Acute diabetic neuropathy following improved glycaemic control: a case series and review

SUMMARY

We present three cases of acute diabetic neuropathy and highlight a potentially underappreciated link between tightening of glycaemic control and acute neuropathies in patients with diabetes. Case 1: A 56-year-old male with poorly controlled type 2 diabetes (T2DM) was commenced on basal-bolus insulin. He presented 6 weeks later with a diffuse painful sensory neuropathy and postural hypotension. He was diagnosed with treatment-induced neuropathy (TIN, insulin neuritis) and obtained symptomatic relief from pregabalin. Case 2: A 67-year-old male with T2DM and chronic hyperglycaemia presented with left lower limb pain, weakness and weight loss shortly after achieving target glycaemia with oral anti-hyperglycaemics. Neurological examination and neuro-electrophysiological studies suggested diabetic lumbosacral radiculo-plexus neuropathy (DLPRN, diabetic amyotrophy). Pain and weakness resolved over time. Case 3: A 58-year-old male was admitted with blurred vision diplopia and complete ptosis of the right eye, with intact pupillary reflexes, shortly after intensification of glucose-lowering treatment with an SGLT2 inhibitor as adjunct to metformin. He was diagnosed with a pupil-sparing third nerve palsy secondary to diabetic mononeuritis which improved over time. While all three acute neuropathies have been previously well described, all are rare and require a high index of clinical suspicion as they are essentially a diagnosis of exclusion. Interestingly, all three of our cases are linked by the development of acute neuropathy following a significant improvement in glycaemic control. This phenomenon is well described in TIN, but not previously highlighted in other acute neuropathies.

LEARNING POINTS

A link between acute tightening of glycaemic control and acute neuropathies has not been well described in literature. Clinicians caring for patients with diabetes who develop otherwise unexplained neurologic symptoms following a tightening of glycaemic control should consider the possibility of an acute diabetic neuropathy. Early recognition of these neuropathies can obviate the need for detailed and expensive investigations and allow for early institution of appropriate pain-relieving medications.

Factors influencing elevated serum apolipoprotein B48 in diabetic and control participants

Factors influencing the concentration of apolipoprotein B48 (apo B48) at fasting and post-prandial time frames are still being elucidated. This study assesses some possible contributing factors including the presence of type 2 diabetes and gender using an established enzyme-linked immunosorbent assay (ELISA) method. Apo B48 and triglyceride (TG) levels were measured before and for two, four and six hours post-prandially in 49 poorly controlled participants with type 2 diabetes and in 60 apparently healthy participants (controls). Apo B48 levels in the control participants increased post-prandially, peaking at four hours (14.81 ± 7.72 μg/mL) with similar responses demonstrated in TG concentrations. Post-prandial apo B48 levels were significantly higher in male control participants as demonstrated by apo B48 area under the curve (AUC); similar responses were also confirmed in triglyceride AUC. Post-prandial apo B48 concentrations in control participants correlated with HOMA-IR (P < 0.05). Apo B48 continued to increase throughout the six hours in participants with type 2 diabetes (17.73 ± 13.46 μg/mL), when levels were significantly greater than in the control participants (13.04 ± 7.67 μg/mL) (P < 0.05) despite a decrease in accompanying TG levels in participants with type 2 diabetes. Using an ELISA method, this study demonstrated that gender, insulin resistance (as evidenced by HOMA-IR) and diabetes status influence serum apo B48 levels. These effects were only apparent post-prandially.

Barriers to exercise in obese patients with type 2 diabetes

BACKGROUND

Although regular exercise is a critical component of the management of type 2 diabetes, many patients do not meet their exercise targets. Lack of exercise is associated with obesity and adverse cardiovascular outcomes.

AIM

We aimed to assess exercise habits in obese Irish patients with type 2 diabetes to determine if patients are adhering to exercise guidelines and to identify perceived barriers to exercise in this group.

DESIGN

A cross-sectional study of obese patients with type 2 diabetes attending routine outpatient diabetes clinics at our institution, a public teaching hospital located on the outskirts of Dublin City.

METHODS

A total of 145 obese patients with type 2 diabetes were administered a questionnaire to evaluate exercise habits and perceived barriers to exercise. Anthropometric details were measured.

RESULTS

About 47.6% (n = 69) of patients exercised for <150 minutes per week (40% of males, 62% of females; P = 0.019) and these patients had a higher body mass index than those meeting targets (35 vs. 33.5 kg/m(2); P = 0.02). Perceived barriers to exercise were varied, with lack of time and physical discomfort being the most common. Reported barriers to exercise varied with age, gender and marital status.

CONCLUSION

This study highlights the challenges facing clinicians in improving exercise levels in patients, and the need to identify the specific barriers to exercise in the individual to improve health outcomes.

Serum prolactin concentration at presentation of non-functioning pituitary macroadenomas

OBJECTIVE

Serum PRL levels at presentation may be useful in distinguishing between disconnection hyperprolactinemia in non-secretory pituitary adenomas and prolactinomas in order to guide appropriate therapy; however, there is a debate regarding the discriminatory PRL thresholds. We aimed to examine PRL concentrations at presentation in a cohort of histologically proven non-functioning pituitary adenomas (NFPA).

