Physical Exam


Laboratory Tests










The genes inherited from parents determine a patient's blood group. There are four blood types; A, B, AB and O. Each blood type has its own antigens on the blood cell surface. So type A has the A antigen, B has the B antigen, AB has both antigens and O contains no antigen. If different blood types mix, an immune response occurs and the person will produce antibodies to attack the foreign blood antigen.

Content 12



Content 9

Since the release of the Hib vaccine there has been a dramatic decrease in the incidence as well as a shift in the bacterial etiology. Most cases are now caused by streptococci, staphylococci, nontypeable H influenzae, and Candida albicans. Adults typically have a more indolent course characterized by "severe" sore throat and odynophagia. Direct thermal injury has been reported as a noninfectious cause. On soft tissue lateral neck x-ray, the epiglottis is seen as rounded and blurred (thumbprint sign). Epiglottitis may progress to complete obstruction if not treated. Differential diagnosis includes acute infectious laryngitis, acute laryngotracheobronchitis (croup), acute spasmodic laryngitis, membranous (bacterial) tracheitis, anaphylactic reaction, foreign body aspiration, retropharyngeal abscess, and extrinsic or intrinsic compression of the airway (tumors, trauma, cysts).



Content 4

Content 3

Content 11


Update as of May 5, 2016

USMLE Reviewer (Subscription Required)