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Question 7#

 A 19-year-old male patient presents with a 1-week history of malaise and anorexia followed by fever and sore throat. On physical examination, the throat is inflamed without exudate. There are a few palatal petechiae. Cervical adenopathy is present. The liver span is 12 cm and the spleen is palpable.

• Throat culture: negative for group A streptococci
• Hgb: 12.5, Hct: 38%
• Reticulocytes: 4%
• WBC: 14,000/µL
• Segmented: 30%
• Lymphocytes: 60%
• Monocytes: 10%
• Bilirubin total: 2.0 mg/dL (normal 0.2-1.2)
• Lactic dehydrogenase (LDH) serum: 260 IU/L (normal 20-220)
• Aspartate aminotransferase (AST): 60 U/L (normal 8-40 U/L)
• Alanine aminotransferase (ALT): 55 U/L (normal 8-40 U/L)
• Alkaline phosphatase: 40 IU/L (normal 35-125)

Which of the following is the most important initial test combination to order?

A. Liver biopsy and hepatitis antibody
B. Streptococcal screen and antistreptolysin O (ASO) titer
C. Peripheral blood smear and heterophile antibody
D. Toxoplasma IgG and stool sample
E. Lymph node biopsy and cytomegalovirus serology

Correct Answer is C

Comment:

This young man presents with classic signs and symptoms of infectious mononucleosis. In a young patient with fever, pharyngitis, lymphadenopathy, and lymphocytosis, the peripheral blood smear should be evaluated for atypical lymphocytes. A heterophile antibody test should be performed. The symptoms described in association with atypical lymphocytes and a positive heterophile test are virtually always caused by Epstein-Barr virus. Neither liver biopsy nor lymph node biopsy is necessary. Workup for toxoplasmosis or cytomegalovirus infection or hepatitis B and C would be considered in heterophile-negative patients. Hepatitis does not occur in the setting of rheumatic fever, and an antistreptolysin O titer is not indicated.