PNEUMONIA IN THE IMMUNOCOMPROMISED HOST

John Mathew D.O.

Defects in Host Defense

Impairment/Breech of body barriers Neutropenia Cell-mediated immunity defect Humeral immunity defect Obstruction

Special risk groups

HIV ALCOHOLICS NURSING HOME ELDERLY TRANSPLANT DIABETICS

Neutropenia

Etiology: Cancer Chemotherapy Meds: Azathioprine, cyclophosphamide Leukemia Acquired immunodeficiency's

Microbes Gram neg bacteria Fungal infections

Cell-mediated immunity defect

Etiology AIDS Lymphoma Organ transplantation and

immunosuppressive meds Microbes

Intracellular bacteria e.g. Listeria Mycobacterium Fungal e.g. Cryptococcus, Pneumocystis

jiroveci Viral e.g. EBV, CMV Protozoa eg Toxoplasmosis

Humoral immunity defect

Etiology Congenital Acquired eg myeloma

Microbes Encapsulated bacteria eg Haemophilus,

Pneumococcus

Pneumonia

Inflammatory condition of the alveoli or gas exchanging portion of the lung

Spread is commonly airborne or aspiration, but also include, direct penetration, hematogenous spread

Etiology depends on Community vs. Nosocomial Age Comorbidities Immunosuppression

pneumonia

Agents of Pulmonary infections

Bacterial Mycobacterial Fungal Protozoal Viral

Pulmonary infections

Bacterial Strep pneumoniae Haemophilus influenzae, Chlamydia,

Mycoplasma Klebsiella Pseudomonas Staph aureus Legionella pneumophila Gram negative bacilli Nocardia

Pneumococcal pneumonia

Gram + cocci in chains or pairs

Lobar pneumonia Presentation

Sudden onset Rigors, bloody sputum,

high fever, chest pain ( classic)

At risk population Chronic diseases Neutropenic, Cell mediated,

and Humeral deficient patients

Asplenia, sickle cell HIV/AIDS Elderly

Klebsiella pneumonia

Gram negative non-motile organism

More common in alcoholic, COPD, smokers, elderly

Presentation with fever, rigors, chest pain

Commonly presenting with lobar infiltrate

Staphylococcus Pneumonia

Gram + cocci in clusters

Pts with chronic lung disease, laryngeal cancer, immunosupressed pt, aspiration risk

Insidious onset, low grade fever. Sputum, and dyspnea

Pseudomonas Gram – rod Seen in pt’s on prolonged

hospitalizations, broad-spectrum antibiotic’s , high dose steroid therapy, nursing home residents, structural lung disease, burn victims, central venous catheters

Severe pneumonia, with cyanosis, confusion, and other systemic symptoms

Haemophilas Influenzae Gram neg

encapsulated organism

Elderly, chronic lung disease, neutropenic pt’s, sickle cell pt’s, alcoholics, and diabetics

Can present both indolently and similar to strep pneumo

CXR bacterial pneumonia

Atypical bacterial pneumonia

Mycoplasma, Legionella, Chlamydia

Unusual presentation Extrapulmonary

features CXR often normal

early in infection WCC normal Diagnosis-serology,

urine Treatment-macrolides,

newer quinolones

Tuberculosis Etiology: Mycobacterium

tuberculosis Subacute infection/Latent

Chronic cough +/- hemoptysis Fever Weight loss Night sweats

Extrapulmonary and atypical pulmonary presentations more common in IC host

Miliary tb- symptoms, include fever, chills, hepatospenomegaly, multi system illness

Risk 100-fold higher in HIV/AIDS

TB diagnosis

Sputum x 3 for AFB and TB culture

+/- Bronchoscopy

Other fluid if involved eg pleural, CSF etc

Mantoux test

TB: CXR Focal infiltrates Cavitation esp upp lobes Hilar adenopathy Pleural effusion Non-specific infiltrates in HIV+

TB screening and prophylaxis

Induration>5mm Close contact Strong suspicion IC host

Induration>10mm Chronic med conditions

Induration>15mm No risk factors

Prophylaxis: Isoniazid

TB Treatment

Isolation Diagnosis confirmed Patient smear negative

Combination therapy Isoniazid+rifampicin+pyrazinamide Add ethambutol is drug resistance is

suspected Duration of therapy dependent on site of

infection- normal 6months, 9 months, in HIV, pregnant females

Fungal pneumonia

Endemic fungi Histoplasmosis Blastomycosis Coccidioidomycosis

Aspergillus Cryptococcus Candida

ENDEMIC FUNGI Coccidioidomycosis

Coccidioides immitus San Joaquin Valley, South West US

Blastomycosis Blastomyces dermatitidis Endemic regions Midwest and South Central US Acute illness more mimics bacterial pneumonia Characteristic skin lesion irregular borders, and crusted

surface Histoplasmosis

H capsulatum Endemic regions include Midwest, South Central US Progressive disseminated histoplamosis can occur in pt’s

with HIV, or other cell mediated deficiency's

Cryptococcus neoformans

Usually found in pigeon or other bird dropping

Very rarely a pulmonary infection, and seldom more than granulomatous inflammatory reaction

