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.

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 (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.

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.