Flashcards in Infectious Diseases Part I Deck (48):
CBC Laboratory Aids (4)
1. Bacterial infections: Leukocytosis with a differential left shift
*Shift to polys or bands
2. Viral infections: Leukopenia.
3 . Specific exceptions
*Pertussis causes an elevated white blood cell count with lymphocytosis).
*Overwhelming sepsis, immunosuppressive drugs, and corticosteroids alters CBC and confuses the picture
4. Monocytosis reflects recovery phase of viral illness
*Common finding as someone is getting better
*Can persist for a couple of weeks
Acute Phase Reactants (5)
1. Sed rate (ESR)
2. C-reactive Protein
*Used a lot with sepsis
4. Serum ferritin
1. Bacteria, viruses, fungi and parasites require different media.
2. Gram stains:
*Helps in antibiotics choice before the culture sensitivity tests are available
*Want them to look at urine and do gram stain to see what the microorganism looks like
3. Blood cultures are sometimes done with a very sick child
*Less concern to do it nowadays with high fever because of PCV13 and Hib vaccines
Serological Tests (4)
1. Specific antisera can cause an agglutination reaction.
2. Measured by dilutional factors.
3. Fourfold rise is considered positive
4. 4x over the normal value is considered a positive serology
*Ex: with syphilis tests
Antibody Detection techniques (3)
1. Complement fixation
2. Hemagglutination inhibition
3. ELISA (enzyme-linked immunosorbent assay) testing.
*Trumped by PCR testing; PCR is usually what we use to test for STDs
Antimicrobial Sensitivity Testing (2)
1. Standard zone diameters indicate sensitivity or resistance of a microbe to a specific antibiotic.
2. Plate the microorganism of test and look for zone of inhibition; you want to pick the one that is the most sensitive when picking for antibiotics
Chest Radiographs (2)
1. PA and Lateral
2. There is no indication for a chest X-ray in a well appearing child with a clinical pneumonia and a normal oxygen
*If you aren’t going to admit child, if it isn’t recurrent, and if it is improving with antibiotics then do not do chest X-ray!
Not recommended because the respiratory tract starts at the beginning of the nose, a sinus series would be positive and so would CT of sinuses but that’s simply because of a cold
*Don’t image unless it’s a recurrent problem
Detection of osteomyelitis or abscesses.
*Ultrasound of abscesses
CT and MRI (3)
1. Abscesses or other purulent material collections
2. Not first choice to do CT because it exposes a child to radiation
3. MRI is good especially for osteomyelitis
Coxsackie Etiology (7)
1. Enterovirus family
2. Related to both polio and echo viruses.
3. RNA viruses
4. A and B
5. Coxsackie enteroviruses and polio enteroviruses
6. Occur in MAY-OCTOBER; strong summertime predilection
7. Can stay on surfaces for over 2 weeks
Coxsackie Epidemiology (5)
Enteroviruses (entero = intestinal)
1. Fecal-oral contamination, especially in diapered children
2. Transmitted during parturition.
3. Worldwide distribution
4. Increased prevalence: May to October.
5. Most commonly 1 to 4 years of age.
Coxsackie Incubation Period (4)
1. 3 to 6 days.
2. Shed for several weeks
3. Child can go back to school as long as not febrile because it is ubiquitous
4. Viable on environmental surfaces for at least two weeks.
Coxsackie Virus Type A - Hand, Food and Mouth Disease (6)
1. Fever, vesicular eruption of the buccal mucosa of the mouth, and a maculopapular rash involving the hands and feet.
2. Acrodermatitis distribution
3. Evolves to vesicles, especially on the dorsa of the hands and the soles of the feet
4. 1 to 2 weeks duration
5. The hallmark disease of coxsackie virus type A
6. No fever, no diarrhea, no vomiting → can go back to school
Coxsackie Virus Type A - Aseptic Meningitis (5)
1. Fever, stiff neck, and headache.
2. Altered sensorium and seizures are common.
3. Epidemics or as unique cases
4. Recover completely.
5. Will not look sick, but if they do then they probably need admission
Coxsackie Virus Type A Paralytic Disease - Guillain–Barré-type syndrome (3)
1. Acute ascending polyneuropathy
2. Weakess starts in lower extremities and goes up
*Difficulty walking = first sign
*Goes on to respiratory failure
*Can even go on to chronic inflammatory polyneuropathy to be treated long-term with IVIG
3. IVIG treats Guillain-Barre by coxsackie 2mg/kg
Coxsackie Virus Type A - Childhood insulin-dependent disease (2)
1. Link between this disorder and Type A coxsackie infection has been proposed but not proven
2. Varicella: yes
Coxsackie Infection Type B - congenital or neonatal infection (13)
