Polypoidal choroidal vasculopathy: an angiographic discussion

The understanding of polypoidal choroidal vasculopathy has evolved rapidly in the past three decades. The hallmark of the disease is the presence of typical hyperfluorescent nodules in the early phase of indocyanine green angiography. Although the classical clinical presentation is recurrent serosanguinous detachment of the retinal pigment epithelium, it may present with clinical features indistinguishable from exudative age-related macular degeneration secondary to choroidal neovascularization. Some cases may present initially with submacular haemorrhage, but later with features of exudative age-related macular degeneration. Studying the associated network of vessels using confocal scanning laser ophthalmoscopy indocyanine green dynamic angiography revealed in many cases feeder vessels, branching pattern, and leakage similar to choroidal neovascularization. Owing to the overlap of clinical and angiographic features, it may be considered as a vascular subtype of exudative age-related macular degeneration. However, having seemingly better natural history, better response to photodynamic therapy, and incomplete response to anti-vascular endothelial growth factor therapy suggests that it should be studied as a separate entity from choroidal neovascularization. Combining angio-occlusion of the polyps using photodynamic therapy and anti-permeability effect of anti-vascular endothelial growth factor therapy on the branching vascular network may provide a synergistic effect. We await the result of EVEREST trial, a multi-centre randomized controlled trial comparing photodynamic therapy, with or without ranibizumab, with ranibizumab monotherapy.

Charles Bonnet syndrome in Asian patients in a tertiary ophthalmic centre

AIMS

To describe the epidemiology of Charles Bonnet syndrome (CBS) among patients in an Asian tertiary ophthalmic centre and to describe the characteristics of the hallucinations experienced.

METHODS

1077 consecutive patients aged 50 years and above were asked a standardised question to determine if they had ever experienced formed visual hallucinations. All patients who experienced these symptoms were further interviewed using a detailed, standardised questionnaire to ascertain if they met the diagnostic criteria established for CBS.

RESULTS

There were 491 men (45.6%) and 586 women (54.4%). The best corrected visual acuity ranged from 20/20 to light perception in the better seeing eye and from 20/20 to no light perception in the worse seeing eye. Four patients (0.4%) were diagnosed with CBS; two men and two women. There were two Chinese and two Indians. The average age of the CBS patients was 76.3 years (range 65-90 years). Two patients had cataracts, one had glaucoma, and one had both cataracts and glaucoma. A wide variety of visual hallucinations were reported. Three out of four patients experienced a negative reaction to their hallucinations. Only one patient had discussed his symptoms with a doctor.

CONCLUSIONS

This is the first report on the epidemiology of CBS in Asian patients. The prevalence rate of CBS (0.4%) is slightly lower than in comparable studies in non-Asian populations. The nature of the hallucinations experienced were similar to those previously reported.

Epidemiology of pterygium on a tropical island in the Riau Archipelago

OBJECTIVES

To describe the epidemiology of pterygium among residents of an island in Indonesia and to examine the roles of age and gender as determinants of bilaterality and severity of the disease.

METHODS

Voluntary eye screening on Pulau Jaloh, Riau Archipelago, Indonesia. Gender difference was tested using the chi2 test. The difference in age between subjects with and without disease was tested using unpaired Student's t-test. Odds ratio (relative risk) for gender was calculated using logistic regression model with adjustment for age.

RESULTS

Of the 550 inhabitants, 477 (86.7%) responded to the eye screening. The overall prevalence rate of pterygium was 17.0%. Out of 211, 48 male (22.7%) and 33 out of 266 female subjects (12.4%) had the disorder, with the gender difference being statistically significant. Adjusted for age, the risk of disease was 3.1-fold higher among the males. In all, 71.6% of subjects with pterygium had bilateral disease. Subjects with pterygium were significantly older, their mean age being 42.9 years compared to 18.7 years among those without disease. The prevalence rates in male subjects increased from age 20 to reach a plateau of 63.6% at age 35 and remained stable thereafter. In the female subjects, the rates also increased with age, albeit at a slower rate, from age 20 to reach a plateau of 46.7% at age 55 and remained stable thereafter.

CONCLUSIONS

There is a high prevalence rate of pterygium among the study subjects, with the rates increasing rapidly with age.

Patients' expectation and experience of visual sensations during phacoemulsification under topical anaesthesia

PURPOSE

To describe what patients expect to see and the visual sensations they actually experience during phacoemulsification under topical anaesthesia. We also sought to determine if patients find their intraoperative visual experience frightening and the factors associated with this.

