Thyroid hormone,
structure of hormone,
synthesis of thyroid hormone,
mechanism of Thyroid hormone action,
Physiological effect of Hormone,
Disorders related with thyroid hormone,
drugs used in treatment for the thyroid disorders.
Thyroid hormone,
structure of hormone,
synthesis of thyroid hormone,
mechanism of Thyroid hormone action,
Physiological effect of Hormone,
Disorders related with thyroid hormone,
drugs used in treatment for the thyroid disorders.
a brief on thyroid gland covering following titles:
Introduction
Anatomy and physiology of thyroid gland
Synthesis of thyroid hormones
Regulation
Mechanism of action
Biological function
The endocrine system is composed of organs positioned throughout the body in widely separated locations. Endocrinology is the study of the structure and functioning of the endocrine system.
Thyroid function tests help to determine if your thyroid is not working correctly. If blood levels of thyroid hormone are high, the brain senses this and sends a message to stop producing TSH.
a brief on thyroid gland covering following titles:
Introduction
Anatomy and physiology of thyroid gland
Synthesis of thyroid hormones
Regulation
Mechanism of action
Biological function
The endocrine system is composed of organs positioned throughout the body in widely separated locations. Endocrinology is the study of the structure and functioning of the endocrine system.
Thyroid function tests help to determine if your thyroid is not working correctly. If blood levels of thyroid hormone are high, the brain senses this and sends a message to stop producing TSH.
This is a content made by the students of Pharmacy dept of Comilla University about the Endocrine system, In this you can easily find the glands in out body and their functions. and specific organs which secrete specific hormones for our body. figures are added to make it more convenient. thank you all.
PHYSIOLOGY
OF
THYROID
HORMONES
Understand the significance of the conversion of tetraiodothyronine (T4) to triiodothyronine (T3) and reverse T3 (rT3) in extrathyroidal tissues.
Understand how thyroid hormones produce their cellular effects.
Describe the physiological effects of thyroid hormones in the body.
Outline the mechanisms for regulation of thyroid hormone.
Correlate knowledge to hypo- and hypersecretion of thyroid hormones
Second ppt on endocrine system, describing hypothalamus, pituitary and thyroid glands.
This describes the hormones from these glands and their mode of action etc
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
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Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
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Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
1. THYROID FUNCTIONS AND
DISORDERS
By
Dr. Basil, B. C – MBBS (Nig),
Department of Chemical Pathology/Metabolic Medicine,
Benue State University Teaching Hospital, Makurdi.
February 2016.
2. OUTLINE:
• Introduction
• Anatomy
• Hormone synthesis/secretion
• Metabolism/Mechanism of action
• Functions and Control
• Disorders and Biochemical findings
• Biochemical Screening and Evaluation of thyroid
disease
• Treatment of Thyroidal Diseases
• Reference.
3. INTRODUCTION:
• The thyroid gland – largest single endocrine
gland in the body (15 – 20g)
• Produces the Thyroid hormones and
Calcitonin
• Thyroid hormones are critical in regulating
body metabolism, neurologic, developmental
and other body functions
• Calcitonin involved in calcium homeostasis –
see calcium and phosphate disorders.
4. ANATOMY
• Consist of 2 lobes and a central isthmus –
anterior to the trachea (shaped like a bow-tie)
• Posteriorly – parathyroid glands
• Originate from Ratke’s pouch at the base of the
tongue at 4-8wks IUL, and secretes hormones by
11wk – critical to neurologic development
• Consist of many small spherical follicles
(functional unit) surrounded by basement
membrane, containing colloid and interspersed
by para-follicular C cells
5. HORMONE SYNTHESIS / SECRETION
• Thyroid hormone synthesis includes the
following steps:
– Iodide (I-
) trapping via Na-I-
symporter (active
transport) by follicular cells (Rate limiting step)
– Diffusion of iodide to the apex of the cell and
transport into the colloid
– Oxidation of inorganic iodide to iodine (by
thyroperoxidase) and incorporation of iodine into
tyrosine residues within the thyroglobulin
molecule in the colloid
6. HORMONE SYNTHESIS / SECRETION
• Steps contd:
– Combination of two DIT molecules to form T4 or
of MIT and DIT to form T3
– Uptake of thyroglobulin from the colloid into the
follicular cell by endocytosis, fusion of the
thyroglobulin with a lysosome, and proteolysis
and release of T4 and T3
– Release of T4 and T3 into the circulation
– MIT and DIT are split into iodine and tyrosine, and
recycled
8. HORMONE SYNTHESIS / SECRETION
• T4 & T3 Circulate predominantly (>99%) bound to
serum proteins
– Thyroxine binding globulin (TBG) – 75%
– Thyroxine binding prealbumin (TBPA) – 15%
– Albumin – 10%
• The bound hormone is not biologically active
• Only 0.04% of T4 and 0.4% of T3 - free
• Changes in the concentration of serum binding
proteins alter the total, but not the free hormone
levels
11. METABOLISM
• 100nm of T4, 5nm each T3 and rT3 secreted daily
• T3 – active form; T4 – prehormone; rT3 –
metabolically inactive; Thyroglobulin –
prohormone.
