because of diagnostic uncertainty. METHODS: An extensive literature search was performed on the MEDLINE/PUBMED, EBSCO and Cochrane CENTRAL databases from January 1985 to January 2022 for original studies and reviews of predetermined diagnoses that include posterior uveitic entities, panuveitis and masquerade syndromes. RESULTS: We described conditions that can present as mimickers of posterior uveitis (i.e., immune check-points inhibitors and Vogt-Koyanagi-Harada-like uveitis; leukemia and lymphoma associated posterior uveitis), inflammatory conditions that present as mimickers of retinal diseases (i.e., Purtscher-like retinopathy as a presentation of systemic lupus erythematosus; central serous chorioretinopathy masquerading inflammatory exudative retinal detachment), and uveitic conditions with rare and diagnostically challenging etiologies (i.e., paradoxical inflammatory effects of anti-TNF-α; post vaccination uveitis; ocular inflammation after intravitreal injection of antiangiogenic drugs). CONCLUSION: This review of unique posterior uveitis cases highlights the overlapping features of posterior uveitis (paradoxical inflammatory effects of anti -TNF α and uveitis; Purtscher-like retinopathy as a presentation of systemic lupus erythematosus, …) and the nature of retinal conditions (ischemic ocular syndrome, or central retinal vein occlusion, amyloidosis, inherited conditions like retinitis pigmentosa, autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV), etc.…) that may mimic them is represented. Careful review of past uveitis history, current medications and recent vaccinations, detailed examination of signs of past or present inflammation, eventually genetic testing and/ or multimodal retinal imaging (like fluorescein angiography, EDI-OCT, OCT-angiography for lupus Purtscher-like retinopathy evaluation, or ICG for central serous retinopathy, or retinal amyloid angiopathy) may aid in correct diagnosis.

Prevalence and Predictors of Hering's Response in Müller's Muscle-conjunctival Resection.

PURPOSE: Determine the prevalence and predictors of Hering's response following Muller's muscle-conjunctival resection (MMCR). METHODS: Seventy-five consecutive patients undergoing unilateral MMCR were recruited in this prospective, multicenter, cohort study. Margin-reflex distance-1 (MRD1) of both eyelids was recorded preoperatively and postoperatively. One hundred forty-three variables were investigated as potential predictors of a late postoperative (≥3 months) Hering's response using regression analyses. Main outcome measures were Hering's response (≥0.5 mm descent of the unoperated eyelid from baseline), and a clinically relevant Hering's response (descent of the unoperated from baseline to a MRD1 ≤ 2.0 mm, or descent from baseline such that the MRD1 of the unoperated eyelid became >1 mm lower than the operated eyelid). RESULTS: Twenty-four (32.0%) patients had a late postoperative Hering's response, but only 6 (8.0%) responses were clinically relevant. A Hering's response at the immediate (OR 16.24, p = 0.02) and 1-week postoperative (OR 8.94, p = 0.04) timepoints predicted a late postoperative response. However, the presence (OR 7.84, p = 0.07) and amplitude (OR 8.13, p = 0.06) of a preoperative phenylephrine Hering's response did not predict a late postoperative response. Of the 10 patients with a clinically relevant phenylephrine Hering's response, only 1 demonstrated a clinically relevant response late postoperatively. CONCLUSION: Unilateral MMCR induces a clinically relevant Hering's response in 8% of patients. A preoperative phenylephrine Hering's response does not predict a late postoperative Hering's response. Therefore, when unilateral phenylephrine testing unmasks contralateral blepharoptosis, only the side with blepharoptosis at baseline should be operated.

Müller Muscle Conjunctival Resection: A Multicentered Prospective Analysis of Surgical Success.

PURPOSE: This is a multicenter prospective cohort study investigating Müller muscle conjunctival resection success rates based on marginal reflex distance-1 (MRD1) and symmetry criteria. A secondary objective was to identify predictors of success. METHODS: One hundred fifty-two patients with unilateral or bilateral blepharoptosis (229 eyelids) undergoing Müller muscle conjunctival resection were consecutively recruited from 2015 to 2020 at the Université de Montréal and University of California San Francisco. Ptosis was defined as MRD1 ≤ 2.0 mm or MRD1 > 1 mm lower than the contralateral eyelid. Patients were selected for Müller muscle conjunctival resection surgery if they demonstrated significant eyelid elevation following phenylephrine 2.5% testing. MRD1 success (operated eyelid achieving MRD1 ≥ 2.5 mm) and symmetry success (patient achieving an intereyelid MRD1 difference ≤ 1 mm) were evaluated for the patient cohort. Predictors of MRD1 and symmetry success were analyzed using multivariate regression analysis. RESULTS: MRD1 success was achieved in 72.1% (n = 165) of 229 operated eyelids. Symmetry success was achieved in 75.7% (n = 115) of 152 patients. MRD1 before phenylephrine testing was the only statistically significant predictor of MRD1 success (odds ratio [OR] 2.69, p = 0.001). Symmetry following phenylephrine testing was the only variable associated with increased odds of symmetry success (OR 2.71, p = 0.024), and unilateral surgery (OR 0.21, p = 0.004), the only variable associated with reduced odds of symmetry success. CONCLUSIONS: Müller muscle conjunctival resection effectively achieves postoperative MRD1 and symmetry success. MRD1 before phenylephrine testing is the strongest determinant of MRD1 success. Neither a large rise in MRD1 with phenylephrine nor increasing tissue resection length adequately counterbalance the effect of a low MRD1 before phenylephrine. Unilateral surgery and the absence of symmetry following phenylephrine predict greater odds of symmetry failure.

