Thymoma and Thymus-Related Disorders

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Which type of lymphocytes are primarily produced by the thymus?

Macrophages

T lymphocytes (correct)

Natural killer cells

B lymphocytes

Which of the following is NOT commonly associated with paraneoplastic syndromes in thymoma patients?

Graves disease

Arthritis (correct)

Pernicious anemia

Cushing syndrome

What is the primary role of anticholinesterase medications in the treatment of myasthenia gravis?

Suppress immune response

Enhance muscle strength (correct)

Reduce inflammation

Improve nerve conduction

Which of the following diseases is NOT specifically mentioned to be commonly associated with thymoma?

Multiple sclerosis Signup and view all the answers

What is the significance of Lambert-Eaton myasthenic syndrome (LEMS) in terms of anesthetic management compared to myasthenia gravis?

Potential for prolonged muscle relaxation Signup and view all the answers

Which type of T cells are responsible for fighting infection and cancer?

Helper T cells Signup and view all the answers

During thymocyte maturation, which hormones in the thymus play a role in the development of T cells?

Thymopoietin and thymosin Signup and view all the answers

What percentage of blood lymphocytes do T cells approximately account for?

65% Signup and view all the answers

Which type of T cells was formerly known as suppressor I cells?

Regulatory T cells Signup and view all the answers

What is the primary function of bone marrow stem cells in the context of T cell development?

Maturation into T cells in the thymus Signup and view all the answers

Which type of T cell has a unique T-cell receptor that recognizes specific cell-bound antigens in lymphoid organs?

Memory T cells Signup and view all the answers

Which part of the thymus is mainly composed of lymphoid cells?

Cortical portion Signup and view all the answers

Where does the thymus receive blood supply from primarily?

Superior and inferior thyroid arteries Signup and view all the answers

At what age does the thymus start to atrophy in response to increased sex hormone levels?

Puberty Signup and view all the answers

Which veins drain venous blood from the thymus?

Innominate veins and thyroid sinus Signup and view all the answers

What happens to the thymus gland over time as a response to increased sex hormones?

It decreases in size Signup and view all the answers

Which immune system cells are primarily responsible for humoral immunity?

B lymphocytes (B cells) Signup and view all the answers

What is the mainstay of treatment for thymomas?

Surgery Signup and view all the answers

Approximately what percentage of all mediastinal tumors do thymomas account for?

20% Signup and view all the answers

Which cell type gives rise to thymic carcinoid tumors?

Kulchitsky cells Signup and view all the answers

In patients with myasthenia gravis (MG), what percentage are found to have a thymoma?

30% to 35% Signup and view all the answers

What is the primary role of chemotherapy in the treatment of thymic tumors?

Shrinking large, malignant tumors preoperatively Signup and view all the answers

Why is it preferable to delay thymectomy until puberty?

To allow for proper immune system development Signup and view all the answers

What is a common symptom associated with thymomas due to phrenic nerve encroachment?

Chronic cough Signup and view all the answers

Which of the following conditions is NOT commonly associated with thymomas?

Renal dysfunction Signup and view all the answers

In what percentage of patients with thymomas is the mass discovered incidentally?

30% to 40% Signup and view all the answers

What is a common paraneoplastic syndrome associated with thymomas affecting multiple systems?

Endocrine disorders Signup and view all the answers

Which of the following is a rare feature of patients with thymomas?

Thymomas are common in children Signup and view all the answers

What is a potential symptom in thymoma patients as a result of a paralyzed hemidiaphragm?

Shortness of breath (SOB) Signup and view all the answers

What is the relationship between thymic dysfunction and immune function in adults?

Thymic dysfunction in adults does not affect immune function. Signup and view all the answers

Which congenital disorder is associated with a lack of functional T cells and severe immunodeficiency?

DiGeorge syndrome Signup and view all the answers

What is the primary target of antibodies in myasthenia gravis?

Postsynaptic nicotinic acetylcholine receptors Signup and view all the answers

What is the role of alpha-fetoprotein in the context of myasthenia gravis?

It inhibits binding of maternal nAChR antibodies to fetal ACh receptors. Signup and view all the answers

Which test is most sensitive for ocular and generalized muscle involvement in myasthenia gravis?

SFEMG Signup and view all the answers

What happens to the architecture of the postsynaptic membrane in myasthenia gravis over time?

It takes on a simplified appearance with fewer nAChRs. Signup and view all the answers

Which condition shows improvement in muscle strength within 5 minutes after administration of edrophonium as a confirmatory diagnostic test?

Myasthenia gravis Signup and view all the answers

Which crisis is characterized by an acute exacerbation of symptoms associated with MG that requires immediate intubation and mechanical ventilation?

Myasthenic crisis Signup and view all the answers

What can trigger acute hypoxemia, hypercarbia, and acidosis in a patient experiencing a myasthenic crisis?

Failure of the respiratory muscle to maintain adequate ventilation Signup and view all the answers

Which of the following symptoms is associated with severe bulbar weakness and increased risk for aspiration during a myasthenic crisis?

