Cryptogenic Organizing Pneumonia

Cryptogenic organizing pneumonia (COP), previously known as Bronchilitis Obliterans Organizing Pneumonia (BOOP), is a distinct clinical entity with predominant features of pneumonia.

To summarize:

- It usually occurs in fifth or sixth decades of life.
- Men and women are affected equally.
- Most patients are symptomatic for less than two months, with a clinical presentation that mimics community-acquired pneumonia.
- Multiple ground-glass opacities and/or consolidations (with air bronchograms) are commonly noted on imaging.
- An open or thoracoscopic lung biopsy is suggested to confirm the diagnosis.
- Histopathology typically demonstrates excessive proliferation of granulation tissue within small airways (proliferative bronchiolitis) and alveolar ducts, associated with chronic inflammation in the surrounding alveoli.
- The diagnosis of COP requires positive histopathology AND the exclusion of any other possible cause of pneumonia (in particular, infectious causes).
 - Glucocorticoid therapy typically induces rapid clinical improvement and clearing of the opacities on chest imaging, usually without significant sequelae.
- Relapses are common upon tapering or discontinuation of glucocorticoids.
- It can be idiopathic, but also associated with connective tissue diseases, a variety of drugs, malignancy, and other interstitial pneumonias.

Please click on this link to read an excellent 2011 review from Chest on this topic.

Respirology Pearls

Here are a few respirology (and non-respirology) pearls for you to mull over today:

1) Correlation between arterial and venous blood gases

Much of the literature surrounding this concept is found in the Emergency Medicine literature. A prospective study involving 95 patients in Emergency Medicine Journal  from 2007 comparing ABG and VBG samples drawn as close in time as possible concluded that VBG analysis for pH, bicarbonate, and pCO2 (but not paO2, not surprisingly) may be a reliable substitute for ABG analysis in the initial evaluation of an adult patient population presenting to the ED. Click on this link to read the full article.

2) Hypertrophic pulmonary osteoarthropathy

Hypertrophic pulmonary osteoarthropathy, also known as Bamberger-Marie disease, is periostitis of the long bones of the upper and lower extremities. It is thought to be a paraneoplastic manifestation of lung carcinoma. These patients often get clubbing and increased bone deposition on long bones. Their presenting symptoms are sometimes only clubbing and painful ankles. Check out this link for an interesting "Images in Clinical Medicine" in NEJM illustrating the paraneoplastic phenomena of hypertrophic pulmonary osteoarthropathy and tripe palms (or acanthosis palmaris).

3) Batson venous plexus

The Batson venous plexus is a network of valveless veins that connect the deep pelvic and thoracic veins draining the inferior end of the bladder, breast, and prostate to the internal vertebral venous plexuses. They are thought to to provide a hematogenous route for metastatic spread of rectal and prostate cancer to the vertebral column or brain. The plexus is named after anatomist Oscar Vivian Batson, who first described it in 1940.

Right Heart Failure

Yesterday's Rapid Fire Morning Report was a testament to the breadth of clinical presentations that Internal Medicine has to offer.

We heard about the smörgåsbord of cases that were seen the evening prior, including cases of:

- transient hypoxia of unclear etiology
- paraspinal absess
- management of cancer-related pain
- right-heart failure

I thought I was take a moment to review the diagnosis and management of right heart failure, which are gleaned from guidelines published by the Canadian Cardiovascular Society in 2009. You can find the full set of guidelines by clicking on this link.

Right heart failure (RHF) can be due to systolic and/or diastolic dysfunction, and can be an isolated occurrence, though it is more commonly associated with left heart failure.

To make the diagnosis, at least two features should be present:

1) Signs and symptoms consistent with RHF. These typically fall into three categories:

- Fluid retention (eg, ascites, peripheral edema, anasarca)
- Exercise intolerance and fatigue (eg, low cardiac output, diastolic and systolic dysfunction)
- Hypotension (especially with atrial and ventricular arrhythmias, and low cardiac output)

2) Objective evidence of abnormal right-sided cardiac structure or function or elevated intracardiac pressures

The etiology of RHF can often be broken down into the following categories:


- Increased afterload, including left-sided heart failure and pulmonary arterial hypertension
- Right ventricular (RV) myopathic process, RV infarction and restrictive heart disease
- Right-sided valvular heart disease (triscuspid and pulmonary)
- Congenital heart disease
- Pericardial disease (a mimic of RHF)

On physical examination, one may find one or more of the following:

- Elevated JVP (with CV waves possibly present with tricuspid regurgitation)
- Hepatomegaly (from passive hepatic regurgitation)
- Ascites
- Peripheral edema
- RV heave
- Palpable P2
- Systolic murmur at left lower sternal border consistent with tricuspid regurgiation
- Right-sided S3

The diagnosis is typically made using:
- Echocardiography
- Consider cardiac MRI and MUGA scan, as indicated
- If the diagnosis of pulmonary arterial hypertension is felt to be the cause, then right-heart catheterization should be considered, as it is the gold standard for the diagnosis of pulmonary hypertension.

In regards to management, generally, diuretics are the mainstay of therapy. However, diuretics should be given judiciously, as patient's LV filling pressures are often low, and overdiuresis may lead to intravascular volume contraction, precipitating hypotension, pre-renal acute kidney injury, etc.

Always be mindful of the patient's electrolyte status (in particular, their potassium and magnesium), as diuretics can lead to hypokalemia and hypomagnesemia - a recipe for arrythmias (and thus, further exacerbation of their heart failure).