|Year : 2017 | Volume
| Issue : 3 | Page : 127-129
Recurrent hypoglycemia: An unusual finding of hypothyroidism
Tek Chand Yadav1, Jaikrit Bhutani1, Manisha Upadhyay2, SK Raghunandan1
1 Department of Medicine, PGIMS, Rohtak, Haryana, India
2 Department of Obstetrics and Gynecology, PGIMS, Rohtak, Haryana, India
|Date of Web Publication||9-Oct-2017|
121-B, Model Town, Karnal, Haryana
Source of Support: None, Conflict of Interest: None
Hypothyroidism is one of the most prevalent endocrine disorders in the world, with a sharp rising incidence. The evaluation of recurrent hypoglycemia in the light of hypothyroidism still remains a major diagnostic challenge for most clinicians. We report a rare case of hypothyroidism presenting as recurrent hypoglycemia with relative adrenal insufficiency. Blunting of hypophyseal–pituitary–adrenal axis, pituitary dysfunction, delayed gastric emptying, decreased production and effect of glucagon on hepatocytes, reduced insulin clearance, gluconeogenesis, and glycogenolysis in patients with hypothyroidism may be the plausible mechanisms of hypoglycemia in such individuals. This will enable clinicians to consider thyroid dysfunction while evaluating causes of hypoglycemia in individuals without diabetes mellitus or treating unexplained hypoglycemic episodes in individuals with diabetes.
Keywords: Low blood glucose, relative adrenal insufficiency, thyroid disorders
|How to cite this article:|
Yadav TC, Bhutani J, Upadhyay M, Raghunandan S K. Recurrent hypoglycemia: An unusual finding of hypothyroidism. Thyroid Res Pract 2017;14:127-9
|How to cite this URL:|
Yadav TC, Bhutani J, Upadhyay M, Raghunandan S K. Recurrent hypoglycemia: An unusual finding of hypothyroidism. Thyroid Res Pract [serial online] 2017 [cited 2019 Jun 26];14:127-9. Available from: http://www.thetrp.net/text.asp?2017/14/3/127/216212
| Introduction|| |
Hypothyroidism is one of the most prevalent endocrine disorders in the world, with a sharp rising incidence. Hypoglycemia has not been described as a typical presenting feature of hypothyroidism in most existing literature, including major thyroidology textbooks. Recent reviewers have emphasized hypothyroidism to be an endocrinopathy responsible for hypoglycemia. This concept has also been rejected by other researchers, who continue to believe that should hypoglycemia exist in the setting of hypothyroidism, it is a manifestation of panhypopituitarism instead of primary thyroid pathology. There have been case reports earlier that link hypoglycemia with congenital hypothyroidism and editorials highlighting the importance of screening for hypothyroidism in hypoglycemic participants. However, the evaluation of recurrent hypoglycemia in the light of hypothyroidism still remains a major diagnostic challenge for most clinicians.
We report a rare case of hypothyroidism presenting as recurrent hypoglycemia with relative adrenal insufficiency.
| Case Report|| |
A 32-year-old female, not a known case of any chronic illness, presented to the emergency service of the Department of Medicine, PGIMS Rohtak, with complaints of generalized fatigue, weakness, and repeated episodes of palpitation and sweating, at intervals of 6–8 h, for 2 weeks. Further enquiring the history, she reported amenorrhea for the past 3 months. There was no other significant history pertaining to hypoglycemia. On examination, her general condition and vitals were stable, and all systemic examination was within normal limits.
Baseline electrocardiogram and chest skiagram were obtained and were normal. Her random plasma glucose was found to be 24 mg/dL. A simultaneous venous sample collected in sodium fluoride vial, processed immediately revealed blood glucose to be 20 mg/dL. Immediate correction of hypoglycemia was done with 25% dextrose solution, and strict glucose monitoring was initiated. After relief of symptoms, she was further evaluated for further causes of hypoglycemia. Pharmacological or toxicological screens for causes of hypoglycemia returned negative. The patient developed similar episode of hypoglycemia (blood glucose level – 37 mg/dL) 6 h later and was corrected as before. These episodes continued to recur at intervals of 6 h. During one of these episodes, blood samples were drawn for serum insulin and C-peptide levels. A low plasma insulin and C-peptide level measured by immunochemiluminometric assay ruled out exogenous insulin administration or presence of an insulinoma or islet cell hypertrophy. To rule out nonislet cell tumors causing hypoglycemia, a contrast-enhanced computed tomography (CECT) of the abdomen was done, which did not reveal any abnormal pathology.
