MEDICAL SPECIALTY LIST

Medical Specialty List

Medical Specialty List

Medical Specialty List

Following are some of the medical specialties that are the major source of concern for the physician with respect to the recovery of the patients.

Radiology

Emergency Medicine

Plastic Surgery

Internal Medicine

Medical Genetics

Preventive Medicine(including Occupational Medicine)

Pediatrics

Neurological Surgery

Psychiatry

Update on Cephalosporins in Pediatrics

The cephalosporins have certain advantages that have made them a popular choice among physicians in the United States. These include a broad range of antimicrobial activity, concentration-independent bactericidal activity, and excellent tolerance in children, with almost no dose-related toxicity. These drugs also can be used safely in most infants and children with hepatic or renal failure. (Ballbriga, 1991) Serious adverse reactions are rare and consist primarily of hypersensitivity with urticaria, nonspecific rash and pruritis. The frequency of these cutaneous reactions is 0.9% to 3.2%. Serious immediate hypersensitivity reactions, such as anaphylaxis and bronchospasm, are rare. Cross-reactivity in penicillinallergic patients is reported to be 5-15%, but this figure is probably inflated. Still, a history of a serious immediate hypersensitivity reaction to penicillin is a contraindication for use of a cephalosporin.

Mechanism of Action and Resistance

The cephalosporins are derived from the parent compound cephalosporin C, a natural antibiotic produced by a strain of the mold Cephalosporium acremonium first isolated in 1948. Cephalosporins resemble penicillins in that they have a ß-lactam structure, but the five-member thiazolidine ring characteristic of the penicillins is replaced by a six-member dihydrothiazine ring (Figure 1). This ring provides the molecule with the ability to resist bacterial enzymes; the antibacterial activity comes from the ß-lactam ring. Two side chains in position 3 and 7 affect the pharmacokinetic and antibacterial spectrum of the cephalosporins. The cephalosporins, like all ß-lactams, act by inhibiting the enzymes that create the cross-linkage of the peptidoglycan polymer leading to interference with the cell wall structure. These enzymes are located beneath the cell wall and are known as “penicillin-binding proteins” (PBP). ß-lactam antibiotics have different binding affinities to the various PBP.

Bacterial resistance to cephalosporins is achieved by distinct mechanisms. These include the inability of the drug to reach its site of action (decreased permeability through the outer membrane of gram-negative organisms), alterations in the PBP's (low affinity of binding as in cephalosporin-resistant pneumococci), or by ß-lactamases that hydrolyze the ß-lactam ring (the most common mechanism of resistance). Cephalosporins are variably susceptible to ß-lactamases; a good example is the relative resistance of second and third-generation agents to hydrolysis by ß-lactamases produced by gram-negative organisms compared ...