LOs: 15-16 Flashcards
15 Rhinitis:
Definition
Cardinal symptom
Usual etiologies (3)
Treatment
- Inflammation of nasal mucosa
- May be accompanied by sinusitis, pharyngitis, headache, & constitutional symptoms
“common cold”
- Rhinovirus
- Coronavirus
- Respiratory Syncytial Virus (RSV)
Symptomatic only (except RSV)
15 Sinusitis:
Definition
Usual etiology
Common bacterial etiologies (3)
Nasal discharge
- Inflammation of the sinuses
- Bacterial sinusitis may present w/ facial pain/tenderness & high fever
Rhinovirus
- Streptococcus pneumoniae (GPC)
- Haemophilus influenzae (GN)
- May have some anaerobic component
Presence of yellow or green nasal discharge DOES NOT distinguish viral from bacterial etiologies
15 Otitis Media:
Definition
Common in…
Usual etiology
Common bacterial etiologies (2)
- Middle ear infection
- May accompany the common cold
Children
Viruses
- Streptococcus pneumoniae (GPC)
- Haemophilus influenza (GN)
15 Pharyngitis/Tonsillitis:
Definition
Usual etiologies (2)
Most common bacterial etiology
- Inflammation of the pharynx/tonsils
- Presents w/ sore throat
Viral
- Rhinovirus
- Coronavirus
Streptococcus pyogens (GPC) - AKA GroupA Streptococcus (GAS) as the cause of “Strep throat”
15 Acute Bronchitis:
Definition
Smoking
Exacerbations
Usual etiologies (3)
Usual bacterial etiologies (3)
- Presents w/ cough, typically productive of sputum
- May sometimes be associated w/ wheeze (bronchospasm)
Heavy smokers may develop emphysema or chronic bronchitis (cough productive of sputum throughout the year)
Viral or bacterial infections may cause exacerbations of bronchitis (“acute on chronic”)
Viral
- Rhinovirus
- Adenovirus
- Influenzavirus
- Streptococcus pneumoniae (GPC)
- Haemophilus influenzae (GN)
- Moraxella catarrhalis (GN)
15 Influenza:
Definition
Caused by…
Isolated from…
Treatment
Sudden onset of chills, accompanied by severe muscle aches, fever, & cough
Influenza virus (A or B)
Nose or pharynx
Specific anti-influenza drugs are available but only effective if give in the first 36-48 hours after the first onset of symptoms
15 Community-Acquired Pneumonia:
Cardinal symptoms
Most common cause
Other common causes (2)
Atypical causes (3)
Cough productive of sputum, pleuritic chest pain, shortness of breath and fever
Streptococcus pneumoniae
- Haemophilus influenzae
- Moraxella catarrhalis
- Chlamydophila pneumoniae
- Legionella pneumophila
- Mycoplasma pneumoniae
15 Hospital-Acquired Pneumonia:
Prone pts
Common causes (5)
Ventilator-associated penumonia (VAP): pts who are mechanically ventilated
- Pseudomonas aeruginosa
- Staphylococcus aureus
- Acinetobacter spp.
- Enterobacter cloacae
- Klebsiella pneumoniae
15 Urinary Tract Infection:
Common in…
Cystitis
- Symptoms
- Etiologies (2)
Acute pyelonephritis
- Symptoms
- Most common cause
- Catheterization causes (4)
Young women
- Dysuria (burning or stinging on passing urine) and increased frequency of passage of urine
- Escherichia coli
& Staphylococcus saprophyticus - Fever & flank pain
- E. coli
- E. coli, Enterococcus faecalis, Proteus mirabilis and Candida albicans
15 Bloodstream Infection:
Bacteremia
Severe sepsis
Vascular line related bacteremia
Causes of vascular line related bactermia (2)
Cause of prolonged bacteremia
Bacteria in the bloodstream
Result of bacteremia, physiologic functions are affected
