Mumps virus: Difference between revisions
From IDWiki
m (Text replacement - "Clinical Presentation" to "Clinical Manifestations") |
No edit summary |
||
Line 1: | Line 1: | ||
+ | == Background == |
||
− | * Presents with a prodrome followed by parotitis |
||
+ | *Presents with a prodrome followed by parotitis |
||
− | == Microbiology == |
||
+ | ===Microbiology=== |
||
− | * Enveloped single-stranded RNA virus in the genus ''Rubulavirus'' and family Paramyxovirus |
||
− | * Only one serotype but 13 genotypes (A to M) |
||
− | * Genome encodes eight proteins: hemagglutinin-neuraminidase (HN), fusion (F), nucleocapsid (NP), phosphoprotein (P), matrix (M), hydrophobic (SH) and L protein |
||
− | ** P contains V and I proteins |
||
− | * Irregular spherical shape with nucleocapsid enclosed by a three-layered envelope |
||
− | ** Surface studded with glycoproteins: HN and F, which are the most important for immunity |
||
− | ** Middle layer is lipid bilayer from the host cell |
||
− | ** Inner layer in membrane protein |
||
+ | *Enveloped single-stranded RNA virus in the genus ''Rubulavirus'' and family Paramyxovirus |
||
− | == Epidemiology == |
||
+ | *Only one serotype but 13 genotypes (A to M) |
||
+ | *Genome encodes eight proteins: hemagglutinin-neuraminidase (HN), fusion (F), nucleocapsid (NP), phosphoprotein (P), matrix (M), hydrophobic (SH) and L protein |
||
+ | **P contains V and I proteins |
||
+ | *Irregular spherical shape with nucleocapsid enclosed by a three-layered envelope |
||
+ | **Surface studded with glycoproteins: HN and F, which are the most important for immunity |
||
+ | **Middle layer is lipid bilayer from the host cell |
||
+ | **Inner layer in membrane protein |
||
+ | ===Epidemiology=== |
||
− | * Worldwide distribution |
||
− | * Epidemics every 2 to 5 years in unimmunized settings, with a peak between January and May |
||
− | * Spread primarily by schoolchildren |
||
− | * Outbreaks have happened amongst immunized people, suggesting that a third dose of MMR may be needed to confer ongoing immunity |
||
− | * Before vaccination, it was the leading cause of viral encephalitis and a common cause of viral meningitis |
||
+ | *Worldwide distribution |
||
− | == Pathophysiology == |
||
+ | *Epidemics every 2 to 5 years in unimmunized settings, with a peak between January and May |
||
+ | *Spread primarily by schoolchildren |
||
+ | *Outbreaks have happened amongst immunized people, suggesting that a third dose of MMR may be needed to confer ongoing immunity |
||
+ | *Before vaccination, it was the leading cause of viral encephalitis and a common cause of viral meningitis |
||
+ | ===Pathophysiology=== |
||
− | * Acquired through virus (contact, droplet, fomites) entering nose or mouth, with tropism for endo/exocrine glands |
||
− | ** Salivary, pancreatis, testicular |
||
− | * Less infectious that measles or varicella |
||
− | * Peak contagion is just before parotitis |
||
− | * Immune response begins with antibodies against NP protein (S antigen), and may be detectable at presentation, but decline quickly over months |
||
− | * Antibodies against HN protein (V antigen) follow, peaking at 2 to 4 weeks and persist for years |
||
− | ** IgM antibodies fall within 2 to 6 months |
||
− | * Neutralizing antibodies to HN and F are detectable during convalescence |
||
+ | *Acquired through virus (contact, droplet, fomites) entering nose or mouth, with tropism for endo/exocrine glands |
||
− | == Differential Diagnosis == |
||
+ | **Salivary, pancreatis, testicular |
||
+ | *Less infectious that measles or varicella |
||
+ | *Peak contagion is just before parotitis |
||
+ | *Immune response begins with antibodies against NP protein (S antigen), and may be detectable at presentation, but decline quickly over months |
