Block 38 Flashcards
Systemic mastocytosis
Clonal mast cell proliferation occurs in the bone marrow, skin, and other organs. Mast cell proliferation often is associated with mutation in the KIT receptor tyrosine kinase.
-these cells are characterized by prominenet expression of mast cell tryptase.
-excessive histamine release from degranulation of mast cells mediates many of symptoms of the disease such as syncope, flushing, hypotension, pruritus and urticaria. In addition, histamine induces gastric acid secretion, which can lead to gastric ulceration. The excess acid also inactivates pancreatic and intestinal enzymes, causing diarrhea. Other GI symptoms include nausea, vomiting and abdominal cramps.
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PV
Presents with increased RBC mass, increased plasma volume, and low EPO levels with normal O2 saturation(only altered in seconday polycythemia due to lung injury).
- additional manifestation include elevated platelet and/or WBC count, thrombotic events, peptic ulceration and pruritus(histamine release from basophils), and gouty arthritis (increased cells turnover).
- plethora, ruddy face and splenomegaly is common.
- the mutation replace valine with phenylalanie at 617 gene position in JAK2 gene rendering the hematopoietic cells —> “sensetive to growth factors”
L.monocytogenes
Its a facultative intracellular organism that can cause signficant disease in patients with cell mediated immunodeficiency, including infants, HIV patients, organ transplant recipient and certain malignancy patients.
- clinical syndrome include febrile gastroenteritis, septicemia and meningoencephalitis. Infection in pregnant women can lead to amnionitis with neonatal sepsis or fetal demise.
- its a common organism in the intestinal tract of cattle and can be transmitted via milk. Outbreak are associated with dairy products(soft cheese, milk , ice cream) also raw fruit or meat.
Tay sachs disease
Is autosomal recessive neurodegenerative disease commonly seen in ashkenazi jewish population. Tay sachs is caused by ß-hexosaminidase A deficiency which results in accumulation of the cell membrane GM2 ganglioside within lysosomes.
- affected nfants typically have normal development in first few months followed by progressive neurologic deterioration.
- weaknes, hypotonia, seizures, spasticity and blindness.
- the center of fovea appears bright red (cherry red macula spot)
- patients have no hepatosplenomegaly
Hypermethioninemia due to homocysteinuria , which amino acid is essential for these patients
Cysteine
Mefipristone
Progesterone and glucocorticods antagonist
- can be used to terminate pregnancy—> apoptosis and necrosis of uterine decidua.
- when misoprostol (PG E1 agonist) is used along mefipristone there is increased success rate.
Minute ventilation
Alveolar ventilation
Dead space
Minute ventilation= tidal volume X breath/min
Alveolar ventilation is volume of new air reaching the gas exchange areas per minute. Therefore it doesnt include dead space volume. (Alveolar ventilation = minute ventilation -deadpace volume.
Physiologic dead space is total dead space in lung. It consist of anatomic dead space of conducting system (approximately 150 ml) and alveolar dead space due to well ventilated but poorly perfused alveoli.
Prolonged cortiocsteroids therapy
Chronic glucocorticod use is charactrized by low CRH, ACTH and cortisol levels that cannot rise in response to stressful stimuli.
This lack of stress response can result in relative glucocorticod deficiency even when the patients baseline glucocorticod regimen is maintained.
Fibrotic focus in lower love of lung in conjunction with calcified lymph node
It can occur in primary TB.
Lower lung lesion (ghon focus) accompanied by ipsilateral hilar adenopathy is described as ghon complex.
The ghon complex occurs during initial infection with M. Tuberculosis.
Obstructive sleep apnea stimulation therapy
Stimulation of hypoglossal nerve using an implantable nerve stimulator causes the tongue to move forward slightly, increasing the anteroposterior diameter of airways
Vascular access during cardiac catheterization from common femoral artery can predispose to
-arterial puncture above the inguinal ligament increases the risk of retroperitoneal hemorrhage.
Highly charged drugs
The volume of distribution refers to the hypothetical volume of fluid into which administred drug would need to be uniformly distributed to produce the observed plasma concentration.
- low volume of distribution indicates that the drug have high molecular weight, high plasma protein binding, high charge and hydrophilicity tend to trap the drug in plasma compartment rather than intracellularly
RNA dependent DNA polymerase activity is seen in DS DNA circular virus
Hepatitis B
Maternal serum AFP screening
High MSAFP:
1. Open neural tube defects
2. Ventral wall defects
3. Multiple gestation
Low MSAFP:
1. Trisomy 18 , 21 (aneuploidies in general)
2. Dating error( search for history of irregular menses)
Combination of nicotinic and muscarinic blockade is highly suggestive of
- clostridium botulinium toxin.
- the toxin inhibit Ach release from presynaptic nerve terminals at the neuromuscular junction, thereby preventing muscular contraction.
- this effect can be seen on EMG as decrease in the compound muscle action potential following stimulation of motor nerve.
- high rate, repetitive nerve stimulation improves the deficit as the rapid depolarization rate increases calcium concentration in the presynaptic nerve terminal.
- classic 3d’s occur —> diplopia , dysphagia and dysphonia within 12-36 hours of consumption.
