Medical Data Interpretation

Cardiac axis Cardiac axis describes the overall direction of electrical spread within the heart. In a healthy individual the axis should spread from 11 o’clock to 5 o’clock. To determine the cardiac axis you need to look at leads I,II and III. Normal cardiac axis In normal cardiac axis:     Lead II has the most positive deflection compared to Leads I and III . Right axis deviation In right axis deviation:      Lead III has the most positive deflection and Lead I should be negative      This is commonly seen in individuals with right ventricular hypertrophy Left axis deviation In left axis deviation:      Lead I has the most positive deflection      Leads II and III are negative      Left axis deviation is seen in individuals with heart conduction defects

Heart Rhythm The heart rhythm can be regular or irregular. Irregular rhythms can be either:      Regularly irregular (i.e. a recurrent pattern of irregularity)      Irregularly irregular (i.e. completely disorganised) Mark out several consecutive R-R intervals on a piece of paper, then move them along the rhythm strip to check if the subsequent intervals are the same. Hint – if you are suspicious that there is some atrioventricular block, map out the atrial rate and the ventricular rhythm separately (i.e. mark the P waves and R waves). As you move along the rhythm strip, you can then see if the PR interval changes, if QRS complexes are missing or if there is complete dissociation between the two.  

Chest X Ray - Four Patterns Lung abnormalities with an increased density - also called opacities - are the most common. A practical approach is to divide these into four patterns: Consolidation Interstitial Nodules or masses Atelectasis  Whenever you see an area of increased density within the lung, it must be the result of one of these four patterns.   Consolidation   - any pathologic process that fills the alveoli with fluid, pus, blood, cells (including tumor cells) or other substances resulting in lobar, diffuse or multifocal ill-defined opacities.   Interstitial   - involvement of the supporting tissue of the lung parenchyma resulting in fine or coarse reticular opacities or small nodules.   Nodule or mass   - any space occupying lesion either solitary or multiple.   Atelectasis   - collapse of a part of the lung due to a decrease in the amount of air in the alveoli resulting in volume loss and increased density.

What is  Air bronchogram Air bronchogram  refers to the phenomenon of  air -filled bronchi (dark) being made visible by the opacification of surrounding alveoli (grey/white). It is almost always caused by a pathologic airspace/alveolar process, in which something other than  air  fills the alveoli.

How to calculate rate in an ECG The heart rate can be calculated by dividing 300 by the number of large squares between each R wave (with machine trace running at the standard speed of 25 mm/sec and deflection of 1 cm/10 mV). • 3 large squares between R waves = rate 100    • 5 large squares = rate 60     Normal rate is 60–100 beats per minute (bpm). • Rate <60 = bradycardia    • Rate >100 = tachycardia   

Bacterial Conjunctivitis Vs other causes A clinical scoring system has been developed to distinguish bacterial from other causes of conjunctivitis in healthy adults who did not wear contact lenses.  A score of +5 to −3 is determined as follows: ~ Two glued eyes (+5); one glued eye (+2); history of conjunctivitis (−2); eye itching (−1). ~ A score of +5, +4, or +3 is useful in ruling in bacterial conjunctivitis with specificities of 100%, 94%, and 92%, respectively. ~ Scores of −1, −2, or −3 are useful in ruling out bacterial conjunctivitis with sensitivities of 98%, 98%, and 100%,  respectively. Allergic conjunctivitis is typically bilateral and accompanied by eye itching. Giant papillary conjunctivitis is a type of allergic reaction, most commonly to soft contact lenses