HSV1: 85% of world considered to be seropositive. HSV1: trigeminal ganglia; HSV2: sacral ganglia. HSV1 tx: penciclovir 1% cream 2g, apply every 2 hours for 4 days. Or acyclovir 400mg TID x 5 days.
Spread by either mucosal contact with ulcerative lesion or by those shedding virus without overt disease. Primary infection usually more extensive lesions with some systemic signs/symptoms. HSV1 initially can be gingiostomatitis/pharyngitis, then recurrence usually herpes labialis. Can also be cause of Bells palsy, herpetic keratitis. Can also cause genital lesions, though primarily HSV2. Recurrence can occur due to exposure to sunlight, fever, menstruation, emotional stress.
Herpetic whitlow is HSV infection of the finger (HSV1 or 2) – left untreated, improves in 2-3 weeks. Herpes Gladiatorum are nongenital skin infection that appear identical to HSV. 20-40% of NCAA wrestlers have occurence of it. Transmission skin to skin; usually in areas of contact during wrestling: face, head, neck, ears, upper extremities. Tx: valacyclovir 1g PO BID x 7.
HSV encephalitis: most common virus is HSV1. Left untreated can be 70% mortality. Usually acute onset of fever and neurologic symptoms (stroke-like, CN abnormalities, focal seizures, ataxia, AMS). MRI (w/ DW very sensitive)/CT showed temporal lobe involvement – can get hypomania initially or KBS (Kluver-Bucy syndrome: loss of anger/fear responses, hypersexual). CSF: lymphatic pleocytosis, PCR very sensitive for HSV – remains positive > 1 week.
Immunocompromised (chemo, organ transplant, HIV, burns): can have widespread dissemination (esophagitis, hepatitis, colitis, pneumonia).
Culture: fluid from unroofed vesicle. PCR preferred. Tzanck test not useful anymore.
Tx: Encephalitis or Disseminated: IV acyclovir (usually for 3-4 weeks). Poor outcome if treated late so start early. Simple HSV1/2: Acyclovir, valacyclovir (higher bioavailability, fewer doses), famciclovir (fewer doses) x 7-10 days. Recurrent herpes labials does not require tx, though if severe/frequent, can do daily suppressive tx. Subclinical shedding common.
Varicella and Herpes Zoster
Higher incidence in winter/spring. Herpes zoster occurs in 10-20% of population with prior VZV infection. Varicella vaccine has virtually eliminated chickenpox in children. VZV originally spread by respiratory secretions. Herpes zoster can be spread with direct contact with vesicle fluid, though not as contagious as chickenpox. Contagious until lesions have crusted over.
Varicella usually febrile illness with vesicular rash. Lesions are at varying stages including papules, vesicles, crusted lesions. Immunized patients can occasionally develop mild chickenpox. Bacterial superinfection with GAS can occur. Usually only lasts 1-2 weeks. Pneumonitis can occur, more common in pregnant women. Tx: usually supportive, though acyclovir decreases number of lesions and shortens course if started within 24 hrs of rash, though impact modest. Varicella less sensitive than herpesvirus and usually requires higher/longer treatment. Famciclovir and Valacyclovir don’t approved for varicella.
Zoster (Shingles) begins as malaise, headache, and photophobia. Initially have pain/itching/paresthesia which then develop into maculopapular rash in dermatome distribution. Does not cross midline. Can get herpes zoster ophthalmicus (optic branch of trigeminal nerve) which can lead to blindness; tx: valacyclovir and be evaluated by opthalmologist. Postherpetic neuralgia (pain > 30 days) can be a complication. Tx: Start antivirals within 72 hrs of onset of rash and consider tx > 72 hrs if new vesicles still present or developing. Disseminated should get IV acyclovir. Steroids don’t help prevent post neuralgia or outcome (NEJM, 1994). Recommend tx with immunocompromised, eye involvement, disseminated. Valacylovir better bioavaliability, less frequent dosing. 1000mg PO TID x 7-14 days. Famciclovir can be 500mg TID as well.
Herpes Zoster Opthalmicus: ophthalmic branch (v1) of trigeminal nerve (supraorbital, lacrimal, nasociliary). Hutchinson’s sign (1/3 of pts): tip of nose involved – 2x more likely to have keratitis (dendrite on fluorecein). If dendrites seen, needs urgent optho evaluation. Tx with acyclovir, famciclovir, or valacyclovir. Get optho consult. Can tx with oral if immunocompetent (Gnann, 2002).
