Clinical relevance of hypothyroidism screening in a child with an unexplained elevated serum creatinine

Mosleh Jabari; Hassan Alshehri

CASE REPORT

Year : 2016 | Volume : 1 | Issue : 1 | Page : 39-41

Clinical relevance of hypothyroidism screening in a child with an unexplained elevated serum creatinine

Mosleh Jabari, Hassan Alshehri
Department of Pediatrics, College of Medicine, Al-Imam Muhammad Ibn Saud Islamic University, Riyadh, Saudi Arabia

Date of Submission	09-May-2016
Date of Acceptance	14-May-2016
Date of Web Publication	7-Oct-2016

Correspondence Address:
Dr. Hassan Alshehri
Department of Pediatrics, College of Medicine, Al-Imam Muhammad Ibn Saud Islamic University, Otham Ibn Affan Road, PO Box 7544, Riyadh 13317-4233
Saudi Arabia

Source of Support: None, Conflict of Interest: None

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Abstract

The association of hypothyroidism with a reduction in glomerular filtration rate and renal plasma flow is widely mentioned in the literature. However, elevation of serum creatinine (SCr) is not frequently described in the textbooks and literature as an indicator of hypothyroidism. Here, we present a 6-year-old girl who had deprived the energy for vigorous physical activity and reported fatigue to perform her daily activities with no other history of significant medical conditions with unremarkable physical examination. All her initial laboratory findings were within the normal range except an increased SCr level (75 μmol/L). The presence of nonspecific symptoms and unexplained elevation of SCr led to endocrinological investigations, which revealed hypothyroidism caused by autoimmune thyroiditis. Replacement therapy with thyroxine improved her hypothyroid state and SCr level to normal after 6 weeks. Therefore, we recommend measurement of thyroid function in these patients to rule out the likelihood of hypothyroidism.

Keywords: Autoimmune, high serum creatinine, hypothyroidism

How to cite this article:
Jabari M, Alshehri H. Clinical relevance of hypothyroidism screening in a child with an unexplained elevated serum creatinine. Imam J Appl Sci 2016;1:39-41

How to cite this URL:
Jabari M, Alshehri H. Clinical relevance of hypothyroidism screening in a child with an unexplained elevated serum creatinine. Imam J Appl Sci [serial online] 2016 [cited 2020 Nov 25];1:39-41. Available from: https://www.e-ijas.org/text.asp?2016/1/1/39/191719

Introduction

The association between underactive thyroid (hypothyroidism) and renal impairment is known for years.^[1] Hypothyroidism reduces glomerular filtration rate (GFR) which, in turn, leads to a reversible elevation in serum creatinine (SCr) concentration.^[2],[3] SCr may also be increased in isolation, without the influence of the GFR.^[1] However, significant elevation of SCr levels is rare in children with hypothyroidism, and only a few cases have been reported.^[4] Although some authors have reported a rise of SCr in the hypothyroid state and suggested a correlation between them,^{[5],[6],[7],[8],[9],[10]} but an elevated SCr level is frequently not mentioned as a possible indicator of hypothyroidism. Therefore, children with unexplained rises in SCr are usually not screened for hypothyroidism.

We report a case of a 6-year-old girl who presented high SCr level with no other potential indicators of hypothyroidism at her initial presentation. Endocrinological investigations revealed the presence of autoimmune hypothyroidism. Thyroxine replacement therapy led to normalization of SCr, thyroid stimulating hormone (TSH), and free thyroxine (FT4) levels after 6 weeks.

Case Report

A 6-year-old girl, who was completely well until 1 month before her presentation. She was admitted to a private hospital in Riyadh with 3 weeks history of decreased activity, generalized weakness, and headache. She deprived the energy for vigorous physical activity and reported fatigue to perform her daily activities. She was without any coexisting diseases. In addition, there was no past or family history of other significant medical conditions.

On physical examination, she was conscious and found with dry skin. No obvious dysmorphic feature was observed. Her weight and stature were normal. She was found with a weight of 20 kg and height of 109 cm, which fall within the normal percentile for her age.

Vital signs were normal, including body temperature, pulse rate, respiratory rate, and blood pressure with the absence of renal impairment signs such as pallor or edema. In addition, she did not show any signs of underlying infectious or inflammatory systemic disorders.

