Hypothyroidism

Review of History and Physical Findings
The client is a 56-year-old Caucasian female who presents with complaints of fatigue that reportedly began 2 to 3 months prior to her visit. She reports that the fatigue is generalized and constant in duration, and has been progressively worsening since onset. The client reports feeling tired all the time and lacking the energy to do anything‘she could normally do’despite sleeping eight hours per night. No relieving factors were identified, although the client reports exertion as a possible aggravating factor. The client is married, has two grown kids, and works as a full-time office manager in an internal medicine office. She reports missing a day of work two weeks ago because she ‘couldn’t get out of bed’. She denies pain, fever, chills, or recent illnesses, but has gained 5 pounds since the last visit 6 months ago.
The client denies visual changes, ear pain, rhinorrhea, ST, or history of sleep apnea, but admits to having tonsillectomy as a child. There is no evidence of lymph node tenderness, cough, wheezing or chest pain, and the client denies nausea, vomiting, diarrhea, and constipation. A review of skin and endocrine system shows that the skin is dry, hair is coarse and there is no evidence of polyuria, polydispia, or cold intolerance. The client, however, reports worsening depressive symptoms, suicidal or homicidal thoughts, and generalized muscle weakness or intermittent cramping. The client’s PMH includes hypertension, depression, and postmenopausal status, and a history of iodine dyes, allergies, and tonsillectomy. She denies cigarette or drug use, but admits to taking 1 to 2 glasses of wine every month. Family history is indicative of mental illness, hyperlipidemia, hypertension, and seasonal allergies.
The physical exam shows the client to be alert, oriented, and cooperative, with head, eyes, ears, nose, cardiopulmonary, and abdomen examinations all normal. The client’s mood is appropriate and pleasant, with the neurology exam showing normal reflexes at the biceps and traceable reflexes at the knees and ankles.
Differential Diagnosis
Three differential diagnoses could be deduced from the subjective and objective information: hyperthyroidism, hypothyroidism, and thyroid cancer. Hyperthyroidism occurs when the thyroid gland overproduces the thyroid hormones T3 and T4, leading to an up-regulation of metabolism that manifests in an increase in heart rate and total body heat production (Dunphy et al., 2019). The clinical presentation includes a combination of anxiety, nervousness, insomnia, weight loss, palpitations, heat intolerance and fatigue (Dunphy et al., 2019). Patients may also report exertional dyspnea, diarrhea, menstrual irregularities, lower extremity edema, exercise intolerance, musculoskeletal weakness, and weight loss even in with increasing appetite (Dunphy et al., 2019).
Hypothyroidism results from the underproduction of thyroid hormones and has the effect of slowing down metabolic processes and many other bodily functions in the same way as thyroid failure (Dunphy et al., 2019). Risk factors for thyroid failure include radiation treatment, use of iodine or lithium, presence of anti-thyroid antibodies, and a family history of thyroid disease (Dunphy et al., 2019). Fundamental symptoms of hypothyroidism include heavy menses, constipation, cold intolerance, slight weight gain, dry skin, and fatigue (Dunphy et al., 2019). Depending on the duration of illness, the patient may also report very dry skin, hypersomnia, continued weight gain, depression, and slight impairment in mental ability (Dunphy et al., 2019). The primary symptom of thyroid cancer is a painless nodule or lump in the neck, although the patient may also complain of neck tightness, difficulty swallowing, hoarseness, and swollen lymph nodes (Dunphy et al., 2019). Depending on the duration of illness, the patient may also report neck pain (Dunphy et al., 2019).
