August 5, 2014 Grand Rounds

Case 1. 52 year old woman with SLE who presents with chronic progressive headache, diplopia, blurring of vision, numbness of her toes, and constitutional symptoms secondary to histoplasmosis.

 From: https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixsT5aJ5G8uBhS4qVZHCyssDojsaqfcvKBj0wnpJ7fwG6WzN6wuFxqrfG1dsTS3zD9rcbGz4wD4dA2aDZEdJcTPMeto4ifEHU-xZyT5-cLe86qSxO1dmSUfnBan6AIxh93JQ35ebEtkkw/s1600/fungal+distribution.png

1. Urine Histoplasma antigen cross-reacts with blastomycosis, paracoccidioidomycosis, penicilliosis, coccidioidomycosis, and African histoplasmosis. Only blastomycosis is endemic in Missouri. Treatment of histoplasmosis is very similar to that of blastomycosis.

2. Blastomyces antibody testing, which is usually done by an immunodiffusion assay, has low sensitivity but relatively good specificity. It cross-reacts with histoplasmosis, however. 

3. Distinguishing blastomycosis and histoplasmosis may be difficult and sometimes rely on isolation of the actual fungus from a tissue specimen. Clinically, they can present similarly as well. However, there are some important distinctions.

• Pulmonary findings are identical (from solitary to multiple lesions, from nodular to cavitary infiltrates).
• Skin findings may help differentiate the two. Histoplasma can give rise to almost any skin findings. Erythema nodosum and erythema multiforme are common. Blastomyces, on the other hand, presents usually with a short list of skin manifestations. This includes pyogranulomatous lesions with pseudoepitheliomatous hyperplasia (sometimes misdiagnosed as skin cancer). It can also present with ulcerating or verrucous lesions or cold abscesses. 
• Brain abscess and bone and joint infection are also more prominent clinical manifestations of blastomycosis.
• To confuse you further, African histoplasmosis (Histoplasma capsulatum var duboisii) presents exactly like blastomycosis (in terms of bulky skin lesions and prominent bone and joint involvement).

Case 2. A 17 year old girl who presents with acute exudative tonsillopharyngitis, fever, and pneumonia secondary to Lemierre's syndrome caused by Fusobacterium necrophorum.

From: http://iam.uic.edu/wp-content/uploads/2012/03/Lemierre-Syndrome-2.jpg

1. Sore throat followed by pneumonia, especially where chest imaging suggests possible septic emolization, should raise suspicion for Lemierre's syndrome. In this situation, get a Doppler ultrasound of the neck to look for internal jugular vein thrombosis.

2. Anticoagulation in cases of Lemierre's syndrome is still a controversial topic. At least two case series of Lemierre's syndrome showed no difference in outcome among patients who received anticoagulation compared to those who did not.

Case 3. A 73 year old man with history of recurrent and metastatic cholangiocarcinoma presents with multiple metastatic versus septic embolization of the liver, spleen, and kidneys as well as a new 3+ aortic regurgitation associated with an aortic valve vegetation.

From: http://classconnection.s3.amazonaws.com/695/flashcards/739695/jpg/me1316628051717.jpg

1. Nonbacterial thrombotic endocarditis (NBTE) (formerly known as marantic endocarditis) are most commonly seen in patients with advanced malignancy (usually lung and gastrointestinal cancer). It can also be seen in patients with rheumatologic conditions. 

2. In a case series of cancer patients with NBTE, one-third had mild to moderate valvular regurgitation (look here).

3. It is very difficult to distinguish NBTE from culture-negative endocarditis. Obtaining a specimen of the valve and the vegetation, which is an impractical approach especially for cancer patients who are not good candidates for surgery, may sometimes be the only way to differentiate the two.