||
+ | *Antibodies against HN protein (V antigen) follow, peaking at 2 to 4 weeks and persist for years |
||
+ | **IgM antibodies fall within 2 to 6 months |
||
+ | *Neutralizing antibodies to HN and F are detectable during convalescence |
||
+ | ==Clinical Manifestations== |
||
− | * Infectious parotitis |
||
− | ** Parainfluenza 3 virus, coxsackieviruses, and influenza A |
||
− | ** HIV infection (bilateral, parotid) |
||
− | ** Staph. aureus or GNBs |
||
− | * Drugs (bilateral, mild) |
||
− | * Metabolic disorders, including diabetes, malnutrition, cirrhosis, and CKD (bilateral, mild) |
||
− | * Tumours, cysts, sialolithiasis, and stricture (unilateral) |
||
− | * Eosinophilic parotitis, often as a drug reaction |
||
+ | *Incubation period of [[Usual incubation period::16 to 18 days]] (range [[Incubation period range::2 to 4 weeks]]) |
||
− | == Clinical Manifestations == |
||
+ | *One-day prodrome of low-grade fever, anorexia, malaise, and headache |
||
+ | *Earache and parotitis soon follow |
||
+ | **Parotitis progresses over 2 to 3 days, with severe pain |
||
+ | **The other parotid usually follows, but it can be unilateral |
||
+ | **Stensen's duct is edematous and erythematous |
||
+ | **Pain exacerbated by citrus |
||
+ | **Can involve other salivary glands in 10% |
||
+ | *Temperature can be as high as 40º C |
||
+ | *Pain, fever, tenderness resolve, with parotid returning to normal within 1 week |
||
+ | *Can lead to sialectasia resulting in recurrent or chronic sialadenitis |
||
+ | ===Mumps epididymo-orchitis=== |
||
− | * Incubation period of 16 to 18 days (range 2 to 4 weeks) |
||
− | * One-day prodrome of low-grade fever, anorexia, malaise, and headache |
||
− | * Earache and parotitis soon follow |
||
− | ** Parotitis progresses over 2 to 3 days, with severe pain |
||
− | ** The other parotid usually follows, but it can be unilateral |
||
− | ** Stensen's duct is edematous and erythematous |
||
− | ** Pain exacerbated by citrus |
||
− | ** Can involve other salivary glands in 10% |
||
− | * Temperature can be as high as 40º C |
||
− | * Pain, fever, tenderness resolve, with parotid returning to normal within 1 week |
||
− | * Can lead to sialectasia resulting in recurrent or chronic sialadenitis |
||
+ | *The most common extrasalivary gland manifestation, occuring in 20-30% of postpubertal men (bilateral in 15%) |
||
− | === Mumps epididymo-orchitis === |
||
+ | *Occurs in first 1-2 weeks after parotitis |
||
+ | *Fevers up to 41º C, chills, headache, vomiting, and testicular pain |
||
+ | *Swollen warm testicles with scrotal erythema |
||
+ | *Fever resolves within 5 days, followed by slower resolution of the orchitis |
||
+ | **Tenderness can sometimes last longer than 2 weeks |
||
+ | *Longterm testicular atrophy in 50% |
||
+ | **If unilateral, no concerns |
||
+ | **If bilateral, sterility is rare, and impotence is not a sequela |
||
+ | ===Mumps oopheritis=== |
||
− | * The most common extrasalivary gland manifestation, occuring in 20-30% of postpubertal men (bilateral in 15%) |
||
− | * Occurs in first 1-2 weeks after parotitis |
||
− | * Fevers up to 41º C, chills, headache, vomiting, and testicular pain |
||
− | * Swollen warm testicles with scrotal erythema |
||
− | * Fever resolves within 5 days, followed by slower resolution of the orchitis |
||
− | ** Tenderness can sometimes last longer than 2 weeks |
||
− | * Longterm testicular atrophy in 50% |
||
− | ** If unilateral, no concerns |
||
− | ** If bilateral, sterility is rare, and impotence is not a sequela |
||
+ | *In 5% of cases in postpubertal women |
||
− | === Mumps oopheritis === |
||
+ | *May cause impaired fertility |
||
