Endocrinology Case Studies - Essay Example

Endocrinology Case Studies Case This is a 50-year-old man with a left thyroid nodule with increased appetite with perhaps loss of weight, so no weight gain. This patient has increased bowel movement, maybe diarrhea. This patient has tachycardia with a low blood pressure. There are ocular signs of thyrotoxicosis manifested by ocular stare and lid lag. The thyroid has enlarged in size, and the mass is a thyroid nodule in the left lobe of the thyroid gland. Common manifestations of thyrotoxicosis include nervousness, frequent bowel movements. Weight loss is usual despite well-maintained or increased appetite. Cardiovascular symptoms predominate in older individuals. These include a wide pulse pressure, sinus tachycardia, and hypotension. The ocular signs include a characteristic stare with widened palpebral fissure, infrequent blinking, a lid lag as a result of sympathetic overstimulation. Therefore this is a case of thyrotoxicosis due to solitary nodule in the left lobe and generalized enlargement of the thyroid gland indicated by increased weight of the gland to 40 g as opposed to normal of 15 to 20 g. In such instances, laboratory tests documenting undetectable TSH, increased radio-iodine uptake (RAIU), increased values of serum T3 and T4 suggesting hyperthyroidism, increased RT3 uptake, and increased free T4 index may suggest the enlarged thyroid mass is due to diffuse hyperactive goiter, and the nodule might be just the beginning of hyperactive nodular goiter. More often an I-131 scan of the thyroid gland may reveal a hypoactive nodule (warm) due to suppression by the surrounding diffusely hyperactive glandular tissue. The diagnosis will be Graves’ disease due to presence of ophthalmopathy. The treatment of such condition will be treatment with anti-thyroid agents like propylthiouracil. Sometimes, treatment with radioiodine may be used for thyroid ablation. Adrenergic antagonists like propranolol may be used for cardiovascular effects. Subtotal thyroidectomy may be another form of therapy, although rarely used. Case #2 This 6-year-old boy is having rapid somatic growth with premature pubic hair growth. He had no abnormality of gestation or no birth injuries or defects. His somatic growth, height, body mass were above average not entirely explicable by the parental pattern. He has a macropenis, Tanner stage II puberty at 6 years of age, testes were small for puberty stage indicating absence of a testicular tumor. He has facial acne from 4 years of age with no neurologic or cardiovascular abnormalities. Clearly, this is a case of precocious puberty with appearance of physical and hormonal signs of pubertal development at an earlier age than the normal expected age for males. For boys, onset of puberty before age 9 is considered abnormal. The early growth spurt causes a tall stature indicated by his height. To establish this case as central precocious puberty (CPP), as suggested by the history, the following analysis is important. CPP is gonadotrophin dependent. This results from early maturation of the hypothalamic- pituitary-gonadal axis that results in expression of full spectrum of physical and hormonal changes of puberty. Most patients are healthy otherwise. The pubertal maturation begins as in this case at the early end of the normal distribution curve of growth. Brain or central nervous system shows no abnormality clinically or by imaging studies. The onset of early puberty happens due to secretion of high-amplitude gonadotrophins releasing hormone (GnRH) from the hypothalamus. This causes pulsatile release of pituitary Luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Increased LH, in turn, causes the testicular Leydig cells to produce sex steroids or androgens. This high level of hormones often reach pubertal levels in prepubertal boys to cause physical changes of puberty prematurely leading to penile enlargement, growth of sexual hair, and lead to pubertal growth spurt. Increased FSH levels also causes enlargement of the testicles to pubertal size and eventually to spermatogenesis. Later, these boys will develop acne, facial hair, and voice changes. The laboratory studies that may be undertaken in this case is measurement of sex steroid level, and measurement of serum testosterone in boys with precocious puberty may prove diagnostic. Early morning testosterone in precocious puberty is higher. Testosterone levels of 11-30 ng/dL may indicate precautious puberty. Levels of adrenal androgens, such as, dehydroepiandrosterone (DHEA), DHEA sulfate may rise in these patients, where DHEA-S is measured for it shows less variability with the time during the day. A level of 20-100 mcg/dL is diagnostic. If congenital adrenal hyperplasia is suspected, though rare, serum17-hydroxy progesterone may prove the diagnosis. A lower random LH is the best screening test. Suppressed levels of LH/FSH with high testosterone indicates central precautious puberty. Following infusion of 100 mcg of GnRH, measurement of LH/FSH ratio will be 0.75 or greater in this case, and that proves the diagnosis. Leuprolide acetate suppresses testicular hormone synthesis and is helpful in depot preparations for these patients. Nafarelin