Thyroid cancer is the least likely diagnosis of the three. The physical exam carried out on the patient shows a supple neck devoid of palpable masses, which is the primary characteristic of thyroid cancer. Further, the client denies swollen lymph nodes, difficulty breathing or any kind of pain, including neck pain. The client’s chief compliant is fatigue, coupled with worsening depressive symptoms and musculoskeletal weakness, all of which are characteristic of hypothyroidism and hyperthyroidism. However, a key identifying symptom of hyperthyroidism is weight loss that prevails even with increasing appetite (Dunphy et al., 2019). The client, however, reports continued weight gain, and has gained 5 pounds over the past six months. Progressive weight gain is a characteristic of hypothyroidism, which makes hypothyroidism the most likely diagnosis for the presenting client. Hypothyroidism is the most likely diagnosis, followed by hyperthyroidism, while thyroid cancer is the least likely diagnosis given the subjective and objective information.
Diagnostic Testing
Three tests would be crucial at this point. First it would be prudent to order thyroid function tests, including the Serum TSH test and the Total FT4 to measure free T4 in the blood (Soh &Aw, 2019). FT4 normal values are between 0.7 and 1.9 mg/dL, while normal TSH values lie between 0.5 and 5.0 uIU/mL (Samuels et al., 2017). The finding of a low FT4 and elevated TSH indicates primary hypothyroidism resulting from disease in the thyroid gland, while a low TSH and low FT4 would be indicative of hypothyroidism due to a problem in the pituitary glands (Samuels et al., 2017). An elevated FT4 and low TSH indicate hyperthyroidism (Samuels et al., 2017).
In conjunction with the thyroid function tests, the clinician may also need to order a complete blood count (CBC) to exclude anemia or infection as potential causes of the client’s depressive symptoms (Lassale et al., 2018). Low levels of thyroid hormones have been associated with abnormalities in lipid metabolism and increases in total cholesterol levels (Dunphy et al., 2019). For this reason, it may be prudent to order lipid assessments to check for the presence of hyperlidemia and measure baseline values before commencing treatment.
Part Two
The CBC shows normal levels for all components save for an elevated TSH (6.7uIU/mL) and low FT4 (0.62mg/dL ), indicative of primary hypothyroidism resulting from disease in the thyroid gland (Samuels et al., 2017). The CBC results rule out the possibility of anemia or infection, and point to the likelihood that the client’s depressive symptoms are caused by her thyroid illness. The client reports a depression score of 10 on the PHQ-9 scale, a 5-point increase from the score during the last visit 6 months ago.
Diagnosis
The most relevant diagnosis given the client’s symptoms is unspecified primary hypothyroidism (ICD-10-CM CodeE03.9). The client shows all the primary symptoms of hypothyroidism, including fatigue, weight gain, worsening depressive symptoms, mild hypertension, muscle weaknesses, dry skin, and coarse, thick hair (Dunphy et al., 2019). There is, however, no evidence of constipation, hypoactive bowel sounds, and a visible goiter, which are also crucial symptoms of hypothyroidism, but which often show up as in the later stages. Judging from the client’s symptom, the illness is likely to have begun long before the 2 to 3 months that she claims in the subjective examination. Symptoms could have gone unrecognized due to the fact that hypothyroidism has an insidious onset and progresses slowly (Dunphy et al., 2019). The most likely cause of the client’s hypothyroidism is her past history with iodine dyes that possibly led to the progressive loss of functional thyroid tissue (Dunphy et al., 2019).
