What do your clinical exam and laboratory findings indicate?
The symptoms of the 50-year-old female patient definitely relate to abnormal hormone level changes. Symptoms and signs of hormonal deficiencies include unintended weight loss or gain, feeling cold, muscle weakness, and vomiting (Nachtigall, 2018). In this case, laboratory findings play the most crucial role in setting diagnosis. Complete blood count (CBC) and differential test results turned to be expected. However, serum-free T4 and thyroid-stimulating hormone (TSH), both produced by the thyroid, were not within normal limits. The average result for free T4 and TSH in adults is 0.8-1.8 ng/dL and 0.5 to 3.0 mIU/L, respectively. Since the patient has a higher level of T4 and adequate TSH, her thyroid may be overactive that associated with unintentional weight loss. Nevertheless, it is not enlarged and not palpable; she instead gained weight, so the initial cause can hardly be hyperthyroidism.
The serum cholesterol of 255 is high, revealing abnormal lipids, while the heart rate is 56, slightly lower than usual. It resembles hypothyroidism that narrows arteries, weakens heartbreak, and ultimately leads to high cholesterol (Rafatjah, 2019). Other essential symptoms spotted during the clinical and neurological exams are dry skin, puffy face, hair loss, depression, constipation, memory loss, and slow speech. Considering mentioned signs and symptoms, one might suppose a systematic disease caused by the pituitary disorder. To make sure, the physician should administer ACTH and cortisol testing together with a CT scanning to the patient.
What is happening at the cellular level to cause these physical changes?
The functioning of the thyroid gland is highly dependable at brain structures, hypothalamus, and pituitary gland, which control the production of thyroid hormones establishing the endocrine feedback system. The functional or anatomical disorder of the hypothalamus and pituitary results in the insufficient TSH level failing to stimulate thyroid hormone synthesis. In this case, thyroid morphology is adequate, and its shortfalls are explained by dysfunctions found somewhere within the hypothalamus-pituitary-thyroid axis (Lewiński & Stasiak, 2017). The disruption of the control system in other endocrine organs can see healthy thyroid underperforming. The inability of the pituitary to secrete TSH is usually caused by a tumor or its infiltration by inflammatory cells. Ultimately, hypothyroidism affects all body functions, slows the mental and physical functioning of the patient.
At the cellular level, a normal homeostatic state of cells is impossible since thyroid hormone fails to reach their nucleus, triggering hypothyroid symptoms. As mentioned, the thyroid gland may even normally function and produce/dump enough hormones into the bloodstream. However, the control system enhances the latter’s deactivation in body cells and tissues, leading to slow metabolism (Lewiński & Stasiak, 2017). This cellular hypothyroidism further causes constipation, cold sensitivity, muscle weakness, tiredness, slow thoughts, hair loss, depression, memory loss, and other physical changes. It may occur even when the thyroid gland is not palpable, functions as always, while tests show normal T4 and TSH levels.
What might be the cause of the systemic disease?
Thus, this systemic disease is caused by insufficient functioning of the pituitary, possibly associated with a tumor. The latter is the most common cause of secondary hypothyroidism, while the primary one occurs due to Hashimoto’s (autoimmune) disease (Rafatjah, 2019). In terms of risk factors, females over 50 years old are more likely to develop this condition than others. What is more, individuals who had head trauma, suffered from chronic stress, or have a family history of pituitary dysfunction are at high risk.
Describe the hypothalamic-pituitary-thyroid axis
The hypothalamic-pituitary-thyroid axis (HPT) is a regulative part of the neuroendocrine system that includes the thyroid gland, the pituitary gland, and the hypothalamus. Its primary function is to ensure normal circulating levels of thyroid hormone (Ortiga-Carvalho, 2016). Typically, the hypothalamus starts the process by releasing the TRH hormone when there are low T3 and T4 in the bloodstream. The TRH reaches the pituitary and stimulates the thyroid-stimulating hormone (TSH) production and secretion. In turn, the TSH makes the thyroid meet the whole system’s demand for T3 and T4. With the help of its hormones, the thyroid maintains negative feedback control over the anterior pituitary and hypothalamus (Ortiga-Carvalho, 2016). Hence, it controls and affects the synthesis and release of both TRH and TSH from the hypothalamus and pituitary, respectively.
