Dermal Peds Infections PDF

Dermal Peds Infections Beatrice Saviola Conflict of Interest Disclosure In relation to this presentation, Dr. Saviola has no financial interests or other conflicts that need to be discloses. 2 References Warren Levinson Med...

Dermal Peds Infections Beatrice Saviola Conflict of Interest Disclosure In relation to this presentation, Dr. Saviola has no financial interests or other conflicts that need to be discloses. 2 References Warren Levinson Medical Microbiology, Chapter 15 Gram Positive Cocci, Chapter 37 Herpesviruses, Poxviruses, Chapter 39 Important Childhood Viruses, Chapter 40 Viruses That Infect the Enteric Tract https://accessmedicine-mhmedical- com.proxy.westernu.edu/book.aspx?bookid=3123# 261979831 Objectives 1. After this lecture the student will be able to formulate the basic microbiology and pathogenesis of medically important bacteria and viruses affecting the pediatric population and the dermis. 2. After this lecture the student will be able to differentiate the various bacteria and viruses affecting the pediatric population that result in dermal infections. 3. After this lecture the student should be able to report the major characteristics of dermal bacterial and viral infections as well as their diagnosis affecting the pediatric population. Outline 1st -6th Disease Maculopapular rash producing pathogens Vesicular pathogens TORCH  Macule Definitions- macule- a flat discolored area of the skin Papule papule- a small raised bump vesicle- a small blister on the skin filled with fluid pustule- pus filled bump Vesicle Pustule Exanthematous diseases When an infection causes an ill person to break out in a rash that covers most of the body, the rash is called an exanthem or an eruption. In antiquity illnesses causing skin manifestations were all lumped together. However, eventually a distinction was made between measles (maculopapular) and pox (vesicular and pustular). Six separate childhood exanthems were defined from what was once called “measles”. Macularpapular rash due to bacterial toxin mediated systemic infections Scarlet fever- red rash followed by desquamation: Second Disease The disease and rash are caused by Streptococcus pyogenes that produces streptococcal pyrogenic exotoxins, these are super antigens that activate T cells non-specifically. It is usually associated with pharyngeal infections with the organism. S. aureus can also cause scarlet fever and rash and disease. Superantigens Viral Macular or Maculopapular exanthems  Measles (Rubeola): 1st Disease Caused by a paramyxovirus- enveloped negative- sense ssRNA virus. syncytia Humans are only known host One antigenic type Labile but may stay infectious in the air in droplet form for several hours.  Portal of entry is the upper respiratory tract, and sometimes the conjunctiva. Large amounts of virus excreted in the mucous. Koplik spots in mouth and then rash. Infected droplet nuclei are usual means of transmission. Very contagious by close contact. Before the development of the vaccine, it was a disease of children, most of whom had immunity by age 10. Now with the vaccine measles has become rare in the U.S. Infection with measles virus causes depression of both cell mediated and humeral immune responses. The virus infects monocytes, T cells and B cells. Children can die from other infections. Rash on about 14th day, a result of exudation of serum and erythrocytes into epidermis. The virus replicates in endothelial cells. Rash not infectious. Rubella (German measles): 3rd Disease Previous designation as a togavirus, now a matonavirus- enveloped positive-sense ssRNA virus. One antigenic type. Contracted through inhalation of droplet nuclei from the respiratory tract of infected persons. Less contagious than measles. Most communicable five days before to five days after onset of the rash. With vaccine, there are very few cases now in the U.S. Spread of rubella virus in the host- can harm fetus! Rash onset coincides with detectable neutralizing antibody. Prevention A good live attenuated vaccine is avaiable and is used extensively in the U.S. It is given as part of the MMR to children at between 12-15 months of age or older. All older children and adults without serological evidence of antibody should also be immunized. Erythema infectiosum (fifth disease, or slapped cheek syndrome) Human parvovirus B-19, a tiny naked ssDNA virus. Mildly contagious, spread by respiratory droplet infection or blood transfusion. Most common in children, but also occurs in adults.  