1. Symptoms occur within two weeks of birth.
2. Transplacental infection occurs
3. Serious disseminated disease affects the fetal liver, heart, meninges, and adrenal cortex.
4. Sudden onset of vomiting
7. Cyanosis, dyspnea
8. Mistaken for pneumonia.
9. Pallor and tachycardia leads to myocarditis and congestive heart failure.
10. May not have a murmur.
11. Cardiac collapse and death can occur
12. If the neonates survives, the recovery can be quite rapid.
13. Very serious; can cause myocarditis, neonatal overwhelming septic infection
Coxsackie Virus Type B - Pleurodynia (11)
(Bornholm’s Disease or devil's grip)
1. Generally epidemic but isolated cases happen
2. Can occur with A, but less likely
3. Sudden severe chest pain, pleuritic in nature and aggravated by deep breathing, coughing, or sudden movements.
4. Waves of spasms of 15-30 minutes duration
5. Being stabbed with a knife
6. Prodrome 1 to 10 days before the onset of chest pain
7. Headache, malaise, anorexia, and myalgia.
8. Fifty percent of patients have crampy abdominal pain.
10. Low to high fever occurs, and a pleural friction rub often is heard.
11. Lasts from 1 to 10 days (mean 3.5 d).
Coronary artery disease, pneumonia or pleural inflammation.
*Because it mimics pain of cardiac problems
1. Causes inflammation of the pleura (lining of lungs) causing them to have severe remarkable pain
2. Patients will complain of spasms
3. Can last from 1-10 days
4. Cough due to pleuritis
5. May have vague symptoms
6. The symptoms come from interferon and interleukin release
Coxsackie Virus Type B - Myocarditis or Pericarditis (5)
1. Mild to severe acute and chronic heart disease.
2. Symptoms are apparent within two weeks after exposure.
3. Chronic heart disability occurs in approximately 20% of cases
4. More common in adult menu
5. Vague complaints but keep index of suspicion up!
Diagnostic Tests for Coxsackie (3 with descriptions)
1. Viral cultures
- Throat, stool, and rectum.
- Laboratory frozen at 4°C (39°F).
- Usually available in < 1 week,
- Routinely, viral cultures are not done unless the child is very sick
2. Polymerase chain reaction (PCR)
- Sensitive for CSF
- Good for viral meningitis
3. Serologic specific titers
- 2 to 4 weeks apart
- In case of EBV, need to wait one week before ordering
- Must wait at least 1 week after presentatiosn before you can send titers, even for early antigen
TYPE OF HERPES VIRUS
1. Affects about 1% of newborn
- Most common infection
2. Most infections are asymptomatic at birth
-Can develop hearing loss in toddler preschool years
-99% are asymptomatic
3. May have neurosensory hearing loss around 4-5 years old
4. If symptomatic, sometimes may get blueberry-muffin rash or hearing problem
5. When symptomatic is seen, treat with gangciclovir
6. Adolescents are the most common group that will give birth and have a CMV+ baby
Herpes Simplex Type I and II (4)
1. Common, contagious, and often recurrent infection of skin and mucous membranes
*One variety is herpes labialis (cold sore)
2. CAUSES VESICLES IN GROUPS
3. Usually ulcerations after vesicles clear up
4. Whole process is usually about 10 days
Herpes Simplex I and II Clinical Manifestations (5)
1. Following a brief prodrome of burning, vesicles filled with yellow fluid erupt on the lip
2. Discrete red, swollen mucosal ulcerations
3. Numerous yellow ulcerations with thin red halos
4. Thick walled vesicles on an erythematous base
5. GROUPED = hallmark
Neonatal Herpes Simplex (4)
1. Occurs in infants born to mothers with genital Herpes Simplex
2. Usually mother is asymptomatic and infant appears normal at birth
3. Can present (day 10-11 most common) with
- 1. Skin, eye, mucous membrane (SEM disease)
- 2. Systemic
- 3. CNS disease
4. Infant progresses to develop sudden onset of fever, lethargy, poor feeding with vesicular lesions, hepatosplenomegaly
Neonatal Herpes Simplex Treatment
Put on acyclovir!
*If you’re given acyclovir even without having herpes, it gets phosphorylated into the active form and it would be passed out of your body unchanged
*Mis-diagnosis is OK
*Herpes cell has thimadine-kinase which causes phosphorylation of the herpes virus
1. Type of Human Herpes Virus 6 and 7
2. For HHV 6: incubation of 9-10 days
3. Can have gastrointestinal symptoms, respiratory tract signs, post occipital adenopathy
*May have some loose stool
*Clear nasal discharge
4. Fever without rash
*If given amoxicillin with the fever, can break out into rash and be misdiagnosed for amoxicillin allergy
*#1 reason for misdiagnosed penicillin allergy
5. Ask what kind of rash it is
*If it is fine, pink truncal rash then it is roseola
6. #1 reason for febrile convulsions
7. Hemiplegia, aseptic meningitis - RARE
Differential Dx for Herpes Viruses (5)
2. Enterovirus disease
4. Atypical measles
5. Drug rashes.
Mononucelosis Causative Organisms (3)
*CMV mono can look like EBV mono
*EBV titers negative → consider CMV mono
*In inner-cities like Newarks, CMV Mono is very common in daycare center
Mono Epidemiology (3)
1. Worldwide in distribution
2, By 5 years of age, 70 to 90% of children in poor urban settings or developing countries are seropositive for Epstein–Barr virus.
*Mild symptoms or is subclinical.
