Vitamin B12 deficiency and diabetic neuropathy in patients taking metformin: a cross-sectional study

OBJECTIVE

Vitamin B12 deficiency resulting from metformin use has been demonstrated in multiple studies. In this study, we aimed to evaluate the prevalence of vitamin B12 deficiency in patients with chronic metformin use and the relationship between vitamin B12 deficiency and diabetic neuropathy.

METHODS

A cross-sectional study was conducted with 162 patients. Vitamin B12 levels were measured by chemiluminescence immunoassay. Diabetic neuropathy was evaluated by patient record, nerve conduction and Michigan test for the diagnosis of diabetic neuropathy. Additional data, including demographic characteristics were collected. A linear regression model was used to evaluate variables that correlated with vitamin B12 levels and diabetic neuropathy.

RESULTS

Low vitamin B12 levels were found in 7.3% (95% CI: 4.0-12%) of patients. In those with diabetic neuropathy, altered (low and borderline) vitamin B12 level was 64% (95% CI: 47-78%) compared to 17% (95% CI: 10-26%) in patients without diabetic neuropathy (coefficient: -110.8; CI 95%: -165.8, -59.7). Those taking a higher metformin dose had lower levels of vitamin B12 (coefficient: -0.061; CI 95%: -0.09, -0.024). In addition, female patients had higher levels of vitamin B12 compared to men (coefficient: 49.1; CI 95%: 2.3-95).

CONCLUSIONS

Vitamin B12 deficiency is highly prevalent, especially in patients with diabetic neuropathy. In this study an inverse correlation was found between diabetic neuropathy and the plasma level of vitamin B12. Higher doses of metformin and male sex were factors related to lower levels of vitamin B12.

Central mechanisms of acute ANG II modulation of arterial baroreflex control of renal sympathetic nerve activity

Short-term intravenous infusion of angiotensin II (ANG II) into conscious rabbits reduces the range of renal sympathetic nerve activity (RSNA) by attenuating reflex disinhibition of RSNA. This action of ANG II to attenuate the arterial baroreflex range is exaggerated when ANG II is directed into the vertebral circulation, which suggests a mechanism involving the central nervous system. Because an intact area postrema (AP) is required for ANG II to attenuate arterial baroreflex-mediated bradycardia and is also required for maintenance of ANG II-dependent hypertension, we hypothesized that attenuation of maximum RSNA during infusion of ANG II involves the AP. In conscious AP-lesioned (APX) and AP-intact rabbits, we compared the effect of a 5-min intravenous infusion of ANG II (10 and 20 ng x kg(-1) x min(-1)) on the relationship between mean arterial blood pressure (MAP) and RSNA. Intravenous infusion of ANG II into AP-intact rabbits resulted in a dose-related attenuation of maximum RSNA observed at low MAP. In contrast, ANG II had no effect on maximum RSNA in APX rabbits. To further localize the central site of ANG II action, its effect on the arterial baroreflex was assessed after a midcollicular decerebration. Decerebration did not alter arterial baroreflex control of RSNA compared with the control state, but as in APX, ANG II did not attenuate the maximum RSNA observed at low MAP. The results of this study indicate that central actions of peripheral ANG II to attenuate reflex disinhibition of RSNA not only involve the AP, but may also involve a neural interaction rostral to the level of decerebration.

Maturity-onset Diabetes of the Young Type 7 (MODY7) and the Krüppellike Factor 11 Mutation (KLF11). A Review

INTRODUCTION

Maturity-onset diabetes of the young (MODY) is a rare disease due to a single gene mutation that affects several family members in most cases. The Krüppel-like factor 11 (KLF11) gene mutation is associated with decreased insulin sensitivity to high glucose levels. KLF 11 has been implicated in the pathogenesis of MODY type 7 but given its low prevalence, prolonged subclinical period, and the emergence of new information, doubts are raised about its association.

METHODS

A literature search of the PubMed, Scopus, and EBSCO databases was performed. The terms "Diabetes Mellitus, Type 2/genetics", "Mason-Type Diabetes" , "Maturity-Onset diabetes of the young", "KLF11 protein, human", and "Maturity-Onset Diabetes of the Young, Type 7" were used"., "Diagnosis" The search selection was not standardized.

RESULTS

The KLF1 mutation is rare and represents <1% of the mutations associated with monogenic diabetes. Its isolation in European family lines in the first studies and the emergence of new variants pose new diagnostic challenges. This article reviews the definition, epidemiology, pathophysiology, diagnosis, and treatment of MODY type 7.

