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Major tachycardias

Narrow QRS complex     A.     Sinus tachycardia              B.     Paroxysmal supraventricular tachycardias (PSVTs)                      1.      Atrial tachycardias, including single-focus or multifocal (MAT) variants                        2.     AV nodal reentrant tachycardia (AVNRT)                       3.     AV reentrant tachycardia (AVRT) involving a bypass tract              C.     Atrial flutter              D.     Atrial fibrillation  Wide QRS complex     A.     Ventricular tachycardia                B.     SVT/AF or flutter, with aberrant ventricular conduction usually caused by either of the following:   1.     Bundle branch block patterns                          2.     Atrioventricular bypass tract (Wolff-Parkinson-White preexcitation patterns)  

Hemodialysis - when to start? / Calculation of normalized eGFR

Hemodialysis should be started when: 1) eGFR is < 6  mL/min/1.73  m 2 2) eGFR is < 15  mL/min/1.73  m 2   and patient is showing signs and symptoms of uremia, unable to control his hydration and blood pressure.  Cockcroft-Gault formula  is a very commonly used formula to get an estimate of the GFR. The unit for eGFR is  mL/min. The classification for stages of chronic kidney diseases  on the other hand is based on normalized eGFR i.e. the eGFR per 1.73  m 2  and the unit being mL/min/1.73   m 2 . Thus we also need to calculate the surface area of the patient's body. It is given by the formula as follows :  Body Surface Area ( m 2 ) = ( [Height(cm) x Weight(kg) ]/ 3600 )½ And the normalized eGFR ( mL/min/1.73   m 2 ) = (eGFR/BSA) x 1.73 A clinical example is given below.   A 45 year old man weighing 70 kg and 180 cm tall has been admitted to the hospital because of fluid overload. He has been treated for the past hours with diuretics but has not been im

Homeostasis - negative feedback loop

A rise of some factor e.g. X of the internal environment is detected by the sensor. This information is relayed to the integrating center that causes the effector to produce a change in the opposite direction. The initial deviation is thus reversed, thus completing the negative feedback loop. The same holds true if the factor X is decreased. The integrating center detects a change from the set point and causes necessary effects to bring it back to normal. Below is a diagram that shows negative feedback loops maintain a state of dynamic consistency within the internal environment.  One such example is regulation of body temperature as explained in the link that follows.  Regulation of body temperature

Penicillin - a fortunate accident

It all started when Alexander Fleming discarded some of his culture plates that had been contaminated with mold. But fortunately, he had a second look to those cultures afterwards. He was amazed to see that in the area around the mold, the growth of bacteria was inhibited. The mold was identified as Penicillium notatum, the active inhibitor named penicillin. Above is a photo taken by Alexander Fleming in 1928.

Antonie van Leeuwenhoek

He was a Dutch merchant and amateur scientist. He was probably the first person to observe live micro-organisms under magnifying lenses. He made a series of drawings of what he called as 'animalcules' i.e. small animals. He observed these by looking through his single-lens microscope at rainwater, his own feces and scrapings from his teeth. He made the drawings shown below.

Cullen's sign

It refers to the superficial peri-umbilical bruising of the subcutaneous fat. It can be seen in the following cases: 1) acute pancreatitis (classically), 2) bleeding from blunt abdominal trauma, rupture of abdominal aorta and ruptured ectopic pregnancy. The sign was actually first described by Thomas Cullen in 1916 in a case of ruptured ectopic pregnancy.

Abciximab - mechanism of action/ indication/ contraindication/ dose

It is a Fab fragment of a humanized monoclonal antibody directed against the glycoprotein IIb/IIIa. The latter is a platelet surface integrin. It is a receptor for fibrinogen which binds platelets to each other causing aggregation. By inhibiting the receptor, abciximab acts as a potent antiplatelet agent.  Indications: 1) myocardial ischemia, 2) percutaneous coronary intervention. Dose: 1) For M.I - initially an I.V bolus of 0.25 mg/kg over 5 min followed by 0.125 µg/kg/min (to a maximum of 10 µg/min) for 12 hours. 2) For P.C.I - initially, 0.25 mg/kg I.V bolus over 5 min 20-60 min prior to angioplasty followed by 0.125 µg/kg/min (to a maximum of 10 µg/min) for next 12 hours. Contraindications: 1) bleeding disorder or use of anticoagulant within 7 days, 2) CVA within 2 years, 3) known allergy to this product, 4) major trauma or surgery within 6 weeks, 5) severe uncontrolled hypertension, 6) active internal bleeding, 7) thrombocytopenia i.e pla