Infections In The Infections In The Immunocompromised HostImmunocompromised 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)

Infections In The Infections In The Immunocompromised HostImmunocompromised 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

Infections In The Infections In The Immunocompromized HostImmunocompromized 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

Infections In The Infections In The Immunocompromized HostImmunocompromized 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

Infections In The Infections In The Immunocompromized HostImmunocompromized Host

HostHost Defects and Associated Prevalent PathogensDefects and Associated Prevalent Pathogens

DefectPathogenGranulocytopeniaStaph. Aureus,CNSS, V strep, Enterococci, E. coli, Pseudomonas

aeruginosa, K.pneumoniae, other gram –ve bacilli, Aspergillus spp

Damaged skin and mucous membrane

CNSS, Staph. Aureus, pseudomonas aeruginosa and other gram-ve bacilli, candida spp, V. strep, enterococci, HSV.

Impaired CMIHSV, VZ, EBV, CMV, RSV, M. tuberculosis, Aspergillus spp and other fungi, Toxoplasma gondi.

Impaired humoral immunity

Streptococcus pneumoniae, Haemophilus influenzae

Spleen dysfunctionStreptococcus pneumoniae, Haemophilus influenzae

Neisseria meningitides.

Complement deficiency

Neisseria meningitides, Neisseria gonorrhea

Fever In Neutropenic PatientFever 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;2002:34:730-751

Fever In Neutropenic PatientFever In Neutropenic PatientSEQUENTIAL INFECTIVE EVENTSSEQUENTIAL INFECTIVE EVENTS

Fever In Neutropenic PatientFever In Neutropenic Patient

Causes of fever in neutropenic patients;

Fever In Neutropenic PatientFever In Neutropenic PatientIDSA guidelines CID;2002:34:730-751

IDSA guidelines CID;2002:34:730-751

IDSA guidelines CID;2002:34:730-751

IDSA guidelines CID;2002:34:730-751

IDSA guidelines CID;2002:34:730-751

IDSA guidelines CID;2002:34:730-751

Fever In Neutropenic PatientFever 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

Infections in Solid-Organ Infections in Solid-Organ Transplant RecipientsTransplant 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

Infections inInfections in Organ Transplant Organ Transplant RecipientsRecipients

Common infection in Specific Organ transplant: o Bone marrow transplant Bloodstream infections, pneumonia,

viral infections o Kidney transplant Urinary tract infections.

o Liver transplant Intra abdominal infections.

o Heart and Heart-Lung Chest, Mediastinitis

transplant

CMR;1997:277-297

Infections inInfections in Organ Transplant Organ Transplant RecipientsRecipients

1 2 3 4 5 6 7 8 9 10

Months post transplantation

Common bacteria

EBV,CMV,HBV

VZV,CMV retinitis

Candida,Aspergillosis

Histoplasma,Nocardia,Toxoplazma,Pneomocystis

TB,Legionella

CID;2001 (supp 1):S5-S8

INFECTIONS IN INFECTIONS IN IMMUNOCOMPROMISED HOSTIMMUNOCOMPROMISED HOST

• Suggested readings:

Davidson's principles and practice of medicine 20th edition

Harrison's Principles of Internal Medicine 16th or 17th edition