Is this primary or secondary hypothyroidism?
Considering the lab results and main symptoms, it is secondary hypothyroidism since free T4 is high, while serum TSH is low. In contrast, primary hypothyroidism is associated with elevated TSH and low T4 levels due to the absence of pituitary feedback inhibition. The latter also relates to direct physical or functional malfunctions of the thyroid itself, whereas the hypothalamus or pituitary gland issues cause the secondary one. The underactive pituitary characterizes secondary gland disease; it does not secrete enough TSH to stimulate correct operation of the thyroid (Rafatjah, 2019). The symptoms of both types are similar; however, the treatment differs considerably. For instance, fatigue, depression, muscle weakness, and puffiness in the face may indicate both. For this reason, correct diagnosis is of high importance for the health and life of a patient with hypothyroidism.
What would the treatment be targeted at?
Hypothyroidism may lead to myxedema coma, nerve injury, peripheral neuropathy, and goiter if left untreated. The treatment of pituitary tumors would be initially targeted at removing or eliminating abnormal cells in its tissues. Standard treatment options include surgery, chemotherapy, drug therapy, and radiation therapy (Holland, 2020). Usually, several of them are applied one after another to cure the patient. For instance, surgery may be accompanied by radiation therapy and then followed by drug therapy to stop a tumor from making a particular hormone. In the case of non-functioning tumors, a patient undergoes transsphenoidal surgery and radiation therapy if needed.
In general, secondary hypothyroidism treatment targets the replacement of the deficient thyroid hormone with synthetic preparations of T3 and T4. The most commonly prescribed drug is levothyroxine, which has many side effects such as heart attacks, insomnia, or anxiety (Rafatjah, 2019). Patients with hypothyroidism are also encouraged to eat a balanced, high-fiber diet and maintain moderate activity to lose weight and avoid constipation (Holland, 2020). Thus, treatment of a pituitary tumor that causes thyroid disease usually includes surgery and then replacement therapy.
If she were to have hyperthyroidism during your care, what would those symptoms look like?
If the patient were to have hyperthyroidism, the symptoms would be significantly different. As it was mentioned, she unintentionally gained weight and felt tired due to slowed metabolism. In the case of hyperthyroidism, the patient would be overactive, full of energy, and experience weight loss due to fast metabolism (Eisnaugle, 2020). The latter is associated with high hormone levels in the bloodstream. Arrhythmia, tachycardia, increased sensitivity to heat, and delicate, brittle hair are among other signs of the condition. It contrasts to low heart rate, cold intolerance, and dry, thinning loss she actually experienced. Furthermore, individuals with hyperthyroidism find it challenging to sleep, are irritated, and have increased appetite (Eisnaugle, 2020). Such symptoms as tiredness, muscle weakness, menstrual changes, and hair loss are consistent with both types.
References
Eisnaugle, J. (2020). Hypothyroidism vs. hyperthyroidism: What is the difference? Healthline. Web.
Holland, K. (2020). Everything you need to know about hypothyroidism. Healthline. Web.
Lewiński A., Stasiak M. (2018). Physiopathology, diagnosis, and treatment of secondary hypothyroidism. In F. Casanueva & E. Ghigo (Eds.), Hypothalamic-pituitary diseases. Endocrinology (pp.1-24). Springer.
Nachtigall, L. B. (2018). Pituitary Tumors: A clinical casebook. Springer.
Ortiga-Carvalho, T. M., Chiamolera, M. I., Pazos-Moura, C. C., & Wondisford, F. E. (2016). Hypothalamus-pituitary-thyroid axis. Comprehensive Physiology, 6(3), 1387–1428.
Rafatjah, S. (2019). What is secondary hypothyroidism? Diagnosis, treatment & more. Prime Health. Web.