Investigations

On admission, her laboratory investigations revealed an SCr of 75 μmol/L. In urinalysis, there was no proteinuria or microscopic hematuria, and midstream urine culture was negative. Ultrasonography of kidney showed normal size and echogenicity of both kidneys with no evidence of urinary obstruction. In view of nonspecific symptoms and unexplained high creatinine, thyroid function was done and revealed significantly high TSH (500 mIU/L), but a low FT4 (1 pmol/L) [Table 1]. SCr was 95 μmol/L, which reflected a sharp increase compared to the previous test finding [Table 1].

Table 1: Main clinical and laboratory data on admission and during follow-up

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She was referred to us for further evaluation and appropriate treatment of hypothyroidism. On physical examination, we observed that she was thriving well with no abnormal vital signs. We thoroughly reviewed her clinical and laboratory investigation results. All of her test findings were within the reference values except an elevated SCr level with low FT4, very high TSH, and positive thyroid antibodies. No anemia or secondary hyperparathyroidism (SHPT) was associated with her renal impairment. After reviewing all the clinical and biochemical data together with the views of our nephrologist and in the absence of the explanation for the rise in creatinine, we came to a conclusion that the high creatinine is secondary to hypothyroidism.

Treatment and follow-up

We started thyroxine replacement therapy at a dose of 50 µg/day. She showed a progressive improvement of symptoms. After 6 weeks, her laboratory investigations revealed normalized SCr, TSH, and FT4 values. We repeated the laboratory test after 3 months of treatment, which showed more improved values for SCr and TSH [Table 1].

Currently, the patient is followed by the pediatric endocrine and nephrology services and her clinical and laboratory parameters within normal.

Discussion

Thyroid dysfunction affects a number of organs in our body, including kidneys.^[1] The association of hypothyroidism and kidney derangements has been widely described in the literature.^[1],[2] Renal and metabolic effects are reported to reduce renal plasma flow, decrease GFR, and disrupt free water excretion in patients with hypothyroidism.^[3] However, despite some known clinical features, renal manifestations of underactive thyroid often have an insidious onset. Hence, a perfect screening of obvious hypothyroidism has been challenging.

In the present case, our patient developed hypothyroidism due to autoimmune thyroiditis but was completely unaware of it at first presentation. Initial laboratory investigations did not show any clinical indicators of hypothyroidism except an increased SCr concentration. Therefore, the patient's treatment was delayed until a complete thyroid profile was done. Thyroxine replacement therapy normalized the patient's hypothyroid state and SCr level. Chronic kidney disease (CKD) is frequently associated with SHPT.^[11] In our patient, the presence of negative proteinuria, hematuria normal result of parathyroid hormone test, and normal kidney size in ultrasonography were enough indicators to exclude the possibility of either CKD or SHPT.

Our patient's unexplained elevation of SCr level and her response to thyroxine administration seemed appropriate to establish a diagnosis of exclusion for hypothyroidism as the main cause for this elevation in SCr.

According to Kreisman and Hennessey,^[5] hypothyroidism is associated with a consistent, reversible increase in SCr concentration. The elevation of SCr in hypothyroid patients is observed in both adults ^[6],[7] and children.^[8],[9],[10] Some authors have also reported such increase in patients with subclinical hypothyroidism.^[12] However, an elevated SCr level is not frequently discussed in the textbooks and literature as a factor indicative of severe hypothyroidism.^{[1],[2],[3],[4]} In addition, only a few previous cases have yet reported such elevation as a matter of clinical relevance.^[4] In our case, our patient's increased SCr level seemed clinically relevant for the screening of hypothyroidism.

Therefore, unexplained elevations in SCr levels may be an indicator of severe hypothyroidism. Clinicians should consider evaluating the thyroid function in a patient whose thyroid profile is not known and who has a modest increase in SCr level.

Conclusion

We report a 6-year-old girl who had no coexisting diseases at first presentation. All her initial laboratory results were normal except an elevation of SCr, which led to the evaluation of thyroid function. She was diagnosed with hypothyroidism caused by autoimmune thyroiditis, and her hypothyroid state and SCr were normalized after thyroxine replacement therapy. Here, we think that in this patient a decline in renal function was probably caused by hypothyroidism. Therefore, we recommend frequent evaluation of thyroid function in all patients with moderate elevation of SCr to exclude the possibility of hypothyroidism.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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