Cough in the immunocompromised host: ACCP evidence-based clinical practice guidelines

Cough in Ambulatory Immunocompromised Adults: CHEST Expert Panel Report

BACKGROUND

Cough is a common symptom prompting patients to seek medical care. Like patients in the general population, patients with compromised immune systems also seek care for cough. However, it is unclear whether the causes of cough in immunocompromised patients who are deemed unlikely to have a life-threating condition and a normal or unchanged chest radiograph are similar to those in persons with cough and normal immune systems.

METHODS

We conducted a systematic review to answer the question: What are the most common causes of cough in ambulatory immunodeficient adults with normal chest radiographs? Studies of patients ≥ 18 years of age with immune deficiency, cough of any duration, and normal or unchanged chest radiographs were included and assessed for relevance and quality. Based on the systematic review, suggestions were developed and voted on using the American College of Chest Physicians (CHEST) methodology framework.

RESULTS

The results of the systematic review revealed no high-quality evidence to guide the clinician in determining the likely causes of cough specifically in immunocompromised ambulatory patients with normal chest radiographs.

CONCLUSIONS

Based on a systematic review, we found no evidence to assess whether or not the proper initial evaluation of cough in immunocompromised patients is different from that in immunocompetent persons. A consensus of the panel suggested that the initial diagnostic algorithm should be similar to that for immunocompetent persons but that the context of the type and severity of the immune defect, geographic location, and social determinants be considered. The major modifications to the 2006 CHEST Cough Guidelines are the suggestions that TB should be part of the initial evaluation of patients with cough and HIV infection who reside in regions with a high prevalence of TB, regardless of the radiographic findings, and that specific causes and immune defects be considered in all patients in whom the initial evaluation is unrevealing.

Cough: a worldwide problem

Cough is a common and important respiratory symptom that can produce significant complications for patients and be a diagnostic challenge for physicians. An organized approach to evaluating cough begins with classifying it as acute, subacute, or chronic in duration. Acute cough lasting less than 3 weeks may indicate an acute underlying cardiorespiratory disorder but is most commonly caused by a self-limited viral upper respiratory tract infection (eg, common cold). Subacute cough lasting 3 to 8 weeks commonly has a postinfectious origin; among the causes, Bordetella pertussis infection should be included in the differential diagnosis. Chronic cough lasts longer than 8 weeks. When a patient is a nonsmoker, is not taking an angiotensin-converting enzyme inhibitor, and has a normal or near-normal chest radiograph, chronic cough is most commonly caused by upper airway cough syndrome, asthma, nonasthmatic eosinophilic bronchitis, or gastroesophageal reflux disease alone or in combination.

Genetic causes of bronchiectasis: primary immune deficiencies and the lung

Primary immune deficiencies (PID) comprise a heterogeneous group of genetically determined disorders that affect development and/or function of innate or adaptive immunity. Consequently, patients with PID suffer from recurrent and/or severe infections that frequently involve the lung. While the nature of the immune defect often dictates the type of pathogens that may cause lung infection, there is substantial overlap of radiological findings, so that appropriate laboratory tests are mandatory to define the nature of the immune defect and to prompt appropriate treatment. At the same time, the recent identification of a large number of PID-causing genes now allows early, even presymptomatic diagnosis, thus representing an essential tool for prevention of lung damage. This review article describes the most common forms of PID, their cellular and molecular bases, and the associated lung abnormalities, and reports on available treatment.