Set 18 Flashcards
How is thyroid hormone made and stored?
Epithelial cells lining the follicle bring in iodine out of the blood using a Na/iodide cotransporter. Once in the cell the iodide is moved into the follicle where it is oxidized by peroxidase I- to I2). Then it is bound to Thyroglobulin (at tyrosine residues) by a process known as organification (by propylthiouracil). This results in MIT or DIT that can be linked to form T3 and T4 (condensation, again propylthiouracil). T4 is most of what is released. It is activated in peripheral tissues by propylthiouracil. Both T3 and T4 are bound to Tg and stored in colloid until TSH leads to proteolytic release of T3/T4 (break down Tg protein) and exocytosis.
A 35-year-old man is seen in the office for his chronic, recurrent peptic ulcer disease. It has been refractory to conventional treatment with PPIs. Your attending mentions that this might be caused by a tumor. What type of tumor may be responsible for this condition? If this patient also presented with renal stones and signs of hypogonadism, what syndrome might you suspect?
Zollinger-Ellison syndrome - gastrin-secreting tumor of pancreas or duodenum. Acid secretion causes recurrent ulcers in distal duodenum and jejunum. Presents with abdominal pain (peptic ulcer disease, distal ulcers), diarrhea (malabsorption). May be associated with MEN1.
MEN1 (Wermer syndrome) - Pituitary, parathyroid and pancreatic tumors. Commonly presents with kidney stones and stomach ulcers. Pituitary tumor may secrete prolactin - hypogonadism.
What is the role of clomiphene in the treatment of PCOS? What is the mechanism of action of clomiphene?
Clomiphene is a SERM, antagonist at estrogen receptors in the hypothalamus. Prevents normal feedback inhibition and increases release of LH and FSH from pituitary, which stimulates ovulation. Used to treat infertility due to anovulation (PCOS). May cause hot flashes, ovarian enlargement, multiple simultaneous pregnancies and visual disturbances.
A 49-year-old trauma patient comes into the ER unconscious and in need of surgery. What are the exceptions to informed consent?
- Patient lacks decision-making capacity or is legally incompetent
- Implied consent in an emergency
- Therapeutic privilege - withholding information when disclosure would severely harm the patient or undermine informed decision-making capacity
- Waiver-patient explicitly waives the right of informed consent
What are the side effects of amiodarone, and what testing should be performed periodically on patients taking it?
Amiodarone: Antiarrhythmic, K+ channel blocker, class III. Also has class I, II, and IV effects and alters the lipid membrane. Increases AP duration, ERP. Used when other antiarrhythmics fail. Increases QT interval. Clinicaly used for afib, atrial flutter and ventricular tachycardia. SE: pulmonary fibrosis, hepatotoxicity, hypo or hyperthryroidism (amiodarone is 40% iodine by weight), corneal deposits, skin deposits (blue/gray) resulting in photodermatitis, neurologic effects, constipation, cardiovascular effects (bradycardia, heart block, CHF).
Check PFTs, LFTs and TFTs when using (pulmonary, liver, thyroid) amiodarone.
Ceftriaxone is used for the treatment of sexually-transmitted N. gonorrhea infections. What generation of cephalosporin is ceftriaxone? Which generation of cephalosporins is effective against Pseudomonas? Are cephalosporins bacteriostatic or bactericidal?
3rd generation
4th generation is effective against Pseudomonas (cefepime). Some third generation (ceftazidime, cefoperzone)
Bactericidal
A 35-year-old white woman presents with a dull ache in her jaw that is made worse by chewing. She states that this pain corresponds to her recent promotion and increase in responsibilities. What is the most likely diagnosis?
TMJ syndrome
- Classic patient: Young woman in 20s/30s.
- 2nd most common cause of facial pain
- Exacerbated by stressful life events
- Nocturnal bruxism
- Clicking of the jaw (not diagnostic)
A patient is undergoing treatment with recombinant interferon for his Hepatitis C. In what ways do interferons interfere with viral protein synthesis?
Interferon-y: activates NK cells to kill virus-infected cells, increases MHC expression and antigen presentation in all cells
Interferon a + b: a part of innate host defense against both RNA and DNA viruses. Interferons are glycoproteins synthesized by viral-infected cells that act locally on uninfected cells, priming them for viral defense. When a virus infects a primed cell —> viral dsRNA activates - RNAase L (degradation of viral/host mRNA) and protein kinase (inhibition of viral/host protein synthesis) - essentially resulting in apoptosis
Summary:
RNA protein kinase (degradation of viral/host mRNA)
Influence the activities of macrophages/dendritic cells
Trigger pro-apoptotic pathways
Your patient develops a cough with the new antihypertensive drug you prescribed her. What are some other side effects associated with this medication?
ACEi: Cough, angioedema, teratogen, increased creatinine (decreased GFR), hyperkalemia, hypotension
In regard to seizures, what do the terms partial, generalized, simple and complex mean?
Partial (focal): affect 1 area of the brain, most commonly originate in medial temporal lobe. Simple partial (consciousness intact) - motor, sensory, autonomic, psychic. Complex partial (impaired consciousness)
Generalized: diffuse. Can be absence (petit mal, no postictal confusion, blank stare), myoclonic (quick, repetitive jerk movements), tonic-clonic (grand mal, alternating stiffening and movement), tonic (stiffening) and atonic (‘drop’ seizures, commonly mistaken for fainting)
