Author: Cheng Ziyun
Unit: Department of Clinical Laboratory, Zhongshan Hospital, Fudan University
Case sharing
A middle-aged woman who did not see improvement in the treatment of persistent hypokalemia in the hospital came to the endocrinology department of our hospital for treatment. Because the patient has a history of early-onset hypertension, the endocrinologist first thinks of the possibility of primary hyperaldosteronism, but the patient examines a decrease in serum aldosterone, which is the exact opposite of the characteristics of orthodonalism. To further explore the cause, the doctor asked for a history in more detail and learned that the patient still had primary amenorrhea and had visited many people for this reason, but none of them found the cause. After that, the patient also gave up looking for the cause and gradually forgot about the problem.
Based on the patient's incorporation of this particular clinical manifestation, the doctors thought of a rare endocrine disease, Congenital Adrenal Hyperplasia (CAH), and prescribed her a complete set of sex hormones, Adrenocorticotropic hormone (ACTH)-cortisol rhythm testing and adreno CT testing.
Table 1. ACTH-Cortisol rhythm test results
Adrenal CT suggests bilateral adrenal thickening, and ACTH-cortisol rhythm test results (table 1) show an increase in ACTH and a decrease in cortisol.
Table 2. Sex hormones six results
Six results of sex hormones (Table 2) showed significantly lower levels of estradiol, testosterone, and dehydroepiandrosterone sulfate and an increase in follicle-stimulating hormone.
Seeing the patient's examination results, the doctor's judgment that she may have CAH became more firm. For further confirmation, doctors prescribe a full set of adrenocorticosteroid mass spectrometry tests. Why do doctors make such judgments? Let's first understand what kind of disease CAH is.
What is CAH?
CAH is an autosomal recessive disorder in which specific adrenal steroid hormones are not synthesized in sufficiently due to enzyme deficiencies in the body. Different enzyme deficiencies cause different changes in hormone levels downstream of the metabolic pathway, leading to different types of CAH.
The clinical manifestations of CAH patients are therefore complex and diverse: for example, abnormal sex hormones may lead to sexual infantilism, secondary sexual characteristic dysplasia, and may also lead to hyperandrogenemia, precocious puberty, and menstrual disorders in women; increased mineralocorticoids are manifested as hypertension, hypokalemia, metabolic alkalosis, and decreased by hypotension, hyponatremia, and hyperkalemia; glucocorticoid deficiency may cause loss of appetite, skin pigmentation, fatigue, hypotension, hyponatremia and other discomforts.
In the face of such a variety of disease manifestations, let's take a look at how steroid hormone testing can find out the culprit hidden behind "hypokalemia, hypertension, menstrual irregularities":
Screening for congenital adrenal hyperplasia
The adrenal cortex is an important place for steroid hormone synthesis in the body. In this process, the participation of multiple enzymes is required to ensure that everything is in order. Defects in enzymes in the adrenal hormone synthesis pathway in patients with CAH can lead to impaired hormone synthesis associated (downstream of the enzyme pathway), causing endocrine disorders. Among them, the most common is 21-hydroxylase deficiency, and other enzyme defects include 11β-hydroxylase deficiency, 17α-hydroxylase deficiency, etc. [1].
At present, CAH screening is mainly carried out clinically through the quantitative detection results of steroid hormones, and the chemical structure of different steroid hormones is very similar to each other (Figure 1). Commonly used immunoassays do not meet the needs of clinical diagnosis in terms of detection accuracy, detection sensitivity, or the number of items that detect hormones [2]. Therefore, the precise detection of steroid hormones has always been an urgent problem for CAH screening.
Figure 1. Structurally Similar Steroids (CCLM 2020)
Liquid chromatography mass spectrometry technology to help the accurate diagnosis and treatment of congenital adrenal hyperplasia
Liquid chromatography mass spectrometry technology uses the high separation ability of chromatography to separate substances and the high resolution ability of mass spectrometry to materials, which can effectively distinguish similar steroid hormones and accurately detect hormone content. Currently, liquid chromatography mass spectrometry is the gold standard for steroid hormone testing [3].
The woman in the case, who measured the full set of adrenocorticosteroids by mass spectrometry (Figure 2), showed that levels of multiple hormones in the adrenal globular band pathway (mineralocorticoids) were significantly elevated, while most of the hormones in the bundle (glucocorticoids) and reticular belt pathways (sex hormones) were significantly lower. In the physiological metabolism of globular band hormones to bundled bands and reticular band hormones, 17α hydroxylase plays a key role.
Figure 2. Adrenocorticosteroid test results in patients
Therefore, based on the above test results, it can be presumed that the patient has a 17α-hydroxylase deficiency. This defect leads to the inability of progesterone to be effectively converted to 17-hydroxyprogesterone, which in turn leads to insufficient glucocorticoid and sex hormone synthesis. Subsequently, the patient also underwent genetic testing, and the results further proved the clinical inference.
Although the aldosterone level of the patient is not high, due to the presence of excessive deoxycorticoids in the body also has the effect of mineralocorticoids, resulting in hypertension, hypokalemia and other manifestations of primary hyperaldosteronism. At the same time, insufficient synthesis of sex hormones due to 17α-hydroxylase deficiencies caused patients to develop menstrual irregularities. Doctors gave the patient dexamethasone treatment, and the patient's severe hypokalemia returned to normal levels.
Liquid chromatography mass spectrometry technology detects the advantages of steroid hormones
Easy sampling: Only peripheral blood samples need to be taken.
Detection accuracy: Liquid chromatography mass spectrometry technology is extremely sensitive and specific, enabling accurate identification and accurate quantification of hormone types.
Multi-component testing: 22 steroid hormones can be detected at the same time, which effectively reflects the overall secretion of steroid hormones and helps to differentially diagnose various adrenal cortical lesions.
The Department of Laboratory, Zhongshan Hospital Affiliated to Fudan University, has carried out liquid chromatography mass spectrometry technology, which covers multidisciplinary fields such as endocrine hormones, vitamins, drug (antibiotics/anti-tumor/anti-epileptic) concentrations, sleep markers, etc., and assists in clinical diagnosis and treatment in the aspects of secondary hypertension etiology screening, infertility, and precision medication. As an emerging clinical laboratory technology, mass spectrometry technology will complement traditional testing methods, continuously improve testing capabilities, and help clinical precision diagnosis and treatment.
【Reference】
[1] El-Maouche D,Arlt W,Merke DP. Congenital adrenal hyperplasia[J]. Lancet,2017,390 (10108):2194-2210.
[2] Gidl f S,Wedell A,Guthenberg C, et al. Nationwide neonatal screening for congenital adrenal hyperplasia in sweden: a 26-year longitudinal prospective population-based study[J]. JAMA Pediatr,2014,168(6):567-74.
[3] Speiser P W,Arlt W,Auchus R J,et al. Congenital Adrenal Hyperplasia Due to Steroid 21-Hydroxylase Deficiency:An Endocrine Society Clinical Practice Guideline[J]. J Clin Endocrinol Metab,2018,103(11):4043-4088.
Editor: Ren Mileage Reviewer: Xiao Ran