One important concept we discussed was the concept of West's zones of lung and ventillation/perfusion (V/Q) matching. The central tenant is that blood flow is proportional to gravity and therefore the best perfusion occurs at the bases in an upright pair of lungs. In a patient with complete collapse of the left lung, oxygenation can be improved by improving V/Q mismatch. This is done by "directing" perfusion to the ventillated lung by placing the good lung down. Sometimes you can even observe this effect at the bedside!
We also discussed thyroid cancer. Evaluation of the thyroid nodule is a relatively common referral to general internists and endocrinologist. A proposed algorithm for the evaluation of solitary thryoid nodules is presented in the figure.
Thyroid malignancies include:
- Differentiated thyroid cancers: Papillary and follicular
- Undifferentiated thyroid cancers: Anaplastic
- Medullary thyroid cancer (neuroendocrine tumor of the C-cells)
- Thyroid lymphoma
- MEN2A -- MTC, pheochromocytoma, primary hyperparathyroidism
- MEN2B -- MTC (aggressive, high risk of death), pheochromocytoma, marfanoid habitus, mucosal neuromas
- Familary Medulary Thyroid Cancer -- like 2A but no pheo/PTH
Inherritable MTC tends to present in the 30's. Measuring serum calcitonin in response to IV calcium can serve as screening in 1st degree relatives. One can also look at the RET oncogene for mutations. Prophylactic thyroidectomy in positives.
Non-syndromic patients tend to present in their 40/50's with a palpable nodule. Often there is metastasis at presentation (primarily to locoregional lymph nodes, occasionally systemic).
Five and ten year survival varies with age. Age <40 have 95% 5 year and 75% 10y survival all-comers.
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