CONCLUSION

MODY type 7 diabetes represents a rare form of monogenic diabetes with incomplete penetrance. Given its rarity, its association with impaired glucose metabolism has been questioned. Strict evaluation of glycemic control and the appearance of microvascular complications are key areas in the follow-up of patients diagnosed with MODY 7. More studies will be required to characterize the population with KLF11 mutation and clarify its correlation with MODY.

MANIFESTATIONS OF GLUCAGONOMA SYNDROME

OBJECTIVE

Glucagonoma is a rare neuroendocrine tumor of the pancreas. We present the case of a young female patient who presented with the major clinical manifestations of glucagonoma syndrome.

METHODS

The major clinical manifestations of glucagonoma syndrome are described in a 44-year-old, female patient. Beyond glucagonoma, the patient also displayed deep venous thrombosis, depression, diabetes, and necrolytic migratory erythema. We discuss the difficulty of treatment of patients with glucagonoma due to the low prevalence of the disorder, scarcity of medical evidence, lateness of diagnosis with liver metastases in most cases, and poor response to chemotherapy with high rates of relapse after surgery. In this case, pancreatectomy and hepatic lobectomy followed by somatostatin analogue therapy was the chosen treatment strategy.

RESULTS

The clinical findings were pancreatic and hepatic masses, proximal deep venous thrombosis, depression, diabetes, and necrolytic migratory erythema. The patient also had elevated levels of glucagon. Pancreatectomy and right hepatic lobectomy were performed and confirmed the glucagonoma.

CONCLUSION

Our case adds new knowledge about glucagonoma which is important due to the low incidence of the disease and the particular characteristics of the syndrome.

The medicalization of testosterone: reinventing the elixir of life

The pursuit of longevity, which during the Renaissance era was limited to longing for miraculous ways of rejuvenation, such as bathing in the fountain of youth, took a scientific turn in 1889 with the publication of Brown-Sequard's self-experiments with an extract of animal testes, which apparently improved his vitality, physical strength and cognition. This extract, marketed then as the "Elixir of Life", was sold for decades throughout Europe and North America. However, recent replication of Brown-Sequard's experiments demonstrated that such an extract only contains homeopathic concentrations of testosterone that are insufficient to exert any biological effect. Thus, the birth of Andrology began with a placebo effect. Over the past few decades, the quest for compounds that might lead to rejuvenation has regained traction, with testosterone being at the forefront. Though clinical practice guidelines advocate testosterone therapy in men with organic hypogonadism-the only indication approved by the Food and Drug Administration-testosterone continues to be marketed as a wonder drug with rejuvenating effects on sexual function, vitality, and a host of other unproven benefits. Additionally, the epidemic of obesity and diabetes, conditions associated with low testosterone, has further brought testosterone into the limelight. Although the number of testosterone prescriptions written have increased several-fold in the past two decades, carefully conducted randomized trials suggest modest benefits of testosterone therapy. At the same time, safety concerns, particularly in older men, remain valid.

Treatment of Grave’s Disease in Adults

Graves disease is an autoimmune disease, with a genetic susceptibility, activated by environmental factors like stress, iodine excess, infections, pregnancy and smoking. It is caused by thyroid stimulating immunoglobulin (TSI) or thyroid stimulating antibody (TSAb) and is the most common cause of hyperthyroidism with an incidence of 21 per 100,000 per year. Treatment of Graves disease includes antithyroid drugs such as methimazole and propylthiouracil, radioactive iodine therapy and thyroidectomy. Methimazole, an antithyroid drug that belongs to the thioamides class, is usually the first line of treatment due to lower risk of hepatotoxicity compared to propylthiouracil. Radioactive iodine therapy is reserved for those patients who do not respond to antithyroid drugs or have contraindication or adverse effects generated by antithyroid drugs, and thyroid surgery is an option in people with thyroid nodular disease with suspected malignancy or large goiters such as predictors of poor response to antithyroid drugs and radioactive iodine therapy. Multiple factors influence the management of patients with Graves disease including patient and physician preferences, access to medical services and patients features such as age, complications and comorbidities.

