1. Infections In The Immunocompromised Host
Objectives of this lecture:
To review the components of the host defense mechanisms
To recognize the importance of immunodeficiency and infections
To know the common infectious complications in major immunodeficiency categories(other than HIV&AIDS)

2. Infections In The Immunocompromised Host
Components of Host Defenses:
Mechanical barriers
Skin, mucous membranes, epiglottis, cilia.
Granulocytes
Cell mediated Immunity
Macrophages, T-lymphocytes, NKC, cytokines
Humoral Immunity
B-lymphocytes, immunoglobulins, complements
Spleen
Davidson's Principles and Practice of Medicine 20th edition chapter 4 pages 64-75

3. Infections In The Immunocompromized Host
The importance of infections in IC host:
Increasing numbers of Immunocompromised patients.
Seriousness of infections in those patients.
Infections with unusual, nonpathogenic microorganisms.
Atypical presentation of infections by common pathogens

4. Infections In The Immunocompromized Host
Causes of immune deficiency:
Primary (congenital);
Rare, more common in children e.g chronic granulomatus disease, combined immunedifiency syndrome, specific Ig deficiency, others.
Secondary (acquired);
The commonest, there are many causes like;
Extremes of age, pregnancy, infections, malignancy, chemotherapy, steroids, burns, trauma, procedures, connective tissue diseases, chronic diseases like DM,CRF etc.
Davidson's Principles and Practice of Medicine 20th edition chapter 4 pages 64-75

5. Infections In The Immunocompromized Host Host Defects and Associated Prevalent Pathogens
Staph. Aureus,CNSS, V strep, Enterococci, E. coli, Pseudomonas aeruginosa, K.pneumoniae, other gram –ve bacilli, Aspergillus spp
Granulocytopenia
CNSS, Staph. Aureus, pseudomonas aeruginosa and other gram-ve bacilli, candida spp, V. strep, enterococci, HSV.
Damaged skin and mucous membrane
HSV, VZ, EBV, CMV, RSV, M. tuberculosis, Aspergillus spp and other fungi, Toxoplasma gondi.
Impaired CMI
Streptococcus pneumoniae, Haemophilus influenzae
Impaired humoral immunity
Neisseria meningitides.
Spleen dysfunction
Neisseria meningitides, Neisseria gonorrhea
Complement deficiency

6. Fever In Neutropenic Patient
Definition:
Fever: Oral temperature of 38c for more than two hours or single temperature of 38.3c or more.
Neutropenia: A Neutrophil count of <500 cells/mm³ or a count of <1000 cells/mm³ with a predicted decline to 500/mm
Approach to patient:
Careful history and examination, investigations (like blood cultures, urine culture, CXR, others), then start antibiotic therapy to cover the most likely organisms.
IDSA guidelines CID;2002:34:

7. Fever In Neutropenic Patient SEQUENTIAL INFECTIVE EVENTS

8. Fever In Neutropenic Patient
Causes of fever in neutropenic patients;

9. Fever In Neutropenic Patient
IDSA guidelines CID;2002:34:

10. IDSA guidelines CID;2002:34:730-751

11. IDSA guidelines CID;2002:34:730-751

12. IDSA guidelines CID;2002:34:730-751

13. IDSA guidelines CID;2002:34:730-751

14. IDSA guidelines CID;2002:34:730-751

15. Fever In Neutropenic Patient
Treatment:
Antibacterial like;
pipracilline+ aminoglycoside or ceftazidime+ aminoglycoside or Imipenem, vancomycine.
Antifungal like;
Amphotericine B, Fluconazole
Antiviral like;
Acyclovir
Granulocyte stimulating factors

16. Infections in Solid-Organ Transplant Recipients
Factors affecting the incidence of infections:
The type of organ transplanted.
The degree of immunosupression.
The need for additional antirejection therapy.
The occurrence of surgical complications.
Presence of latent infection in the donor or recipient.
CID;2001 (supp 1):S5-S8

17. Infections in Organ Transplant Recipients
Common infection in Specific Organ transplant:
Bone marrow transplant Bloodstream infections, pneumonia, viral infections
Kidney transplant Urinary tract infections.
Liver transplant Intra abdominal infections.
Heart and Heart-Lung Chest, Mediastinitis
transplant

18. CMR;1997:

19. Infections in Organ Transplant Recipients
TB,Legionella
Histoplasma,Nocardia,Toxoplazma,Pneomocystis
Candida,Aspergillosis
EBV,CMV,HBV
VZV,CMV retinitis
Common bacteria 1 2 3 4 5 6 7 8 9 10
Months post transplantation
CID;2001 (supp 1):S5-S8

20. INFECTIONS IN IMMUNOCOMPROMISED HOST
Suggested readings:
Davidson's principles and practice of medicine 20th edition
Harrison's Principles of Internal Medicine 16th or 17th edition