Infections in the immunocompromised Flashcards
Who is immunocompromised?
- Congenital defects
- Immunosuppressive therapy (cancer treatment, steroids)
- Physiological immunosuppression (diabetes, elderly, pregnancy, neonates)
- Autoimmune disease
- Splenectomy
- Toxicity due to alcohol
- HIV
What is the definition of neurtopaenia?
<0.5-1.0 x 10^9/l
Greatest risk if prolonged and <0.1
How is infection post-splenectomy managed?
- Immunisation
- Long-term antibiotic prophylaxis
What are some causes of a splenectomy?
- Trauma
- Functional asplenia : ulcerative colitis, coeliac disease, sickle cell, SLE, Rheumatoid arthritis
What types of infection does a splenectomy put people at risk of?
Infections due to encapsulated bacteria
Eg Streptococcus pneumoniae, N.meningitidis and Haemophilus influenzae
When is Pneumocystis pneumonia (PCP) most common?
- Most common life threatening infection in AIDS. It’s an AIDS defining illness
- Lymphoproliferative disorders
- CLL
- Post stem cell transplant
- Prolonged corticosteroid therapy
What is the treatment for PCP?
Trimethoprim/ Sulfamethoxazole Dapsone/clindamycin
Pentamidine iv
Steroids
If HIV + and CD4 count <200 should be given PCP prophylaxis +HAART
What is Pneumocystis pneumonia (PCP)?
A unicellular eukaryote-Fungus
Causes infection in underlying T-lymphocyte disorders
What is the role of the different immunoglobulins?
IgM: Primary response
IgG: Secondary response (75% of all Ig’s)
IgA: protects mucus membranes
IgE: against parasites
IgD: unknown
What can cause hypogammaglobulinemia?
- Common variable immunodeficiency (CVID) (Genetic, affects respiratory system immunity)
- X linked agammaglobulinemia (XLA) (An x-linked, male only, mutation affecting maturation of B-cells)
- Lymphomas and myelomas present with altered levels of immunoglobulins
What is a complement deficiency?
Unable to form the membrane attack complex (MAC) responsible for killing capsulated organisms because certain components are missing
What is the difference between group A and group b streptococcus?
Group A: sore throat, fever, and swollen lymph nodes
Group B: serious infections
What are the different types of herpes virus?
There are 8 types
Herpes simplex virus (HSV-1 and 2)
- Causes mouth, lip, and genital sores
Varicella-zoster virus
- Chicken pox and shingles
Epstein-Barr virus
- Infectious mononucleosis
- Associated with Hodgkin’s, non-Hodgkin’s, and Burkitt’s lymphoma, and nasopharyngeal carcinoma
Cytomegalovirus
- Mononucleosis and hepatitis
- Can cause developmental issues in the new-born
- Mostly issues in immunocompromised
Human herpes virus-6
- Fever-induced seizures in infants
Human herpes virus-7
- Roseola (high temperature and rash)
Human herpes virus-8
- Kaposi’s sarcoma and lymphoma
What is the difference between bacteraemia and septicaemia?
Bacteraemia: presence of bacteria in the bloodstream
Septicaemia: bacteria in the bloodstream that is spreading and multiplying
What are the complications of orbital/peri-orbital cellulitis?
- Meningitis
- Hearing loss
- Sepsis
- Cavernous sinus thrombosis
- Optic nerve damage/ vision loss
