smallpox & alastrim
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Etiology
- viral infection with Variola major (smallpox) & Variola minor (alastrim)
Epidemiology
- last case of endemic smallpox in 1977 (Somalia)
- last case of smallpox reported in U.S. in 1949
- World Health Organization has declared smallpox has been eliminated world-wide as a result of global vaccination & eradication program
- humans are the sole reservoir for infection
- no carrier state
- only 2 known remaining respositories worldwide, USA & Russia
- relatively non-contagious disease, requiring close contact for several hours for transmission
- infection spread through aerosolized droplets
- immunity from vaccination prior to 1972 is 'iffy' at best
- consider smallpox through occupational exposure to an act of bioterrorism as a likely diagnosis if clinical manifestations are consistent with smallpox[4]
- absence of any case reports
Clinical manifestations
- incubation period of 7-17 days, average 12 days
- initial presentation of fever (> 38.3 C, 101.3 F) prior to rash onset
- fatigue, headache, vomiting, back pain, abdominal pain
- macular rash beginning 2-3 days after onset of fever, with progression to vesicular & pustular lesions over 1-2 weeks
- lesions may become umbilicated or confluent
- rash begins on buccal & pharyngeal mucosa, face, proximal arms & legs, then spreads to chest & distal extremities
- rash is in the same stage in all locations at any one time, i.e. all papules -> all vesicles -> all pustules -> all scabs[4]
- each stage lasts 1-2 days
- lesions scab in about 2 weeks
- may leave permanent scarring
- patient become infectious with onset of rash
- conjunctivitis[4]
- alstrim is a clinically milder form of smallpox
* images[8]
Laboratory
Differential diagnosis
- chickenpox: rash is in different stages at different locations i.e. a mix of vesicles papules, pustules & scabs
Management
- patient isolation
- notify health department
- airbone precautions
- mass public vaccination if epidemic[4]
- tecovirimat FDA-approved July 2018[9][10]
- cidofovir may be helpful
- prognosis:
- smallpox mortality 20-50%
- mortality of alastrim is 1%
- prevention:
- vaccinia vaccine (live virus vaccine)
- smallpox antiviral Arestvyr effective even if given 3 days after exposure
Notes
- potential agent of bioterrorism[6]
More general terms
Additional terms
- chickenpox
- smallpox vaccine; vaccinia vaccine (Dryvax, Arestvyr, Jynneos, Ankara-Bavarian Nordic vaccine, MVA-BN vaccine)
- Variola major (smallpox virus)
References
- ↑ Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 1095
- ↑ Prescriber's Letter 9(12):72 2002
- ↑ 3.0 3.1 Internal Medicine News, Jyly 2005, pg 63
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 Medical Knowledge Self Assessment Program (MKSAP) 14, 15, 16, 17, 18, 19. American College of Physicians, Philadelphia 2006, 2009, 2012, 2015, 2018, 2021.
- ↑ Physician's First Watch, March 14, 2013 David G. Fairchild, MD, MPH, Editor-in-Chief Massachusetts Medical Society http://www.jwatch.org
McNeil DG Wary of Attack With Smallpox, U.S. Buys Up a Costly Drug http://www.nytimes.com/2013/03/13/health/us-stockpiles-smallpox-drug-in-case-of-bioterror-attack.html - ↑ 6.0 6.1 Guharoy R, Panzik R, Noviasky JA, Krenzelok EP, Blair DC. Smallpox: clinical features, prevention, and management. Ann Pharmacother. 2004 Mar;38(3):440-7. Epub 2004 Jan 30 PMID: https://www.ncbi.nlm.nih.gov/pubmed/14755066
- ↑ Breman JG, Henderson DA. Diagnosis and management of smallpox. N Engl J Med. 2002 Apr 25;346(17):1300-8. PMID: https://www.ncbi.nlm.nih.gov/pubmed/11923491
- ↑ 8.0 8.1 Brady MP (images) Cutaneous and Mucosal Manifestations of Viral Diseases. Medscape. March 2017 http://reference.medscape.com/features/slideshow/viral-skin
- ↑ 9.0 9.1 Grosenbach DW, Honeychurch K, Rose EA Oral Tecovirimat for the Treatment of Smallpox. N Engl J Med 2018; 379:44-53. July 5, 2018 PMID: https://www.ncbi.nlm.nih.gov/pubmed/29972742 https://www.nejm.org/doi/full/10.1056/NEJMoa1705688
- ↑ 10.0 10.1 FDA News Release. July 13, 2018 FDA approves the first drug with an indication for treatment of smallpox. https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm613496.htm
- ↑ Petersen BW, Damon IK, Pertowski CA et al Clinical guidance for smallpox vaccine use in a postevent vaccination program. MMWR Recomm Rep. 2015 Feb 20;64(RR-02):1-26. PMID: https://www.ncbi.nlm.nih.gov/pubmed/25695372 Free Article
- ↑ National Institute of Allergy and Infectious Diseases (NIAID) Smallpox https://www.niaid.nih.gov/diseases-conditions/smallpo