Gen Med Examination 4

This is know as a "negative myoclonic jerk", or in other words the patient is unable to sustain a fixed posture such as flexing the wrists back. This causes a flapping tremor in the hands, like a bird flapping its wings. It is best ilicited by full and sustained wrist extension. This can also be caused by encephalopathy, cardiac failure, brain lesions, metabolic imbalance, and medication overdosing. It is not specific to respiratory failure.

Make sure the thumbs touch centrally with expiration. A 2-5cm gap between thumbs is normal upon inspiration as the ribs move up and out. Unequal expansion is pathological.

Symmetrical and generalised hyperresonance is caused by air trapping and over expansion of the airways in COPD. The hyperexpansion means there is more air and less lung tissue per cm3, therefore percussion is more resonant. The airway trapping can be seen physically in some patients, with the presence of a barrel chest. Please don't forget, in unilateral hyperresonance always think pneumothorax.

Acidosis refers to the process or condition that leads to an increase in the concentration of hydrogen ions. Acidemia refers specifically to the condition where the blood pH is abnormally low (below 7.35). Therefore you can have respiratory acidosis (Co2 retention leading to more H+) without acidaemia IF there is a compensatory mechanism e.g. high bicarbonate, as in this gas. Bicarbonate takes time to rise in response to an acidosis, the high bicarbonate therefore suggests an element of chronic respiratory acidosis. Stating this in an exam would certainly give honours marks.