NBME 2-peds - dreamdoc

[ArchivalUser]

7 week old boy presents with fever, irritability, lethargy for 3 days. No vomiting, diarrhea, or symptoms or an URTI. Always seems hungry to his mother despite being fed 3 ounces of forumla every 3 hours. His mother also notes he has many wet diapers through the day and night. Currently appears irritable. T 37.8 BP 80/50 P 150 R 25 Exam: sunken fontanelle, dry mucus membranes, tenting of skin. No other abnormalities. Urinalsis is negative for glucose and protein.

Which labs:

A- Na 132 Cl 89 K 2.8 HCO3 39 urine pH 5.0 Specific gravity 1.025

B- Na 133 Cl 110 K 3.9 HCO3 16 urine pH 6.0 Specific gravity 1.015

C- Na 163 Cl 117 K 4.3 HCO3 22 urine pH 5.5 Specific gravity 1.003

D- Na 165 Cl 115 K 4.5 HCO3 19 urine pH 5.0 Specific gravity 1.030

[ArchivalUser]

C Diabetes insipidus

[ArchivalUser]

Child with polyphagia, polyruia, 7wks , fever , hypotension, sunken fontanelle =Dg???

[ArchivalUser]

fever due to hypernatremia, hypernatremia due to dehydration...polyuria due to lack of ADH which will cause a diluted urine.
Other possibilities include CAH but no vomiting and BP is ok (CAH kind of out since 21 OH is more Hypotension) and they don't mention anything about ambiguous genitalia.

[ArchivalUser]

what about this one a_antobody?