Exam 1 - Thyroid and Shock Flashcards
Why is it hard to diagnose a thyroid hormone disorder?
Thyroid hormones are very lipid soluble, staying inside plasma protiens; making it hard to quantify the free level of hormone.
What may be the only symptom of hyperthyroidism?
Increased HR at rest
What does PTH control?
Blood calcium levels
Why major concern is there for thyroid surgeries or invasive airways (cricothyrotomy)?
The thyroid gland is highly vascular and can lead to major blood loss
The nerves that innervate the voice box are branched from the ____ ?
Vagus nerve
What are 1 and 2 below?
- Right recurrent laryngeal nerve or right inferior laryngeal nerve
- Left recurrent laryngeal nerve or left inferior laryngeal nerve
What happens if we lose one laryngeal nerve?
Both laryngeal nerves?
- raspiness of voice
- complete loss of voice
What does the T stand for in T3/T4?
Tyrosine
What does the 3 and 4 stand for in T3/T4?
The number of iodide groups attached to the tyrosine
The thyroid gland produces ____ % T3 and ____ % T4?
7%, 93%
What is another name for T4?
Thyroid hormone or thyroxine
What is another name for T3?
Thyroid hormone and 3,5,3 - Triiodothyronine
How are the molecules of T3 and T4 produced?
Tyrosine + iodine → Monoiodotyrosine (T1)
Tyrosine + 2 iodine → Diiodotyrosine (T2)
T1 + T2 → T3
T2 + T2 → T4
How are the structures of T1/T2 different from T3/T4?
T3 and T4 have two benzene rings
How much iodine do we need in our diet for normal thyroid hormone production?
50 mg/year
Where is TSH produced and release from?
What is another name for TSH?
- The anterior pituatary gland (adenohypophysis)
- Thyrotropin
What compound and organ controls TSH release?
TRH (Thyrotropin Releasing Hormone) by the hypothalamus
What 3 things carry thyroid hormone around the body?
Where are these produced?
- TBG - thyroxine binding globulin
- Thyroxine binding pre-albumin
- Albumin
All are made by the liver
Which thyroid hormone has the primary effect on the cells?
T3
Thyroid hormone binds to the ____ in the ____ of cells.
This causes ____, which activates synthesis of new proteins.
thyroid hormone receptor, nucleus, gene transcription
What intracellular process create an increased metabolism after thyroid hormone activation? (there are a lot.)
↑ Mitochondria
↑ N/K/ATPase
↑ O2 consumption
↑ Glucose absorption
↑ Gluconeogenesis
↑ Glycogenolysis
↑ Lipolysis
↑ Protein synthesis
↑ BMR
What are CV effects from increased metabolism?
↑ CO (from reduced SVR)
↑ Tissue blood flow
↑ HR
↑ Respiration (to meet cellular O2 demands)
What population are highly dependent on normal thyroid hormone levels?
Children - thyroid hormone is necessary for proper growth and development
What positive side effect occurs from hyperthyroidism?
Blood cholesterol levels are low from increased cellular use
How long does it take for thyroid hormone to have an effect?
Peak effect?
- 6-8 hrs
- 10 days
What blood lab values would be seen in a patient with a pituatary tumor?
↑ TSH, ↑ Thyroxine, ↓ TRH
What blood lab values would be seen in a patient with a thyroid tumor?
↑ Thyroxine, ↓ TRH, ↓ TSH
What blood lab values would be seen in a patient with a hypothalamic tumor?
↑ TRH, ↑ TSH, ↑ Thyroxine
This enzyme converts T4 to T3 inside the cell?
Iodinase
What is Grave’s disease?
Autoimmune-mediated hyperthyroidism caused by antibodies that activate TSH receptors, increasing thyroid hormone release
What eye condition is caused by high levels of thyroid hormone?
Exopthalmos
This disease creates antibodies that destroy the thyroid gland?
Hashimoto’s Thyroiditis
What are the sequale of low iodine intake?
↑TSH and TRH in an attempt to stimulate thyroid hormone production - causing a goiter
But no thyroid hormone can be produced without iodine (no exopthamos)
What treatment is common for thyroid cancer?
I-131 - radioactive iodine
What counterintuitive effect may high levels of iodine have?
May actually decrease thyroid hormone release - can be used to treat hyperthyroidsim acutely
What drug can cause hypothyroid effects?
Amiodarone - packaged with a high level of iodine; stunting the thyroid gland
What concern do we have for older patients with hypothyroidism?
Less metabolism = less cholesterol use = athlerosclerosis
What do we do in anesthesia that can cause neurogenic shock?
General anesthesia and high spinal - takes SNS control of CV system offline
What causes the deleterious effects seen in anaphylactic shock?
Histamine - causes widespread vasodilation
Sepsis is usually caused by gram ____ bacteria.
Positive
At what percentage of blood loss are both CO and arterial pressure maintained?
10 %
What happens to our arterial blood pressure and CO at 20 % blood loss?
Why is this bad for us in anesthesia?
- Arterial pressure remains normal from vasoconstriction by the SNS
Increased SVR reduces CO - Most of the time we are not directly measuring CO, so we may see a normal BP and not realize CO may be dropping
A drop in MAP of ____ % of normal from volume loss is survivable. But a MAP less than ____ % of normal is not.
- 50
- < 45
What compensations are made by the body with large volume losses?
- ↑ SNS
- ↑ volume retention
- Fluid shift from plasma and cells into CV system
- Shift of blood storage pools into CV system
What is progessive and non-progessive shock?
Non-progessive: survivable with body compensations
Progressive: not survivable despite body compensations
Where can the body recruit more blood from during shock?
Spleen, pulmonary circulation, and GI system
Explain the renal physiology happening in this diagram:
The heart is severely failing causing a reduced CO and BP. The kidneys only monitor BP and because its low, it begins to retain volume in an attempt to reach a normal BP. It continues to do this even when it is harmful, causing and overstretched heart and even further reducing CO (point D-F).
How can we prevent the kidneys from causing harm from too much fluid retention?
Diuretics - allows body to maintain adequate (not perfect) blood pressure, without overloading the heart
