Diseases Due To Infection

Diseases due to Infection Major manifestations of infection Principles of Management Diseases due to Chlamydia, bacteria, spirochets, Fungi, arthropod, STD

• Incubation period: time gap when micro organism enters body & symptoms of disease starts. It is the time when microorganism or microbe invade the body defenses, multiply there & cause structural &/or functional disturbance.

Defense of human host • 1st line defense: skin, mucus membrane Mucus- mechanical barrier, IgA antibody & enzyme HCL Ciliated epithelium Commensal Flora • 2nd line Defense: cellular & Humoral.

Reaction of Host to specific Infection: • Viral Infection-stimulates local lymphocytic response • Worm-Eosinophil • Bacterial infection-Polymorphs • Typhoid & paratyphoid-Monocytic response

Manifestations or Presentation of Infection • Fever • Fever & Rash • Pain-local ,chest pain, pain abdomen, head ache • Cough • Swelling

Fever Viral fever, Dengue, typhoid ,paratyphoid Malaria, pneumonia, Temp: controlled by hypothalamus • Fever/hyperthermia: 36.6 to 37.4,rectal temp.0.5oc high, axillary 0.50 c lower Diurnal variation 0.5-10c Pyrogen (Toxins) are substances which cause fever-most pyrogens are microbial product microbial toxins or microbe.

Fever & Rash Macule (flat, color change) papule (raised<5mm), plaque(>5mm), nodule, (round >5mm) vesicle(<5mm) & Bullae (>5mm),petechial rash Chicken pox, measles, viral disease, Dengue fever, SLE • Drug rash

Cough • Common cold, URTI, Sinusitis, • Pneumonia, acute bronchitis, chronic bronchitis, tuberculosis

Chest pain • Pneumonia • Pleuritis, Pleural effusion • Lung abscess

Pain abdomen • • • • •

Liver abscess Pyelo nephritis Appendicitis peritonitis Gynecological infections

Management • Confirming the Diagnosis & • Treatment Diagnosis: 1 Clinical History (symptoms) 2 Examination 3 Lab investigations

Lab investigatations • CBC,ESR • Peripheral smear:MP,filaria • Isolation of microbe- microscopic examination of sputum, urine, stool or other body fluids like CSF, pleural or peritoneal fluid Culture of blood or any other body fluid • Antibody detection: widal test, IgG, IgM antibodies for mycobacteria,Hepatitis TORCH

• Radiology: X-ray, ultrasound,CT scan

Diseases due to Bacteria • • • • • • •

Streptococus-Beta hemolytic,pneumone Staphylococus Nisseria Meningococus,N.Gonorrhoeae Vibrio cholera Diptheria Tetanus-chlostridium tetni Chronic-Tuberculous, Syphilis,Leprosy

Gram Positive Bacteria •

Streptococcal Infection- Beta hemolytic Pharyngitis -RHD Skin infection-AGN

• Pneumococal Infection-Streptococcal pneumonniae

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Staphylococcus aureus- skin,soft tissue ,bone infection

Anaerobic Bacteria Gram positive rods • Clostridium Myonecrosis- Gas gangrene • Clostridium Tetani • Clostridium Botulism-canned or smoked food

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Presumptive infection due to anaerobic bacteria.

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1. Most of the organisms colonizing mucosal sites are harmless commensals; very few cause disease.

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2. For anaerobes to cause tissue infection, they must spread beyond the normal mucosal barriers.

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3. Conditions favoring the propagation of these bacteria, particularly a lowered oxidation-reduction potential, are necessary. These conditions exist at sites of trauma, tissue destruction, compromised vascular supply, and complications of preexisting infection, which produce necrosis.

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4. There is a complex array of infecting flora. For example, as many as 12 different types of organisms can be isolated from a suppurative site.

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5. Anaerobic organisms tend to be found in abscess cavities or in necrotic tissue. The failure of an abscess to yield organisms on routine culture is a clue that the abscess is likely to contain anaerobic bacteria. Often smears of this "sterile pus" are found to be teeming with bacteria when Gram's stain is applied. Malodorous pus suggests anaerobic infection. Although some facultative organisms, such as Staphylococcus aureus, are also capable of causing abscesses, abscesses in organs or deeper body tissues should call to mind anaerobic infection.

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6. Gas is found in many anaerobic infections of deep tissues.

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7. Some species (the best example being the B. fragilis group) require specific therapy. However, many synergistic infections can be cured with antibiotics directed at some but not all of the organisms involved. Antibiotic therapy, combined with debridement and drainage, disrupts the interdependent relationship among the bacteria, and some species that are resistant to the antibiotic do not survive without the coinfecting organisms.

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8. Manifestations of disseminated intravascular coagulation are unusual in patients with purely anaerobic infection

Gram Negative Bacteria • • • • •

Bordetella Pertussis( whooping cough) Neisseria Meningitidis,N.Gonorrhoeae Salmonella Typhi,paratyphi Shigella – dysentry Vibrio Cholerae

Acid Fast Bacilli • Myco. tuberculosis • Myco.Leprae

Infestation • This term is used for ectoparasites like arthropods –lice, flea,maggots or worm

Viral Diseases • • • • • • •

Measles Rubella-German measles- fetus abnormal Mumps Chickenpox Polio Influenza encephalitis

Protozoa • • • • •

Malaria Amoeba-EH, Giardia Sleeping sickness: Trypanosomiasis Leishmaniasis-Kala Azar Helminthiasis-pin worm, hook worm, round worm, tape worm, hydatid cyst

Chlamydia • Chlamydia pneumoniae –atypical pneumonia • LGV • Psittacosis • Trachoma

Rickettsiae •

• 1. 2. 3. 4.

Rickettsiae are intermediate between virus & bacteria & require living cells for their multiplication. Lice, flea borne Typhus fever Scrub typhus Rocky mountain spotted fever Q fever

Helminthes • • • • •

Tape worm-Taenia solium,T.Sagginata Eccinococus granulosus –Hydatid cyst Ascariasis Hookworm-Ankylostoma duodenale Wucheria Bancrofti-Filariasis

STD