Hypothyroidism
For patient information click here
Hypothyroidism Main page |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mahshid Mir, M.D. [2]
Synonyms and keywords: Myxedema; myxoedema; thyroid activity decreased; hypothyroid
Overview
Classification
Origin of the defect | Causes | |||||
---|---|---|---|---|---|---|
Endagenous causes | Exagenous causes | |||||
Thyroid | Pituirtary | Hypothalamus | Surgery or radiation | Other causes | ||
Primary hypothyroidism | + | - | - |
|
|
|
Transient hypothyroidism | + | + | - |
|
||
Secondary hypothyroidism | - | + | - |
|
|
|
Tertiary hypothyroidism | - | - | + |
|
|
|
hei
- Primary hypothyroidism
- Congenital hypothyroidism
- Autoimmune (Hashimoto's) thyroiditis
- Iodine deficeincy
- Drug induced thyroiditis
- Amiodarone
- Lithium
- Thionamide
- Iodine
- Iterferon
- Sunitinib
- Rifampicin
- Thalidomide
- Thyroidectomy
- Radioiodine therapy
- Transient hypothyroidism
- Subacute (de Quervain’s) thyroiditis
- Postpartum thyroiditis
- Secondary hypothyroidism (due to decreased levels of TSH)
- Pituitary mass lesions, especially pituitary adenomas
- cysts and abscesses
- meningiomas
- dysgerminomas
- metastatic tumors
- craniopharyngiomas
- surgery or radiation therapy for pituitary adenomas or other mass lesions near pituitary gland
- head trauma with injury of the stalk
- pituitary apoplexy
- Sheehan syndrome (postpartum pituitary necrosis)
- Idiopathic isolated TSH deficiency
- Tertiary hypothyroidism
- Infiltrative disorders affecting the pituitary or the hypothalamus include hemochromatosis, and histiocytosis
- autoimmune lymphocytic hypophysitis
- Developmental abnormalities
- internal carotid aneurysms
- Other central nervous system (CNS) tumors
- Idiopathic isolated TRH deficiency
Differential diagnosis
Disease | History and symptoms | Laboratory findings | Additional findings | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Fever | Goiter | Serum glucose | Urinary Glucose | Urine PH | Serum Sodium | Urinary Glucose | 24 hrs cortisol level | C-peptide level | Serum glucagon | |||||
Primary hypothyroidism | + | + | + | + | - | ↑ | ↑ | Normal | Normal | N/↑ | Normal | ↓ | Normal | Auto antibodies present
(Anti GAD-65 and anti insulin anti bodies) |
Transient hypothyroidism | + | + | + | + | - | ↑ | ↑ | Normal | Normal | ↑ | Normal | Normal | ↑ | Acanthosis nigricans |
Subclinical hypothyroidism | + | + | + | - | + | ↑ | ↑ | Normal | Normal | ↑ | Normal | Normal | N | - |
+ | + | - | - | - | Normal | Normal | Normal | ↓ | Normal | Normal | Normal | Normal | - | |
+ | + | - | - | - | Normal | Normal | Normal | ↑ | Normal | Normal | Normal | Normal | - | |
Transient hyperglycemia | - | - | - | - | - | ↑ | ↑ | Normal | Normal | ↑ | Normal | Normal | N/↑ | In hospitalized patients especially in ICU and CCU |
Steroid therapy | + | - | - | - | + | ↑ | ↑ | Normal | Normal | ↑ | ↑ | N/↑ | N/↑ | Acanthosis nigricans, |
RTA 1 | - | - | - | + | - | Normal | Normal | ↑ | Normal | ↑ | Normal | Normal | Normal | Hypokalemia, nephrolithiasis |
Glucagonoma | - | - | - | - | - | ↑ | Normal | Normal | Normal | - | Normal | Normal | ↑ | Necrolytic migratory erythema |
Cushing syndrome | - | - | - | - | + | ↑ | - | Normal | ↓ | N/↑ | ↑ | Normal | Normal | Moon face, obesity, buffalo hump, easy bruisibility |
General feature
Symptoms
Constituitional | Local | Reproductive | Neuropsysiological | Others | Physical exam | |
---|---|---|---|---|---|---|
cold intolerance
puffiness decreased sweating coarse skin hypothermia Fever if accompanied by thyroiditis weight gain coarse, brittle, straw like hair with hair loss |
obstructive sleep apnea (secondary to macroglossia) | Females can present with galactorrhea and menstrual disturbances | depression | paresthesia and nerve entrapment syndromes | decreased systolic blood pressure
increased diastolic blood pressure bradycardia pericardial effusion abdominal distension ascites (uncommon) non-pitting edema (myxedema) pitting edema of lower extremities hyporeflexia with delayed relaxation ataxia | |
fullness and pain in the throat and neck | infertility | emotional lability | constipation | |||
|
blurred vision | macroglossia | ||||
goiter | Attention deficit | periorbital puffiness | ||||
slowed speech and movements |
- Metabolic abnormalities associated with hypothyroidism include:
- anemia,
- dilutional hyponatremia,
- hyperlipidemia,
- reversible increase in creatinine
Complications
Myxedema coma
Rare, severe form of hypothyroidism, a life-threatening condition
- Altered mental status,
- hypothermia,
- bradycardia,
- hypercarbia, and
- hyponatremia.
- Cardiomegaly,
- pericardial effusion,
- cardiogenic shock, and
- ascites
- commonly occurs in individuals with undiagnosed or untreated hypothyroidism who is subjected to an external stress, such as low temperature, infection, or medical intervention (e.g., surgery or hypnotic drugs)