MATERIALS AND METHODS

Ninety-eight patients who underwent phacoemulsification and intraocular lens implantation under topical anaesthesia were interviewed preoperatively on what they expected to see with their operated eye during surgery and again postoperatively on what they actually saw. No patient received counselling about possible intraoperative visual sensations. A logistic (multivariate) regression model was used for statistical analysis.

RESULTS

Preoperatively, 36 patients (36.7%) expected at least light perception, 38 (38.8%) expected no light perception, and 24 (24.5%) were unsure what to expect. Some patients also expected a variety of different visual sensations. Postoperatively, all patients (100%) reported seeing light intraoperatively and many experienced various other visual sensations. Nineteen patients (19.4%) found their visual experience frightening. The following factors were statistically associated with a frightening visual experience: preoperative anxiety, previous cataract surgery in the fellow eye, experiencing an intraoperative increase in clarity, not seeing movement intraoperatively, and not knowing what to expect.

CONCLUSIONS

The majority of patients in this study either expected that they would see nothing at all during the surgery or were unsure of what to expect. All patients subsequently saw at least some light, and many perceived various other visual sensations that were frightening to nearly one in five patients. Preoperative counselling should inform about possible intraoperative visual experience.

Genetic variants in the receptor for advanced glycation end products (RAGE) gene were associated with circulating soluble RAGE level but not with renal function among Asians with type 2 diabetes: a genome-wide association study

Background

The soluble receptor for advanced glycation end products (sRAGE) has been shown to play an important role in diabetic complications. We conducted genome-wide association study (GWAS) of sRAGE in Asian type 2 diabetes mellitus (T2DM) patient and validated the association in an independent cohort of T2DM.

Methods

GWAS for sRAGE was performed in 2058 T2DM patients. Associations between single-nucleotide polymorphisms (SNPs) and plasma sRAGE level were analyzed in an additive model using a linear mixed model. To validate the associations, we performed de novo genotyping in an independent cohort (n = 1984). We selected the top SNP for assessment with diabetic kidney disease (DKD).

Results

The strongest SNP, rs2070600C>T (P = 1.21 × 10-52), was a genotyped, missense SNP located on chromosome 6, corresponding to the RAGE (AGER) gene locus, the gene encoding RAGE. Conditioning analysis on rs2070600 revealed that rs2071288C>T was the top genotyped independent SNP (P = 8.36 × 10-10). Both SNPs were strongly and dose-dependently correlated with sRAGE level (TT = 399.6 pg/mL, CT = 737.0 pg/mL and CC = 967.0 pg/mL, P < 0.001 for rs2070600; TT = 687.9 pg/mL, CT = 737.6 pg/mL and CC = 904.7 pg/mL, P < 0.001 for rs2072188). Both SNPs were robustly replicated in the independent cohort, especially among Chinese patients (P = 9.02 × 10-72 for rs2070600; P = 1.13 × 10-9 for rs2071288). Log-transformed sRAGE was associated with DKD after adjustment for age, gender and ethnicity in pooled cohorts [odds ratio 2.536 (95% confidence interval 1.864-3.450), P < 0.001]. However, we did not observe any significant association between rs2070600 and DKD.

Conclusions

Common variants in RAGE are strongly associated with plasma sRAGE level, which is associated with DKD. However, we did not find a causal link between sRAGE and renal function by Mendelian randomization.

A survey on the knowledge and attitudes of anaesthesia providers in the United States of America, United Kingdom and Singapore on visual experiences during cataract surgery

BACKGROUND AND OBJECTIVE

To assess the knowledge, beliefs and attitudes of anaesthesia providers on the patients' possible intraoperative visual experiences during cataract surgery under local anaesthesia.

METHODS

Anaesthesia providers from the Ophthalmic Anaesthesia Society (USA); British Ophthalmic Anaesthesia Society (UK); Alexandra Hospital, National University Hospital, Tan Tock Seng Hospital, Singapore General Hospital and Changi General Hospital (Singapore) were surveyed using a structured questionnaire.

RESULTS

A total of 146 anaesthesiologists (81.6%), 10 ophthalmologists (5.6%) and 23 nurse anaesthetists (12.8%) responded to the survey. Most respondents believed that patients would experience light perception and many also felt that patients might encounter other visual sensations such as movements, flashes, colours, surgical instruments, hands/fingers and the surgeon during the surgery. A significantly higher proportion of anaesthesia providers with previous experience of monitoring patients under topical anaesthesia believed that patients might experience the various visual sensations compared to those who have not previously monitored. For both topical and regional anaesthesia, anaesthesia providers who routinely counsel their patients are (1) more likely to believe that preoperative counselling helps or (2) were previously told by patients that they could see intraoperatively and/or that they were frightened by their visual sensations. These findings were statistically significant.

