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Showing posts from October, 2011

Inferior wall and right ventricular infarct - ECG

ECG shows an inferior wall infarct i.e ST segment elevation in leads II, III and aVF. The precordial V leads are actually right sided on this ECG. This is evident because the tracing in V6 does not resemble lead I and aVL. Also the P waves in V4 to V6 are flat. ST depression in I and aVL along with ST elevation in right sided V3-V6 indicates right ventricular infarct.

Depression - cause, signs and symptoms

Depression is a mood disorder whereby mood is sad. About 30% of psychiatric cases deal with depression. Both males and females are affected but females are slightly more prone to be depressed. Cause: The biological cause is that there is a decrease in the serotonin neurotransmitter. Signs and symptoms: A simple mnemonic to remember is SIPS CAGE. 1) Sleep - There is late onset of sleep, intermittent awakening and early morning awakening i.e. around 2 hours before the normal waking up time. Rarely, the patient may over sleep. 2) Interest - Patient will have a decrease interest in the daily activities. This can result in social withdrawal, decreased ability to function in occupational and interpersonal areas. At times there is the inability to experience pleasure aka anhedonia . 3) Psychomotor activity - In younger patients, there is slowness in the thinking process and activities also are carried out at a slow pace. In elderly on the other hand, there is restlessness and inc

Effect of sleep on work

Sleep is an integral part of our lives. An average adult should sleep around 7-8 hours per day. Sleep is important to maintain metabolic-caloric balance, thermal regulation and even immune competence. Sleep is also essential for learning and memory consolidation as well as increasing one's concentration. An advice to students will be to sleep well after studying. Your learning sessions will not show any improved performance until you have a slow wave or slow wave plus REM sleep. Slow wave sleep refers to a deep sleep while REM sleep refers to the period in sleep whereby there is a characteristic movement of the eyeballs during the sleep. Medical interns and residents are known to burn the midnight oil. But unfortunately for them, working for more than 24 continual hours make them around 40% more prone to make medical errors. Residents are twice more likely to have attentional failure i.e. they forget what they are actually doing. Studies  have shown that 1 in 5 residents believ

Second degree atrioventricular block - ECG / Mobitz type I, type II

It consists of two types of blocks: 1) Mobitz type I block, 2) Mobitz type II block. Mobitz type I It is also called as Wenckebach pattern. In this condition, each stimulus from the atria appears to have more difficult time to pass through the AV junction. Finally one stimulus is not conducted through the defective AV node. A characteristic ECG shows progressive lengthening of the PR interval until a beat is dropped. i.e. the P wave is not followed by a QRS complex. It is also important to note that the PR interval after the dropped beat is always shorter than that before the non conducted P wave. Also the R-R interval encompassing the non conducted P wave is less than twice the preceding R-R interval. This ECG is also shows a Wenckebach pattern and we can clearly see at first glance that the narrow QRS complexes appear to be clustered and separated by a pause. This is called as group beating. If ever you find such a pattern, look out for the progressively increasing P

First degree atrioventricular block - ECG

In this condition, there is a delay in conduction between the atria and the ventricles. There is a prolongation of the PR interval to more than 200 ms. i.e > 5 small squares on a usual 25 mm/s ECG tracing. The normal duration for PR interval is 120 - 200 ms. A QRS complex follows each P wave and the PR interval is relatively constant from beat to beat. The pathology is usually due to a delay within the AV node if we have a normal QRS complex. But if the QRS complex is wide, the problem is more distal.

Ginkgo biloba

Ginkgo extracts are derived from the leaf of the ginkgo plant. It is the most commonly purchased herbal remedy in the USA. It is believed to help in non-dementia related memory problems, Alzheimer's disease, vertigo and even peripheral vascular diseases. There is documented evidence that ginkgo inhibits platelet activating factor and hence it is useful to decrease blood viscosity. The dosage to treat claudication is 40-80 mg three times daily. Caution must be taken if patient is taking heparin, warfarin, clopidogrel or aspirin as there may be increased chances of bleeding.

Latin abbreviations in prescribing drugs

a.c - ante cibum i.e. before food. p.c - post cibum (after food). o.m - omni mane (every morning). o.n - omni nocte (every night). o.d - omni die (once daily). b.d - bis die (twice daily). t.i.d - ter in die ( three times daily). t.d.s - ter die sumendum (to be taken three times daily). q.d.s - quater die sumendum (to be taken four times daily). p.r.n - pro re nata (when required). stat - immediately.

Molecular biology - central dogma

The central dogma for molecular biology refers to the flow of information from DNA to RNA to proteins. Nucleic acids are required for the storage and expression of genetic information. There are two chemically distinct types of nucleic acids: 1) deoxyribonucleic acid (DNA) and 2) ribonucleic acid (RNA). DNA is the store of genetic information and is present not only in chromosomes in the nucleus of eukaryotic organisms, but also in mitochondria and the chloroplasts of plants. Prokaryotic cells, which lack nuclei, have a single chromosome, but may also contain nonchromosomal DNA in the form of plasmids. The genetic information found in DNA is copied and transmitted to daughter cells through DNA replication. The DNA contained in a fertilized egg encodes the information that directs the development of an organism. This development may involve the production of billions of cells. Each cell is specialized, expressing only those functions that are required for it to perform its r

Grading of murmur

The intensity of a systolic murmur is not always proportional to the hemodynamic disturbance. Yet murmurs are classified according to the loudness. Freeman and Levine were the first to introduce a numerical scale for grading heart murmur intensity in 1933. This grading is still used but with some modifications. Grade 1 - so faint that it can be heard only with special effort. Grade 2 - faint but can be heard easily. Grade 3 - moderately loud but no thrill. Grade 4 - very loud and thrill may be there. Grade 5 - extremely loud and can be heard if only the edge of stethoscope is in contact with skin. Grade 6 - exceptionally loud and can be heard with stethoscope just removed from skin contact. Keren, Tereschuk and Luan suggested that we can use heart sounds as an internal reference to differentiate between grades 1-3, the only limitation of the study being a small sample used. The grading is the same as above but. . . Grade 1 - clearly softer than the heart sounds. Grade 2 -

Venous thrombo embolism / Pulmonary embolism - Anticoagulation

As soon as a diagnosis of VTE / PE is strongly suspected, anticoagulant therapy should be started unless there are contraindications. Parenteral drugs like unfractionated heparin (standard heparin) and low molecular weight heparin (lovenox) are started and therapy shifted to a long term stable vitamin K antagonist like warfarin. Unfractionated heparin The anticoagulant action is by binding to and accelerating the activity of antithrombin III. This inactivates thrombin, factor IXa and Xa and thus prevents further clot formation. The classical regimen for the dosage is a loading dose of 5000 - 10000 units followed by a continuous infusion of 1000 - 1500 units/hour. Unfortunately we all do not have the same weight. So, a more appropriate dosage is a loading dose of 80 units/kg and a continuous infusion of 18 units/kg/hr. The aim is to achieve a target activated partial thromboplastin time (aPTT) aka partial thromboplastin time with kaolin (PTTK) of 2-3 times the normal laboratory val