{"id":4129,"date":"2011-11-29T09:36:45","date_gmt":"2011-11-29T09:36:45","guid":{"rendered":"http:\/\/www.homeobook.com\/?p=4129"},"modified":"2022-01-17T02:56:32","modified_gmt":"2022-01-17T02:56:32","slug":"diphtheria-applied-aspect","status":"publish","type":"post","link":"https:\/\/www.homeobook.com\/diphtheria-applied-aspect\/","title":{"rendered":"Diphtheria \u2013 Applied aspect"},"content":{"rendered":"
Dr Sunila <\/strong>BHMS,MD(Hom)<\/p>\n DIPHTHERIA<\/strong> Coryne bacterium diphtheriae<\/strong> C.diphtheriae is classified into three main types<\/em> based on the colony morphology on tellurite medium, bio chemical reactions and hemolytic property.<\/p>\n Virulent strains produce an exotoxin which is responsible for producing remote effects. Around 90-95% of the gravis and intermedius strains are toxigenic while only 80-85% of mitis are so. The toxin is a labile protein of molecular wt 62,000 and it is inactive when released by the bacterium.<\/p>\n Epidemiology<\/strong>: Schick test<\/strong>: This test was introduced by Schick in 1913 and is performed to assess the immunity against diphtheria in children above 2 months of age.<\/p>\n The test comprises of injecting intradermally 0.2 ml of diphtheria toxin which 1\/50\u03bcLD of toxin in the left forearm. Similar dose of heat inactivated toxin is injected in the right forearm. Readings are taken after 24-48 hours and then after 5-7 days of inoculation. The following types of reactions may be observed:<\/p>\n Pathogenesis and pathology<\/strong><\/p>\n The exotoxin<\/em> causes tissue necrosis, which favors further growth of the organism and toxin production. The epithelium degenerates and serofibrinous exudate develops which contains inflammatory cells and fibrin. The coagulation of these exudates on the ulcerated, necrotic surface creates a bluish white membrane over the involved area. The membrane is adherent and when removed forcibly it leaves a raw bleeding surface. Site of predilection for the primary lesions is the respiratory tract<\/em>. Other sites of infection are nose, ears, conjunctiva, genitalia and skin.<\/p>\n Clinical features:<\/strong> The disease starts with sore throat, low grade fever, head ache, malaise, vague aches and pains, and catarrhal symptoms. As the disease progresses, tachycardia, nausea, vomiting, pallor and weakness follows.<\/p>\n Pharyngeal Diphtheria:<\/strong> The term \u2018malignant diphtheria\u2019<\/em> is given to condition characterized by marked oedema of the sub mandibular areas and anterior part of the neck. There is moderate leukocytosis (14,000-16,000\/cumm) with polymorphs forming 60-80%\u00a0<\/strong><\/p>\n Laryngeal Diphtheria: The clinical features include barking cough, hoarseness, dyspnoea, stridor and cyanosis. Infants with laryngeal diphtheria may refuse to suck the breast due to choking.<\/p>\n Nasal Diphtheria:<\/strong> Cutaneous Diphtheria:<\/strong> There may be coexistent pharyngeal diphtheria in 20% of the cases.<\/p>\n Other sites of lesion are the conjunctiva, vulva, vagina, uterine cervix, bladder, urethra, penis, middle ear, buccal mucus membrane and oesophagus.\u00a0<\/strong><\/p>\n Complications:\u00a0<\/strong>Mechanical obstruction of the air way<\/em> by the spreading membrane is a dreaded complication.<\/p>\n Diagnosis:<\/strong> Differential Diagnosis:<\/strong> Agranulocytosis and 3. Acute leukaemia: in these there is no true membrane. The tonsils are red, enlarged and necrotic or hemorrhagic. Hematological examination establishes the diagnosis.<\/p>\n Prevention<\/strong> References<\/strong><\/p>\n Dr Sunila BHMS,MD(Hom) DIPHTHERIA Diphtheria is an acute communicable disease caused by Coryne bacterium diphtheriae. It usually occurs in children and results in the formation of a yellowish-grey pseudomembrane in the mucosa of nasopharynx, oropharynx, […]<\/a><\/p>\n<\/div>","protected":false},"author":1,"featured_media":42452,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[903],"tags":[918],"class_list":{"0":"post-4129","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-applied-pathology","8":"tag-diphtheria-applied-aspect"},"yoast_head":"\n
