JULY 25, 2017 GRAND ROUNDS

CASE 1

21 year old previously healthy male w/ fever, cough, sore throat, and acute numbness of the left side of the face; CXR showed left lower lobe cavity and head CT demonstrated a right parietal lobe abscess; blood culture grew Fusobacterium necrophorum (Lemierre’s syndrome)

1. Lemierre’s syndrome is an infectious thrombophlebitis of the internal jugular vein that is notorious for causing septic embolization to the lungs (97%; which can appear as a cavity, an infiltrate, abscess, or empyema), brain, bone and joint. 92% of cases are caused by Fusobacterium.

2. It should be suspected in patients with a prior history of pharyngitis and now p/w fever and septic embolization (“an infectious embolic disease similar to infective endocarditis”).

3. Prolonged antibiotics is required (usually 4 weeks). The use of anticoagulation is controversial but is usually beneficial if thrombosis continues to progress despite antibiotic therapy. Ligation of the jugular vein is reserved for patients with persistent sepsis despite antibiotics.

CASE 2

A 12 week old term infant w/ 6 weeks of fever and diffuse interstitial nodular opacities on CXR; exam: 1^st percentile for weight/length, hepatosplenomegaly; BAL showed Pneumocystis jirovecii on stain and Histoplasma capsulatum on fungal culture; urine Histoplasma antigen was highly positive; immunodeficiency work-up showed pan-T cell lymphopenia that were naïve and thymic-derived; suspected to have dyskeratosis congenital

1. High yield facts about dyskeratosis congenita:

•       Mutation in a variety of genes involved in telomere lengthening/protection
• I     Inheritance: recessive (X-linked or autosomal), autosomal dominant
•       Can be seen in adults: median age of diagnosis is 15 years but the range of presentation is wide (birth to 75 years)
•       Classic triad (ABSENT in the neonatal period but seen in <50% of older patients and ¾ of cases will have at least 1): abnormal skin pigmentation (reticular hyperpigmentation in the neck/chest), nail dystrophy, oral leukoplakia
•           Complications: bone marrow failure (50% by age 50), immunodeficiencies (lymphocyte subset most prone) à most common cause of death; others: pulmonary fibrosis, head/neck squamous cell carcinoma, myelodysplastic syndrome
•       Treatment: bone marrow transplant (for bone marrow failure), androgen therapy

CASE 3

78 previously healthy male from Fairport, New York, p/w fever and chills for 10 days; labs showed anemia (Hgb 10.7), thrombocytopenia (58,000), and mildly elevated liver enzymes; other w/u showed a haptoglobin < 1 and an elevated LDH; smear showed evidence of babesiosis (3% parasetemia) and Babesia microti PCR was detected

1. Suspect babesiosis in patients you suspect to have tickborne illness (fever, elevated transaminases, and thrombocytopenia). It is transmitted through the bite of the deer or blacklegged tick Ixodes scapulars.

2. Ixodes scapularis also transmits: Anaplasma, Borrelia burgdorferi (Lyme disease), and Powassan virus type II.

3. Babesiosis can by asymptomatic (made manifest only during splenectomy or w/ development of an immune compromising condition), mild (this can be self-limited), or severe. Hemolytic anemia is the principal clue in a lot of cases (“think, malaria w/o a history of travel to malaria-endemic areas; the trophozoite/merozoite forms in the blood can look like malaria).

4. Typically has long incubation period after a tick bite (up to 3 months; typically 1-6 weeks) and even longer after blood transfusion (up to 6 months; typically 1-9 weeks).

5. Co-infection w/ Anaplasma or Lyme sometimes occurs. Hence, suspect concurrent babesiosis in patients who don’t respond to therapy for Anaplasma or Lyme. Diagnosis is through blood smear and PCR testing.

6.Treatment:

• Asymptomatic parasetemia requires treatment to prevent transmission and progression to disease especially in immunocompromised patients.
• Mild: atovaquone + azithromycin
• Severe (e.g. >4% parasetemia): clindamycin + quinine; consider exchange transfusion
• Duration: 7-10 days for immunocompetent patients; at least 6 weeks or up to 2 weeks after parasites are no longer present on smear (whichever is longer) for immunocompromised hosts

7. Rapid review of ticks (for more information, click here):

• Ixodes scapularis (Eastern, northern Midwest): as mentioned above
• Ablymoma americanum (lone start tick; Midwest, Southern, southeastern): Ehrlichia, Heartland, southern tick-associated rash illness (STARI), tularemia, Bourbon (? maybe)
• Dermacenteor variabilis (American dog tick; eastern, south central, Pacific coast): RMSF, tularemia
• Dermacentro andersoni (Rocky Mountain wood tick; west of Mississippi, Pacific coast): RMSF, tularemia, Colorado tick fever