• T4 >> T3: outer ring 5’monodeiodination (80% of
T3) by iodothyronine deiodinase (3 types) –
inhibited by Propylthiourasil etc
• Inner ring deiodination >> rT3 (3,3’,5’
triiodothyronine)
• 10% T4 cleared: 80% deiodinated, 20%
glucuronidation in liver and sulfation in liver and
kidneys
• Half-life: T4= 7days, T3=1 day
12. MECHANISM OF ACTION
• T4 dissociates with its carrier protein and
diffuse though cellular membrane into the
cytosol where it is converted to T3 by
deiodinase enzyme
• T3 binds with Nuclear receptor protein >>
Hormone-Receptor protein complex >> binds
to the hormone receptor element (or Thyroid
Response Element) on the DNA >> initiation of
transcription and protein synthesis
14. FUNCTIONS
• General metabolism:
– Increase the metabolic rate and oxygen consumption
of most of tissues of the body (exceptions include
testes, uterus, lymph nodes, anterior pituitary)
– Increase synthesis and activity of many intracellular
enzymes e.g. Na+
-K+
ATPase utilizes energy, increase
heat production
– Increase the size, number & activity of mitochondria
>> increase the rate of formation of ATP to energise
cellular function
15. FUNCTIONS
• Growth and Development:
– Essential for normal growth of soft tissue and
skeleton
– Required for production & action of growth
hormones and IGF
• Respiration:
– Increased respiration due to increased rate
– Dissociation of oxygen from hemoglobin by
increasing the amount of 2,3 DPG in RBC
16. FUNCTIONS
• Cardiovascular:
– Increase number & affinity of beta-1, adrenergic
receptors in the heart, also increase its sensitivity
to catecholamine
– Increases rate of blood flow in the skin for heat
elimination
– Increased cardiac output >> ↑systolic BP, but ↓
diastolic blood pressure thus >> ↑ pulse pressure
17. FUNCTIONS
• Gastrointestinal:
– Increase secretion of digestive juices and motility
>> increase appetite and food intake
– Necessary for the hepatic conversion of carotene
to Vit.A, so if thyroid hormones are decreased,
carotenaemia result
• Reproduction:
– Essential for normal menstrual cycles and fertility
– Increase milk secretion in lactating women
18. FUNCTIONS
• Nervous System:
– Promotes growth and development of the brain
(fetal life & for the first few years)
– Essential for normal myelination & development
of the nervous system in infant
– Increased response of the brain to catecholamines
& increases activation of RAS
19. FUNCTIONS
• Carbohydrate metabolism:
– Increases the rate of absorption of CHO from GIT,
thus blood glucose level increases after meal but
fall again as rate of glucose utilization is also
increased
– Enhance gluconeogenesis & glycolysis
– Increases cell metabolic enzymes acting on CHO
20. FUNCTIONS
• Protein metabolism:
– Small doses of thyroid hormone increase the rate
of formation of proteins by the ribosomes
– It increase RNA synthesis by the genes
– Large doses of thyroid hormone lead to excess
catabolism of muscle protein
21. FUNCTIONS
• Lipid metabolism:
– All aspects of fat metabolism increased
– Thyroid hormone accelerates the oxidation of
fatty acids by the cells
– Lowers level of cholesterol, phospholipid &
tryglycerides in the blood
– Stimulate formation of LDL receptors
24. CONTROL OF THYROID FUNCTION
• TRH >> (+)TSH >> (+)T4/T3 >> (-)TSH/TRH
• T4 released by the thyroid is mostly converted
to T3 by the liver and kidney by type 1
iodothyronine 5’-deiodinase
• Type 2 iodothyronine 5’-deiodinase found in
the brain and pituitary maintain constant
levels of T3 in the CNS
25. CONTROL OF THYROID FUNCTION
• TSH/Thyrotropin – Primary Regulation
– Glycoprotein hormone
– Made up two units α and β (2 different
chromosomes)
– α subunit is identical to that of LH, FSH, hCG
– β subunit confers specificity
– t½ is 60 minutes
– Acts via the TSH receptor – G protein coupled (7
transmembrane domain)
26.
