CP/RF/Epi/
Comp.
Comp.
List at least 3 complications that occur from diphtheria (400 pts).
Kidney failure
Myocarditis (damage to the heart muscle)
Polyneuropathy (nerve damage)
What are the common agar media used to grow C. diphtheriae? (500 pts)
Löeffler - formation of metachromatic granules
What is the purpose of a urinalysis? (300 pts)
Diphtheria toxin can injure the kidneys; can detect kidney failure
What is the mechanism of erythromycin? (400 pts)
Binds the 50S ribosomal subunit to inhibit bacterial protein synthesis
What are the components of the SIRS criteria? (400 pts)
Bonus: Give the ranges of the components.
Temperature abnormality - fever; >38°C (100.4°F) or hypothermia; <36°C (96.8°F)
Heart rate - tachycardia; >90 beats/minute
Respiratory rate - tachypnea; >20 breaths/min
WBC count - leukocytosis, leukopenia, or bandemia (white blood cells >1,200/mm3, <4,000/mm3 or bandemia ≥10%).
List at least 3 symptoms/physical exam findings for diphtheria. (400 pts)
Bonus: How does cutaneous diphtheria present?
A sore throat and hoarseness
A thick, gray membrane covering the throat and tonsils
Swollen glands (enlarged lymph nodes) in the neck
Difficulty breathing or rapid breathing
Nasal discharge
Fever and chills
Tiredness
Bonus: Cutaneous - may present as a scaling rash or ulcers with clearly demarcated edges and membrane. These skin infections are slow to heal; more common in tropical climates; rare.
What is the major virulence factor for diphtheria? (300 pts)
Bonus: Describe the pathogenesis of diphtheria.
Diphtheria toxin
Bonus: transfer of ADP-ribosylation of the elongation factor-2 (EF-2) → inhibition of EF-2 → arrested protein translation and synthesis → cell death and necrosis
What is the purpose of troponin T level, creatine kinase-MB level, pro-brain natriuretic peptide level? (400 pts)
troponin T level - elevated; critical marker for myocardial damage and a predictor of high mortality
creatine kinase-MB level - elevated; cardiac enzyme; high CK-MB usually reflects a heart muscle injury (infarction, inflammation, trauma, surgery or heart biopsy)
pro-brain natriuretic peptide level - elevated; precursor hormone released by the heart when it's under stress; most commonly indicating heart failure, where higher numbers suggest greater severity
What is the class and subclass of erythromycin? (300 pts)
Class - antibiotic
Subclass - macrolide
Aside from vaccinations, what are other preventative measures for Corynebacterium diphtheriae? (300 pts)
Bonus: why is it important to give childhood vaccinations?
isolation until the 14-day course of antibiotic treatment has concluded and 2 cultures at least 24 hours apart are negative
Bonus: A baby’s immune system is not fully developed at birth, so they face a greater risk of becoming infected. Vaccination protects babies by helping build up their natural defenses
What is the incubation period for diphtheria? (300 pts)
usually 2 - 5 days but may occasionally be longer (range is 1-10 days)
What is the purpose of an Elek test? (400 pts)
Bonus: Describe how to perform an Elek test.
using immunodiffusion on an agar plate with antitoxin-impregnated paper to detect visible precipitin bands; Positive if the strain is toxicogenic
Bonus:
A filter paper strip containing diphtheria antitoxin (antibody) is placed on an agar plate.
The suspected bacteria are streaked across the plate, perpendicular to the strip.
If the bacteria produce diphtheria toxin (antigen), the toxin diffuses out and meets the antitoxin at the strip, forming a visible, white precipitate line
What is the purpose of radiographs, ECG, and cardiac ultrasound? (400 pts)
Radiograph - view neck swelling and airway
ECG/cardiac ultrasound - normal; diphtheria can cause myocarditis which can cause abnormal ECG findings or impaired heart functions
What is the purpose of administering IV methylprednisolone? (300 pts)
Bonus: What is the mechanism of action of IV methylprednisolone?
anti-inflammatory effect
binding to intracellular glucocorticoid receptors; repressing the enzyme phospholipase A2 to inhibit the synthesis of prostaglandins and leukotrienes
List at least 3 indications for intubation. (400 pts)
injury or trauma to your abdomen, chest or neck that affects your airways
Loss of consciousness (fainting) or a low level of consciousness, which can make you lose control of your airway
Need for surgery that will make you unable to breathe on your own
Respiratory failure
Risk for breathing in an object or substances, like food, vomit or blood (aspiration)
Something is caught in your airway and blocking the flow of air (airway obstruction)
Sudden loss of heart function (cardiac arrest)
A temporary stop in breathing (apnea)
What parts of the world is diphtheria most and least common in? (400 pts)
an endemic in third world countries in Africa, Latin America, Asia, the Middle East, and parts of Europe where vaccination rates are low
very rare in the United States and Western Europe where children have been vaccinated against the condition for decades.
Describe the morphology/characteristics of C. diphtheriae. (3 features); (400 pts)
Gram‑positive club-shaped bacillus
Aerobic or facultative anaerobe
Nonencapsulated
Nonmotile
nonspore forming
catalase positive
Explain the findings of the blood test. (500 pts)
WBC - high
Hemoglobin and Hematocrit - low
Urea nitrogen - high
Creatinine - high
WBC - high; sign of infection/inflammation
Hemoglobin and Hematocrit - low; anemia due to infection
Urea nitrogen - high; indicating renal impairment or metabolic stress caused by the bacterial toxin
Creatinine - high; indicates significant, often severe, renal involvement (acute kidney injury) caused by the diphtheria toxin
What is the mechanism of action of IV diphtheria antitoxin? (300 pts)
Bonus: What animal does the antitoxin come from?
neutralizing the circulating exotoxin produced by Corynebacterium diphtheriae before it binds to tissues, preventing further systemic damage.
Bonus: Horses!
What are the 4 types of vaccines that are given to prevent diphtheria? (500 pts)
Bonus: when are these vaccines given?
DTaP
Tdap
DT
Td
List at least 3 risk factors for diphtheria (300 pts)
Children and adults who don't have up-to-date vaccinations
People living in crowded or unsanitary conditions
Anyone who travels to an area where diphtheria infections are more common
Having a weakened immune system
Being under age 5 or over 40
What is the mode of transmission for C. diphtheriae? (300 pts)
airborne respiratory droplets from coughing or sneezing
direct contact with infected skin sores or contaminated items
What is the purpose of a liver function and erythrocyte sedimentation test? (400 pts)
Liver function - normal in case; evaluate potential systemic complications caused by the bacterial toxin, such as liver damage
erythrocyte sedimentation - normal in case but typically elevated; faster settling means more inflammation due to cells clumping together
What is the class and subclass of IV methylprednisolone? (400 pts)
Class - corticosteroids
Subclass - synthetic glucocorticoid
Aside from antibiotics and antitoxin, give at least one treatment option for Corynebacterium diphtheriae. (400 pts)
Sometimes a tracheostomy is needed for severe breathing difficulties.
cutaneous diphtheria - thorough cleansing of the lesion with soap and water and administration of systemic antibiotics for 10 to 14 days, depending on the severity of the infection are recommended
other medicines to reduce the risk of adverse reactions of medications/vaccine (e.g. antihistamines)