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ID Department, Yinghu Chen Cell phone: 13857154891 chenyinghu@sina.com Children’s Hospital of Zhejiang University Jun 1 3, 2017. Measles. Outline. Etiology Epidemiology Pathogenesis Clinical manifestations Lab findings Treatment Complications Preventions. Introduction.
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ID Department, Yinghu Chen Cell phone: 13857154891 chenyinghu@sina.com Children’s Hospital of Zhejiang University Jun 13, 2017 Measles
Outline Etiology Epidemiology Pathogenesis Clinical manifestations Lab findings Treatment Complications Preventions
Introduction Historically widespread but now very rare Characterized by fever, coryza, cough, Koplik’s spots, and maculopapular rash
Etiology Measles virus, a single-stranded RNA paramyxovirus with one antigenic type. Humans are the only natural host Found in nasopharyngeal secretions, blood and urine, during the prodromal period and for a short time after the rash appears Remain active for 1-2 days at room temperature
Epidemiology Spread throughout the world, vaccine-preventable disease For susceptible persons, 90% of the exposed acquire disease Infection sources: patients and person with latent infection Contagious period: 5 days before and after the rash appearance, accompanied with pneumonia, prolonging to 10th day Transmission: airborne and contact Season: spring, Age: 5-10yr New trends: measles appears in <8m infants and elders, due to inadequate vaccination as well as vaccine failure
Pathogenesis Process of virus in the body (two times of viremia) Invade airway endothelial cells, portal lymph node, and multiply (warthin-Finkeldey giant cell) Some invade to blood Captured by Monocyte - macrophage system, and replicates greatly, Invade blood second time, cause disseminated lesions, some target T cells The host immunity decrease, induce secondary bacterial infection and TB reactivation Endothelial cells Dendritic cell T cells
Pathogenesis Koplik spots Consist of serous exudate and proliferation of endothelial cells Interstitial pneumonia due to measles virus Bronchopneumonia may due to secondary bacterial infection Perivascular demyelinization in brain and spinal cord Subacute sclerosing panencephalitis (SSPE) Degeneration of the cortex and white matter with inclusion bodies, occur 7-11yr after measles, measles antibodies are detected in CSF
Clinical manifestaions Persons with typical symptoms immunocompetent children who didn’t receive measles vaccine, or vaccine failure, and didn’t receive immunoglobulin Four stages Incubation stage: 6-12d, may transmit virus by 9-10th day Prodromal stage: 3-5d, fever, cough, coryza, Koplik spots Rash stage: rash erupts for 2-3d , and fades Recovery stage
Prodromal stage Last 3-5d, low-grade to moderate fever, dry cough, coryza, and conjunctivitis, photophobia, Koplik spots.
Koplik spots and Stimson line Koplik spots: 1-2d before rash, grayish white dots, as small as grains, opposite the lower molars, may spread over the buccal mucosa, last 12-24hr Stimson line: transverse line of inflammation along the eyelid margin
Rash stage Temperature rises abruptly as the rash appears and often reaches 40℃ or higher The rash appears and fade downward sequence: stars (faint macules) on the upper lateral part of neck, behind the ears, along the hairline, cheek, spreads to entire face (maculopapular), neck, upper arms, chest back, abdomen, entire arm, thighs, and finally reach feet on the 2nd-3rd day In uncomplicated cases, as the rash appears on the legs and feet, the patients may appear desperately ill, but the symptoms subside within 2d Branny desquamation within 7-10d
Black measles Hemorrhagic type of measles Bleeding may occur from mouth, nose, or bowel, thrombocytopenia Occurs in immunocompromised or secondly infection patients Rash is confluent, petechiae Often accompanied with pneumonia, heart failure, disseminated intravascular coagulation (DIC), high mortality
Modified measles Mild cases Occurs in person with partial protection against measles, such as vaccine, immuoglobulin
Laboratory findings Cytopathic change Warthin-Finkeldey cells: consist of multinucleated giant cells with intranuclear inclusions Antigen: in nasal mucosa PCR Virus isolation Antibodies IgM and IgG become detectable when the rash appears Leucocytopenia with a relative lymphocytosis
Chest radiograph May show interstitial or perihilar infiltrates, but do not distinguish measles pneumonia and bacterial superinfection.
