This document discusses hypothyroidism, including its causes, signs and symptoms, and clinical manifestations. It begins by listing various causes of primary and secondary hypothyroidism such as autoimmune disorders, iatrogenic causes, congenital disorders, and infiltrative disorders. It then describes the common signs and symptoms of hypothyroidism which affect the skin, eyes, cardiovascular system, gastrointestinal tract, neurological and neuromuscular systems, and other body systems. The document also discusses laboratory abnormalities seen in hypothyroidism and compares features of primary and secondary hypothyroidism.

1. Dr PRABHAT AGRAWAL
PG DEPARTMENT OF MEDICINE SNMC
AGRA

10. Primary –
autoimmune – hashimotos thyroiditis,atrophic thyroiditis
Iatrogenic
;I131 treatment ,subtotal or total thyroidectomy; external
irradiation of neck for lymphoma or cancer
Drugs-
iodine excess(including iodine containing contrast media
and amiodarone)lithium ,antithyroid drug,p-amino salisalic
acid,interferon alpha
Congenital hypothyroidism-
absenteectopicthyroid,dyshormonogenesis,tsh-r mutation
iodine defieciency
Infiltrative disorder-
amylodosis,sarcoidosis,hemochromatosis,scleroderma,
cystinosis, riedels thyroiditis

11. Transient-
silent thyriditis,including post partum thyroididtis
Subacute thyroiditis
Withdrawl of thyroid treatment in indiviual with intact
thyroid
Secondary-
hypopituitarism:tumour ,pituatry surgery or irradiation,infiltrative
disorder,sheehans syndrome,trauma,genetic form of combined
pituatryhormone deficiencies
Isolated Tsh deficiency or inactivity
Bexaretone treatment

13. Signs and symptom of hypothyroidism
Symptoms
Tiredness,weakness
Dry skin
Feeling cold,hairloss
Hair loss
Difficultyconcentratin
g and poor appetite
Dysponea
Hoarse voice
Menorrhagia(later
oligomenorrhea)
Signs
Dry coarse skin cool
periphral extremities
Puffy face,hands,and
feet (myxedema)
Diffuse alopecia
Bradycardia
Peripheral edema
Delayed tendon
reflexation
Carpal tunnel
syndrome

14. Clinical Manifestations of Hypothyroidism --
Skin
Cool and pale skin  blood flow 
Dry roughness of skin  the epidermis has an
atrophied cellular layer and hyperkeratosis
Decreased sweating  calorigenesis and acinar gland
secretion 
Generalized nonpitting edema (myxedema) in severe
hypothyroidism  infiltration of the skin with
glycosaminoglycans and associated water retention

15. Clinical Manifestations of Hypothyroidism -- Eyes
Periorbital edema -- as a manifestation of
generalized nonpitting edema or Graves'
ophthalmopathy.
Graves' ophthalmopathy may persist or worsen
when hypothyroidism develops after treatment of
Graves' hyperthyroidism. Patients will have
variable degrees of stare, protrusion of the eyes,
and extraocular muscle weakness.

16. Clinical Manifestations of Hypothyroidism --
Cardiovascular System
Bradycardia  reductions in heart rate
Impaired muscular contractility
Reduced cardiac output  decreased exercise capacity
and shortness of breath during exercise
ECG: low voltage of QRS complexes and P and T waves
CXR: cardiomegaly  interstitial edema, myofibrillary
swelling, LV dilatation, pericardial effusion

17. Clinical Manifestations of Hypothyroidism --
Cardiovascular System
Myxedema induces coronary artery disease ??
CAD more common in p’ts with hypothyroidism
Symptoms and signs of congestive heart failure are
usually absent in patients who have no other cardiac
disease
Congestive heart failure or angina may worsen when
hypothyroidism develops in patients with heart
disease

18. Clinical Manifestations of Hypothyroidism --
Cardiovascular System
Hypertension  peripheral vascular resistance 
In normotensive patients, BP increases are small
(<150/100 mmHg).
The BP of patients with established hypertension
may increase further with the development of
hypothyroidism.

