MICROBIOLOGY AND IMMUNOLOGY VMS I, 2002

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MICROBIOLOGY AND IMMUNOLOGYVMS I, 2009
PROBLEM 8 SORE THROAT AND INFLAMED KIDNEYS LUC
VAN KAER, PhD
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CASE DESCRIPTIONA seven-year-old
boy who had no prior known major illness
developed a soar throat and fever of 103oF on
November 18th. The fever and sore throat lasted
for three days. On November 28th, he developed
hematuria, puffy eyelids, and swollen
ankles. He went to a physician, who noted a
reddened throat, with enlarged cervical lymph
nodes. The patient had pitting edema of his feet
and lower legs, and a blood pressure of 165/105
mm Hg. The urine analysis showed 4 protein, 20
to 30 erythrocytes and 25 to 30 leukocytes per
high-powered field, and one erythrocyte cast.
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CASE DESCRIPTION -- continuedThe physician
admitted the patient to a hospital where he made
certain that laboratory investigations included
throat culture, serum for titers of
antistreptolysin O and C3 component of the
complement system, and evaluation of renal
function. The patient was placed on bed rest and
treated with 1,200,000 units of procaine
penicillin intramuscularly. The throat culture
revealed Group A streptococci. The
anti-streptolysin O titer was 800 C3 was 53 mg
per 100 ml (normal, 110 to 160 mg per 100 ml)
the serum creatinine was 2.5 mg per 100 ml
(normal, lt1 mg per 100 ml). Several days later a
research laboratory reported that the
streptococci were M antigen-type 12. The patient
gradually returned to normal over a 4-week period.
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Questions1) What is the diagnosis in this
case and what role did infection play in its
pathogenesis? What is the epidemiology of
poststreptococcal glomerulonephritis? What is the
usual niche of the Group A streptococcus
(Streptococcus pyogenes) and what kinds of
infections does it cause?
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Questions2) What distinguishes suppurative
from nonsuppurative Group A streptococcal
diseases? What are the clinical features of the
other nonsuppurative complication of
streptococcal infection, i.e., acute rheumatic
fever (ARF)? How do you make the diagnosis of
ARF? How has the epidemiology of Group A
streptococcal disease changed in the United
States in the past 50 years and how does the
situation in the US differ from developing
countries? Why do we treat Group A streptococcal
pharyngitis?
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Questions3) What is the basis for
classification of Streptococci? What is the
significance of M antigen type 12?
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Questions4) How are the respective tissue
injuries thought to be induced in acute post
streptococcal acute glomerulonephritis (APSGN)
and acute rheumatic fever (ARF)? What mechanisms
account for the fact that some streptococci are
nephritogenic while most are not? Do circulating
immune complexes generally cause the same renal
damage as illustrated here?
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Questions5) How was streptococcal infection
diagnosed in this case? Why was penicillin
therapy given? Would you also have given
penicillin in a case of ARF, and if so, why?
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Questions6) What are the prospects for
developing an effective anti-Group A
streptococcal vaccine? What are potential
problems?
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