27. CONTROL OF THYROID FUNCTION
• Actions of TSH:
– Increased proteolysis of the thyroglobulin (occurs
within minutes)
– Increased activity of the iodide pump
– Increased iodination of tyrosine
– Increased size and increased secretory activity of
the thyroid cells
– Increased number of thyroid cells
29. HYPER-FUNCTIONING STATES:
• Definitions:
– Thyrotoxicosis: Hypermetabolic state produced
due an excess of thyroid hormones
– Hyperthyroidism: Hypermetabolic state due to an
excessive activity of the thyroid gland
– Hyperthyroidism is a cause of thyrotoxicosis but
Thyrotoxicosis is not always as a result of
hyperthyroidism
• Women are more prone to develop hyper-
thyroidism than men
33. HYPER-FUNCTIONING STATES:
• Grave’s disease:
– accounts for more than 60% of all thyrotoxicosis
– diffuse glandular hyperplasia
– 10 times more common in women
– Autoimmune basis: thyroid stimulating
immunoglobulins (TSI) that bind to the TSH-Receptor
• Toxic Adenoma:
– solitary hyper-functioning nodules
– acquired somatic activating mutations in the TSH-R.
which induce constitutive receptor coupling to Gs
– clinical features are milder than above
34. HYPER-FUNCTIONING STATES:
• Multi-nodular goiter:
– multiple nodules, maybe polyclonal or monoclonal in
origin
– usually do not have TSH-R mutations
– may present with subclinical or mild thyrotoxicosis
• Subacute Thyroiditis (De Quervain’s, Bacterial,
Granulomatous, or Viral thyroiditis):
– follicular destruction releases thyroid hormones
– later phase may be hypothyroid, with depletion of
thyroid hormones
35. Biochemical findings:
• In primary hyperthyroidism – T4 and T3 are elevated,
while TSH is suppressed to undetectable
concentrations
• Secondary hyperthyroidism is characterized by
elevated levels of TSH, free T4 and/or free T3 levels.
• T3 concentration is often elevated to a greater degree
than is T4 in the early stages of Graves’ disease and in
patients with T3 thyrotoxicosis (solitary or multinodular
toxic goiters)
• In subclinical hyperthyroidism, there is normal
concentration of serum T3 and FT4 and persistently
suppressed serum TSH
36. HYPOFUNCTIONING STATES
• Primary Hypothyroidism:
– Autoimmune hypothyroidism: Hashimoto’s
thyroiditis, atrophic thyroiditis
– Iatrogenic: 131
I treatment, subtotal or total
thyroidectomy,
– External irradiation of neck for lymphoma or cancer
– Drugs: antithyroid drugs, amiodarone, lithium
– Congenital hypothyroidism
– Iodine deficiency
– Infiltrative disorders
37. Causes:
• Transient Hypothyroidism:
– Silent thyroiditis
– Subacute thyroiditis
– Withdrawal of thyroxine treatment in individual
with an intact thyroid
– After 131
I treatment or subtotal thyroidectomy for
Graves’ disease
39. HYPOFUNCTIONING STATES
• Iodine deficiency:
– Commonest cause of worldwide
– Responsible for endemic goiter and cretinism (mental and
growth retardation in children)
– Incidence also impacted by thiocynates in cassava and
selenium deficiency
• Hashimoto’s thyroiditis:
– Autoimmune based disease
– Destruction of thyroid cell by CD8+ cytotoxic T cells
– Antibody markers include Anti TPO, TG and TSH-R blocking
Ab
– Clinical course: subclinical (or mild) to clinical (or overt)
41. HYPOFUNCTIONING STATE
• Peripheral Resistance to Thyroid Hormones:
– The most common cause of the syndrome are
mutations of the β (beta) form (THRB gene) of the
thyroid hormone receptor
– Mutations in MCT8 and SECISBP2 have also been
associated with this condition
– Also referred to as impaired sensitivity to thyroid
hormone
42. HYPOFUNCTIONING STATES
• Myxedema is a severe form of hypothyroidism in
which there is accumulation of mucopolysacchrides
in the skin and other tissues, leading to thickening of
facial features and a doughy induration of the skin
• Cretinism is the term used to describe severe
hypothyroidism that develops in the newborn period
• Congenital hypothyroidism: may be as a result of a
complete absence of thyroid gland (athyreosis) or
defects in thyroid hormone synthesis, which can lead
to irreversible neurological damage without early
treatment
43. Biochemical Findings:
• Primary hypothyroidism:
– Low T4 and T3 lead to pituitary hypersecretion
evidenced by elevated serum TSH concentration
an important finding particularly in early detection
of thyroid failure
– In mild or subclinical cases, thyroid hormone
concentrations remain within the reference range
but TSH is elevated.
