Chapter 20 Flashcards
Microbial Diseases of the Nervous System and Eyes (13 cards)
Bacterial Meningitis (29)
-Signs & Symptoms
Sudden high fever; severe meningeal inflammation, and increased white blood cells in the CSF; inflammation causes most signs & symptoms; infection of the brain causes encephalitis; can results in brain changes, coma, and death; can develop rapidly
-Pathogens and Virulence Factors
NEISSERIA MENINGITIS
STREPTOCCUS PNEUMONIAE-MOST COMMON IN ADULTS
HAEMOPHILUS INFLUENZAE _leading cause ***
LISTERIA MONOCYTOGENES- CAN OCCUR IN PREGNAN WOMEN-FETUSES, NEWBORNS, AND ELDERLY AND IMMUNOCOMPROMISED
STREPTOCOCCUS AGALACTIA-CAUSES BACTEREMIA, PNEUMONIA, AND MENINGITIS IN NEWBORNS
Diagnosis, treatment, and prevention
Treated with intravenous antimicrobial drugs, vaccines available
Hansen’s Disease (Leprosy) 30
-Signs & Symptoms
TUBERCULOID LEPROSY: non aggressive form of disease; strong cell-mediated immune response
LEPROMATOUS Leprosy: More virulent form, weak-cell mediated immune response
-Pathogen & Virulence Factors
MYCOBACTERIUM LEPRAE is the causative agent; distinctive slow growth rate; resistant to antimicrobial drugs
Pathogenesis: best grows in cooler regions of the body; can live inside infected cells for years; may destroy nerve and tissues
Epidemiology: Leprromatous leprosy is becoming rate; transmitted by person to person contact or breaks in the skin
Diagnosis, treatment, & Prevention
confirmed by acid fast vacilli in samples; treated with multiple antimicrobials; may be lifelong treatement; vaccine provides some protection
Botulism (31)
Sign & Symptoms
Intoxication with 3 manifestations: Foodborne botulism; Infant botulism (no honey if under 1 yr); Wound botulism
Progressive paralysis on both sides of the body
Pathogen & Virulence Factors
CLOSTRIDIUM BOTULINUM ; Gram positive endospore forming bacillus
Epidemiology
infant botulism most common form in US
Diagnosis, Treatment, and Prevention
3 Approaches to treatment; wash intestinal tract; administration of botulism immune globulin; antimicrobial drugs; prevented by destroying endospores in contaminated food
Tetanus (32)
Signs & Symptoms
TIGHTENING OF THE JAW; spasms and contractions may spread to other muscles; irregular heartbeat and blood pressure and profuse sweating may occur
Pathogen & Virulence Factors
CLOSTRIDIUM TETANI is causative agent; found in soil, dust, and the intestines of humans and animals; produce a neurotoxin called tetanospasmin
Pathogenesis:
Can aquire through break in the skin or mucous membrane
-Epidemiology
MORTALITY RATE IS 50% IF UNTREATED; INCIDENCE HAS DECREASED WORDWIDE
Diagnosis & Prevention
Diagnosis based on characteristic of muscle contraction; Vaccine is available against tetanus
Viral Meningitis (32)
Signs & Symptoms
Similar to those of bacterial meningitis; usually milder then those of bacterial or fungal meningitis
Pathogens & Virulence Factors
90% caused by RNA viruses in genus ENTEROVIRUS; COXSACKIE A VIRUS, COXSAKIE B VIRUS, ECHOVIRUS
Spread by fecal contamination of food, water, or hands
Pathogenesis
Damage to cells in the meninges triggers meningitis
Epidemiology
More common than bacterial and fungal meningitis; spread via respiratory droplets and feces
Diagnosis, treatment & prevention
Difficult to prevent spread of Enterovirus, no specific treatment available, characteristic signs in the absence of bacteria in CSF
Poliomyelitis (34) (Poliovirus)
Epedemics of Polio were common in the past; soon to be eradicated
Signs & Symptoms
ASYMPTOMATIC INFECTIONS: 90% OF CASES
MINOR POLIO; NON SPECIFIC SYMPTOMS 5% OF CASES
NONPARALYTIC POLIO: MUSCLE SPAMS AND BACK PAIN 2% OF CASES
PARALYTIC POLIO: PRODUCES PARALYSIS-LESS THEN 2%
Post polio syndrome can be debilitating
Pathogen & Pathogenesis
Poliovirus is causative Agent; transmitted by drinking water
Epidemiology
Currently exists in Africa & Asia; difficult to control because of high population and poor sanitation, and political/religious tension
Prevention
2 Effective Vaccines available
Rabies (35)
Sign & Symptoms
Characteristic neurological virus reaches CNS; Hydrophobia, seizures, hallucination, paralysis
Pathogen & Virulence Rabies Virus (-ssRNA virus)
Pathogenesis
Transmitted via vite, scratch from infected animal; virus replicates in muscle cells and then moves into neurons
Epidemiology
ZOONOTIC DISEASE
Diagnosis, treatment, & prevention
Postmortem detection of NEGRI BODIES in the brain; diagnosis by unique neurological symptoms; treated with immunoglobulin, vaccine injections, and cleansing infection site; prevented by controlling rabies in domestic animals.