Poor or absent gag reflex Signup and view all the answers

What symptom differentiates a cholinergic crisis from a myasthenic crisis?

Preservation of deep tendon reflexes Signup and view all the answers

Which condition is characterized by flaccid muscle paralysis due to overadministration of an anticholinesterase medication?

Cholinergic crisis Signup and view all the answers

Which feature is NOT typically present during a cholinergic crisis?

Hypertension Signup and view all the answers

Which approach is recommended for surgical access in patients with early-stage thymoma?

Upper sternal split with division of manubrium Signup and view all the answers

What postsurgical complication is associated with thymectomy near the innominate vein?

Postoperative thrombosis Signup and view all the answers

Why should the inspired oxygen concentration during anesthesia not exceed 28%?

To avoid pulmonary interstitial edema Signup and view all the answers

Which test is NOT part of the preoperative testing for patients with a history of doxorubicin treatment?

CXR Signup and view all the answers

What should be strictly observed during the insertion of intravenous lines in patients with a recent history of chemotherapy?

Use of aseptic technique Signup and view all the answers

What is the primary reason for delaying thymectomy until puberty?

Reduced surgical risk Signup and view all the answers

What is the purpose of an edrophonium challenge test in patients with myasthenic crisis or cholinergic crisis?

To distinguish between myasthenic crisis and cholinergic crisis Signup and view all the answers

What is the immediate response expected during an edrophonium challenge test in a patient with myasthenic crisis?

Muscle strength improvement Signup and view all the answers

Which side effect may warrant careful monitoring during an edrophonium challenge test in patients?

Significant bradycardia Signup and view all the answers

What is recommended for patients with myasthenic crisis after an initial IV test dose of edrophonium?

Additional doses of an anticholinesterase Signup and view all the answers

What is the primary management strategy for cholinergic crisis?

IV administration of atropine sulfate Signup and view all the answers

In the context of thymomas, what is the primary goal of surgical resection?

Treating patients with a thymoma Signup and view all the answers

For which stage of thymomas is surgery not indicated according to the text?

Stage IVb Signup and view all the answers

What may be necessary for invasive stage IVa thymomas during surgery according to the text?

Resection of invaded local structures Signup and view all the answers

What is the main aim of postoperative radiotherapy following complete resection in thymoma patients?

Decreasing recurrence rate Signup and view all the answers

In thymoma patients, what surgical approach may be used to allow a simple thymectomy for myasthenic patients?

Video-assisted thoracoscopic surgery (VATS) Signup and view all the answers

What is the primary concern in postoperative management for a patient with myasthenia gravis?

Development of postoperative respiratory failure Signup and view all the answers

How do symptoms differ in unilateral versus bilateral phrenic nerve damage post-thymectomy?

Unilateral damage presents with respiratory difficulty and atelectasis, while bilateral damage results in reduced lung capacity Signup and view all the answers

Why is mechanical ventilation often required in patients with bilateral phrenic nerve damage following thymectomy?

To support lung function due to paralysis of both hemidiaphragms Signup and view all the answers

In the context of thymectomy, why is continued mechanical ventilation crucial for some patients postoperatively?

To manage hypoxemia and hypercapnia from phrenic nerve injury Signup and view all the answers

What is the expected resolution time for transient neurapraxia following phrenic nerve injury during a thymectomy?

7-10 days Signup and view all the answers

How do symptoms differ between unilateral and bilateral phrenic nerve damage following a thymectomy?

Unilateral damage manifests as hoarseness and atelectasis, while bilateral damage decreases vital capacity and total lung capacity Signup and view all the answers

Which of the following medications is NOT associated with acute exacerbations of myasthenia gravis?

Tetracycline Signup and view all the answers

Which of the following drug categories has NOT been linked to acute exacerbations of myasthenia gravis?

Antipsychotics Signup and view all the answers

Among the following, which medication is paradoxically associated with acute exacerbations of myasthenia gravis?

Lithium Signup and view all the answers

Which drug, commonly used in cardiac conditions, is associated with acute exacerbations in myasthenia gravis?

Quinidine Signup and view all the answers

Which of the following medications has NOT been implicated in causing acute exacerbations of myasthenia gravis?

Trimethaphan Signup and view all the answers

What is the primary role of acetylcholinesterase in the neuromuscular junction?

Breakdown of acetylcholine Signup and view all the answers

In myasthenia gravis, what is the main consequence of a reduced number of postsynaptic acetylcholine receptors?

Impaired neuromuscular transmission Signup and view all the answers

Where is acetylcholinesterase primarily located in the neuromuscular junction?

Synaptic folds Signup and view all the answers

What is the consequence of failed neuromuscular transmission in myasthenia gravis?

Weakened muscle strength Signup and view all the answers

What occurs to acetylcholine after its diffusion across the synaptic cleft in a neuromuscular junction?

Hydrolyzed by acetylcholinesterase Signup and view all the answers