Long-term outcomes in a series of idiopathic retinal vasculitis, aneurysms, and neuroretinitis (IRVAN) syndrome.

OBJECTIVE: Idiopathic retinal vasculitis, aneurysms, and neuroretinitis (IRVAN) syndrome is a rare entity with a potentially poor visual prognosis. Our objective is to review the clinical presentation and long-term outcomes of patients with IRVAN syndrome. DESIGN: This is a retrospective case series. METHODS: We reviewed the charts of all the patients diagnosed with IRVAN syndrome at our tertiary care centre from 2002 to 2015. RESULTS: We included the long-term clinical outcomes of 7 eyes (5 patients) diagnosed with IRVAN syndrome. After a mean follow-up of 84.9 months, best-corrected visual acuity was 20/40 or better in the majority of eyes (70%). Four (57.1%) patients had systemic conditions, namely, multiple sclerosis, ischemic stroke, and positive antiphospholipid titres. All eyes were treated with laser photocoagulation. Four (40%) eyes received adjunctive intravitreal bevacizumab injections. CONCLUSION: IRVAN is an important diagnosis for clinicians to recognize. When treated in a timely manner, long-term visual outcomes can be favourable.

Tonic diaphragmatic activity in critically ill children with and without ventilatory support.

BACKGROUND: Infants have to actively maintain their end expiratory lung volume (EELV). In mechanically ventilated infants, the diaphragm stays activated until the end of expiration (tonic activity), contributing to EELV maintenance. It is unclear whether tonic activity compensates for the lack of laryngeal braking due to intubation or if it is normally present. OBJECTIVE: To determine if tonic diaphragm activity remains after extubation in infants, and if it can be observed in older children. METHODS: Prospective observational study of pediatric patients ventilated for >24 hr. Diaphragm electrical activity (EAdi) was recorded using a specific nasogastric catheter during four periods: (i) the acute phase, (ii) pre-extubation, (iii) post-extubation, and (iv) at PICU discharge. Tonic EAdi was defined as the EAdi in the last quartile of expiration. RESULTS: Fifty-five patients, median age 10 months (Interquartile range: 1-48) were studied. In infants (<1 year, n = 28), tonic EAdi was always present, and represented 33% (22-43) of inspiratory EAdi at PICU discharge. No significant change was observed between pre- and post-extubation periods. In older patients (n = 27), tonic activity was negligible as a whole, but 10 patients exhibited significant tonic EAdi at one time-point during PICU stay. Bronchiolitis was the only independent factor associated with tonic EAdi. CONCLUSIONS: In infants, tonic EAdi remains involved in ventilatory control after extubation and restoration of laryngeal braking. Tonic EAdi may play a pathophysiological role in bronchiolitis and it can be reactivated in older patients. The interest of tonic EAdi as a tool to titrate mechanical ventilation warrants further evaluation.

Evolution of inspiratory diaphragm activity in children over the course of the PICU stay.

PURPOSE: Diaphragm function should be monitored in critically ill patients, as full ventilatory support rapidly induces diaphragm atrophy. Monitoring the electrical activity of the diaphragm (EAdi) may help assess the level of diaphragm activity, but such monitoring results are difficult to interpret because reference values are lacking. The aim of this study was to describe EAdi values in critically ill children during a stay in the pediatric intensive care unit (PICU), from the acute to recovery phases, and to assess the impact of ventilatory support on EAdi. METHODS: This was a prospective longitudinal observational study of children requiring mechanical ventilation for ≥24 h. EAdi was recorded using a validated method in the acute phase, before extubation, after extubation, and before PICU discharge. RESULTS: Fifty-five critically ill children were enrolled in the study. Median maximum inspiratory EAdi (EAdimax) during mechanical ventilation was 3.6 [interquartile range (IQR) 1.2-7.6] µV in the acute phase and 4.8 (IQR 2.0-10.7) µV in the pre-extubation phase. Periods of diaphragm inactivity (with no detectable inspiratory EAdi) were frequent during conventional ventilation, even with a low level of support. EAdimax in spontaneous ventilation was 15.4 (IQR 7.4-20.7) µV shortly after extubation and 12.6 (IQR 8.1-21.3) µV before PICU discharge. The difference in EAdimax between mechanical ventilation and post-extubation periods was significant (p < 0.001). Patients intubated mainly because of a lung pathology exhibited higher EAdi (p < 0.01), with a similar temporal increase. CONCLUSIONS: This is the first systematic description of EAdi evolution in children during their stay in the PICU. In our patient cohort, diaphragm activity was frequently low in conventional ventilation, suggesting that overassistance or oversedation is common in clinical practice. EAdi monitoring appears to be a helpful tool to detect such situations.