– Presence of a circulating autoantibodies especially
TPOAb in serum
44. Biochemical Findings:
• Secondary hypothyroidism:
– Serum concentration of thyroid hormone is low,
but TSH is either low or within the healthy
reference interval
• Peripheral resistance to thyroid hormones:
– T4 and T3 are elevated but TSH is not suppressed
(or not as suppressed as expected)
45. OTHER DISORDERS
• Non-Thyroidal Illnesses/Sick Euthyroid Syndrome
– Any acute or chronic severe illness causing
abnormalities in circulating TSH or thyroid hormone
levels in the absence of underlying thyroid disease.
– Reduced T4 ->T3 conversion but normal/increased rT3
– Importance is because of misleading information from
thyroid testing during periods of acute illness.
– Unless a thyroid disorder is strongly suspected, routine
testing of thyroid function should be avoided in acutely
ill patients
46. OTHER DISORDERS
• Biochemical Findings in Non-Thyroidal Illness/
Euthyrois sick syndrome:
– Low serum T3 level
– High serum rT3 level
– Normal or Low serum T4 levels
– If serum TBG levels are low, serum T4 would be
low
– Serum TSH levels are usually normal, but may
show mild depression during acute phase and
mild elevation during recovery phase
47. OTHER DISORDERS
Thyroid Malignancies – 4 types:
• Papillary carcinoma (PC):
– Well differentiated, very good prognosis; 90% 20 year
survival post treatment.
•Follicular carcinoma (FC):
– Well differentiated, very good prognosis; 90% 20 year
survival post treatment.
•Medullary carcinoma of thyroid (MCT):
– Poorly differntiated. 50% 10 year survival
– High calcitonin is a marker
•Anaplastic carcinoma:
– Poorly differentiated. Mortality approaches 100%
48. OTHER DISORDERS
Thyroid Neoplasia:
•Solitary Thyroid Nodules:
– As many as 50% of these are benign
– Occasionally, thyroid nodules can take on
characteristics of malignancy and require either a
needle biopsy or surgical excision
49. OTHER DISORDERS
• Biochemical findings in Euthyroid Hyper-
thyroxinaemia:
– Serum total T4 level is high
– Serum T3, TSH and TRH response are normal
• FT4 level compares well with the functional
condition of the thyroid than Total T4
• Causes: Bisalbuninaemia, increase oestrogen,
pregnancy, liver disease, acutely hospitalized
psychiatric pxt, familial dysalbuminaemia
50. BIOCHEMICAL SCREENING AND
EVALUATION OF THYROID DISEASE
• NEONATAL SCREENING:
• When to screen:
– Normal hospital delivery at term – (filter-paper
collection ideally at 2 – 4days of age or at the time
of discharge)
– NICU/Preterm home birth – (within 7days of birth)
– Maternal history of Thyroid medication/family
history of Congenital hypothyroidism – (cord
blood for screening)
51. BIOCHEMICAL SCREENING
Type of Screening:
•Primary TSH + Backup T4
– May miss:
• TBG deficiency
• Hypothalamic-pituitary Hypothyroidism
• Hypothyroxinemia with delayed TSH elevation
– For better sensitivity – use sensitive TSH assay and age
adjusted TSH cutoff (20 – 25mU/L at 24hr of age)
•Primary T4 + Backup TSH:
– Will miss delayed TSH elevation with initial normal T4
•Primary T4 and TSH:
– Ideal screening approach
53. EVALUATION OF THYROID DISEASE
• EVALUATION OF THYROID DISEASE:
• TSH:
– The most useful test for assessing thyroid function
– Used to monitor and adjust thyroid hormone
replacement therapy as well as screen for both
hyperthyroidism and hypothyroidism
– Have been deployed in the management of subclinical
thyroid disease
– For pregnant women with previously diagnosed
hypothyroidism, serum TSH levels should be
measured every 3-4 weeks during the first half of
pregnancy and every 6-10 weeks thereafter
54. EVALUATION OF THYROID DISEASE
Low free T4 Normal free T4 High free t4
Low
TSH
Secondary
hypothyroidism
Severe NTI
Subclinical
hyperthyroidism
NTI
Hyperthyroidism
