Vignette ID # 1

Commonest causative organisms:

I) Otitis infection:
Ac OE: pseudomonas aeruginosa, staph aureus

Ac OM with perforation: Pneumococcus, H influenzae , Moraxella catarrhalis

CSOM: Pseudomonas aeuroginosa, Staph aureus

Ac Mastoiditis: similar to the organisms that cause otitis media: Streptococcus pneumoniae and Haemophilus influenzae. Moraxella sp typically do not cause mastoiditis.

Ac Sinusitis ( as well as Ch):

Streptococcus pneumoniae,
nontypeable Haemophilus influenzae,
Moraxella catarrhalis

But Staph aureus, other streptococci, fungi, and anaerobes play a more prominent role.

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DRUG OF CHOICE:
1. Meningitis: Pediatric age > 5 months
Vancomycin + ceftraixone to begin with

Vanco will cover MRSA.

2. Brain Abscess:
Vanco + Metrogyl + ceftriaxone

3. Post-op Appendicitis with abscess: Ampi/sulbactum + Genta

4. After Dog-bite: Ampicillin + Clavulanic (augmentin)

If patient has penicillin-allergy: use Clindamycin + septran

5. Presumptive treatmemnt for ac urethritis in a 17 yrs old boy who comes with purulent urethral discharge:
= Azithromycin 1 g POx 1 plus cefixime 400 mg PO x 1 (for chlamydia and gonococcus)

6. Chlamydia infection (in adolescents):
azithromycin l g orally x 1 dose or doxycycline 100 mg orally BID x 7 days.

7. A peritonsillar abscess or quinsy: amp/sulbactum

8. Dental infection: penicillins

9. Anal pinworm infection: mebendazole in a single dose and repeated in 2 weeks

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CULTURE MEDIA:

1. Campylobacter jejuni: incubation at 42°C and microaerophilic conditions

2. Modified Thayer-Martin for gonococci

3. Bordet-Gengou or Regan-Lowe for Bordetella pertussis

4. Loeffler or Tinsdale agar for Corynebacterium diphtheriae.

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Period of Infectivity:

1. Measles (Rubeola):
Patients are contagious from 24 to 48 hours prior to the onset of symptoms until approximately 4 days after the rash appears.

2. Strep throat: Treatment of the index case (patient) renders the patient non-contagious within 24 hours.

=========================================================================================== Some Disease Characteristics:
1. Erythema Infectiosum (V Disease):

# Etilogy: erythema infectiosum (fifth disease), is the most common clinical expression of infection with human parvovirus B19.

# Clinical picture: Buzz words: slap cheek appearance . Note that on the exam, they may also show lacy-reticulated erythema on extrimites. This would be Erythema infectiosum.

In some patients, fever, malaise, myalgia, or headache precede the eruption by 7 to 10 days. The rash begins as confluent erythema of both cheeks (the so-called "slapped-cheek" appearance), followed by a lacy, reticulated, pink erythema of the extremities or trunk.

After 3 to 5 days, the eruption fades, although it may return for up to 4 months following exercise, overheating, or sun exposure.

Note: Other infections caused by Parvo Virus B19:

i) an atypical rash (eg, one that mimics rubella or a petechial eruption involving the hands and feet [papular purpuric "gloves and socks" syndrome]).

ii) transient aplastic crisis in patients who have hemolytic anemias,

iii) Bone marrow failure in immunodeficient individuals.

iv) Infection during pregnancy, particularly during the first half of pregnancy, may cause fetal hydrops and death.


2. Roseola Infantum: (exanthema subitum or sixth disease)

One board question shows macular rash on trunk and belly. Frankly, looks like a measles rash. THus, to remember, such a rash would more likely be roseola infantum (in USA), while think of measles/ rubeola if the description is in a developing nation).

i) A febrile illness occurring almost exclusively in children younger than 3 years of age (peak, 6 to 15 months of age).

ii) Cause: human herpesvirus type 6 (HHV 6) and, less frequently, by HHV 7.

iii) C/Fs: Patients have elevated temperatures (mean, 103°F [39°C]) for 3 to 5 days, followed by a rash that develops after a rather abrupt defervescence. The rash appears within 12 to 24 hours of fever resolution, beginning as small, slightly raised pink lesions on the trunk that subsequently spread to the neck, face, and extremities and disappear within 1 to 3 days.

NB: 10% to 15% of affected infants Febrile seizures during the febrile phase of roseola.

Roseola caused by HHV 7 occurs in slightly older infants, is associated with a lower mean temperature, and has a shorter duration compared with disease caused by HHV 6.

The abrupt defervescence followed by the development of a rash is a very distinct feature of roseola.

3. Scarlet fever:

In a pt with symptoms and signs that include fever, sore throat, a "strawberry tongue, " and tonsillar exudates; If you find a sand paper rash = Scarlet fever.

NB: Scarlet fever often manifests also facial erythema and perioral pallor. The rash is composed of fine, rough-feeling erythematous papules (sand paper) that are concentrated in flexural areas.