Treatment Plan
The Food and Drug Administration (FDA) recommends the use of Levothyroxine as replacement therapy for primary hypothyroidism in both children and adults (FDA, 2017). The goal of treatment in primary hypothyroidism is to normalize and not suppress the TSH (Dunphy et al., 2019). The proposed medication plan is to begin Levothyroxine (Brand Name: LEVO-T) at a starting dose of 50mcg tablet once daily, to be titrated upwards to a maximum dose of 75mcg daily. To reduce the client’s depressive symptoms, the clinician could also begin SSRI therapy (Zoloft, Generic Name: Sertraline) at a starting dose of 25mg twice daily. The proposed prescription is as written out below:
Prescription
Rx): LEVO-T 50mcg (Levothyroxine Sodium Tablets)
Disp: #28
Sig: one tablet by mouth once daily, taken 1-11/2 hours before breakfast
Refill (Rf): Do not Refill
Rx: Zoloft 25mg (Sertraline Tablets)
Disp: #28
Sig: one tablet by mouth twice daily
Refill (Rf): 1
Patient Education
There is a need for the clinician to sensitize the patient that the goal of treatment for patients with primary hypothyroidism is to normalize rather than suppress TSH (Dunphy et al., 2019). It is important for the client to understand that in the case of post-menopausal clients such as herself, over-replacement could cause decreased bone mineral density, leading to osteoporosis (Dunphy et al., 2019). It may also be prudent to educate the client on the importance of adhering to the prescribed medication dosage until a full replacement is achieved because untreated hypothyroidism may slowly progress into a life-threatening state of multiple organ failure referred to as myxedema coma, which could be fatal (Dunphy et al., 2019). Finally, the client needs to be advised to take the medication in the morning to avoid the risk of nighttime insomnia (Dunphy et al., 2019).
Referral
Refer the client to a nutritionist for dietary advice and lifestyle changes as her current BMI is indicative of overweight.
Problem List for the Client
The following problems are evident from the evaluation conducted on the client:
i) The client is overweight, with a BMI of 28.2
ii) The client has a history of hypertension and tonsillitis
iii) The client’s family has a rich history of hyperlidemia, hypertension, seasonal allergies, and mental illness, particularly bipolar disorder
iv) The client faces a lot of stress as she has to work full-time and still take care of her two children undergoing treatment for bipolar disorder and seasonal allergies
Changes to Treatment Plan
The FDA advises that the therapeutic effect of LEVO-T may not be attained for 4 to 6 weeks (FDA, 2017). As such, there may be a need for the clinician to wait at least 4 weeks before making any changes to the treatment plan. During this time, the client is to be closely monitored for adverse effects, particularly cardiac adverse reactions resulting from over-treatment with LEVO-T (FDA, 2017). If the client reports no serious adverse effects by the end of four weeks, the dosage of LEVO-T could be titrated upwards towards the maximum of 75mcg daily in view of the client’s TSH levels then. If cardiac symptoms are reported before 4 weeks, however, the clinician could consider reducing the dosage to 25mcg daily (FDA, 2017). Treatment with the SSRI Zoloft is to be sustained for a minimum of 6 weeks, after which the clinician will assess the client’s progress and determine whether to continue.
Follow-Up
Given the risks associated with over-treatment using LEVO-T for postmenopausal clients, the clinician needs to organize a review in 4 weeks to measure TSH levels and check for any cardiac-related adverse effects before deciding whether or not to modify the dosage.
References
FDA (2017). LEVO-T: Highlights of Prescribing Information. Food and Drug Administration. Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/021342s023lbl.pdf
Lassale, C., Curtis, A., Abete, I., Van der Schouw, Y., Verschuren, M., Lu, Y., &Mesquita, B. (2018). Elements of the Complete Blood Count Associated with Cardiovascular Disease Incidence: Findings from the EPIC-NL Cohort Study. Scientific Reports, 8(1), doi: org/10.1038/s41598-018-21661-x
Samuels, M. H., Kolobova, I., Antosik, M., Niederhausen, M., Purnell, J., &Schuff, K. (2017). Thyroid Function Variation in the Normal Range, Energy Expenditure, and Body Composition in L-T4 Treated Subjects. Journal of Clinical Endocrinology & Metabolism, 102(7), 2533-42.
Soh, S., & Aw, T. (2019). Laboratory Testing in Thyroid Conditions – Pitfalls and Clinical Utility. Annals of Laboratory Medicine, 39(1), 3-14.
Dunphy, L.M., Winland-Brown, J. E., Porter, B. O., & Thomas, D. J. (2019). Primary Care: The Art of Science of Advanced Practice Nursing (5thed.). Philadelphia, PA: F.A Davis Company