19. Clinical Manifestations of Hypothyroidism --
Gastrointestinal Disorders
Constipation, even ileus  gut motility 
Decreased taste sensation
Gastric atrophy  presence of antiparietal cell
antibodies. Pernicious anemia occurs in 10% of
patients with hypothyroidism caused by chronic
autoimmune thyroiditis.
Weight gain  decreased metabolic rate +
accumulation of fluid (nonpitting edema) that is rich
in glycosaminoglycans
Ascites, rare

20. Clinical Manifestations of Hypothyroidism --
Neurological Dysfunction
General depression of central nervous system function
Sleepiness, inability to concentrate
Sluggish thought processes
Respond slowly to questions
Less able to retrieve information from memory
Agitated psychosis, rare (“myxedema madness”)
PET: 23% reduction in cerebral blood flow and a 12%
reduction in cerebral glucose metabolism

21. Clinical Manifestations of Hypothyroidism --
Neuromuscular Abnormalities
A delay in the relaxation phase of deep tendon
reflexes
Carpal tunnel syndrome
Paresthesia
Asymptomatic elevation in serum CPK level to
muscle hypertrophy (which may be accompanied
by muscle cramps) to proximal muscle weakness
to, in rare cases, rhabdomyolysis.

22. Clinical Manifestations of Hypothyroidism --
Metabolic Abnormalities
Hyponatremia may result from a reduction in free
water clearance
Reversible increases in serum creatinine occur in 20 ~
90% of hypothyroid patients
lipid clearance may be decreased, resulting in an
elevation in the serum concentrations of free fatty
acids and total and low-density lipoprotein cholesterol
Plasma homocysteine concentrations are increased in
some hypothyroid patients,

23. Clinical Manifestations of Hypothyroidism --
Respiratory System
Fatigue, shortness of breath on exertion, and
decreased exercise capacity  impaired respiratory
function + cardiovascular disease
Hypoventilation (shallow and slow respirations) 
respiratory muscle weakness + reduced pulmonary
responses to hypoxia and hypercapnia
Obstructive sleep apnea  macroglossia

24. Clinical Manifestations of Hypothyroidism --
Renal Function
Decreased glomerular filtration rate (GFR )
Impaired ability to excrete a water load
The drug clearance (ex, antiepileptic,
anticoagulant, hypnotic and opioid drugs), is
decreased.  Drug toxicity may occur if drug
dosage is not reduced.
During T4 replacement, drugs that are
administered at effective doses in patients who are
hypothyroid may become less effective.

25. Clinical Manifestations of Hypothyroidism --
Anemia
Impaired hemoglobin synthesis  thyroxine
deficiency
Iron deficiency  increased iron loss with
menorrhagia + impaired intestinal absorption of iron
Folate deficiency  impaired intestinal absorption of
folic acid
Pernicious anemia  vitamin B12-deficient
megaloblastic anemia

26. Clinical Manifestations of Hypothyroidism --
Reproductive Abnormalities
 Women with hypothyroidism may have either oligo-
or amenorrhea or hypermenorrhea-menorrhagia.
 Decreased fertility
 Increased likelihood for early abortion
 Hyperprolactinemia may occur, and is occasionally
sufficiently severe to cause amenorrhea or
galactorrhea
 The serum sex hormone-binding globulin
concentration may be low in hypothyroidism. This
will lower serum total but not free sex hormone
concentrations.

28. features Primary secondary
skin Thick and without wrinkle Thick with fine wrinkle
Hair coarse fine
Menstrual irregularities menorrhagia amenorrhea
Secondary sexual changes Normal poor
Heart size May be enlarged small
Goitre May be present absent
Soft tissue edema Marked absent
Blood pressure Normal or high low
cholestrol increased normal
TSH high low
Plasma cortisol normal low
TRHstimulation test Exaggerated response No response
Thyriod auto anti bodies May be present absent
hypothyriodism

29. Hashimoto’s Thyroiditis
Chronic lymphocytic thyroiditis
Probably the most common cause of
hypothyroidism
With goiter(younger patients) or without goiter
(older patients – atrophy gland after destruction by
immunologic process)
High titer of autoantibodies to thyroidal
antigens (Thyroglobulin Ab, Thyroperoxidase
Ab = TPO Ab = Antimicrosomal Ab = AMA)

37. LOWNORMALHIGH
FREETHYROXINEorFT4
EUTHYROID
SUB-CLINICAL
HYPERTHYROID
NON THYROID
ILLNESS - NTI
NTI or Pt.
on ELTROXIN
SUB-CLINICAL
HYPOTHYROID
SECONDARY
HYPERTHYROID
SECONDARY
HYPOTHYROID
PRIMARY
HYPERTHYROID
PRIMARY
HYPOTHYROID
LOW NORMAL HIGH
THYROID STIMULATING HORMONE - TSH