Questions:
Task 1:
A 43-year-old female presented with a 15 month history of weight gain, hirsuitism, weakness that had increased over time, and oligomenorrhea. Her blood pressure was 175/105 mm Hg.
Laboratory Data
Sodium 153 mmol/L
Potassium 2.7 mmol/L
Chloride 107 mmol/L
Bicarbonate 34 mmol/L
Glucose 118 mg/dL
The physician ordered an 8:00 a.m. and 4:00 p.m. plasma cortisol. The 8:00 a.m. value was 22 g/dL and the 4:00 p.m. value was 24 g/dL.
1. The laboratory results are most indicative of which of the following disease states? Defend your answer. Also, state why the other disease states CANNOT be the causative agent.
a. Addison’s disease
b. Adrenogenital syndrome
c. Cushing’s syndrome
d. Conn’s syndrome
2. What two screening tests are recommended for detecting Cushing’s Syndrome? How are they useful in the diagnosis?
3. Explain the sodium and potassium levels based on the diagnosis of this patient.
4. What are the hormones involved, the primary symptoms, and the lab tests used to aid in the diagnosis of the following conditions?
Addison’s disease
Hyperaldosteronism
Adrenogenital syndrome
5. How are plasma ACTH levels useful in the differential diagnosis of Cushing’s Syndrome?
Task 2:
A 50-year-old female complains of excessive sweating and heart palpitations. On physical examination, her skin is warm and moist, pulse 120/minute, and blood pressure 150/95 mm Hg. She has noticed excessive watering and a foreign body sensation in her eyes. A blood test for thyroid function yields the following results.
Free T4 = 3.20 ng/dL
TSH = <0.03 U/mL
1. Based on the results provided, how would you assess the patient’s thyroid function?
2. What are three common causes of hyperthyroidism?
3. What would be the next step in thyroid testing to further pinpoint the cause of the patient’s symptoms? Explain your reasoning.
4. The patient tests positive for TRAb. Based on these results, what would be the patient’s diagnosis? Explain the pathophysiology of this disease.
5. What would be the expected results of the following tests in this case?
a. T4
b. T3
6. Suggest three treatment strategies for hyperthyroidism.
7. Suggest an explanation for the low TSH value.
8. What is a major function of thyroid hormones?
9. What laboratory test(s) would best differentiate primary and secondary hyperthyroidism?
10. What is the formula for calculating free thyroxin index? What is its diagnostic utility in diagnosing thyroid disorders?
11. What screening tests for congenital hypothyroidism are commonly performed?
Answers:
Task 1:
- The laboratory results of the 43-year-old woman indicate a case of Cushing’s disease. All of her symptoms point towards this disease. Her history of weight gain, hirsuitism, increased weakness, oligomenorrhea; high blood pressure and increased plasma cortisol are the symptoms of this disease (Melmed et al., 2015).
Addison’s disease cannot be the causative agent because the primary symptoms of the disease are low blood pressure and insufficient production of steroid hormones. Adrenogenital syndrome is a congenital disease; thus, it cannot initiate in a 43-year-old woman, and Conn’s syndrome is not the causative agent because it is the hyper-production of aldosterone hormone which lowers the renin level (Melmed et al., 2015).
2. The two tests that are used for the diagnosis of Cushing’s syndrome are the 24-hour urinary free cortisol test and the measurement of plasma cortisol at midnight and saliva cortisol level at late night (Melmed et al., 2015).
The 24-hour UFC test determines the cortisol level in the urine. High level of cortisol suggests Cushing’s syndrome.
The midnight or late night test measures the cortisol level in the blood. Usually, at night, there is no production of cortisol but in Cushing’s syndrome cortisol is produced at night (Melmed et al., 2015).
3. The sodium level is high, and potassium level is low in the patient. The Pathophysiology of Cushing’s syndrome is the retention of sodium and water and wasting of potassium due to the effects of high cortisol in the body. This imbalance in the electrolytes results in the high blood pressure in a patient with Cushing’s syndrome (Melmed et al., 2015).