Underlying Mechanisms Between Diabetes Mellitus and Osteoporosis

Several studies have linked diabetes mellitus with an increased risk of bone fractures. Patients with type 1 diabetes have lower bone mineral density and patients with type 2 diabetes have an increased risk of fracture despite normal or high bone mineral density, measured by dual energy x-ray absorptiometry. Different mechanisms have been proposed in the pathophysiology of bone disease in diabetic patients. The mechanisms involved include microvasculature changes, advanced glycation end products accumulation, and altered osteoblast–osteoclast function with increased sclerostin, decreased insulin-like growth factor 1 (IGF1), decreased osteocalcin, and other molecular alterations, leading to a decrease in bone turnover and altered bone quality. Other factors, such as increased risk of falls related to diabetic neuropathy and diabetic retinopathy have also been proposed. Different diagnostic methods have been described for the study of bone disease in patients with diabetes, due to the lack of correlation between bone mineral density measured by dual x-ray absorptiometry and the fracture risk in this group of patients. These methods include the evaluation of bone turnover markers, the FRAX score, the trabecular bone score, and the evaluation of microarchitecture with high-resolution peripheral quantitative tomography. This editorial provides a short overview of the underlying mechanisms between diabetes mellitus and osteoporosis, and the diagnostic methods used to evaluate these patients.

Maturity-onset diabetes of the young type 3 and premature ovarian insufficiency: chance or causality: a case report and literature review

SUMMARY

We present the case of a 23-year-old patient with maturity-onset diabetes of the young type 3 (MODY 3) and premature ovarian insufficiency (POI). There is no known correlation between MODY 3 and POI, although POI can impair glucose metabolism, and MODY can cause microvascular complications such as POI. We did not find literature describing a correlation between these two pathologies nor did we find similar cases described in the literature.

LEARNING POINTS

Maturity-onset diabetes of the young type 3 (MODY 3) is an infrequent cause of diabetes that should be considered in young patients with atypical presentation of type 1 or type 2 diabetes. MODY 3 can be associated with microvascular complications of diabetes, which is why it is important to diagnose as early as possible. Impairment of glucose metabolism has been demonstrated in patients with premature ovarian insufficiency and menopause.

Heterotopic bone formation with extramedullary haematopoiesis in a thyroid nodule

The presence of mature bone and bone marrow in the thyroid gland is an exceedingly rare occurrence. Extramedullary haematopoiesis (EMH) and heterotopic bone formation (HBF) should be suspected when cytology of thyroid nodules reveals evidence of megakaryocytes or bone marrow fat, respectively. The cause of these abnormalities has not been fully elucidated, but the role of bone morphogenic factors (BMPs) in their pathogenesis has been suggested. Both EMH and HBF can be seen in both benign and malignant primary thyroid conditions, and although they have not been definitively associated with significant pathology, it is recommended that extension studies be considered in the event of these findings to rule out concomitant haematological conditions.

Evaluation of pituitary tumor volume as a prognostic factor in acromegaly: A cross-sectional study in two centers

BACKGROUND

Acromegaly is caused by a pituitary neuroendocrine tumor (PitNET) with excessive production of growth hormone (GH), leading to multisystem complications. Previous studies have identified predictors of disease persistence following surgery and poor response to medical treatment, including tumor size, vertical and horizontal extensions of the adenoma, hyperintensity in T2-weighted magnetic resonance imaging, granulation density, and pre- and postoperative GH and insulin-like growth factor 1 (IGF-1) levels.

AIM

To evaluate PitNET volume as a complementary prognostic factor in patients with acromegaly.

METHODS

This is a retrospective descriptive study with an analytical component evaluating the correlation between the volumetric analysis of GH-producing PitNETs, IGF-1 levels before and after surgery, disease control during follow-up, and the line of therapy required for disease control in a cohort of patients treated at two centers: Endocrinology Department of the Central Military Hospital and Centros Médicos Colsanitas, Bogotá, Colombia.

RESULTS

A total of 77 patients with acromegaly (42 men, 35 women) were included in this study. The mean age at diagnosis was 42 years (standard deviation [SD]: 12), with a mean disease duration of 9.9 years (SD: 7.2). The mean pituitary tumor volume was 4358 mm³ (SD: 6291, interquartile range [IQR]: 13602). Patients with controlled acromegaly had a mean PitNET volume of 3202 mm³ (SD: 4845, 95%CI: 621-5784) compared to 5513 mm³ (SD: 7447, 95%CI: 1545-9482) in the uncontrolled group (P = 0.15). A PitNET volume exceeding 3697 mm³ was associated with a higher likelihood of requiring third or fourth-line therapy (50% vs 36%; P = 0.03).

CONCLUSION

PitNET volume was associated with the need for higher-line therapy to manage acromegaly but did not correlate with long-term disease control or with pre- or postsurgical IGF-1 levels. Nevertheless, a trend towards an inverse relationship between tumor volume and future disease control was observed. While macroadenoma classification remains crucial, among patients with macroadenomas, those with a volume exceeding 3697 mm³ could have worse prognosis.