3. In more affluent social economic groups, symptomatic cases of IM present during adolescence and in young adults
Mono Mode of Transmission (4)
1. Close personal contact (e.g., kissing/saliva).
-Main source of transmission;
2. 35% household transmission
3. Fomite contamination
-Clothing, tables, all non-human type of pick up
-Can shed EBV long after having it
-Stays in B-cell
4. Shedding is greater when on steroids or immunocompromise
*Up to 50% of patients on immunosuppressive therapy, including those on steroids, shed virus.
Mono Incubation Period (3)
Infectious mononucleosis virus
1. Saliva and blood of clinically ill and asymptomatic infected persons for many months
2. Period of communicability is difficult to assess
3. Period of incubation is thought to be from 2 to 6 weeks (average 20-30 days).
Mono Clinical Signs (9)
1. Sore throat
8. Maculopapular rash
9. Symptoms are variable and can last up to 2-3 weeks.
Mono and Lymph Nodes
1. Disease of the primary lymphoid tissue and peripheral blood.
2. Enlargement of lymphoid tissue: regional lymph nodes, tonsils, spleen, and liver.
3. Atypical lymphocytes in peripheral blood
4. Classic sore throat + fever + monocytosis and no atypical lymphocytes → answer is NOT EBV if rapid strep was negative
5. Almost all body organs are involved, including but not limited to the lungs, heart, kidneys, adrenals, central nervous system, and skin.
6. EBV mono and strep like each other; 25% incidence of having both
*Always use PCN in these cases, not Amox
<103 degrees lasting 1-3 days is very common
Mono Sore Throat (6)
1. Few days after the fever.
3. Tonsils enlarge
4. Grayish-colored exudates
5. Ulceration, and pseudomembrane formation.
6. Palatal Petechiae
Mono Lymphadenopathy (4)
1. Anterior, but especially the posterior cervical nodes
2. Any lymphoid tissue can be affected.
3. Firm but usually non-tender, and discrete in nature.
4. Lymphadenopathy spares the jaw line but can be very severe
*If airway is compromised → admit
*Ex: marked tonsillar hypertrophy
Mono Splenomegaly and Hepatomegaly
Splenomegaly: Occurs in 50 to 75% of cases. Rupture is rare, must use scratch test
*Abnormal liver function tests common
*5 to 25%clinical hepatitis.
Mono Skin Rash (2)
1. 20% of cases. Can be maculopapular, urticarial, scarlatiniform, hemorrhagic, or nodular.
2. Associated with taking amoxicillin and probably represents a form of arteritis or vasculitis.
Other Mono Manifestations
1. Periorbital edema
*Reported in 25% of cases
2. Myalgia, arthralgia, chest pain, ocular pain, photophobia, conjunctivitis, gingivitis, abdominal pain, diarrhea, cough, pneumonia, rhinitis, epistaxis, bradycardia, aseptic meningitis, Guillain-Barré syndrome, Bell palsy, Reye syndrome, and acute cerebellar ataxia. (less common)
Mono Differential Dx (13)
1. Gram positive alpha-beta hemolytic streptococcal pharyngitis
3. Lymphoreticular malignancies
11. Drug reactions
13. Burkitts lymphoma
*Especially if the child is from Africa
Mono Diagnostic Testing (5)
1. WAIT ONE WEEK!
*More than 10% atypical lymphocytes and 50% lymphocytosis.
3. Serological tests.
* Serum heterophile test
-Positive in 80%-90% of infected patients over four years of age.
- Children older than 4 years of age usually must be ill for approximately 2 weeks before seroconverting.
4. Viral culture
5. Epstein–Barr specific core and capsule antibody testing
Epstein–Barr specific core and capsule antibody testing (5)
1. Early antigen: will be the first antigen to be positive
2. EBV-IGM: Second antigen that will be positive
*IGM is an acute serology for any antigen
3. EBV-IGg: As body starts to recover, IGg gets elevated (ex: with hepatitis vaccine)
4. EBNA IGM and IGG: Elevated if mono is reactivated
5. Test for CMV in patients with Negative EBV serology
*CMV is common in daycares (or from sibling)
Mono Complications (5)
1. Splenic rupture, thrombocytopenia, agranulocytosis, hemolytic anemia, orchitis, myocarditis and chronic infectious mononucleosis.
2. Can’t do contact sports due to risk of splenic rupture
3. Fatal disseminated disease, or B-cell lymphoma, occurs in patients with congenital or acquired cellular immunity deficiencies.
4. Burkitt B-cell lymphoma and nasopharyngeal carcinoma are also caused by Epstein–Barr virus; these conditions are more commonly found in Central Africa and Southeast Asia.
5. Death from infective mono occurs in approximately 1 out of 3000 cases.
Mono Management (5)
1. Treatment is supportive with adequate fluids and calories.
2. Corticosteroids and acyclovir are not recommended for routine disease.
3. Acyclovir has little effect.
*Because the virus doesn’t have thiamadine kinase in it
4. Contact sports and strenuous exercise should be avoided if the patient has hepatosplenomegaly.
5. Participation is acceptable after the splenomegaly has resolved.