Diagnosis Contact history Characteristic clinical picture Laboratory confirmation is rarely needed
Differential diagnosis All kind of fever with red rashes Such as: Rubella, roseola, scarlet fever, meningococcemia, drug fever, Kawasaki disease, serum sickness, infectious mononucleosis, toxoplasmosis, etc
Differential diagnosis Enteroviral and adenoviral infections, rubella: The rashes are less striking without desquamation Roseola infantum: the rash appears as fever disappears Serum illness and drug fever: The absence of administration of a drug history
Red rash in bacterium infection Acute meningococcemia The rash is petechial, and purpuric without cough and conjunctivitis Streptococcal scarlet fever The diffuse, finely papular rash has a “goose flesh” texture, “sandpaper” texture, strawberry tongue, red pharynx. Perioral and periorbital area, palm, and soles have no rash. Rash desquamates after 7-14d Staphylococcal scarlet fever Resembles streptococcal scarlet fever Except strawberry tongue, pharynx, and focal infection usually presents
Treatment No specific antiviral therapy Supportive treatment: antipyratic, bed rest, fluid intake, avoiding exposure to strong lights Vitamin A: 7-12m infant: 100,000IU, ≥1y: 200,000IU, reduce the morbidity and mortality Complications such as encephalitis, giant cell pneumonia, DIC must be assessed individually Secondary infection requires antimicrobial therapy Immune globulin and corticosteroids has limited value
Complication Pneumonia Interstitial pneumonia: may be caused by measles virus (giant cell pneumonia), measles pneumonia in HIV-infected patients is often fatal. However, bacterial superinfection and bronchopneumonia is more frequent Reactivation of TB infection, and anergy to PPD Myocarditis An infrequent serious complication, varies from transient ECG changes to heart failure, and cardiogenic shock.
Complication in nervous system Eary encephalitis 1-2/1000 cases, occur from prodromal period to final stage Late encephalitis Demyelinization, probably an immunopathologic phenomenon. Subacute sclerosing panencephalitis (SSPE) A chronic encephalitis caused by persistant measles virus infection of the central nervous system, occur 8-10yr after measles Insidiously onset, subtle changes in behavior, and deterioration of schoolwork, and finally dementia. 1/1,000,000 measle
Prognosis Deaths: bronchopneumonia or encephalitis(15%), with malignancy or HIV infection SSPE
Prevent Attenuate live measle vaccine Two times(8m, 4-6yr), not booster, but intensive immunization Contraindications: Immunocompromised states, pregnancy or recent administration of IVIg
Postexposure prophylaxis Vaccine within 72 hr (produce antibody within 7-12d) Immune globulin within 6d
Typical temperature curve of measles and the effectiveness of passive immunization
Take home points Koplik spots Feature of measles maculopapular rash Differential diagnosis of red rash Complications Post exposure prophylaxis
Quiz 1. The contagious period of measles is ( ) A. 5 days before and after the rash appearance, accompanied with pneumonia, prolonging to 15th day. B. 7 days before and after the rash appearance, accompanied with pneumonia, prolonging to 14th day. C. 5 days before and after the rash appearance, accompanied with pneumonia, prolonging to 10th day. D. 6 days before and after the rash appearance, accompanied with pneumonia, prolonging to 12th day. E. 3 days before and after the rash appearance, accompanied with pneumonia, prolonging to 6th day.
2. About measles virus, which one is wrong ( ) A. A DNA virus of the genus morbillivirus in the family paramyxoviridae. B. Only one antigenic type. C. Found in nasopharyngeal secretions, blood and urine, from 1 to 2 days before symptoms (about 5 days before onset of rash) to 4 days after the appearance of the rash. D. Infection sources: patients and person with latent infection. E. Remain active for at least 34 hours at room temperature.
① Incubation stage: 6-12d, may transmit virus by 9-10th day, slight fever; ② Prodromal stage: 3-5d, fever, cough, coryza, conjunctiva, Koplik spots; ③ Rash stage: the rash appears downward in sequencerash for 2-3d, high fever; ④ Recovery stage: the rash fades downward in sequencerash, it undergoes brownish discoloration and desquamation. 3.Please describe the features of each stage of typical clinical manifestations of measles.