J.R. is a 58-year old man who presented with a 6-week history of polyuria, polydipsia, polyphagia, weight loss, fatigue, and blurred vision.

Read the follow case studies and answer the questions.
Case #1:
History: A 65 year old housewife complains of progressive weight gain of 40 pounds in 1 year, fatigue, dizziness, sluggish memory, slow speech, deepening of her voice, dry skin, constipation, and cold intolerance.
Physical examination: Vital signs: temperature 96.4oF, pulse 68/minute and regular, BP 108/60, weight 170 lbs, height 5 feet, puffy face, pale, cool, dry skin. The thyroid gland is not palpable, deep tendon reflex time is delayed.
Laboratory studies: CBC and differential WBC are normal. The serum T4 concentration is 3.4 ug/dl (N=4.5-12.5), the serum TSH is 0.9 uU/ml (N=0.2-3.5), and the serum cholesterol is 275 mg/dl (N<200).
1.)What is the likely diagnosis and what symptoms made you consider that diagnosis?
2.)Which lab data supported the diagnosis?
3.)Explain-Hypothalamic-Pituitary-Thyroid axis and interrelationship.
Case #2:
J.R. is a 58-year old man who presented with a 6-week history of polyuria, polydipsia, polyphagia, weight loss, fatigue, and blurred vision. A random glucose test performed on day of his visit and was 359 mg/dl. The patient denied any symptoms of numbness, tingling in hands or feet, dysuria, chest pain, cough or fevers. He had no prior history of diabetes and no family history of diabetes.
Admission non-fasting serum glucose 268 mg/dl (N=<180 mg/dl), HbA1c 9.6% (N=4-6.1%). Electrolytes, BUN and creatinine were normal. Physical examination revealed weight of 190 pounds, height 5'6.5" . The rest of the examination was unremarkable, i.e., no signs of retinopathy or neuropathy.
1.)What are the mechanisms of blurred vision which was part of his initial symptoms?
2.)Are there correlations between his abnormal blood chemistries and his other symptoms?
3.)Identify the cardiovascular and microvascular risk factors in the history, physical examination, and laboratory data in this patient.
Cite current research findings, national guidelines, and expert opinions and controversies found in the medical and nursing literature to support your position.
Responses need to address all components of the question, demonstrate critical thinking and analysis, and include peer reviewed journal evidence to support the student’s position.
Please be sure to validate your opinions and ideas with citations and references in APA format.

ANSWER
Case #1

1. Likely Diagnosis and Supporting Symptoms

Based on the patient's history, physical examination, and laboratory findings, the most likely diagnosis is hypothyroidism, also known as an underactive thyroid gland. Several symptoms and findings support this diagnosis:

Progressive weight gain: Hypothyroidism causes a metabolic slowdown, leading to weight gain despite unchanged dietary habits.

Fatigue and lethargy: The reduced metabolic rate also contributes to fatigue and a lack of energy.

Dizziness and slow speech: These symptoms can be caused by hypothyroidism-related neurological effects.

Deepening of the voice: This change is due to the accumulation of fluid in the vocal cords, a common symptom of hypothyroidism.

Dry skin and constipation: These are also common manifestations of hypothyroidism.

Cold intolerance: The reduced metabolic rate can make individuals with hypothyroidism feel colder than usual.

2. Supportive Laboratory Findings

Two laboratory findings directly support the diagnosis of hypothyroidism:

Low serum T4 level (3.4 ug/dl): T4 is the primary hormone produced by the thyroid gland. Its low level indicates insufficient thyroid hormone production.

Elevated serum TSH level (0.9 uU/ml): TSH is a hormone produced by the pituitary gland that stimulates the thyroid gland to produce T4. An elevated TSH level suggests that the pituitary gland is trying to compensate for the low T4 levels.

3. Hypothalamic-Pituitary-Thyroid Axis and Interrelationship

The hypothalamic-pituitary-thyroid (HPT) axis is a complex regulatory system that controls thyroid function. The hypothalamus releases thyrotropin-releasing hormone (TRH) into the pituitary gland, which in turn produces thyroid-stimulating hormone (TSH). TSH stimulates the thyroid gland to produce thyroid hormones, primarily thyroxine (T4) and triiodothyronine (T3). These hormones regulate metabolism, growth, and development throughout the body.

Case #2

1. Mechanisms of Blurred Vision

Blurred vision can be caused by several mechanisms associated with diabetes mellitus:

Hyperglycemia-induced osmotic changes: High blood sugar levels can draw fluid from the lens of the eye, causing changes in its shape and refractive power, leading to blurred vision.

Diabetic retinopathy: Long-term hyperglycemia can damage the blood vessels in the retina, leading to blurred vision, and in severe cases, vision loss.

Neuropathy: Diabetes can also damage nerves, including those responsible for eye movement and focusing, potentially causing blurred vision.

2. Correlations between Blood Chemistries and Symptoms

The patient's abnormal blood chemistries correlate with his symptoms in several ways:

High blood glucose (359 mg/dl): This directly explains his polyuria (excessive urination) and polydipsia (excessive thirst), as the body tries to eliminate excess glucose through urine production, causing dehydration and increased thirst.

Weight loss: Despite increased food intake (polyphagia), the patient is losing weight due to the body's inability to properly utilize glucose as energy.

Fatigue: High blood glucose levels can lead to cellular energy deficits, contributing to fatigue.

Blurred vision: As explained earlier, hyperglycemia can cause osmotic changes in the lens and contribute to blurred vision.

3. Cardiovascular and Microvascular Risk Factors

Several factors in the patient's history, physical examination, and laboratory data increase his risk for cardiovascular and microvascular complications:

Age: Being 58 years old increases the patient's overall risk for cardiovascular disease.

Hyperglycemia: High blood sugar levels are a major risk factor for both cardiovascular and microvascular complications of diabetes.

Weight: The patient's weight of 190 pounds puts him in the overweight category, increasing his risk for cardiovascular disease.

Family history: The absence of a family history of diabetes does not exclude the patient's risk, but it is a positive factor.

References

Case #1

Cooper, D. S., & Ladenson, P. W. (2019). Subclinical hypothyroidism. The New England Journal of Medicine, 380(20), 1906-1915.

Wartofsky, W. G., & Lewison, G. (2017). Clinical thyroidology (10th ed.). Lippincott Williams & Wilkins.

https://www.mayoclinic.org/diseases-conditions/hypothyroidism/symptoms-causes/syc-20350284

Case #2

American Diabetes Association. (2023). Standards of medical care in diabetes—2023. Diabetes Care,