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complement deficiency

Etiology: 1) C3 deficiency a) congenital liver disease b) systemic lupus erythematosus 3) C5 deficiency: congenital 4) C6, C7, C8 deficiency a) congenital b) systemic lupus erythematosus 5) deficiencies in alternate pathway - sickle cell disease Pathology: 1) C3 deficiency pathogens a) Staphylococcus aureus b) Streptococcus pneumonia c) Pseudomonas species d) Proteus species 2) C5 deficiency pathogens a) Neisseria species b) gram-negative rods 3) C6, C7, C8 deficiency pathogens a) Neisseria gonorrhoeae b) Neisseria meningitidis 4) deficiencies in alternate pathway pathogens a) Streptococcus pneumonia b) Salmonella species c) Neisseria [1] Clinical manifestations: - recurrent sepsis with encapsulated bacteria with early complement component deficiency - recurrent gonorrhea or meningococcal infection with terminal complement component deficiency [1] Laboratory: - CH50 is screening test* - if CH50 is low, follow-up with measurement of individual complement components [3] - see ARUP consult [4] * all patients with recurrent episodes of gonorrhea or meningococcal infection [1] Management: - patients respond to standard antibiotics [1] - see asplenism - vaccination is the most effective way of preventing infections [1] - meningococcal vaccination for C6, C7, C8 complement deficiency

Related

complement cascade

General

humoral immune dysfunction

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 14, 15, 16, 17, 18, 19. American College of Physicians, Philadelphia 2006, 2009, 2012, 2015, 2018, 2021. - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  2. Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 49
  3. Complement Levels Lab Tests Online: complement_levels
  4. ARUP Consult: Complement Deficiency The Physician's Guide to Laboratory Test Selection & Interpretation https://www.arupconsult.com/content/complement-deficiency - ARUP Consult: Complement Deficiency Testing Algorithm https://arupconsult.com/algorithm/complement-deficiency-testing-algorithm
  5. Ram S, Lewis LA, Rice PA. Infections of people with complement deficiencies and patients who have undergone splenectomy. Clin Microbiol Rev. 2010 Oct;23(4):740-80 PMID: 20930072
  6. Tichaczek-Goska D. Deficiencies and excessive human complement system activation in disorders of multifarious etiology. Adv Clin Exp Med. 2012 Jan-Feb;21(1):105-14. Review. PMID: 23214307 Free Article
  7. Audemard-Verger A, Descloux E, Ponard D et al Infections Revealing Complement Deficiency in Adults: A French Nationwide Study Enrolling 41 Patients. Medicine (Baltimore). 2016 May;95(19):e3548. PMID: 27175654 Free PMC Article