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.

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.

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.

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.

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.

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.

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.