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
How is glandular fever spread?
AKA infectious mononucleosis
Spread by:
- Saliva
- Coughs and sneezes
What is mumps?
Viral infection
Most people recover by themselves, but can lead to inflammation of organs causing death
What is the treatment for measles?
Supportive care, no specific anti-viral therapy
What is strongyloides?
A helminth infection that can cause threadworms
If untreated, it will spread and cause chronic disease in the bowel
What is schistosomiasis?
Live is freshwater snails, spread through contaminated water
Causes rash, fever, chills, itchy skin, muscles aches
Can cause chronic disease of bowel and increase risk of liver fibrosis and bladder cancer
What is toxoplasma?
Spread through infected stool of cats and meat
- Treated with antimicrobials, but infection may leave cysts leading to recurrence
It can spread to lungs and brain in immunocompromised people
What is leishmania?
Parasite found in tropics
Causes skin sores, fever, weight loss, organomegaly, anaemia
Treated with antimicrobials
What is Lyme disease?
Bacterial infection spread by ticks
Endemic everywhere
Causes fatigue, muscle pain, joint pain, headaches, fever, chills, neck stiffness
Treatment: 2-4 week course of antibiotics
What is dengue fever?
Viral infection spread by mosquitos common in the tropics
Causes high fever. severe headache, nausea, vomiting, lymphadenopathy, rash, myalgia
No treatment, just support
Complications: haemorrhagic fever, dengue shock, low platelets