Most significant complication is in Cell mediated immunity defects

Cryptococcal Meningitis

Invasive aspergillosis:at risk

10-20% leukemia

5-25% heart or lung transplant

Advanced Aids Chronic high

dose steroid users

34% respond to current therapy

Fungal infections: invasive aspergillosis

IA: diagnosis and treatment

Bronchoscopy Antifungal agent

Amphotericin Imidazoles Caspifungins

Granulocyte colony stimulating factor Supportive measures

Pneumocystis jiroveci pneumonia

The most common life threatening infection in AIDS patients in developed countries

AIDS defining illness in 60% Occurs in 80% of AIDS patients in

absence of antibiotic prophylaxis

Pneumocystis: overview

Unicellular eukaryote-Fungus Ubiquitous geographic distribution Caused infection in patients with

underlying T-lymphocyte disorders AIDS Lymphoproliferative disorders CLL Post stem cell transplantation Prolonged corticosteroid therapy and

Cushing's disease

Clinical manifestations

SYMPTOMS Gradual onset

over weeks Non-productive

cough Dyspnoea Fever

SIGNS Cyanosis Increased resp

rate Often normal lung

examination Other OI eg oral

thrush

PCP: radiology

Bilateral perihilar infiltrate

Normal heart size

Pneumothorax occasionally

PCP: radiology

PCP: diagnosis

LABORATORY ABG : hypoxemia Elevated LDH CD4 <200

HISTOLOGY Induced sputum Bronchoscopy and

BAL Lung biopsy Autopsy

PCP: histology

Normal alveoli PCP

Treatment of PCP

Trimethoprim/ sulfamethoxazole

Dapsone/clindamycin

Pentamidine iv Steroids

Prophylaxis for PCP

INDICATIONS CD4 count < 200 Prior episode of

PCP Oral candidiasis

TMP/SMX daily Dapsone daily Pentamidine

aerosolised monthly

Viral infections

Influenza Cytomegalovirus (CMV) Herpes simplex virus (HSV)

Influenza virus

Orthomyxovirus ssRNA virus Influenza A,B,C Subtypes based on

(HA) and neuramindase (NA)

Yearly vaccine developed on H/N type

Influenza

Clinical presentation Acute onset fever Apathy, headache Anorexia, myalgia Dyspnoea Cough-later

Duration 5-7d Complications

Bacterial pneumonia

encephalitis

Diagnosis Virus isolation Antigen

detection Serology (HA

antigen)

‘Flu: Prevention and treatment

Vaccination Adequate immune

response takes 2 weeks

Immunity weans in few months

Contraindication with egg allergy and allergy to other vaccine components

Amantidine /Ramantidine Targets envelope

protein Used in prev. and

Rx NA inhibitors

Oseltamivir or ranamivir

Use at onset of Sx- uto 48 hours

Reduce Sx by 1 day

CMV pneumonitis

CMV pneumonitis is the most serious infection of the spectrum of disease from CMV

Median onset CMV- 50 days- in transplant patients

It should always be in the differential of Transplant pt

Sustained fever, non productive cough, and dyspnea. Marked hypoxia is an indicator of if threatening infection

Special Populations

Alcoholics: Aspiration risk Higher rate of

colonization with gram neg

Alcoholism depresses depresses granulocyte and lymphocyte counts

Special Populations

Diabetes Independent risk

factor for pneumonia

Diabetes in age of 25-64 are 4x more likely to have pneumonia

Impaired chemotaxis

Special Populations

Elderly Most common infection

pneumonia Many comorbid

conditions Most common atypical

agent is Legionella Most common viral illness

is influenza Poor prognostic indicators

include: hypothermia, fever >100.9, low wbc count, gram neg bacteria, staph infection, b/l infiltrates

Special Populations

Nursing Home Similar risk factors as the

elderly 8 independent factors

that predict pneumonia in this population: > pulse rate, RR > 30, Temp > 100.4, decreased LOC, acute confusion, lung crackles, absence of wheezes, > leukocyte count

Most common infections: Strep, gram neg, H flu, and influenza

Special populations

HIV/AIDS Strep most

common infection >800 cd4 bacterial

infections 250-500 – TB,

Cryptococcus , Histoplasmosis

< 200 –PJP < 50 MAI