Intravascular lines or devices may become bacteremic because these foreign bodies serve as a ready portal for bacteria from skin to the blood
- Staphylococcus aureus
- Coagulase negative staphylococci
Endovascular source
- Intravascular device (catheter, pacemaker)
- Heart valve (endocarditis)
15 Meningitis and Encephalitis:
Encephalitis
Meningitis
Meningoencephalitis
Etiologies of encephalitis (2)
Causes of meningitis (4)
Inflammation of the brain
Inflammation of the meninges
Inflammation of both the brain and the meninges
- Herpes simplex virus
- Vector borne infections (for example, West Nile virus)
- Neisseria meningitidis
- Streptococcus pneumonia
- Listeria monocytogenes
- The enteroviruses
15 Sexually Transmitted Infections:
Causes of urethritis (2)
Causes of genital ulcers (2)
Causes of genital warts (1)
- Chlamydia trachomatis
- Neisseria gonorrhoeae
- Herpes simplex virus
- Syphilis (Treponema pallidum)
Human papillomavirus
15 Diarrhea:
Causes outside hospital
- Bacteria (4)
- Protozoa (2)
- Viruses (2)
Cause within hospital (1)
Bacteria
- Salmonella
- Campylobacter
- Shigella
- E. coli
Protozoa
- Giardia lamblia
- Cryptosporidium
Viruses
- Rotavirus
- Norovirus
Clostridium difficile
15 Cutaneous Infections:
Cauess of dermatitis (2)
Causes of superficial cellulitis (1)
Causes of abscesses (1)
Causes of systemic (generalized) infections (3)
Causes of chronic ulcers (diabetics) (3)
- Dermatophytes
- Candida
Streptococcus
Staphylococcus
Infective endocarditis
- Pseudomonas aeruginosa bacteremia
- Disseminated fungal infections
- First gram+ cocci (Staph/Strep)
- Then gram- (E. coli) & Enterococcus
- Then resistant gram- (Pseudomonas)
15 Infection Susceptibility & Immunodeficiencies:
Immunodeficiency definition
Opportunistic infections
- Definition
- Examples (4)
A state in which the response of the host to a foreign antigen is not normal (congenital or acquired)
- Normal colonizing organisms that exploit some weakness in the host defense
- Splenectomy
- Neutropenia
- T-cell depletion (HIV, transplant)
- Hypogammaglobulinemia
15 Opportunistic Organisms:
Abnormalities in opsonization and reticulo-endothelial system (RES)
- Complement deficiency: Lupus (SLE)
- Asplenia: liver cirrhosis, splenectomy, sickle cell disease
Encapsulated organisms (3)
Haemophilus influenzae
Neisseria meningitidis
Streptococcus pneumoniae
15 Opportunistic Organisms:
Granulocyte or neutrophil abnormalities
- Chronic granulomatous disease (CGD)
- Neutropenia (low # of neutrophils)
Catalase positive organisms (3)
Staphylococcus aureus
Aspergillus
Pseudomonas aeruginosa
15 Opportunistic Organisms:
Lymphocytes
- B cells
- IgA deficiency
- IgG deficiency (multiple myeloma, common variable imm-def. (CVID))
- T cells
- HIV/AIDS
- Immunosuppressant medications
Protozoa (1)
Encapsulated organisms (3)
Fungi & yeasts (3)
Parasites (1)
Mycobacteria (2)
Viruses (6)
Giardia
Neisseria meningitidis
Haemophilus influenzae
Streptococcus pneumonia
Cryptococcus
Candida
Pneumocystis jaroveci
Toxoplasma
Tuberculosis
MAC
HSV VZV CMV KSHV HPV JC
16 Most common entry routes for pathogens causing exogenous infections (6)
Inhalation (respiratory)
- M. tuberculosis
- Influenza virus
Ingestion - Salmonella spp.
- Rotavirus
Blood - Hepatitis B virus
Arthropods - Borrelia burgdorferi
- Plasmodium spp.
