Forensic Medicine

Wednesday, May 20, 2015

Medicine Facts from Previous Papers

·         lowered CSF glucose: hypoglycorrhachia
·         heroin: a/w wound botulism
·         crack cocaine: a/w syphilis
·         Note that isolated dextrocardia is more likely to have underlying cardiac malformations like VSD...etc. Here we can see dextrocardia with left-sided liver and right-sided stomach (situs invertus) in which the heart is usually normal!
·         The combination of diabetes mellitus, hypertension, obesity, insulin resistance, and dyslipidemia (increased VLDL, increased triglyceride, and decreased HDL) is called syndrome X or Coronary artery disease, Hypertension, Atherosclerosis, Obesity, and Stroke (CHAOS).
·         Physicians should be able to calculate different cholesterol levels (mg/dL) using the following simple formulas:
1. Total cholesterol = HDL + VLDL + LDL
2. VLDL = Triglycerides/5
3. LDL = Total cholesterol -HDL -[Triglycerides/5]
·         Patients with peripheral vascular disease should be evaluated with a penile/brachial index. An index <0.06 suggests vascular impotence. Endocrine ED may be due to testicular failure (rare) or prolactinomas
·         The differential diagnosis for microcytic hypochromic anemia is TICS (Thalassemia, Iron deficiency, Chronic disease, and Sideroblastic).
·         Tangier disease is a rare inherited disorder of lipoprotein metabolism. Patients present with a low serum cholesterol level, virtually no HDL cholesterol, a normal or elevated triglyceride level, orange-colored tonsils, corneal opacities, and a relapsing polyneuropathy. The disorder does not lead to premature atherosclerosis and treatment is not required.
·         Dose of Anthracyclines need NOT be modified in renal failure pts.

·         Blood test that differentiates seizures from pseudoseizures – Prolactin level (Blood samples must be drawn within 20 mins of the episode)
In GTCS – Prolactin level ↑
In non-epileptic seizures – Prolactin level normal

·         MC metastatic tumor causing Diabetes insipidus – Breast Ca
·         Antiarrythmic drug without any direct effect on heart – Phenylephrine (It terminates arrhythmia reflexly, via the baroreceptors, in response to a vasopressor effect)
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MURMURs


·         Austin Flint murmur : Austin Flint murmur is a mid-diastolic rumbling audible in subjects with severe aortic regurgitation that is best heard at the apex with little radiation. Several theories have been suggested for the origin of the murmur: (1) vibration of the anterior mitral valve leaflet due to the regurgitant jet, (2) collision of the jet with mitral inflow, (3) increased mitral inflow velocity due to narrowing of the valve orifice by the jet, and (4) vibration from the jet impinging on the myocardial wall. It differs from mitral stenosis murmur in that ,it occurs in the presence of a murmur of aortic valve insufficiency and in the absence of the rheumatic, mitral opening snap.
·         Carey Coombs murmur : Mitral valvulitis associated with acute rheumatic fever may cause a low-pitched mid-diastolic rumble. It can be differentiated from the diastolic murmur of Mitral stenosis by the absence of (1)an opening snap, (2)presystolic accentuation & (3)loud first heart sound.
·         Cruveilhier-Baumgarten murmur : Venous hum heard in epigastric region (on examination by stethoscope) due to collateral connections between portal system and the remnant of the umbilical vein in portal hypertension.
·         Duroziez's murmur : Its a to & fro murmur heard over the femoral artery during both systole& diastole. It is elicited by applying gradual arterial compression with the diaphragm of the steth. This compression not only produces systolic murmur(which is the normal result of arterial compression) but also a diastolic murmur(which is pathologic & suggestive of aortic regurgitation).Sensitivity of 58-100%.False positives occur in high output states. In high output states the double murmur is due to forward flow. In Ar one murmur is due to forward flow& the other due to reverse flow.The two can be differnetiated by applying pressure first on the more cephalad edge of the diaphragm & then on its more caudal edge. The murmur of forward flow is enhanced by compressing the cephalad edge. Conversely the reverese flow murmur is enhanced by compressing the caudad edge.
·         Gibson murmur :The typical continuous "machinery-like" murmur of patent ductus arteriosus.train in tunnel murmur
·         Graham Steell's murmur : Due to pulmonary regurgitation in patients with pulmonary hypertension and mitral stenosis. It is a high pitched early diastolic murmur heard best at the left sternal edge in the second intercostal space with the patient in full inspiration.
The murmur is heard due to a high velocity regurgitant flow across the pulmonary valve; this is usually a consequence of pulmonary hypertension. The Graham Steell murmur is often heard in patients with chronic cor pulmonale as a result of chronic obstructive pulmonary disease.
·         Means-Lerman "scratch" murmur: Increased flow across the pulmonary valve in Thyrotoxicosis may be associated with ejection systolic murmur.The ejection systolic murmur owing to hyperthyroidism may have a scratchy quality (Means-Lerman scratch), and, frequently, the intensity of P2 is increased because of mild to moderate pulmonary hypertension.
·         Roger's Murmur: A loud pansystolic murmur caused by interventricular septal defect of the heart; maximal at the left sternal border.
·         Seagull murmur: a raucous murmur with musical qualities, such as that heard occasionally in aortic insufficiency.A "seagull’s cry murmur" is defined as a murmur imitating the cooing sound of a seagull. This type of murmur is typically characterized by a musical timbre and a high frequency, and may occur as a result of various valve diseases. It is usually described as a sign of tight calcific aortic stenosis, when the murmur’s high frequency components are transmitted to the lower left sternal border and the cardiac apex during most of systole (Gallavardin’s phenomenon). In this condition, the typical harsh timbre of the ejective murmur tends to assume a musical high pitched quality, resembling that of mitral regurgitation, which may be reminiscent of the cry of a seagull. A protodiastolic murmur with similar characteristics, typically in decrescendo, may occur in severe aortic valve regurgitation, particularly when the regurgitant flow presents high velocities. However, a seagull’s cry murmur may also be the sign of mitral regurgitation or prolapse. Similarly, the musical and holosystolic sound reflects the presence of high frequency components due to high velocities of reflow.
·         Still's murmur: An innocent musical murmur resembling the noise produced by a twanging string; almost exclusively in young children, of uncertain origin and ultimately disappearing.{There are five innocent murmurs of infancy and childhood: (i) pulmonary flow murmur, (ii) Still's murmur, (iii) venous hum, (iv) carotid bruit, (v) physiologic pulmonary branch stenosis murmur of neonate}

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