Etiology
Microbiology
Of the microflora characterised in aggressive periodontitis, approximately 65-75% of bacteria are Gram-negative bacilli, with few spirochaetes or motile rods present. Aggressive periodontitis is often characterised by a rapid loss of periodontal attachment associated with highly pathogenic bacteria and an impaired immune response. Various studies have associated Aggregatibacter actinomycetemcomitans, formerly known as Actinobacillus actinomycetemcomitans, with aggressive periodontitis. An early study dating back to 1983 explains its prevalence and documents its role in localised aggressive periodontitis.Virulence factors are the attributes of microorganisms that enable it to colonise a particular niche in its host, overcome the host defences and initiate a disease process. Fives Taylor et al. (2000) have categorised the virulence factors of Aggregatibacter actinomycetemcomitans as follows. Samaranayake notes the evidence for the specific involvement of Aggregatibacter actinomycetemcomitans includes: an increased incidence of it found in subgingival plaque obtained from lesional sites, high level of its antibody which tends to fall following successful treatment, its possession of a wide range of potentially pathogenic products and its elimination with concordant disease regression, following treatment with successful periodontal therapy and adjunctive tetracycline.Porphyromonas gingivalis is a Gram-negative anaerobe associated with the pathogenicity of periodontal disease, and aggressive periodontitis is no exception. Greater numbers of both Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans were found in active, destructive periodontal lesions in comparison to non-active sites.Capnocytophaga spp are implicated as prime periodontal pathogens, especially in localised aggressive periodontitis.
Ischemia or ischaemia is a restriction in blood supply to any tissues, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems with blood vessels, with resultant damage to or dysfunction of tissue i.e. hypoxia and microvascular dysfunction. It also means local hypoxia in a given part of a body sometimes resulting from constriction (such as vasoconstriction, thrombosis or embolism). Ischemia comprises not only insufficiency of oxygen, but also reduced availability of nutrients and inadequate removal of metabolic wastes. Ischemia can be partial (poor perfusion) or total blockage. The inadequate delivery of oxygenated blood to the organs must be resolved either by treating the cause of the inadequate delivery or reducing the oxygen demand of the system that needs it. For example, patients with myocardial ischemia have a decreased blood flow to the heart and are prescribed with medications that reduce chronotrophy and ionotrophy to meet the new level of blood delivery supplied by the stenosed so that it is adequate. Signs and symptoms
The signs and symptoms of ischemia vary, as it can occur anywhere in the body and depends on the degree to which blood flow is interrupted. For example, clinical manifestations of acute limb ischemia (which can be summarized as the "six Ps") include pain, pallor, pulseless, paresthesia, paralysis, and poikilothermia.Without immediate intervention, ischemia may progress quickly to tissue necrosis and gangrene within a few hours.