Ramsey Hunt Syndrome (Herpes Zoster Oticus): unilateral facial paralysis, herpetiform rash, hearing loss/dizziness. Can see rash in ear drum and decreased taste, though usually around auricle. Facial nerve involved. Can go as far down as the shoulder. Severe pain and outcomes worse than Bells palsy. Tx: antiviral x 7-10 days w/ steroid taper prednisone 60mg over 3 weeks. (5 minute video on Ramsey Hunt Syndrome)
Post-herpetic Neuralgia: Can try TCAs for pain relief: Amitriptyline 10-25mg PO daily. Gabapentin: Day 1: 300mg, Day 2: 300mg BID, Day 3: 300mg TID; dose may be titrated as needed for pain relief (range 1800-3600mg/day, though doses > 1800 do not show much more benefit).
Smallpox: always board bioterrorism question – lesions larger, distributed more on extremities, lesions in same stage of development.
Infectious mononucleosis, EBV associated with B-cell lymphoma, Hodgkin disease, Burkitt lymphoma, and nasopharyngeal carcinoma.
Transmitted via salivary secretions. Two age peaks: early childhood and early adulthood. Fever (can persist for > 7days), lymphadenopathy (more posterior than anterior), pharyngitis. Tonsillar exudates common, sometimes necrotic. Splenomegaly in > 1/2 of patients. Resolve over 2-3 weeks. Severe fatigue can be prominent for several months. If mistaken for strep and tx with amoxicllin/ampicillin, will develop morbilliform rash. Rare causes of other organ involvement: encephalitis, meningitis, GBS, hepatitis, myocarditis. In young children, more prolonged fever and adenopathy, less likely to have pharyngitis. Can get mild anemia. Also get mildly elevated LFTs.
Monospot: identifies heterophile antibodies. Poor sensitivity in the first week, better sensitivity in older children/adults. High sensitivity/specificity. Recommend avoiding all contact sports for minimum 4 weeks to avoid splenic injury (rupture 1:1000, usually in first 3 weeks). Consider giving steroids 40mg PO x 5 days, though Cochrane review showed no benefit. Can be contagious for several months (even years) after infection. Serology testing available, though rare to use in the ED. Can also diagnose with > 10% atypical lymphocytes on CBC.
Similar to herpesviruses that it causes primary infection and then goes into latent state. Transmitted by sex, saliva, breastfeeding, transplant, transplacent, blood transfusion. Fetal CMV infection risk highest in first trimester – is a teratogen. Transplant patients can get infected usually in the first and fourth months post-transplant.
Primary infection presents usually either asymptomatic or mild infectious mononucleosis syndrome. No exudative pharyngitis though. Histologic culture: large cell containing basophilic intrnuclear ‘owl’s eyes.’ Can get mildly elevated LFTs. Can also diagnose with > 10% atypical lymphocytes on CBC.
HIV patients (CD4 < 50): retinitis is the most common manifestation of CMV. Also can get encephalopathy, colitis, peripheral polyradiculopathy.
Tx: Bone Marrow Transplant (pneumonia, GI, graft-vs-host): IV ganciclovir + IVIG; AIDS patient (retinitis, GI, neurologic): IV ganciclovir, valganciclovir; Organ Transplant (pneumonia, GI, infection of transplanted organ, nonspecific febrile illness): IV ganciclovir.
For the immunocompetent patient, supportive care only.
Caused by mosquito, tick, flies bite. Typically seasonal. Major hosts are mammals/birds. Immune system usually creates IgM and kills virus. If unable to, get hemorrhagic fever or encephalitis.
4 syndromes: fever and myalgias, arthritis and rash, encephalitis (fever, headache, AMS), and hemorrhagic fever (gums, petechiae, and GI bleeding). Can overlap as well.
Japanese encephalitis: one of the most common viral encephalitis in the world; prominent in Asia, usually affects children. Adults have been exposed/immune.
West Nile Virus encephalitis: US/Canada/Mexico; usually elderly. 38% in Texas. 80% are asymptomatic. Only 1/150 who are bit develop symptoms. No human transmission. Caused by asian tiger mosquito (also vector for dengue and chikungunya, day feeders). Main vector birds (american crow and bluebird – leave the dead birds alone). Only need 30% DEET for any mosquito repellant. Usually present with fever/headache/myalgias. Can get low WBC, low platelets. WNV RNA PCR has cross reactivity, lots of early negatives as well. Also can get poliomyelitis (spinal cord involvement).
Hemorrhagic fever: usually caused by Dengue, yellow fever (Africa/South America), Rift Valley fever, or chikungunya. Aedes aerqupti is the mosquito vector for yellow fever.
St. Louis encephalitis: US/Canada/Mexico; elderly at risk
CSF showed lymphatic pleocytosis, elevated protein. Serologic testing for IgM antibodies preferred, can be false negative early in course. Usually review titers over time. Supportive care is the treatment.
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