STI - HIV virus
- N. gonorrhoeae
Wounds - C. perfringens
16 Intoxications vs. Infections:
Intoxications
Infections
- Invasive pathogens acquired by ingestion
- In vivo enterotoxin production by ingestion-acquired pathogens
Ingestion of preformed toxin is sufficient to obtain disease
- Often involve heat- and pH-stable toxins
- Symptoms develop quickly
- Symptoms often involve the GI tract: vomiting, diarrhea, cramps
Ingested pathogen must be present in the body
- Cause GI symptoms (EHEC also damages kidneys)
- Symptoms develop slowly
- Cause inflammation & GI symptoms
- Remain in GI tract or disseminate
- Produce toxins after becoming in present in GI tract
- Noninvasive (except Shigella)
16 Transmission & Initial Disease Symptoms:
Fecal-oral contamination
Food poisoning
Waterborne infections
Most ingestion-acquired pathogens are transmitted this way
- Symptoms: diarrhea, cramping, vomiting, sometimes fever
- Result from incomplete cooking, poor sanitation, & poor food storage
- From aging water or equipment breakdowns
- Pathogens highly resistant to chlorination
- Great potential public health threat
16 Most Common Food Poisoning Bacteria (6)
Nontyphoid Salmonella Clostridium perfringens Shigella spp. Campylobacter jejuni E. coli Staphylococcus aureus
16 Defenses in the GI tract & how ingestion-acquired pathogens overcome these defenses (3)
(1) Physical & chemical defenses
GI tract: gastric acid, bile, intestinal proteases, mucus, intestinal motility
Pathogens: ingestion in large numbers, acid/bile resistance, ingested in food, produce urease to raise pH, shelter in mucus, adherence
(2) Immune defenses
GI tract: IgA, GALT
Pathogens: countermeasures against immune defenses
(3) Normal microbial flora
GI tract: protect against GI pathogens
Pathogens: produce pili to adhere to unoccupied sites in the GI tract
16 Campylobacter jejuni:
Biologic Characteristics
Reservoirs/Transmission
Pathogenesis
Prevention/Treatment
- Motile
- Curved/gull winged shaped
- Oxidase positive
- Gram-negative rods
- Fastidious
- Microaerophilic
- Grow best at 42*C
R: animal (zoonotic)
T: contaminated food (esp poultry) & water
Adhesions (attachment) & LPS (inflammation)
- Ingestion, attaches to intestine, invades, induces inflammation
- Symptoms start within a few days & resolve ~5 days later
- Symptoms: cramps, diarrhea, fever
P: hygiene, cooking, no vaccine
T: symptomatic therapy, fluid replacement, antimicrobials (severe)
16 Giardia spp.:
Biologic Characteristics
Reservoirs/Transmission
Pathogenesis
Prevention/Treatment
- Vegetative form (trophozoites) & infectious form (cysts)
- Ingested cysts transport to small intestines to become trophozoites
- Resistant to chlorination
R: wild animals
T: contaminated water & food, fecal-oral
- Infectious cysts are ingested, become trophozoites, & multiply in the duodenum
- Symptoms start within 1-3 weeks & resolve 1-4 weeks later
- Symptoms: explosive, sudden onset diarrhea involving a foul-smelling, greasy stool devoid of blood or mucus
P: water treatment, hygiene, no vaccine
T: metronidazole
16 Cryptosporidium parvum:
Biologic Characteristics
Reservoirs/Transmission
Pathogenesis
Prevention/Treatment
- Intracellular protozoan
- Multiplies in GI tract by sexual & asexual reproduction
- Sporozoites –> trophozoites –> merozoites –> oocysts
- Shed in stool
R: zoonotic (farm animals, pets)
T: contaminated water, fecal-oral
- Oocysts ingested & –> sporozoites
- Sporozoites invade enterocytes under brush border & –> trophozoites (inflammation)
- Symptoms start 1 week later & persist for 1-2 weeks
- More severe in immunocompromised (chronic –> death)
P: hygiene, water treatment
T: Nitazoxanide for immunocompetent, antiretroviral & supportive therapy in immunocompromised
16 Rotavirus:
Biologic Characteristics
Reservoirs/Transmission
Virulence Factors
Pathogenesis
Prevention/Treatment
- Reovirus (dsRNA, 11 segments)
- Icosahedral capsid
- No envelope
- Acid resistant
R: humans
T: fecal-oral, withstand acidity, winter
Nonstructural protein (NSP4): enterotoxin
- Ingestion, multiples in intestine
- Symptoms start within 48 hours & continue for days to a week
- Symptoms: diarrhea, vomiting, fever
- Most common diarrhea cause in children <2
P: new vaccine
T: restore fluid/electrolyte balance
16 Hepatitis A Virus (HAV):
Biologic Characteristics
Reservoirs/Transmission
Pathogenesis
Prevention/Treatment
- Picornavirus, +ssRNA
- Nonenveloped
- 1 serotype
R: humans
T: fecal-oral, common worldwide, Chi Chi’s outbreak
- Ingestion, replicates in gut
- If sufficient HAV-neutralizing antibodies, no further development
- If not, HAV invades blood, spreads to liver, & causes acute inflammatory disease & jaundice
- Acute: completely recovers within 2 months, provides life-long immunity
- Fulminant hepatitis can be fatal
Hygiene, recent HAV exposure, HAV vaccine
