Chapter 4 Flashcards
(107 cards)
whether an organism can cause disease depends on what
- the microorganism
- the body’s defenses
what are the 2 types of microorganisms divided according to
- pathogenic (disease causing)
- nonpathogenic (non disease causing)
what are the classes of infectious disease that can gain entry to the body
- bacterial
- fungal
- viral
- protozoan
- helminthic
what is an opportunistic infection
- when an organism that usually is nonpathogenic causes disease
what is an infectious disease
- microorganisms that penetrate epithelial surfaces as foreign bodies and stimulate a response
what are a few different routes of infection
- transferred through the air on dust particles or water droplets
- some may require intimate and direct contact
- some may be transferred by hands or objects
what can affect oral flora
- changes in salivary flow
- administration of antibiotics
- changes in the immune system
what happens when microorganisms penetrate the epithelial surfaces as foreign bodies
- stimulate the inflammatory response: nonspecific response that results in edema and the accumulation of a large number of white blood cells
- stimulate the immune system: a highly specific response that results in the production of antibodies to the microorganisms that act as antigens
what is tonsillitis/pharyngitis
- often caused by bacteria/viruses
- streptococcal, influenza, epstein barr
what is strep throat and scarlet fever caused by and what are common symptoms
- endotoxins of group A beta-hemolytic streptococci
- produces rash on body and strawberry tongue – fungiform papillae are prominent
what is rheumatic fever
- can follow strep infection
- affects the heart, joints, CNS
what is tuberculosis caused by
- usually an organism called mycobacterium tuberculosis
- chief form of disease is an infection of the lungs caused by the bacteria
- this organism is resistant to destruction by macrophages
- after being engulfed, they multiply in the macrophages and then disseminate in the bloodstream
what are signs and symptoms of tuberculosis
- fever, chills, fatigue and malaise, weight loss, persistent cough
what is miliary tuberculosis
- involvement of organs such as kidney and liver in widespread areas of the body – enters bloodstream and becomes systemic
- potential oral lesions but they are rare. appear as painful, nonhealing, superficial or deep slowly enlarging ulcers
when is tuberculosis contagious
- when it is active
how is tuberculosis spread
- coughing
- laughing
- sneezing
- singing
- talking
how can we diagnose tuberculosis
- oral lesions: identified by biopsy and microscopic examination
- chronic granulomatous lesions with areas of necrosis surrounded by macrophages, multinucleated giant cells, and lymphocytes
- tissue may be stained to reveal organisms
how do we test for TB
- skin test: an antigen is injected into the skin (purified protein derivative – mantoux test)
- a positive inflammatory reaction occurs if the person has previously been exposed to the antigen
- chest radiographs may be taken after a positive skin test to see if lung damage/disease is present
- sputum test for culture purposes
how can we treat TB
- combination medications, including isoniazid and rifampin
- tx may continue for 6 mo or years
- ptes usually become noninfectious shortly after tx begins
- pte’s physician should be consulted to determine whether pte is infectious
what causes syphillis
- spirochete Treponema pallidum
- transmitted by direct contact: the organisms die when exposed to air and changes in temperature
- can penetrate mucous membranes, but not intact skin
- usually transmitted through sexual contact but may be transmitted through transfusion of infected blood or to a fetus from an infected mother
what are the 3 stages of syphilis
- within about 21 days of contact, but can be sooner or up to 90 days
- primary stage
- secondary stage
- tertiary stage
what is the primary stage
- within about 21 days of contact, but can be sooner or up to 90 days
- lesion of the primary stage is a chancre (shang-ker)
- forms where the spirochete enters the body (mouth, anus, penis, vagina)
- highly infectious BUT painless so can go un-noticed
- heals spontaneously (within 3-6 weeks) and the disease enters a latent period
what is the secondary stage
- diffuse eruptions occur on skin and mucous membranes
- mucous patches: oral lesions that appear as multiple, painless, grayish white plaques covering ulcerated mucosa
- these lesions are the MOST INFECTIOUS
- undergo spontaneous remission but may recur for months or years
- fever, malaise, swollen lymph nodes, fatigue
- latent stage occurs after this (period of remission)
what is the tertiary stage
- can be 10-30 years later
- chiefly involves the cardiovascular system and the nervous system
- lack of muscle coordination, paralysis, numbness, dementia
- multiple organ involvement – eyes, heart, joints
- gumma: a firm mass, noninfectious, a destruction lesion that can result in perforation of the palatal bone