Normal
TSH
Secondary
hypothyroidism
Severe NTI
Normal Artifact
Pituitary
hyperthyroidism
Lab draw within 6hrs
of thyroxine dose
High
TSH
Primary
hypothyroidism
Subclinical
Hypothyroidism
Test artifact
Pituitary
hyperthyroidism
Thyroid hormone
resistance
55. EVALUATION OF THYROID DISEASE
• Thyroglobulin:
– Ideal tumor marker for thyroid cancer patients and its
detection is a proof of thyroid tissue either benign or
malignant
– The accuracy of the assay is primarily dependent on
the specificity of the antibody used and the absence
of antithyroglobulin autoantibodies which interfere
with measurements
– Its prevalence is noted to be 3% of the general
population, 12 – 30% of patients with Graves’ disease,
and 35 – 60% with Autoimmune hypothyroidism
56. EVALUATION OF THYROID DISEASE
• Thyroid Autoimmunity:
– In autoimmune thyroid disease, antibodies are
directed at thyroid tissue with variable responses
– In Graves’ disease (the most common cause of
hyperthyroidism), the antibody is directed to the TSH
receptor, stimulating it and leading to growth of the
thyroid gland and production of an excess amount of
thyroid hormone
– Tests for TSH receptor antibodies detect any antibody
(stimulating or blocking) against TSH receptor
57. EVALUATION OF THYROID DISEASE
• Thyroid Autoimmunity – contd
– Both stimulating and blocking antibody assays will
be positive in most patient with Graves’ disease
– In Hashimoto’s thyroiditis, Thyroid peroxidase
antibody mediate decreased thyroid hormone
production
58. EVALUATION OF THYROID DISEASE
• Urinary Iodine measurements
– Iodine essential for normal thyroid gland function
– Iodine deficiency responsible for endemic goitre
and cretinism
– Majority of ingested iodine is excreted in the urine
– Only reflects recent dietary pattern
– Major use is for epidemiologic purposes
– Use 24 hour urine sample
59. EVALUATION OF THYROID DISEASE
• OTHER TOOLS:
– Nuclear Medicine Evaluation – RAIU Assay
• High uptake – metabolically active gland
• Concurrent TSH assay done
• Low uptake -
– Thyroid Ultrasound – detects very small nodules
– Fine-Needle Aspiration Biopsy – first step and
most accurate tool in the evaluation of thyroid
nodules
60. TREATMENT OF THYROIDAL DISEASES
HYPERTHYROIDISM:
•Use of beta-blockers for symptomatic relief:
– To be commenced after oral rehydration if necessary, and
avoided in known asthmatics
– If beta-blockers are contraindicated or poorly tolerated,
calcium channel blockers (verapramil or diltiazem) can be
administered
•Use of anti-thyroid drugs(e.g Carbimazole, Methimazole,
Propylthiouracil):
– Carbimazole, initial dose 30-40mg/day; maintainance 15-20
mg/day
– Preferred in younger age group, especially children
– More useful in Small diffuse gland and mild disease and in
cases of expected remission, especially immunological
background
– Therapy needs to be continued up to 12 months. Remission
rate is 40-50%
61. TREATMENT OF THYROIDAL DISEASES
• Use of radioactive iodine-131 (131 I) therapy:
– 5-7 mCi single dose 131l therapy; 1/3 will require a second
dose
– Recommended for more than 35 years of age and in cases of
Severe thyrotoxicosis, Systemic illness that prevents other
methods of treatment and Recurrence after antithyroid
drugs, surgery or radioablation
– There is minimal risk involved; symptoms abate in 3 weeks
to 3 months
• Surgical approach (thyroidectomy):
– Subtotal thyroidectomy (leave 2-3 g of tissue; prepare
suitably with antithyroid drugs) is preferred in cases where
there is
• Large size of gland
• Multinodularity
• Pressure symptoms
• Retrosternal goiter
62. TREATMENT OF THYROIDAL DISEASES
• In thyroid crisis, treatment has to be aggressive:
– Propranolol 1-2 mg slowly IV or 40-80 mg orally is the first
step. This can be repeated 6 hourly.