\nDiphtheria is an acute communicable disease caused by Coryne bacterium diphtheriae. <\/em>It usually occurs in children and results in the formation of a yellowish-grey pseudomembrane in the mucosa of nasopharynx, oropharynx, tonsils, larynx and trachea. C.diphtheriae elaborates an exotoxin<\/em> that causes necrosis of the epithelium which is associated with abundant fibrinopurulent exudates resulting in the formation of pseudomembrane. Absorption of exotoxin in the blood may lead to more distant injurious effects such as myocardial necrosis, polyneuritis, parenchymal necrosis of the liver, kidney and adrenals. The constitutional symptoms such as fever, chills, malaise, obstruction of air ways and dyspnoea are quite marked.<\/p>\n
\nCoryne bacterium diphtheriae<\/em> are gram positive rods<\/em> 3×3\u03bcm in size, pleomorphic, non-motile, non-sporing, non-capsulate, generally aerobic and facultatively anaerobic. These bacilli exhibit characteristic arrangement in smear preparations. Adjacent bacteria lie at various angles to each other giving \u2018V\u2019 or \u2018L\u2019 appearances which collectively resemble arrangement of Chinese letters or cuneiform writing<\/em>. This arrangement is because of incomplete separation of daughter cells at the moment of division.<\/p>\n\n
\nThe disease has been almost wiped out from developed countries, but in India it is still prevalent. Diphtheria is more common in children. In unvaccinated population, children below 2-15 years of age are at the highest risk. Disease is spread by droplets, contaminated vessels shared by children or by direct inoculation into skin abrasions or eyes. The organism is harbored by carriers and cases. Unimmunized children in a partially immunized community are highly susceptible. Untreated cases are infective for more than two weeks. During outbreaks susceptible individuals can be identified by the Schick intra-dermal test.<\/em><\/p>\n\n
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\nThese depend on the primary site of involvement, duration of the illness, systemic effect of the toxin and resistance of the heart.<\/p>\n
\nIt is the most common form and the membrane is present over the tonsils and the pharynx. Gross cervical lymphadenopathy (described as bull neck<\/em>) is evident and respiratory obstruction may develop, especially in children. In severe cases circulatory collapse occurs. Local effects of the toxin lead to paralysis of the palate and pharynx.<\/p>\n
\n<\/strong>This forms 25% of the cases. It produces respiratory obstruction early, which may be fatal. (Inflammation and necrosis of subjacent tissues permit dislodgement and aspiration of the membrane, result in acute respiratory obstruction.<\/p>\n
\nIt occurs in 2-3% cases. The membrane is limited to the septum or turbinate and is usually unilateral. The condition may present with a foul smelling serosanguinous nasal discharge or frank epistaxis.<\/p>\n
\nCoryne bacterium diphtheria cannot penetrate the intact skin and it gains entry through wounds, burns or abrasions. It causes ulceration. The typical ulcer usually punched out and 0.5 cm or more in size. In the early stage the ulcer is covered by a grayish yellow or brownish membrane.<\/p>\n\n
\nThe diagnosis of diphtheria is essentially clinical. Confirmation of diagnosis depends on the demonstration of the oranges in the stained smears made from the membrane and by the culture using Loeffler\u2019s medium<\/em>. Fluorescent anti toxin staining provides a method for rapid diagnosis. Toxigenicity can be assessed by genuine pig inoculation, passive agar gel diffusion (Elekplate method<\/em>) or counter immuno electrophoresis.<\/em>\u00a0<\/em><\/p>\n
\nAcute follicular tonsillitis: In follicular tonsillitis the exudates is confined to the tonsils, it is yellowish and can be wiped off without being adherent. Fever is high in acute tonsillitis where as it is only mild in diphtheria. Regional lymphadenopathy is more marked in diphtheria than in acute tonsillitis.<\/p>\n
\nIt includes general active immunization and management of contacts. Active immunization is done with diphtheria, pertussis, and tetanus (DPT) vaccine which is also known as triple antigen. The first dose should be given at 2 months and thereafter two more doses at 4 weeks intervals. Booster doses should be given at the second and fifth year.<\/p>\n\n