+ | ===Mumps meningitis=== |
||
− | * In 5% of cases in postpubertal women |
||
− | * May cause impaired fertility |
||
+ | *Fever, headache, vomiting, and nuchal rigidity, with an aseptic CSF (lymphocyte-predominant more often than neutrophil-predominant) |
||
− | === Mumps meningitis === |
||
+ | **Amylase may be elevated |
||
+ | *Onset usually after parotitis, but can be 1 week before or up to 2 weeks after |
||
+ | *Can also occur without parotitis |
||
+ | *Lasts 3 to 10 days, with complete recovery |
||
+ | ===Mumps encephalitis=== |
||
− | * Fever, headache, vomiting, and nuchal rigidity, with an aseptic CSF (lymphocyte-predominant more often than neutrophil-predominant) |
||
− | ** Amylase may be elevated |
||
− | * Onset usually after parotitis, but can be 1 week before or up to 2 weeks after |
||
− | * Can also occur without parotitis |
||
− | * Lasts 3 to 10 days, with complete recovery |
||
+ | *Non-focal encephalitis, high fever, altered LOC, seizures, paresis, aphasia, and involuntary movements, with an aseptic CSF |
||
− | === Mumps encephalitis === |
||
+ | **Fever can be up to 41º C |
||
+ | *Can occur concurrent with or up to 10 days after onset of parotitis |
||
+ | *Early-onset is from virus; late-onset is a postinfectious autoimmune demyelinating disease; but there is likely a continuum between these two extremes |
||
+ | *Gradually resolves over 1 to 2 weeks |
||
+ | *Can cause sequelae, including psychomotor retardation, seizures, and death |
||
+ | ===Other complications=== |
||
− | * Non-focal encephalitis, high fever, altered LOC, seizures, paresis, aphasia, and involuntary movements, with an aseptic CSF |
||
− | ** Fever can be up to 41º C |
||
− | * Can occur concurrent with or up to 10 days after onset of parotitis |
||
− | * Early-onset is from virus; late-onset is a postinfectious autoimmune demyelinating disease; but there is likely a continuum between these two extremes |
||
− | * Gradually resolves over 1 to 2 weeks |
||
− | * Can cause sequelae, including psychomotor retardation, seizures, and death |
||
+ | *Cerebellar ataxia, facial palsy, transverse myelitis, Guillain-Barré syndrome, and poliomyelitis-lik syndrome |
||
− | === Other complications === |
||
+ | *Migratory polyarthritis, usually starting 10-14 days after parotitis and lasting up to 5 weeks |
||
+ | *Pancreatitis |
||
+ | *ECG changes with ST depression and T-wave changes, 1st degree heart block |
||
+ | **Myocarditis is rare |
||
+ | ===Pregnancy=== |
||
− | * Cerebellar ataxia, facial palsy, transverse myelitis, Guillain-Barré syndrome, and poliomyelitis-lik syndrome |
||
− | * Migratory polyarthritis, usually starting 10-14 days after parotitis and lasting up to 5 weeks |
||
− | * Pancreatitis |
||
− | * ECG changes with ST depression and T-wave changes, 1st degree heart block |
||
− | ** Myocarditis is rare |
||
+ | *Pregnant women who are infected have increased risk of spontaneous abortion in the first trimester, as well as low birth weight |
||
− | === Pregnancy === |
||
+ | *Not clearly related to any significant birth defects |
||
+ | |||
+ | == Differential Diagnosis == |
||
+ | *Infectious [[parotitis]] |
||
− | * Pregnant women who are infected have increased risk of spontaneous abortion in the first trimester, as well as low birth weight |
||
+ | **[[Parainfluenza]] 3 virus, [[coxsackievirus]], and [[Influenza virus|influenza A]] |
||
− | * Not clearly related to any significant birth defects |
||
+ | **[[HIV]] infection (bilateral, parotid) |
||
+ | **[[Staphylococcus aureus]] or [[Gram-negative bacilli]] |
||
+ | *Drugs (bilateral, mild) |
||
+ | *Metabolic disorders, including [[diabetes]], [[malnutrition]], [[cirrhosis]], and [[CKD]] (bilateral, mild) |
||