CONCLUSIONS

The majority of anaesthesia providers in the USA, UK and Singapore are aware that patients may experience a variety of visual sensations during cataract surgery under regional or topical anaesthesia. Those who have previously managed patients undergoing cataract surgery under topical anaesthesia are more likely to believe this compared to those who have not.

Glucokinase activating mutation causing hypoglycaemia diagnosed late in adult who fasts for Ramadhan

SUMMARY

Activating mutation of glucokinase gene (GCK) causes resetting of insulin inhibition at a lower glucose threshold causing hyperinsulinaemic hypoglycaemia (GCK-HH). This is the first reported case who tolerated years of regular fasting during Ramadhan, presenting only with seizure and syncope now. We describe a case with GCK gene variant p.T65I diagnosed in a 51-year-old woman with hypoglycaemia unawareness even at glucose level of 1.6 mmol/L. Insulin and C-peptide levels during hypoglycaemia were suggestive of hyperinsulinism, but at a day after intravenous glucagon, hypoglycaemia occurred with low insulin and C-peptide levels, pointing against insulinoma as the underlying aetiology. Imaging studies of the pancreas and calcium arterial stimulation venous sampling were unremarkable. A review of old medical records revealed asymptomatic hypoglycaemia years ago. Genetic testing confirmed activating mutation of GCK. Hypoglycaemia was successfully controlled with a somatostatin analogue. This case highlights the importance of consideration of genetic causes of hypoglycaemia in adulthood, especially when imaging is uninformative.

LEARNING POINTS

Consider genetic causes of endogenous hyperinsulinism hypoglycaemia in adulthood, especially when imaging is uninformative. Late presentation of activating mutation of GCK can occur because of hypoglycaemia unawareness. Long-acting somatostatin analogue may be useful for the treatment of activating mutation of GCK causing hypoglycaemia. Depending on the glucose level when the blood was taken, and the threshold of glucose-stimulated insulin release (GSIR), the serum insulin and C-peptide levels may be raised (hyperinsulinaemic) or low (hypoinsulinaemic) in patients with activating mutation of GCK. Glucagon may be useful to hasten the process of unmasking the low insulin level during hypoglycaemia below the GSIR level of which insulin released is suppressed.

Precision medicine for a man presented with diabetes at 2-month old

A 22-year-old man was referred for continuation of diabetes mellitus treatment. He was first diagnosed with diabetes mellitus 2 months after birth, when he failed to thrive and showed symptoms of diabetic ketoacidosis. There was no family history of diabetes mellitus. The patient did not exhibit the full set of features to be qualified for any developmental delay, epilepsy and neonatal diabetes mellitus (DEND) syndrome. Insulin replacement therapy was initiated; however, management was challenged by wide glycemic excursion, hypoglycemic unawareness and insulin-associated cutaneous lipo-hypertrophy. Re-evaluation, including genetic testing, revealed a heterozygous missense p.Arg201Cys variation in the KCNJ11 gene encoding the potassium channel subunit Kir6.2. Successful treatment conversion from insulin to glibenclamide was achieved over an extended period of 2 months (up-titrating to a dose of 1.0 mg/kg) in this patient despite his long diabetes duration of 27 years with elimination of hypoglycemia unawareness and achievement of excellent glycemic control sustained over more than 5 years. This case highlights the importance of after having secured a firm genetic diagnosis, to undertake conversion to sulphonylurea with careful dose titration and perseverance over months. Confirmation of variants with functional implications by genetic testing in patients suspected of neonatal diabetes is important for accurate molecular diagnosis and precision-treatment strategy with optimal outcome.

MODY5 Hepatocyte Nuclear Factor 1ß (HNF1ß)-Associated Nephropathy: experience from a regional monogenic diabetes referral centre in Singapore

From our monogenic diabetes registry set-up at a secondary-care diabetes center, we identified a nontrivial subpopulation (~15%) of maturity-onset diabetes of the young (MODY) among people with young-onset diabetes. In this report, we describe the diagnostic caveats, clinical features and long-term renal-trajectory of people with HNF1B mutations (HNF1B-MODY). Between 2013 and 2020, we received 267 referrals to evaluate MODY from endocrinologists in both public and private practice. Every participant was subjected to a previously reported structured evaluation process, high-throughput nucleotide sequencing and gene-dosage analysis. Out of 40 individuals with confirmed MODY, 4 (10%) had HNF1B-MODY (harboring either a HNF1B whole-gene deletion or duplication). Postsequencing follow-up biochemical and radiological evaluations revealed the known HNF1B-MODY associated systemic-features, such as transaminitis and structural renal-lesions. These anomalies could have been missed without prior knowledge of the nucleotide-sequencing results. Interestingly, preliminary longitudinal observation (up to 15 years) suggested possibly 2 distinct patterns of renal-deterioration (albuminuric vs. nonalbuminuric chronic kidney disease). Monogenic diabetes like HNF1B-MODY may be missed among young-onset diabetes in a resource-limited routine-care clinic. Collaboration with a MODY-evaluation center may fill the care-gap. The long-term renal-trajectories of HNF1B-MODY will require further studies by dedicated registries and international consortium.