– Appropriate sedation by phenobarbitone may relieve
anxiety. Barbiturates retard the peripheral deiodination of
the hormone
– Thyroid hormone release can be inhibited by IV iodine in the
form of sodium iodide 1 g IV in 24 hours or by oral Lugol’s
iodine 5 drops every 6 hours. Drugs such as amiodarone can
be used as well.
– This is followed by thionamide or thiouracil administration in
regular dosage.
– Corticosteroids (especially dexamethasone) are indicated if
there is slightest suspicion of limitation of the adrenocortical
reserve
– Fluid and electrolyte balance should be adequately
corrected.
63. TREATMENT OF THYROIDAL DISEASES
HYPOTHYROIDISM:
•Use of Levothyroxine (LT4) for Thyroid hormone
replacement – treatment of choice:
– Started as full replacement in young individuals but in
the elderly and those with IHD, treatment with quarter
to half the required dose is initiated and raised gradually
over 4-6wks
– For mild to moderate conditions, starting dose is about
50-75µg/day
– Clinical benefits begin btw 3-5days and level off after 4-
6wks but TSH take several months to get to target range
due to delayed re-adaptation of the hypothalamic-
pituitary axis
– In central hypothyroidism, T4 levels are used to guide
treatment instead of TSH levels
64. TREATMENT OF THYROIDAL DISEASES
• In pregnant women with hypothyroidism, the LT4 dose
should be adjusted so as to keep the serum TSH below
2.5 mIU/L. TSH and free T4 levels should be measured 3-
4 weeks after every dosage adjustment.
• In subclinical hypothyroidism, guidelines from the
American Association of Clinical Endocrinologists (AACE)
recommend treatment in patients with TSH levels higher
than 10 mIU/L and in patients with TSH levels of 5-10
mIU/L in conjunction with goiter or positive anti-TPO
antibodies;
– These patients have the highest rates of progression to overt
hypothyroidism.
– An initial LT4 dosage of 50-75 µg/day can be used, which can
be titrated every 6-8 weeks to achieve a target TSH of
between 0.3 and 3 mIU/L
65. TREATMENT OF THYROIDAL DISEASES
• In patients with myxedema coma:
– Give 4 µg of LT4 per kilogram of lean body weight
(approximately 200-250 µg) as an IV bolus in a
single or divided dose, depending on the patient’s
risk of cardiac disease
– 24 hours later, give 100 µg IV
– Subsequently, give 50 µg/day IV, along with stress
doses of IV glucocorticoid
• Adjust the dosage on the basis of clinical and
laboratory findings
66. REFERENCES
• Teitz Textbook of Clinical Chemistry and Molecular
Diagnostics; 5th ed., by Burtis et al
• Clinical Chemistry – Principles, Techniques and
Correlations, 7th ed., by Micheal L. Bishop et al.
• Thyroid Function and Disorders; Abuja Revision Course,
NPMCN, Feb 2016, by Christian Ogoegbunem Isichie.
• Robbins and Cotran - Pathologic Basis of Disease 7th ed., by
Kumar et al.
• Bolarin’s Aids to Chemical Pathology, New ed., by Debayo
M. Bolarin
• Clinical Chemistry and Metabolic Medicine, 7th ed., by
Martin Crook.
• Clinical Chemistry in Diagnosis and Treatment, 6th ed., by
Philip D. Mayne