Specific and Non-specific Infections.pdf

Specific and Non-specific Infections Syphilis Treponema Pallidum Acquired by sexual contact, transfusion of infected blood or transplacental inoculation of fetus Chancre forms at site of Spirochete entry ; resembles traumatic ulcer, squamous...

Specific and Non-specific Infections Syphilis Treponema Pallidum Acquired by sexual contact, transfusion of infected blood or transplacental inoculation of fetus Chancre forms at site of Spirochete entry ; resembles traumatic ulcer, squamous cell carcinoma and Non-hodgkin's lymphoma. 3 stages of Syphilis: 1) Primary syphilis It occurs a few weeks after exposure and has a characteristic chancre formation (chancre is painless, indurated, rolled margins). Chancres are found on genitalia and also the oro-labial area. 2) Secondary Syphilis It occurs a few weeks or months later after primary syphilis. However, patients infected via blood transfusion begin from this stage. Features : Maculopapular rashes (hands and soles of feet) Condyloma Lata Snail track Ulcers Dissemination White lateral tongue lesions and oral mucous patches Fever, Lymphadenopathy, split papules at commissures 3) Tertiary Syphilis May take many years to develop Features: Gummas (necrotic inflammatory non-cancerous lesions) CNS involvement Palatal perforation  (May lead to cardiovascular disease or neurosyphilis) Congenital Syphilis Hutchinson’s Triad : 1) Interstitial Keratitis 2) Eighth Nerve deafness 3) Hutchinson’s incisors and Mulberry molars Systemic features: Growth retardation Jaundice, Hepatosplenomegaly Histopathology: Proliferative Endarteritis (inflammation of the inner lining of an artery) Infiltration of plasma cells, presence of macrophages and lymphocytes Spongiosis and Exocytosis Endothelial cells proliferate within small arteries Gummas may show necrosis, increased number of macrophages and a granulomatous lesion Surface epithelium is ulcerated or hyperplastic Differential Diagnosis: Squamous cell carcinoma, chronic traumatic ulcers, TB, T-cell Lymphoma Definitive diagnosis is done the basis of: 1) Dark field microscopy of scrapings 2) Silver stain of biopsy tissue 3) Serological tests for anti-bodies against Treponema Pallidum Drug of choice: Penicillin If the patient is allergic to Penicillin, give Erythromycin or Tetracyclines  Tuberculosis Mycobacterium Tuberculosis (acid fast bacilli) Airborne infection transmitted via inhalation of infected droplets Pathogenesis: Phagocytosis by macrophages Focus is a nodule that can form in the apex of the lung when a primary TB infection elsewhere in the body spreads to the lung apex via the bloodstream Granulomatous inflammatory response in which inflammatory foci undergo dystrophic calcification These foci may be re-activated at a later date Primary TB: No symptoms, skin test positive, chest x-ray positive Reactivated (Secondary) TB: Low grade fever, night sweats, malaise, weight loss Progressive TB: Cough, Hemoptysis, Chest pain, Pleural involvement * Primary TB causes middle and lower lung opacities whereas Secondary TB causes upper lobe opacities, cavities or fibrotic scar tissue. Primary TB is not highly contagious as the bacteria are contained within the granulomas. Secondary TB is highly contagious as the bacteria can be expelled from the lungs. Oral Manifestations: Indurated, chronic, non-healing painful ulcers (commonly found on tongue and palate) Bony involvement in the mandible and maxilla → TB & Osteomyelitis  Pharyngeal involvement leads to painful ulcers that may cause Dysphagia (difficulty in swallowing), voice changes and Odynophagia (pain while swallowing). Histopathology: Granulomatous inflammation, Central Caseous Necrosis. Focal zones of macrophages surrounded by lymphocytes and fibroblasts. Epithelioid cells Fusion of macrophages → Langerhans giant cells Nuclei distributed around periphery Differential Diagnosis: Infectious diseases: Syphilis, Deep fungal diseases Non-infectious diseases: Sarcoidosis, Crohn’s disease, chronic traumatic ulcer *A definitive diagnosis is made on the basis of a Ziehl Neelsen or Fite stain. First line drugs: (RIPE) Rifampin Isoniazid Pyrazinamide Ethambutol Vaccine: BCG  Actinomycosis Actinomyces Israelii Not contagious Present in the normal flora of majority of healthy individuals Found in tonsillar crypts, gingival crevices, carious lesions and non vital dental root canals Infection usually appears after trauma, surgery or previous infection Clinical Features: Indurated (hardened), mandibular swelling May form drainage sinus Bony sites may be infected Maxillary involvement leads to Osteomyelitis Lesions contain Pus that contain Sulfur granules (yellow) Radiographically seen as a radiolucency with ill defined and irregular margins Histopathology: Granulomatous inflammation Abscess formation Colonies of Gram + organisms present in Abscess Sulfur Granules (filaments with clubbed ends that radiate from the center) Sinus tracts and Fistulas Differential Diagnosis: Osteomyelitis Soft tissue infections of neck → Scrofula Staphylococcal infections → Botryomycosis Treatment: Definitive diagnosis made on the basis of: 1) Direct examination of exudate 2) Microscopic evaluation of tissue sections First line drug is Penicillin. Other options are Erythromycin and Tetracyclines. Incision + drainage Debridement Surgical excision Pericoronitis Defined as an inflammatory condition that affects the soft tissues surrounding a partially erupted or impacted tooth, most commonly the third molars. A raised gum flap known as an Operculum develops over the incompletely erupted tooth. Caused by the Streptococcus Milleri group of bacteria. 3 types: Acute, Sub-acute and Chronic. Acute Pericoronitis: Sudden onset, more severe than other types. Severe, continuous pain, severe redness, trismus, halitosis. Lymphadenitis. Pyrexia associated with Tachycardia. Sub-Acute Pericoronitis: More gradual onset, symptoms less severe but persist for a longer time. Severe pain in the retromolar region. Facial space infections of neck and mandible (Ludwig’s Angina). Chronic Periodontitis: Continuous, dull pain. Long standing and persistent course. Symptoms come and go with periods of exacerbation and remission. Differential Diagnosis: Foreign body granuloma Peripheral Ossifying Fibroma Peri apical abscess Periodontitis Pyogenic Granuloma Treatment: If the tooth is not erupting straight, and is either partially or fully impacted, then we will extract it. However, If the tooth is erupting straight and the treatment plan does not support extraction, we will advise the patient the following: 1) Improve oral hygiene + warm saline rinses 2) Antibiotics 3) Operculectomy