+ | *Tumours, cysts, [[sialolithiasis]], and stricture (unilateral) |
||
+ | *[[Eosinophilic parotitis]], often as a drug reaction |
||
− | == |
+ | ==Diagnosis== |
− | * |
+ | *Traditionally a clinical diagnosis |
− | * |
+ | *CBC and diff are normal or mild leukopenia; amylase may be up from parotitis, or lipase from pancreatitis |
− | * |
+ | *Can be diagnosed with serology or PCR |
− | * |
+ | *ELISA for IgM, or a fourfold rise from acute to convalescent ELISA or HAI serologies, are diagnostic |
− | ** |
+ | **HAI may be affected by parainfluenza |
− | * |
+ | *PCR or culture detectable in saliva, though relatively low level after 5 days; also found in CSF |
− | ** |
+ | **Can be detected in urine up to 2 weeks after onset |
− | == |
+ | ==Management== |
− | * |
+ | *Symptomatic |
− | * |
+ | *Immune globulin not helpful |
− | * |
+ | *Post-exposure immunization may not be helpful, though in an outbreak situation, may consider giving an MMR booster |
− | * |
+ | *Isolation for 5 days after onset of parotitis to reduce spread |
− | * |
+ | *Reportable disease, public health may do outbreak investigation and consider booster MMR in high-risk populations |
− | == |
+ | ==Prevention== |
− | * |
+ | *Live attenuated vaccine in the MMR is given at 12-15 months and again at 4-6 years |
− | * |
+ | *Vaccine 65-70% effective, so need high vaccination rate to achieve herd immunity |
− | * |
+ | *Titres positive for at least 10 years, but immunity wanes |
− | * |
+ | *Contraindicated in pregnant women |
[[Category:Paramyxoviridae]] |
[[Category:Paramyxoviridae]] |
Latest revision as of 10:05, 5 August 2020
Background
- Presents with a prodrome followed by parotitis
Microbiology
- Enveloped single-stranded RNA virus in the genus Rubulavirus and family Paramyxovirus
- Only one serotype but 13 genotypes (A to M)
- Genome encodes eight proteins: hemagglutinin-neuraminidase (HN), fusion (F), nucleocapsid (NP), phosphoprotein (P), matrix (M), hydrophobic (SH) and L protein
- P contains V and I proteins
- Irregular spherical shape with nucleocapsid enclosed by a three-layered envelope
- Surface studded with glycoproteins: HN and F, which are the most important for immunity
- Middle layer is lipid bilayer from the host cell
- Inner layer in membrane protein
Epidemiology
- Worldwide distribution
- Epidemics every 2 to 5 years in unimmunized settings, with a peak between January and May
- Spread primarily by schoolchildren
- Outbreaks have happened amongst immunized people, suggesting that a third dose of MMR may be needed to confer ongoing immunity
- Before vaccination, it was the leading cause of viral encephalitis and a common cause of viral meningitis
Pathophysiology
- Acquired through virus (contact, droplet, fomites) entering nose or mouth, with tropism for endo/exocrine glands
- Salivary, pancreatis, testicular
- Less infectious that measles or varicella
- Peak contagion is just before parotitis
- Immune response begins with antibodies against NP protein (S antigen), and may be detectable at presentation, but decline quickly over months
- Antibodies against HN protein (V antigen) follow, peaking at 2 to 4 weeks and persist for years
- IgM antibodies fall within 2 to 6 months
- Neutralizing antibodies to HN and F are detectable during convalescence
Clinical Manifestations
- Incubation period of 16 to 18 days (range 2 to 4 weeks)
- One-day prodrome of low-grade fever, anorexia, malaise, and headache
- Earache and parotitis soon follow
- Parotitis progresses over 2 to 3 days, with severe pain
- The other parotid usually follows, but it can be unilateral
- Stensen's duct is edematous and erythematous
- Pain exacerbated by citrus
- Can involve other salivary glands in 10%
- Temperature can be as high as 40º C
