Hyperthyroidism resident survival guide

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Pervaiz Laghari, MD[2]

Overview

Hyperthyroidism and thyroid storm are disease states that result from thyroid hormone-induced hypermetabolism. The excess thyroid hormone is released from the thyroid gland as a result of excess thyroid hormone production, or by processes that disrupt the follicular structure of the gland with subsequent release of stored hormone [1]. Most patients with severe hyperthyroidism present with a dramatic symptom constellation. Hyperthyroidism's typical symptoms include palpitations,heat intolerance, increased bowel movement frequency tremor, anxiety, weight loss despite normal or increased appetite and shortness of breath.Goiter is commonly found on physical examination.

Specific organ systems

Cardiovascular Heart rate is increased,Systolic hypertension ,pulse pressure is widened, congestive heart failure, Atrial fibrillation
Neuropsychiatric Anxiety, tremor, restlessness, irritability,insomnia,psychosis, agitation,depression, seizures
Respiratory Dyspnea, tracheal obstruction, exacerbate underlying asthma,Pulmonary arterial systolic pressure is increased
Gastrointestinal Weight loss,hyperphagia,hyperdefecation and malabsorption
Skin Sweating,Onycholysis,Hyperpigmentation,Thinning of the hair
Eyes Stare and lid lag, ophthalmopathy.
Genitourinary Urinary frequency and nocturia
Hematologic Normochromic, normocytic anemia
Neck Thymic enlargement
Bone Osteoporosis and an increased fracture risk

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

Common Causes

Diagnosis

Shown below is an algorithm summarizing the diagnosis of hyprthyroidism according to the American Thyroid Association guidelines[5].

 
 
 
 
 
 
 
Clinical assessment of signs & symptoms for hyperthyroidism:
  • Tachycardia
  • Palpitations
  • Anxiety, insomnia
  • Fine tremors in outstretched hands
  • Heat intolerance
  • Diaphoresis
  • Weight loss
  • irregular pulse (in atrial fibrillation)
  • dyspnea
  • orthopnea
  • brisk deep tendon reflexes
  • proximal muscle weakness
  • pretibial myxedema (Graves’ disease)
  • lid lag, lid retraction, decrease lacrimation (thyroid eye disease)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Measure serum Thyroid stimulating hormone levels
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Low TSH (usually<0.01mU/L)
 
 
 
 
 
 
 
High TSH
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Mild hyperthyroidism: Serum T4 and T3 values in normal range or only T3 levels are elevated.
 
 
 
Overt hyperthyroidism: Both serum T3 and T4 levels elevated
 
 
 
 
Elevated serum T4 and T 3 levels
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Perform thorough physical examination of thyroid gland and look for signs for thyroid eye disease. Thyroid gland diffusely enlarged with symmetrical hypertrophy and new onset of ocular symptoms
 
 
 
 
 
Repeat TSH levels in serial dilution
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Yes. Graves' disease
 
No
 
 
Positive
 
 
Negative
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Measure serum assays of TRAb and radioactive iodine uptake thyroid scan
 
 
 
High TSH levels due to hetrophilic antibodies
 
 
Look out for pituitary lesion
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Measurement of serum levels of human anti-mouse antibodies
 
 
 
  • Perform MRI Brain
  • High ratio of the serum level of alpha subunit of the pituitary glycoprotein hormone
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Diffuse increase in iodine uptake
 
 
 
Localized increase in iodine uptake
 
 
 
Subnormal or absent uptake of iodine
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Graves' disease
 
 
Toxic nodular goiter
 
Subacute thyroiditis/ Postpartum thyroiditis
 
Factitious ingestion of thyroid hormones
 
Excess intake of iodine recently
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
High levels of thyroglobulin in serum
 
Low thyroglobulin levels
 
Measure spot urine iodine or 24 hour urine iodine level
 

Treatment

Shown below is an algorithm summarizing the treatment of Graves' disease according to the American Thyroid Association guidelines[6] [7].

Do's

  • Beta-blockers are recommended for symptomatic relief of systemic symptoms like tachycardia, anxiety, and tremors. It is strongly recommended for elderly patients with a resting heart rate greater than 90 beats per minute and coexisting cardiovascular diseases[6].
  • The total T3 to T4 plasma levels ratio can assess the etiology of thyrotoxicosis in patients in whom the radioactive iodine uptake scan is contraindicated. An overactive thyroid gland will release more t3 compared to t4. Hence in Graves’ disease and toxic nodular goiter total t3 to t4 ratio will be high (i.e. >20), while in sub-acute or post-partum thyroiditis, the ratio of T3 to T4 will be low (i.e. <20)[8] [9].
  • TRAb is faster and more cost-effective compare to radioactive iodine thyroid uptake scan to diagnose Graves’ disease. It should be preferred for the diagnosis of Graves’ disease[10].
  • Near-total or total thyroidectomy is the treatment of choice for toxic multinodular goiter. Isolated lobectomy or isthmusectomy is carried out for toxic adenoma[5]. Radioactive iodine ablation therapy have resulted in severe thyrotoxicosis with worsening of cardiac rythms including supraventricular tachycardia, atrial flutter or atrial fibrillations in patients with non-toxic and toxic multi-nodular goiter[11].