Further, while evaluating for abnormalities in hypothalamic–pituitary–adrenal (HPA) axis as a cause of hypoglycemia, basal morning 8 am cortisol and adrenocorticotropic hormone (ACTH) tests were done. While cortisol levels were markedly reduced, ACTH levels were borderline and on the higher end. A high-dose ACTH stimulation test revealed adequate rise in ACTH levels; however, cortisol remained markedly low. The presence of very long-chain fatty acids and antibodies against 21-hydroxylase in serum returned negative, thus eliminating autoimmune causes and adrenoleukodystrophy. For ruling out other adrenal pathologies, a repeat CECT abdomen was done focusing on adrenals which turned out to be normal. Since the patient had no hypotensive crisis or other symptoms of acute adrenal insufficiency, a provisional diagnosis of relative primary adrenal insufficiency (PAI) was considered.
Treatment was initiated for relative PAI, with 6 hourly 100 mg hydrocortisone. Despite therapy, hypoglycemic episodes continued to occur at similar intervals. After unsuccessful 1 week of therapy with hydrocortisone, a thyroid profile, follicle-stimulating hormone, luteinizing hormone levels, and magnetic resonance imaging of the brain was ordered for the completeness of workup of adrenal insufficiency. Everything returned normal except thyroid profile which revealed thyroid-stimulating hormone (TSH) to be elevated (40.75 μIU/ml), and total T3 (0.34 ng/ml) and total T4 (1.40 mcg/dL) were reduced. Thyroid replacement was initiated at a dose of 50 mcg/day, appropriate to the patient's body weight. Within 1 week, the patient improved symptomatically and hypoglycemic episodes reduced to twice a day. Hydrocortisone was tapered off as no hypoglycemia occurred, and the patient was discharged on only 50 mcg of thyroxine.
The patient visited for follow-up after 6 weeks in the outpatient department and was symptom free. Basal cortisol, ACTH, TSH, T3, and T4 levels were repeated and were within normal range. The reported laboratory values before and after thyroid replacement are summarized in [Table 1].
| Discussion|| |
Hypoglycemia is a common presenting complaint in the endocrine clinic. Although harmful, it is an unavoidable part of treatment of both type 1 and type 2 diabetes mellitus, irrespective of the use of insulin, or oral glucose-lowering drugs. Another common endocrine disorder, hypothyroidism, is linked with numerous neurohormonal, metabolic, and nervous derangements which may lead to hypoglycemia.
Blunting of HPA axis in hypothyroid people has been well demonstrated. These patients are susceptible to develop relative adrenal insufficiency, if not primary adrenal failure. Counter regulatory release of cortisol in response to insulin-induced hypoglycemia is also blunted in such cases leading to further worsening. Furthermore, it has been shown that pituitary dysfunction leading to rather thyroid dysfunction may actually be a consequence of primary hypothyroidism. It has been shown that hypothyroidism leads to reduction in both basal and stimulated growth hormone by acting on both hypothalamus and pituitary. A similar hypothesis can explain the low basal and stimulated cortisol levels in our case. The process of gluconeogenesis and glycogenolysis is also impaired in hypothyroidism, both in skeletal muscle and in adipose tissue.
Other less significant metabolic abnormalities in hypothyroidism include reduced glucagon production and its action on hepatocytes  and reduced insulin clearance. The gastrointestinal system is also affected, with delayed gastric emptying, decreased intestinal glucose absorption, and portal venous flow. These biochemical disturbances together may be responsible for hypoglycemia in hypothyroid persons.
Thus, it maybe clinically relevant for all patients with or without diabetes, and hypoglycemia to undergo screening for hypothyroidism, and vice versa as these metabolic disorders may coexist and affect the treatment strategy.
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Conflicts of interest
There are no conflicts of interest.
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