acetate is a potent GnRH analogue that reduces secretion of LH and FSH that reduces testosterone secretion. Case #3. This is a patient with adrenal hyperplasia leading to increased production of cortisol by the adrenal gland. In most cases, the cause is bilateral adrenal hyperplasia due to hypersecretion of pituitary ACTH. The incidence of pituitary dependent adrenal hyperplasia is frequent in women especially following parturition. The cause is debated. Many of the signs and symptoms follow logically from the actions of the glucocorticoids. Hypercortisolism promotes deposition of adipose tissue in upper face, producing the typical moon face. However, truncal obesity or buffalo hump occurs in variable numbers of patients. It is well known that this type of fat deposition is associated with insulin resistance and elevated insulin levels. The face appears plethoric even in the absence of increased red blood cell concentration indicated by normal hematocrit and hemoglobin levels in this patient. The patient has hypertension that is common in such conditions. Emotional changes are profound ranging from irritability and emotional lability to severe depression, confusion, to the extent of frank psychosis. Increased levels of adrenal androgens caused hirsutism, oligomenorrhea. It could have caused amenorrhea even if she was not breast feeding. The diagnosis, therefore, is Cushing syndrome. The diagnosis depends on demonstration of increased cortisol levels and failure to suppress cortisol secreation normally when dexamethasone is administered. For screening, overnight dexamethasone suppression test is used. Measurement of 24-hour urinary free cortisol can be used also. A level greater than 275 nmol/d is diagnostic. The definitive diagnosis is made by failure of urinary cortisol to fall below 80 nmol/d or plasma cortisol to fall below 140 nmol/d after a standard low-dose dexamethasone suppression test with 0.5 mg every 6 hours for 48 hours prior to the test. Other associated abnormalities are diagnosed by serum potassium level, serum chloride level, and tests to rule out metabolic alkalosis. Plasma ACTH levels, CRH infusion tests, and metyrapone infusion tests may be undertaken. CT scan of abdomen and MRI of brain are also important adjunctive investigations. Total adrenalectomy with life-long mineralocroticoid and glucocorticoids supplements are mainstays of therapies in cases the etiology of hormonal excess is not apparent. Case #4. Obviously, this 48-year-old woman, otherwise physically normal, has recurrent mental symptoms with normal chemistry levels and abnormally raised calcium and chloride phosphate ratio. Perhaps, with treatment she was normal for last 2 years. She has bizarre psychotic behavior with disorientation to time and place. Taking for granted that she has no malignancy, hypercalcemia results most commonly from primary hyperparathyroidism. Markedly elevated serum calcium is associated with acute signs and symptoms of hypercalcemia. Plasma calcium is maintained within the normal range as a result of a complex interplay between parathromone, vitamin D, and calcitonin. For hypercalcemia to develop as a result of parathyroid excess that causes excess calcium absorption from the intestine. This is mediated by PTH-mediated calcitriol synthesis that enhances calcium absorption. PTH-mediated calcium reabsorption in distal tubule leads to reduced excretion of calcium by the kidneys. The incidence of primary hyperparathyroidism is more in females, malignancy-related hypercalcemia has no sex predilection. Increased calcium levels may cause nausea, vomiting, altered mental status, abdominal pain, constipation, lethargy, depression, weakness, confusion, and headache. There are sparse physical findings. Therefore, this is a case of hyperparathyroid hypercalcemia. Corrected total calcium level is calculated as measured total calcium + 0.8 (4.4- measured albumin g/dL). If suspected of inaccuracy, a serum free ironized calcium level is measured. Hypercalcemia may be a manifestation of disordered renal function, hence a complete renal profile is a must to undertake. EKG should be done to rule out any EKG abnormality from high calcium levels. The most appropriate test is to perform a circulating PTH test. The reference range is 2-6 mol/L. In presence of hypercalcemia, an unsuppressed PTH indicates hyperparathyroidism. Parathyroid hormone related peptide (PTHrP) can be assayed to rule out other malignancies. High calcitriol indicates hypercalcemia of sarcoidosis. Serum phosphate in this case is normal toward the lower range. However, serum chloride levels are higher in hyperparathyroidism, usually above 102 mEq/L and consequently gives rise to a high chloride/phosphate ratio. In this case, CT scan of the head, MRI, and nuclear parathyroid scan may be useful further elaborate the etiology. Treatment should be admission to the hospital with immediate hydration. To stabilize and reduce the calcium level, pamidronate or mithramycin may be used. Calcitonin can be used. Gallium nitrate can be used to decrease bone resorption. Potassium phosphate may be used as phosphate binders. Sensipar reduces PTH levels. 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