- Pain, fever, tenderness resolve, with parotid returning to normal within 1 week
- Can lead to sialectasia resulting in recurrent or chronic sialadenitis
Mumps epididymo-orchitis
- The most common extrasalivary gland manifestation, occuring in 20-30% of postpubertal men (bilateral in 15%)
- Occurs in first 1-2 weeks after parotitis
- Fevers up to 41º C, chills, headache, vomiting, and testicular pain
- Swollen warm testicles with scrotal erythema
- Fever resolves within 5 days, followed by slower resolution of the orchitis
- Tenderness can sometimes last longer than 2 weeks
- Longterm testicular atrophy in 50%
- If unilateral, no concerns
- If bilateral, sterility is rare, and impotence is not a sequela
Mumps oopheritis
- In 5% of cases in postpubertal women
- May cause impaired fertility
Mumps meningitis
- Fever, headache, vomiting, and nuchal rigidity, with an aseptic CSF (lymphocyte-predominant more often than neutrophil-predominant)
- Amylase may be elevated
- Onset usually after parotitis, but can be 1 week before or up to 2 weeks after
- Can also occur without parotitis
- Lasts 3 to 10 days, with complete recovery
Mumps encephalitis
- Non-focal encephalitis, high fever, altered LOC, seizures, paresis, aphasia, and involuntary movements, with an aseptic CSF
- Fever can be up to 41º C
- Can occur concurrent with or up to 10 days after onset of parotitis
- Early-onset is from virus; late-onset is a postinfectious autoimmune demyelinating disease; but there is likely a continuum between these two extremes
- Gradually resolves over 1 to 2 weeks
- Can cause sequelae, including psychomotor retardation, seizures, and death
Other complications
- Cerebellar ataxia, facial palsy, transverse myelitis, Guillain-Barré syndrome, and poliomyelitis-lik syndrome
- Migratory polyarthritis, usually starting 10-14 days after parotitis and lasting up to 5 weeks
- Pancreatitis
- ECG changes with ST depression and T-wave changes, 1st degree heart block
- Myocarditis is rare
Pregnancy
- Pregnant women who are infected have increased risk of spontaneous abortion in the first trimester, as well as low birth weight
- Not clearly related to any significant birth defects
Differential Diagnosis
- Infectious parotitis
- Parainfluenza 3 virus, coxsackievirus, and influenza A
- HIV infection (bilateral, parotid)
- Staphylococcus aureus or Gram-negative bacilli
- Drugs (bilateral, mild)
- Metabolic disorders, including diabetes, malnutrition, cirrhosis, and CKD (bilateral, mild)
- Tumours, cysts, sialolithiasis, and stricture (unilateral)
- Eosinophilic parotitis, often as a drug reaction
Diagnosis
- Traditionally a clinical diagnosis
- CBC and diff are normal or mild leukopenia; amylase may be up from parotitis, or lipase from pancreatitis
- Can be diagnosed with serology or PCR
- ELISA for IgM, or a fourfold rise from acute to convalescent ELISA or HAI serologies, are diagnostic
- HAI may be affected by parainfluenza
- PCR or culture detectable in saliva, though relatively low level after 5 days; also found in CSF
- Can be detected in urine up to 2 weeks after onset
Management
- Symptomatic
- Immune globulin not helpful
- Post-exposure immunization may not be helpful, though in an outbreak situation, may consider giving an MMR booster
- Isolation for 5 days after onset of parotitis to reduce spread
- Reportable disease, public health may do outbreak investigation and consider booster MMR in high-risk populations
Prevention
- Live attenuated vaccine in the MMR is given at 12-15 months and again at 4-6 years
- Vaccine 65-70% effective, so need high vaccination rate to achieve herd immunity
- Titres positive for at least 10 years, but immunity wanes
- Contraindicated in pregnant women