Don'ts

  • The content in this section is in bullet points.

References

  1. Roth RN, McAuliffe MJ (1989). "Hyperthyroidism and thyroid storm". Emerg Med Clin North Am. 7 (4): 873–83. PMID 2680469.
  2. Kravets I (2016). "Hyperthyroidism: Diagnosis and Treatment". Am Fam Physician. 93 (5): 363–70. PMID 26926973.
  3. Vanderpump MP (2011). "The epidemiology of thyroid disease". Br Med Bull. 99: 39–51. doi:10.1093/bmb/ldr030. PMID 21893493.
  4. Pearce EN, Farwell AP, Braverman LE (2003). "Thyroiditis". N Engl J Med. 348 (26): 2646–55. doi:10.1056/NEJMra021194. PMID 12826640.
  5. 5.0 5.1 "Correction to: Thyroid 2016;26:1343-1421. DOI: 10.1089/thy.2016.0229". Thyroid. 27 (11): 1462. 2017. doi:10.1089/thy.2016.0229.correx. PMC 5672663. PMID 29035639.
  6. 6.0 6.1 Ross, Douglas S.; Burch, Henry B.; Cooper, David S.; Greenlee, M. Carol; Laurberg, Peter; Maia, Ana Luiza; Rivkees, Scott A.; Samuels, Mary; Sosa, Julie Ann; Stan, Marius N.; Walter, Martin A. (2016). "2016 American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis". Thyroid. 26 (10): 1343–1421. doi:10.1089/thy.2016.0229. ISSN 1050-7256.
  7. Nwatsock, JF; Taieb, D; Tessonnier, L; Mancini, J; Dong-A-Zok, F; Mundler, O (2012). "Radioiodine Thyroid Ablation in Graves′ Hyperthyroidism: Merits and Pitfalls". World Journal of Nuclear Medicine. 11 (1): 7. doi:10.4103/1450-1147.98731. ISSN 1450-1147.
  8. Carlé A, Knudsen N, Pedersen IB, Perrild H, Ovesen L, Rasmussen LB; et al. (2013). "Determinants of serum T4 and T3 at the time of diagnosis in nosological types of thyrotoxicosis: a population-based study". Eur J Endocrinol. 169 (5): 537–45. doi:10.1530/EJE-13-0533. PMID 23935127.
  9. Shigemasa C, Abe K, Taniguchi S, Mitani Y, Ueda Y, Adachi T; et al. (1987). "Lower serum free thyroxine (T4) levels in painless thyroiditis compared with Graves' disease despite similar serum total T4 levels". J Clin Endocrinol Metab. 65 (2): 359–63. doi:10.1210/jcem-65-2-359. PMID 3110204.
  10. McKee A, Peyerl F (2012). "TSI assay utilization: impact on costs of Graves' hyperthyroidism diagnosis". Am J Manag Care. 18 (1): e1–14. PMID 22435785.
  11. Koornstra JJ, Kerstens MN, Hoving J, Visscher KJ, Schade JH, Gort HB; et al. (1999). "Clinical and biochemical changes following 131I therapy for hyperthyroidism in patients not pretreated with antithyroid drugs". Neth J Med. 55 (5): 215–21. doi:10.1016/s0300-2977(99)00066-2. PMID 10593131.


Template:WikiDoc Sources

 
 
 
 
 
 
 
Overt Graves' disease
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Antithyroid medications
 
 
Radioactive iodine ablation
 
 
Surgery
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  • Methimazole (MMI) is a drug of choice because of its lower side effects profile.
  • It should be continued for a minimum duration of 12 to 18 months.
  • Regular monitoring with TSH and TRAb should be done.
 
 
  • Administered in patients with persistent thyrotoxicosis after anti-thyroid medications or patients who cannot tolerate anti-thyroid medications.
  • Risk of worsening of existing thyroid eye disease.
  •  
     
     
     
    Total or near-total thyroidectomy is recommended. The advantages are:
  • High cure rate
  • Zero recurrence rate with total thyroidectomy.
  •