Clinical case - Sheet1

Question 1

exanthema definition

Answer 1

1. A skin eruption occurring as a symptom of an acute viral or coccal disease.
2. A disease, such as measles or scarlet fever, accompanied by a skin eruption.

Question 2

fifth disease

Answer 2

Caused by Parvovirus (non-enveloped, SS DNA and linear (-), smallest DNA virus), “Slapped cheeks”, Fever and joint pain, Diagnosis by history and exam, no lab

Question 3

scarlet fever

Answer 3

group A strep, begins with fever and sore throat, rash begins on neck and chest, diagnosis–throat swab for strep. Differential with Mono via mono test.

Question 4

pemphigus

Answer 4

blistering autoimmune disease, desmoglein glues epidermal cells together. Diagnosis made via skin biopsy after looking for viral/bacterial infection.

Question 5

Kawasaki disease

Answer 5

autoimmune vasculitis, affects skin, mucous membrane, blood vessels, and heart. Exfoliation. High fever. Diagnosis via history and physical only.

Question 6

Scalded skin syndrome

Answer 6

caused by coagulase positive staphylococci (with an extracellular toxin) which elaborates exfoliation (epidermolysin). Gram positive (purple). No fever. Diagnosis–history, appearance, no recent vaccinations. Lab–CRP increased, Gram stain. Treat–B-lactemase resistant penicillin or penicillinase-resistant penicillin (nafcillin). Mortality – 3-10% in children, 50% in adults. **Produces ET-A and ET-B. ET-A, is a superantigen. It allows simultaneous binding to MHC class-2 molecules and T-cell receptors, leading to the direct stimulation of T cells and IL-2 production. In response, there is a dramatic increase in production of cytokines IL-1 and TNF, and a systemic inflammatory response occurs.

Question 7

Exotoxin A and Exotoxin B

Answer 7

Produced by Staph aureus and Strept pyrogens. Recognize a single peptide bond in desmoglein-1 protein and cleave it–so cells break apart and skin sluffs off. Cause SSSS and bullous impetigo.

Question 8

Impitigo

Answer 8

Caused by Staph. aureus (fluid filled bolllous–aka bullous impetigo), and Strept pyrogens (cause honey crusted lesions).

Question 9

ET-A

Answer 9

Superantigen. Causes overwhelming release of IFN-y and IL-2 resulting in shock. Targets peptide bond in Desmoglein-1 protein and causes skin to sluff off. Gene found in lysogenized phage. Associated with Bullous Impetigo.

Question 10

ET-B

Answer 10

targets peptide bond in Desmoglein-1 protein and causes skin to sluff off. Gene found in plasmid (extrachromosomal). Associated with Scalded Skin Syndrome.

Question 11

ESR and infections

Answer 11

demonstrates the presence/absense of inflammation. Doesn’t necessarily suggest systemic infection.

Question 12

What is a distinguishing feature between Scalded Skin Syndrome and Scarlet Fever?

Answer 12

Fever in SF. No Fever in SSS.

Question 13

Epstein Barr Virus

Answer 13

A herpesvirus. Can cause mononucleosis.
Infects B cells. Characterized by fever, hepatosplenomegaly, pharyngitis, and lymphadenopathy (especially posterior cervical nodes). Peak incidence 15-20 yearsofage.