DESIGN AND METHODS

Retrospective case note analysis was performed. Clinical, biochemical, histopathological and radiological data were recorded and analyzed. Complete data were available for 250 subjects with NFPA.

RESULTS

Of the study population, 44.8% were hyperprolactinemic at presentation, 55.3% of whom were female. Of those with hyperprolactinemia, 73.2% had PRL<1000 mIU/l on presentation, 24.1% had PRL between 1000 and 1999 mIU/l. Only 2.7% (no.=3 females, 1.2% whole cohort) had PRL>2000 mIU/l (94.3 ng/ml), 2 of whom were pregnant. No male subject and no subjects with an intrasellar macroadenoma had serum PRL>1000 mIU/l (47.2 ng/ml). Overall, serum PRL was not higher among 43 subjects taking medications known to raise PRL.

CONCLUSIONS

Our data support recent evidence that the serum PRL concentration is rarely >1000 mIU/l in males, or >2000 mIU/l in females, with non-functioning macroadenomas and that, once other contributing factors to the hyperprolactinemia have been excluded, a trial of dopamine agonist therapy for such lesions is indicated.

Leucocytosis in women with polycystic ovary syndrome (PCOS) is incompletely explained by obesity and insulin resistance

OBJECTIVES

Low-grade chronic inflammation predicts cardiovascular outcomes and is observed in women with polycystic ovary syndrome (PCOS). Whether this is entirely a cause or consequence of insulin resistance (IR) is unknown.

METHODS

Seventy pairs of women with and without PCOS, matched for age, body mass index (BMI) and IR (HOMA, QUICKI and Avignon index), were generated from a larger cohort of 103 women with and 104 BMI-matched women without PCOS. Women with PCOS were studied in the follicular phase of the menstrual cycle. White cell count (WCC), high-sensitivity CRP (hsCRP) and a series of 12 cytokines and growth factors were measured. These inflammatory markers were also compared between women with PCOS and 10 normal women studied in the follicular, peri-ovulatory and luteal stages.

RESULTS

When all subjects were compared, WCC (6.75 × 10(9) vs 5.60 × 10(9 ) g/l, P < 0.005), hsCRP (4.04 vs 2.90 mg/l, P < 0.05) and IL-6 (1.11 vs 0.72 pg/ml, P < 0.05) were greater in women with PCOS. Pair-matching for IR eliminated between-group differences in hsCRP and cytokines but did not alter the difference in WCC (6.60 × 10(9) vs 5.60 × 10(9 ) g/l, P < 0.005). WCC was greater in PCOS compared to normal women at all stages of the menstrual cycle.

CONCLUSIONS

Low-grade inflammation occurs in PCOS. Increased hsCRP and cytokines are associated with IR, but increased WCC is observed even when IR is accounted for. The explanation for this and its clinical significance is unknown.

High-molecular-weight adiponectin is selectively reduced in women with polycystic ovary syndrome independent of body mass index and severity of insulin resistance

CONTEXT

High-molecular-weight (HMW) adiponectin contributes to insulin resistance (IR), which is closely associated with the pathophysiology of polycystic ovary syndrome (PCOS). Abnormalities in adipocyte function have been identified in PCOS and potentially contribute to lower adiponectin concentrations.

OBJECTIVE

Our objective was to determine which variables in plasma and adipose tissue influence HMW adiponectin in a well characterized cohort of women with PCOS.

DESIGN

This was a cross-sectional study.

SETTINGS AND PARTICIPANTS

A teaching hospital. Women with PCOS (n = 98) and body mass index (BMI)-matched controls (n = 103) (including 68 age-, BMI-, and IR-matched pairs).

INTERVENTIONS

A standard 75-g oral glucose tolerance test was performed for each participant. Subcutaneous adipose tissue samples were taken by needle biopsy for a subset of PCOS women (n = 9) and controls (n = 8).

MAIN OUTCOME MEASURES

Serum levels of HMW adiponectin and their relation to indices of insulin sensitivity, body composition, and circulating androgens as well as adipose tissue expression levels of ADIPOQ, TNFalpha, PPARgamma, and AR were assessed.

RESULTS

HMW adiponectin was significantly lower in women with PCOS compared with both BMI- and BMI- and IR-matched controls (P = 0.009 and P = 0.027, respectively). Although BMI and IR were the main predictors of HMW adiponectin, an interaction between waist to hip ratio and plasma testosterone contributed to its variance (P = 0.026). Adipose tissue gene expression analysis demonstrated that AR and TNFalpha (P = 0.008 and P = 0.035, respectively) but not ADIPOQ mRNA levels were increased in PCOS compared with controls.

CONCLUSIONS

HMW adiponectin is selectively reduced in women with PCOS, independent of BMI and IR. Gene expression analysis suggests that posttranscriptional/translational modification contributes to reduced HMW adiponectin in PCOS.