How does older people’s immune system place them at high risk of sepsis and death?

Increased risk of sepsis and death from infectious causes among the elderly is a well-known phenomenon—particularly as witnessed in the Covid-19 era— and is in part due to 2 major age-related alterations of their immune system: 1. Defective T and B cell functions in response to acute infections; and 2. Once infection sets in, inadequate control of sepsis-induced pro-inflammatory response and its attendant procoagulant state. Interestingly, the essential elements of the innate immunity (eg, neutrophils, dendritic cells, complements) are generally spared from the effects of aging.1,2

Increased susceptibility of the elderly to acute infections is in part caused by poorer T helper cell function and suboptimal B cell humoral response to neoantigens. Despite this, serum levels of pro-inflammatory cytokines such as IL-1, IL-6,TNF-alpha, and IFN-gamma are intact.  In fact, production of IL-6 and its duration of response is actually increased in the elderly.1,2

Poor control of the inflammatory state due to sepsis in older patients may be related to the difficulty in clearing a pathogen or dysfunction in the signaling by counter-regulatory cytokines, such as IL-10.2 Either way, unchecked inflammatory response is deleterious to the patient and is associated with increased risk of thrombosis and thromboembolism, multiorgan system failure, septic shock and death. 

Bonus Pearl: Did you know that even in the absence of infection, older people are more prone to thrombosis and thromboembolism , in part related to elevated plasma levels of fibrinogen, as well as factor VII, VIII, and IX, among others?2,3  

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 References

  1. Ticinesi A, Lauretani F, Nouvenne A, et al. C-reactive protein (CRP) measurement in geriatric patients hospitalized for acute infection. Eur J Intern Med 2017;37:7-12. https://pubmed.ncbi.nlm.nih.gov/27594414/
  2. Opal SM, Girard TD, Ely EW. The immunopathogenesis of sepsis in elderly patients. Clin Infect Dis 2005;41: (Suppl 7) S504-12. https://pubmed.ncbi.nlm.nih.gov/16237654/
  3. Mari D, Coppola R, Provenzano R. Hemostasis factors and aging. Experimental Gerontology 2008;43:66-73. https://www.sciencedirect.com/science/article/abs/pii/S0531556507001404?via%3Dihub

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, its affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

 

How does older people’s immune system place them at high risk of sepsis and death?

Why is my patient with systemic amyloidosis at higher risk of bleeding?

The major mechanism of bleeding tendency in primary systemic amyloidosis (AL) appears to revolve around amyloid deposit infiltration of the vasculature and musculature, leading to amyloid angiopathy, fragility, impaired vasoconstriction, tears and hemorrhage. 1,2 Other potential mechanisms include:

  • Presence of plasma inhibitors of fibrinogen conversion to fibrin
  • Deficiencies of factor X, IX and V due to their affinity for amyloid substance
  • Presence of circulating heparin-like anticoagulants
  • Uremic platelet dysfunction in the presence of renal involvement

In a study involving 36 patients with AL, ~30% had bleeding symptoms with alterations of 1 or more clotting tests found in ~85%: prolonged prothrombin time (PT) ratio (22%), activated partial thromboplastin time (aPTT) (65%) and thrombin time (85%).

Clinical manifestations of amyloidosis related to its bleeding diathesis include petechiae, ecchymoses, purpura (“raccoon eyes when periorbital), uncontrollable epistaxis, gingival bleeding, and gastrointestinal bleed or submucosal hematomas. 1-6

Due to its convenience and relative safety, a biopsy of abdominal fat or minor salivary glands is often initially performed for definitive diagnosis of amyloidosis, followed by biopsy of specific organs (eg, kidney, liver), if needed. 3,6

Due to the potential risk of bleeding complications, transjugular liver biopsy is preferred over percutaneous approach. This is because the liver capsule is not perforated with transjugular liver biopsy and if bleeding occurs, the blood returns directly into the venous system rather than into the peritoneum. 7-8 

Bonus Pearl: Did you know that AL amyloidosis is the most common type of systemic amyloidosis in western countries? This is because the incidence of the other major type of amyloidosis (AA), often related to chronic infections or inflammatory diseases, has been dropping in these countries.3

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References

  1. Gamba G, Montani N, Anesi E, et al. Clotting alterations in primary systemic amyloidosis. Haematologica 2000;85:289-92. https://moh-it.pure.elsevier.com/en/publications/clotting-alterations-in-primary-systemic-amyloidosis
  2. Marconcini LAL, Stewart FM, Sonntag L, et al. AL amyloidosis complicated by persistent oral bleeding. Case Reports in Hematology 2015, Article ID 981346. https://www.hindawi.com/journals/crihem/2015/981346/
  3. Desport E, Bridoux F, Sirac C, et al. AL Amyloidosis. Orphanet Journal of Rare Diseases 2012, 7:54. https://ojrd.biomedcentral.com/articles/10.1186/1750-1172-7-54
  4. Yoshii S, Mabe K, Nosho K, et al. Submucosal hematoma is a highly suggestive finding for amyloid light-chain amyloidosis: Two case reports. W J Gastroenterol 2012;4:434-37. https://www.ncbi.nlm.nih.gov/pubmed/23125904
  5. Kon T, Nakagawa N, Yoshikawa F, et al. Systemic immunoglobulin light-chain amyloidosis presenting hematochezia as the initial symptoms. Clin J Gastroenterol 2016;9:243. http://europepmc.org/article/med/27318996
  6. Petre S, Shah IA, Gilani N. Review article:gastrointestinal amyloidosis-clinical features, diagnosis and therapy. Alim Pharmacol Ther 2008;27:1006-16. https://www.ncbi.nlm.nih.gov/pubmed/18363891
  7. Grant A, Neuberger J. Guidelines on the use of liver biopsy in clinical practice. Gut 1999;45(Suppl IV):IV1-IV11. https://www.ncbi.nlm.nih.gov/pubmed/10485854
  8. Dohan A, Guerrache Y, Boudiaf M, et al. Transjugular liver biopsy: Indications, technique and results. Diagnostic and Interventional Imaging 2014;95:11-15. https://www.ncbi.nlm.nih.gov/pubmed/24007769
Why is my patient with systemic amyloidosis at higher risk of bleeding?