Arboviral Encephalitis (36)
ARTHROPOD-BORNE VIRUSES; transmitted by blood sucking arthropods; mosquitos*
Signs & Symptoms
Arbovirus usually cause mild, coldlike symtoms; can cause encephalitis if it crosses the blood brain barrier; can infect many different animals; 6 arboviruses cause most of the viral encephalitis in Americans; WEST NILE VIRUS IS THE MOST SIGNIFICANT IN THE US BY THE CULEX MOSQUITO
Diagnosis, Treatment, Prevention
Diagnosis based on symptoms, confirmed by arbovirus-specific antibodies in CSF; treatment is supportive; prevention involves limiting contact with mosquitos; vaccines only for horses
Cryptococcal Meningitis (37) (Fungal)
Signs & Symptoms
Similar to those of bacterial meningitis; loss of vision & coma may occur in later states
Pathogen & Virulence Factors
CRYPTOCOCCUS NEFORMANS is causative agent; two varients of YEAST found worldwide; RESISTS PHAGOCYTOSIS BY DEFENSIVE CELLS
Pathogenesis & Virulence Factors
Infections follow inhalation of spores or dried yest cells; occurs in terminal AIDS patients and in transplant recipients
Diagnosis, treatment, prevention
Diagnosed by detection of fungal antigen in CSF, treated with intravenous antifungal drugs; hospital try to prevent entry with air filtration
African Sleeping Sickness (38) (protozoan)
Signs & Symptoms
3 clinical stages; site of bite becomes lesion; parasites in the blood create fever, lymph nodes swelling, and headache; protozoa invade CNS, causing meningoencephalitis; characterized by cyclic waves of parasitemia
Pathogen & Virulence Factors
Caused by TRYPANOSOMA BRUCEI; evades immune system by changing surface glycoproteins
Diagnosis, treatment, and prevention
Diagnosed by microscopic observation of trypanosomes in blood, lymph, spinal fluid, or tissue biopsy
Treatment based on disease stage; must begin soon after infection to be successful; insecticide application can help reduce occurrence
Primary Amebic Meningoencephalopathy (protozoan)
Signs & Symptoms
Same as those of meningitis and encephalitis caused by other microbes
Pathogen, pathogenesis, & epidimiology
Caused by ACANTHAMOEBA AND NAEGLERIA; enter hose through abrasions on the skin or the eyelid or by inhalation of contaminated water; rare but almost always fatel
Diagnosis, treatment, and prevention
Detect amoebae in sample from the eye or brain, or in CSF, drugs have limited success; prevented by avoiding contaminated water supplies
Spongiform encephalopathies (40) (Prion)
Includes SCRAPIE AND “MAD COW” disease; leaves the brains of victims full of holes; can occur spontaneously in the elderly; humans can contract by eating meat from infected cattle
VARIANT CREUTZFELDT-JAKOB DISEASE
Signs & Symptoms
Insomnia, weight loss, memory failure; progressive worsening of muscle control
Pathogen, pathogenesis, and epidimiology
Caused by a abnormal form of prion protein; turn normal prions into abnormal; medical procedures can spread the disease, prions may remain dormant for years
Diagnosis, treatment, and prevention
Diagnosed by characteristic signs & symptoms; can be confused with other forms of dementia in elderly; no treatment is available; destruction of prions outside of body is difficult; prevent by avoiding prion contaminated meat
Trachoma (41)
Leading cause of nontraumatic blindness; scarring of conjunctiva and cornea, caused by CHLAMYDIA TRACHOMATIS multiplies in conjuctiva; purulent discharge causes deformed eyelids; scarring can lead to blindness, typically affects children
