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Which immune deficiency in this 9 months old child!

4K views 8 replies 6 participants last post by  tunde michael 
#1 ·
9 months old boy is brought to physician because discharge from left ear for 1 day, he has frequent infection since age of 4 months, he had strept pneumonia bacteremia at age 4 month, H.influenza meningitis at age 6 months, recurrent strept pneumonia infection he also had two episodes of frequent infection during this period he is the only child in this family there is no family history of frequent infections, his immunization up to date, he is 20th percentile for weight and 3rd percentile in length he is not in acute distress now .

what most likely diagnosis ?

A- Chronic granulomatous disease
B- Transient hypogammaglobulinemia
C-DiGeorge syndrome
D- X-linked agammaglubulinemia
E- Sever combined immunodefeciency
 
#3 ·
should start after 6 months age
ur right about b cell infection but age dont match
and not CGD need purulent meterial leak out from ulcer or Lymph node

not digeorge (presented with hypo ca )

SCID is combine t cell (HIV - varcella- candidia -pcp) and b cell infection (sinopulmonary infections )

the answer is
B- Transient hypogammaglobulinemia (appear in age 4 months till 11 month disappear.B-cell defect cause sinopulmonary infections
 
#4 ·
my answer is also B.
cuz there is no family history, therefore ruling out SCID and X-linked
in Dieorge we have hypocalcemia and also T-cell def but here seems like we are lacking B cell def.
and CGD is out of questions cuz strep Pneumonia is not cat Poisitive
 
#6 · (Edited)
this question really confusing i choose B also because they mention in question that no family history of frequent infection

but the correct answer is D ( but i am not agree )

the source of question from SAMPLE practice and orientation material step2 ck

fro web site usmle .org new version 2011

i found this explanation from kaplan qbank they give you explanation

i upload file PDF LOOK AT QUESTION NUMBER 120

they said this explanation but i am not satisfied with it:

Answer B. X-linked agammaglobulinemia: This disorder is characterized by low Ig and B cell levels, intact cellular immunity, and onset of infections after the maternal antibodies disappear (4-6 months of age). Patients have recurrent pyogenic infections often involving the lungs, sinuses, and bone, often including pathogens such as pneumococcus, Haemophilus, and Streptococcus. The genetic defect involves the inability to form B cells from pre-B cells.

A Chronic granulomatous disease of childhood: This condition is typically associated with lymphadenopathy and recurrent abscess formation not described in this case.
E-Severe combined immunodeficiency: This is a severe immunodeficiency condition usually affecting children in early infancy with recurrent, severe infections of the lungs and GI tract.
C. Thymic-parathyroid dysplasia (DiGeorge syndrome): Features of this disorder that are not reported in this case include hypocalcemia leading to tetany (in the early neonatal period), a characteristic facies (low set ears, hypertelorism, micrognathia, and a shortened philtrum), and congenital heart defects. The primary problem is hypoplasia of the thymus and parathyroid glands. The immune effects include partial to complete T-cell immunodeficiency, but normal B cell immunity.

D. Transient hypogammaglobulinemia of infancy: This condition results from the slow development of antibodies in infants, resulting in recurrent infections starting at 3-6 months (when maternal antibodies decrease). This period of recurrent infections typically ends by the first year as the immune system becomes more fully
developed. While a possibility in this case, this condition is more common in premature infants.
 

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#7 · (Edited)
@kemoo,

I'll go with D

X-linked agammaglobulinemia
-Male child( the single most important clue on the exam)
-Early onset
-Predominant B-cell related defects.

only few cases of Transient hypogammaglobulinemia occur earlier than 6mths.

"Approximately 5% of infants with Transient Hypogammaglobulinemia of Infancy are symptomatic when they are younger than 6 months, 50% become symptomatic at 6-12 months, and 25% become symptomatic when they are older than 12 months"

source: http://emedicine.medscape.com/article/888706-clinical
 
#9 ·
Concerning family history in recessive conditions, If the family tree was not followed into the past long enough, an affected individual may not be uncovered.

-The recessive gene might have been masked in asymptomatic female carriers (X-linked) for a long time, hence only genetic testing of parents reliably exclude disease.

-Moreover, rarely, spontaneous mutations have been described as a cause.

But for dominant conditions, family history carries significant weight.
 
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