4. Addison’s disease: the hormones that are involved in Addison’s disease are glucocorticoids, mineralocorticoids, and androgens. Symptoms include weight loss, extreme fatigue, decreased appetite, hyperpigmentation, low blood pressure and sugar, abdominal pain, muscle pain and salt craving. Tests to diagnose the disease are the blood test for cortisol, sodium and potassium level; ACTH stimulation test; imaging and insulin-induced hypoglycemia test (Melmed et al., 2015).
Hyperaldosteronism: the hormone involved in this disease is aldosterone. Symptoms are low potassium level which may lead to weakness, muscle spasms, temporary paralysis for short periods and tingling. Diagnostic tests are measurement of aldosterone level and CT and MRI scan to determine the cause- hyperplasia or tumor (Melmed et al., 2015).
Adrenogenital syndrome: hormones involved in this disease are androgen, estrogen, and corticotrophin. Symptoms include virilization, ambiguous genitalia, precocious puberty, menstrual irregularity and clitoromegaly in women, and enlargement of the penis in men. Diagnostic test for this disease is the measurement of 21-hydroxylaasw CAH at birth (Melmed et al., 2015).
5. Plasma ACTH levels help in determining the source of hypercortisolism in Cushing’s syndrome. The source can be a tumor or adrenal disease (Melmed et al., 2015).
Task 2:
- The 50-year-old female patient’s tests results suggest that she has hyperthyroidism (Braverman & Cooper, 2012).
2. There can be various causes of hyperthyroidism. The most common cause is Graves’ disease. Other causes are excess iodine and thyroiditis; and tumors in the pituitary or thyroid gland, testes, and ovaries (Braverman & Cooper, 2012).
3. CT scan, MRI scan or X-ray can be done to pinpoint the cause of the symptoms further. These tests can determine the size of the thyroid gland. Condition of the thyroid gland can shed light on the causes of the symptoms in the patient (Braverman & Cooper, 2012).
4. As the patient is diagnosed to be positive for the TRab test, it can be inferred that she has Graves’ disease. Graves’ disease is an autoimmune disease. The body of the patients with Graves’ disease produces TSH receptor antibodies. Antibodies to thyroglobulin, T4 and T3 can also be generated (Braverman & Cooper, 2012).
5. In this case, the patient with Graves’ disease will have high levels of T4 and T3 in the blood. This occurs because the antibodies misdirect the thyroid gland to produce high amounts of T3 and T4 (Braverman & Cooper, 2012).
6. Three treatments available for the treatment of hyperthyroidism are:
Radioactive iodine administered orally can be used to treat hyperthyroidism. This drug reduces the size of the thyroid gland gradually. The symptoms start to ceases within 3 to 6 months (Braverman & Cooper, 2012).
Anti-thyroid medications cure hyperthyroidism by restraining the production of excess hormones by the thyroid gland. Some anti-thyroid drugs are methimazole and propylthiouracil (Braverman & Cooper, 2012).
Thyroidectomy can be done to remove most of the thyroid gland (Braverman & Cooper, 2012).
7. The TSH levels are low because the antibodies produced due to the autoimmune aberration binds to the TSH receptors which increase the production of thyroxine and triiodothyronine. The increased amounts of thyroxine bind with thyroxine receptors in the pituitary that suppresses the release of TSH. Due to this negative feedback loop, the TSH level becomes low and T3 and T4 levels become high (Braverman & Cooper, 2012).
8. The major function of thyroid hormones is to maintain the metabolism rate of the body (Braverman & Cooper, 2012).
9. Tests to measure the TSH and FT4 levels can be used for differential screening of primary and secondary hyperthyroidism (Braverman & Cooper, 2012).
10. The formula for calculating Free Thyroxine Index (FTI) is:
Free Thyroxine Index = Total T4 x T3 uptake
This formula is used in the diagnosis of hyperthyroidism. If FTI is high, then it indicates hyperthyroidism, and if FTI is low then it indicates hypothyroidism (Braverman & Cooper, 2012).
11. Tests to determine the level of TSH and T4 is performed to screen congenital hypothyroidism (Braverman & Cooper, 2012)
References:
Braverman, L. E., & Cooper, D. (2012). Werner & Ingbar’s the thyroid: a fundamental and clinical text. Lippincott Williams & Wilkins.
Melmed, S., Polonsky, K. S., Larsen, P. R., & Kronenberg, H. M. (2015).Williams textbook of endocrinology. Elsevier Health Sciences.