Viremia occurs and the virus replicates in rapidly dividing erythroid precursors. There is a temporary halt in erythrocyte production. There is permanent immunity after infection. Adult infections are often subclinical. Can cause harm or death to a developing fetus. Roseola infantum (exanthem subitum, or sixth disease) Caused by Human Herpesvirus 6 (HHV-6) a large enveloped dsDNA virus Acquired by infant or young child through close contact with an adult secreting virus into saliva. It is the most common febrile exanthem seen in infants under two years of age. It is characterized by 3-5 days of high fever followed by a maculopapular rash. Vesicular Exanthems  Varicella-Zoster (VZV) (chicken pox, herpes zoster) live attenuated virus vaccine “ProQuad” or “Varivax” is available and is required for school entry in California. “Shingrix” recombinant vaccine for shingles. Varicella (chicken pox)- childhood primary disease, passed by respiratory route, very contagious. Primary maternal varicella may cause birth defects in fetus. Viremic spread to epithelium. Herpes zoster (shingles)- reactivation of latent virus from dorsal root of ganglia or cranial nerve roots. Skin eruptions occur in areas innervated by these.  The live attenuated vaccine ProQuad itself can in rare cases cause a rash and be transmitted to others and would be a potential danger to the immunocompromised and pregnant. Tzank smear also useful- syncytia. Cowdry type A inclusion bodies. The virus can cause fetal harm if a pregnant woman is not immune and is infected with VZV during her pregnancy. Model of varicella-zoster virus (VZV), Varicella or chickenpox  Positive strand ssRNA viruses- RNA alone is infectious. It acts as messenger RNA Picornaviridae (small RNA viruses) Naked icosahedral nucleocapsid, usually cytolytic infections Specific viruses causing infection in man: Enteroviruses: acid-stable, resistant to harsh environmental conditions, transmitted by fecal-oral route. Pathogenesis of picornavirus infection  Hand Foot and Mouth Disease Etiology, Coxsackie A virus (most commonly A16) or Enterovirus 71 but occasionally others. These are Picornaviruses and in the enterovirus subfamily. Quite contagious, especially in day care centers and schools; transmission is by fecal oral or repiratory route. There are sores in the mouth and blisters on the palms and backs of hands and heels and soles of the feet. Usually not serious, but the child feels sick and uncomfortable. The same virus may occasionally cause aseptic meningitis or in the case of Enterovirus 71, encephalitis or acute flaccid paralysis. Torch Syndrome-diseases acquired in utero or at birth with some similarities. Acronym: Toxoplasmosis, Other, Rubella, Cytomegalovirus, Herpesvirus TORCH is the name given to a group of infections that babies might get from their mothers in utero, natally, (or sometimes postnatally). Can cross placenta to infect fetus. If a mother has one of these infections during pregnancy, it can harm the baby. Most arise from primary acute infection in the mother! Potential Manifestations- Infants symptomatic at birth, may have microcephaly, hydrocephaly, cerebral calcification, blindness, chorioretinitis, hearing loss, liver problems, jaundice, and skin manifestations. Infants asymptomatic at birth may go on to develop blindness, epilepsy, psychomotor or learning disabilities months or years later. Other HIV- retrovirus + SSRNA virus that uses reverse transcriptase in its life cycle. HBV- DNA virus HCV- RNA virus Treponema pallidum- syphilis Parvovirus B19- DNA virus Enteroviruses (picornaviruses) VZV (DNA herpes virus causing chicken pox and zoster) Zika Virus  Congenital Syphilis In utero infections can lead to serious fetal disease, multiorgan malformations, eighth nerve deafness, ocular interstitial keratitis, or death of the fetus. Can cause widespread desquamating maculopapular rash, and bone and teeth malformations. Blueberry muffin syndrome- distinctive purpura rash Rubella Toxoplasmosis Herpes simplex Coxsackie virus Parvovirus Syphilis Cytomegalovirus (herpes family virus)