Plasma Proteomics of Diabetic Kidney Disease Among Asians With Younger-Onset Type 2 Diabetes

CONTEXT

Patients with younger onset of type 2 diabetes (YT2D) have increased risk for kidney failure compared to those with late onset. However, the mechanism of diabetic kidney disease (DKD) progression in this high-risk group is poorly understood.

OBJECTIVE

This work aimed to identify novel biomarkers and potential causal proteins associated with DKD progression in patients with YT2D.

METHODS

Among YT2D (T2D onset age <40 years), 144 DKD progressors (cases) were matched for T2D onset age, sex, and ethnicity with 292 nonprogressors (controls) and divided into discovery and validation sets. DKD progression was defined as decline of estimated glomerular filtration rate (eGFR) of 3 mL/min/1.73 m2 or greater or 40% decline in eGFR from baseline. A total of 1472 plasma proteins were measured through a multiplex immunoassay that uses a proximity extension assay technology. Multivariable logistic regression was used to identify proteins associated with DKD progression. Mendelian randomization (MR) was used to evaluate causal relationship between plasma proteins and DKD progression.

RESULTS

Forty-two plasma proteins were associated with DKD progression, independent of traditional cardiorenal risk factors, baseline eGFR, and urine albumin-to-creatinine ratio. The proteins identified were related to inflammatory and remodeling biological processes. Our findings suggest angiogenin as one of the top signals (odds ratio = 5.29; 95% CI, 2.39-11.73; P = 4.03 × 10-5). Furthermore, genetically determined plasma angiogenin level was associated with increased odds of DKD progression.

CONCLUSION

Large-scale proteomic analysis identified novel proteomic biomarkers for DKD progression in YT2D. Genetic evidence suggest a causal role of plasma angiogenin in DKD progression.

An unusual presentation of a giant frontal sinus mucocele manifesting with a subcutaneous forehead mass

INTRODUCTION

To describe the unusual manifestation of a giant frontal sinus mucocele.

CLINICAL PICTURE

A 33-year-old female presented with blurring of vision in the left eye, periorbital swelling and a painless forehead mass. There was proptosis, partial ptosis, and an elongated, soft, subcutaneous mass over the left side of the forehead. CT scan showed a mass arising from the frontal sinus with both intraorbital and intracranial extension.

TREATMENT

Surgical excision of the mass confirmed the diagnosis of a mucocele.

OUTCOME

Postoperatively, the patient was asymptomatic.

CONCLUSIONS

A subcutaneous soft-tissue mass may be the presenting complaint of a frontal mucocele. Careful examination of the surrounding skin may suggest the diagnosis of sinus-related disease and thus direct appropriate investigations.

A Unique Phenotype of Maturity-Onset Diabetes of the Young With a Novel Disease-Causing Insulin Gene Variant

Maturity-onset diabetes of the young (MODY) represents 1% to 5% of patients with diabetes mellitus (DM), and numerous genes associated with MODY have been identified. While mutations of the insulin gene (INS) are known to cause permanent neonatal DM, rare disease-causing variants have also been found in MODY. These patients demonstrate variable clinical phenotypes-from milder forms requiring lifestyle or oral agent interventions to severe forms requiring lifelong insulin. We present a case of MODY arising from a novel disease-causing INS variant, in an adolescent with atypical features. He was obese with clinical evidence of insulin resistance, diagnosed with DM through opportunistic oral glucose tolerance testing. He developed symptomatic hyperglycemia with worsening glycemic trend, requiring treatment with high-dose insulin and metformin. After 2.5 years, his glycemic profile normalized following weight loss, and pharmacotherapy was discontinued. Targeted gene testing revealed a de novo novel missense variant in exon 2 of the INS gene (p.His29Tyr), confirmed using bidirectional Sanger sequencing. Insulin resistance in patients with MODY can worsen their clinical course and increase risks of long-term complications. Management of these patients should be individualized. This case highlights the utility of genetic testing in diagnosing uncommon and variable forms of MODY, particularly those with atypical features.