Bertha is a 71-year-old woman who takes daily medication for ...

[student77]

Bertha is a 71-year-old woman who takes daily medication for Hashimoto thyroiditis. Last winter, she developed pneumonia. While she did her best to run errands for her husband, she got tired easily and needed to rest frequently.
 
  One day, after shoveling the snow outside, her husband came inside to find Bertha lying on the sofa covered in blankets. Her face appeared puffy and her eyelids hung. When he spoke to her, Bertha's voice was hoarse and her words did not make sense to him. Her respirations were also shallow and slow. Suspecting low thyroid hormone levels were causing the signs, her husband called for an ambulance.
 
  When testing for hypothyroidism, why is the free T4 level an important measurement? What would the TSH and T4 test results indicate in someone with primary hypothyroidism?
 
  Using your knowledge of the function of thyroid hormone in the body, explain why Bertha's respiratory rate was decreased? Why might pleural effusion be present in someone with hypothyroidism?
 
  What factors in Bertha's history leave her susceptible to myxedematous coma? What are the physiological aspects involved in myxedematous coma?

Question 2

Juan is a 44-year-old who works in a warehouse. He is 58, weighs 185 pounds, and has a waist circumference of 41. At his last visit to the health clinic, Juan's blood pressure was 140/60 mm Hg.
 
  Shortly after having a series of blood tests, his physician called him in to talk about the results. Juan had a fasting plasma glucose level of 107 mg/dL, an HDL level of 37 mg/dL, and a serum triglyceride level of 210 mg/dL.
 
  What condition is Juan likely presenting with? What are the spectrum of physiological abnormalities that occur with this disorder?
 
  What is the significance of Juan's waist diameter? How is truncal obesity hypothesized to increase insulin resistance in the body?
 
  In type 1 diabetes, there are hypoinsulinemia and hyperglycemia. In type 2 diabetes, it is common to see hyperinsulinemia and hyperglycemia. Why do the differences exist?

[KKcool]

Answer to Question 1

The free T4 test is important because it measures the level of serum T4 that is unbound and readily available to enter cells. In an individual with primary hypothyroidism, one would expect a decrease in T4 and an increase in TSH levels. This would indicate the inability for the thyroid to produce T4 and the hyperfunction of the anterior pituitary in an attempt to stimulate the thyroid.

Thyroid hormone acts to maintain metabolic rate in the body. When metabolism is generated by thyroid hormone, both oxygen consumption and the production of metabolic wastes increase. The respiratory system is therefore stimulated to ensure homeostasis by adequate uptake of oxygen and elimination of carbon dioxide. Bertha's hypothyroidism lowered metabolic activity and therefore respiratory function. Myxedema involves the presence of a mucopolysaccharide substance in the tissues and edema throughout the body. The fluid accumulation occurs in not only the interstitial spaces but also the pericardial and pleural spaces.

Bertha is elderly and has likely had thyroid dysfunction for some time. Exposure to cold is also considered a precipitating factor to myxedema coma. The physiologic aspects of myxedema coma involve carbon dioxide retention and hypoxia due to hypoventilation. Metabolic dysfunction leads to fluid and electrolyte imbalances, hypoglycemia, and lactic acidosis. Seriously depressed metabolic function also contributes to hypothermia, cardiovascular collapse, and coma.

Answer to Question 2

Metabolic syndrome is a condition having multisystem manifestations. Serum lipid abnormalities include elevated triglyceride and low HDL levels. Systemic inflammation is seen together with abnormal fibrinolysis, defective endothelium function, and macrovascular disease. The patient presenting with metabolic syndrome is usually obese with hypertension and elevated serum glucose levels.

An increased waist circumference (as opposed to peripheral or lower body obesity) correlates with insulin resistance in the body and poor suppression of glucose production by the liver. It is thought that truncal obesity contributes to an increased concentration of free fatty acids (FFAs). The chronic elevation of FFAs creates beta cell dysfunction in the pancreas and insulin resistance in peripheral cells. Free fatty acids also inhibit peripheral cells from uptaking and storing glucose. Finally, hepatocytes respond to excess FFA levels by becoming less sensitive to the effects of insulin. The result is an increase in glucose production by the liver and subsequent hyperglycemia.

In type 1 diabetes, there is destruction of the pancreatic beta cells and subsequent loss of insulin production. Cellular uptake of glucose does not occur, and hyperglycemia results. In type 2 diabetes, insulin resistance by tissue cells occurs in tandem with an increase in glucose production by the liver. In the early course of the disease, the pancreas secretes excess insulin in an attempt to lower serum glucose levels. The result is an increase in both insulin and glucose levels in the blood.

[student77]

Excellent

[robbielu01]

TYSM