Evaluation of pituitary tumor volume as a prognostic factor in acromegaly: A cross-sectional study in two centers

BACKGROUND

Acromegaly is caused by a pituitary neuroendocrine tumor (PitNET) with excessive production of growth hormone (GH), leading to multisystem complications. Previous studies have identified predictors of disease persistence following surgery and poor response to medical treatment, including tumor size, vertical and horizontal extensions of the adenoma, hyperintensity in T2-weighted magnetic resonance imaging, granulation density, and pre- and postoperative GH and insulin-like growth factor 1 (IGF-1) levels.

AIM

To evaluate PitNET volume as a complementary prognostic factor in patients with acromegaly.

METHODS

This is a retrospective descriptive study with an analytical component evaluating the correlation between the volumetric analysis of GH-producing PitNETs, IGF-1 levels before and after surgery, disease control during follow-up, and the line of therapy required for disease control in a cohort of patients treated at two centers: Endocrinology Department of the Central Military Hospital and Centros Médicos Colsanitas, Bogotá, Colombia.

RESULTS

A total of 77 patients with acromegaly (42 men, 35 women) were included in this study. The mean age at diagnosis was 42 years (SD: 12), with a mean disease duration of 9.9 years (SD: 7.2). The mean pituitary tumor volume was 4358 mm³ (SD: 6291, interquartile range [IQR]: 13602). Patients with controlled acromegaly had a mean PitNET volume of 3202 mm³ (SD: 4845, 95%CI: 621-5784) compared to 5513 mm³ (SD: 7447, 95%CI: 1545-9482) in the uncontrolled group (P = 0.15). A PitNET volume exceeding 3697 mm³ was associated with a higher likelihood of requiring third or fourth-line therapy (50% vs 36%; P = 0.03).

CONCLUSION

PitNET volume was associated with the need for higher-line therapy to manage acromegaly but did not correlate with long-term disease control or with pre- or postsurgical IGF-1 levels. Nevertheless, a trend towards an inverse relationship between tumor volume and future disease control was observed. While macroadenoma classification remains crucial, among patients with macroadenomas, those with a volume exceeding 3697 mm³ could have worse prognosis.

Características de estudios publicados en áreas del conocimiento de Medicina Interna incluyendo calidad, idioma y década de publicación

Introducción: Los usuarios de literatura médica disponen de gran cantidad de estudios publicados, con calidad metodológica variable por diversos motivos. Realizamos una descripción de las características de publicaciones recuperadas en Pubmed de Cardiología, Endocrinología, Nefrología y Neumología, incluyendo características de calidad por filtros Clinical Queries de Pubmed, idioma y década de publicación. Metodología: Realizamos un estudio descriptivo. Se seleccionaron diez términos MeSH (Medical Subject Headings) de Medline, representativos de Cardiología, Endocrinología, Nefrología y Neumología. Se realizaron búsquedas en Pubmed con y sin filtros de calidad de Clinical Queries en diagnóstico y tratamiento, búsqueda por idiomas y por década de publicación. Resultados: Se realizaron 520 búsquedas en Pubmed. Se encontraron 498.952 publicaciones en diagnóstico y tratamiento, el 16% son estudios con características de calidad; en cardiología 23%, neumología 13%, endocrinología 13% y nefrología 6,5%. El 98% de estudios publicados en inglés, mientras solo el 2% distribuido proporcionalmente en español y francés. En la década del 2000 aumentó 2,4 veces el número de estudios con filtros de calidad, comparado con la década de 1990. Conclusiones: Existe un alto número de estudios publicados en Medicina Interna; Cardiología y Endocrinología representan la mayoría, Cardiología tiene la mayor proporción de estudios con características de filtros de calidad, Neumología y endocrinología tienen una proporción similar. En inglés se encuentran la mayoría de publicaciones con filtros de calidad, comparado con español y francés.

Response to sorafenib in a locally advanced oncocytic cell carcinoma of the thyroid

We present the case of a female patient in her late 70s, diagnosed with widely invasive oncocytic cell carcinoma, with extrathyroidal extension, infiltration into the extrathyroidal muscle, involvement of the sternohyoid muscle and infiltration into the external muscle fibres of the oesophagus. Over the following year, metastases were documented in the lungs, bones and brain. Additionally, there was progression of the locally advanced lesion involving the airway and upper gastrointestinal tract. After considering iodine refractoriness, treatment with sorafenib was initiated. Notably, regression of the locoregional lesion at the cervical level was observed following treatment with the multikinase inhibitor.