Mediastinoscopy/Mediastinal mass Flashcards
What all is in the mediastinum?
all organs in chest except lungs
Anterior, middle, and posterior mediastinum:
Anterior: bordered by sternum front and pericardium posteriorly
Middle: pericardium and all of its contents
Posterior: posterior to pericardial wall, and anterior to thoracic vertebral bodies
4 most common medicinal masses. What disease is present in some people with mediastinal masses?
Thymoma: terrible, lymphoma, teratoma, ectopic thyroid. Myasthenia graves is present in 25% of people with mediastinal mass.
Speaking of Myasthenia Gravis, what exactly is it? Do symptoms get better or worse with movement? What is the drug of choice to treat this and how does it work?
It’s an autoimmune disease that attacks the post synaptic nicotinic ACh receptors at the NMJ.
Things get worse with movement
pyridostigmine and it is an anti cholinesterase
As far as the CNS and PNS, what is always there to start-from the spinal cord? When you go to PNS, what does that synapse on? Somatic system? What about sympathetic (there are four parts to this answer)
-ACh
-ACh synapse on muscarinic terminals (G protein on cardiac and smooth muscle, gland cells, and nerve terminals) (PNS)
Somatic: ACh nicotinic
Sympathetic: Sweat glands: sympathetic, but innervated by cholinergic muscarinic fibers
Cardiac, smooth muscle : alpha and Beta NE
Renal vascular smooth muscle: Dopamin
Adrenal medulla: Epi, NE
Always advise MG patients of what? What are the criteria that correlate with the need for mechanical ventilation during the post op period?
The fact that they may require ventilatory support after surgery
- disease longer than 6 years
- COPD unrelated to MG
- daily dose of pyridostigmine higher than 750 mg
- Vital capacity less than 2.9 L (40 mL/kg)
- Upper abdominal surgery
- steroid use!!!
What are you looking for on Physical exam of MG patient? Be careful not to give more cholinesterase inhibitor than usual-meaning:
chest infection, degree of muscle weakness, signs of other AI diseases (RA, hypothyroidism)
Meaning-1 mg of neostigmine is equal to 120 mg of PO pyridostigmine-you could trigger a cholinergic crisis
Things to keep in mind with MG patients? When would you know whether or not to give aspiration ppx?
Be careful with opines, use multimodal tx. be careful with extubation. Myasthenia crisis?
Bulbar involvement typically requires aspiration prophylaxis due to higher chance of aspiration.
Patients with My. Grav are sensitive to which paralytics? resistant to which? IV pyridostigmine is 1/__ of PO pyridostigmine? Acute exacerbations can be treated with:
After surgery they need to go to:
sensitive to NDMB Resistant to succinylcholine 1/30 IV Immunoglobulin ICU or step down unit-NOT regular post surgical ward
What are contraindications to mediastinoscopy?
Thoracic aortic aneurysms, SVC syndrome, Cerebrovascular disease-careful because occlusion the innominate artery can cause cerebral ischemia,
tracheal deviation
If you develop increased airway resistance during any surgery, what are you thinking?
Bronchospams Foreign body tension pneumothorax Endobronchial intubation poor compliance secondary to lung disease Mediastinal mass
What is a sign on flow volume loops on intrathoracic compression? What are you looking for on Echo? What if there is severe compression on RVOT?
collapse during expiration
On Echo, we’d be looking for RV outflow obstruction, or right heart dysfunction
If severe compression on RVOT, consider local0talk with surgeon.
Can you use a pulse ox instead of right sided arterial waveform?
You can, but its’ not as reliable
So, what’s your plan for putting people with a mediastinal mass to sleep? What happens if you lose the airway?
Keep them breathing! don’t paralyze until your’e certain you can ventilate. You can do an inhalational induction with sevo in the sitting position, but you could lose that airway.
If you lose the airway, change patient’s position to lateral or prone. reverse muscle relaxant, use a rigid bronchoscope to push past the obstruction
SOB in a patient who has a lung mass and is a smoker:
(1) pulmonary
disease resulting from his tobacco abuse (i.e. COPD and/or pneumonia); (2) mass-
induced ventilation perfusion mismatching; (3) mass-induced post-obstructive
pneumonia; ( 4) superior vena cava syndrome secondary to neoplastic invasion of the
vessel wall (usually in association with intravascular thrombosis), with the resultant
obstruction of venous drainage leading to mucosa! edema and venous engorgement of
the airways and subsequent dyspnea, orthopnea, and coughing; (5) mass compression
of the heart or other great vessels (i.e. direct cardiac compression, pericardia!
effusion, pulmonary artery compression); (6) cardiac disease in this older male
smoker with hypertension and known carotid disease; or (7) a late finding of
Lambert-Eaton Myasthenic syndrome (LES), a known paraneoplastic syndrome that
may also present with signs of autonomic dysfunction, such as constipation and
orthostatic hypotension.
Common paraneoplastic syndromes: SIADH Cushing's Lambert Eaton Humor hypercalcemia
-Syndrome of Inappropriate secretion of Antidiuretic Hormone (SIADH) -
tumor production of arginine vasopressin can lead to hyponatremia, decreased
serum osmolarity, and inappropriately increased urine osmolarity in the
setting of euvolemia and normal thyroid and adrenal function.
-Cushing’s Syndrome - increased secretion of ACTH or CRH can lead to
hypokalemia, alk:alosis, hypertension, .and psychosis.
-Lambert-Eaton Myasthenic Syndrome - most commonly associated with
small cell lung cancer.
-Humoral Hypercalcemia - Tumor release of parathyroid hormone-related
peptides can lead to muscle weakness, cardiac arrhythmias, nausea, vomiting,
and renal failure.