LYMPHOMA

Q) An 18-year-old boy presents with cough, chest pain, and low-grade nightly fevers of severalweeks duration. He has a 4-year history of smoking two packs of cigarettes per day. Chest x-ray reveals a large mass in the mediastinumwith extension into the right upper chest. Which of the following is the most likely diagnosis?
(A) adenocarcinoma
(B) squamous cell carcinoma
(C) small cell carcinoma
(D) lymphoma
(E) metastatic Wilms tumo

Ans: D.

The differences between adults and children are frequently emphasized in medical training.

The differences between adults and adolescents should also be recognized. The differential diagnosis for many conditions, such as an intrathoracic mass seen in this case, is age dependent. While carcinoma of the lung is a leading cause of intrathoracic mass in adults, it is very rare in adolescents, even those who have a significant smoking history. That eliminates choices (A), (B), and (C). While it is true that Wilms tumor frequently metastasizes to the lung, this malignancy almost always presents in the first few years of age and would be unheard of in an 18-year-old. That leaves lymphoma as the only remaining choice and the most likely diagnosis. (D) is the correct answer. Other causes, such as tuberculosis, histoplasmosis, and sarcoid need to be considered but were not listed as choices

CAH

Q.) 3-week-old infant is admitted with vomiting of 5 days’ duration. Physical examination reveals a rapid heart rate, evidence of dehydration, and ambiguous genitalia. Serum electrolytes are Na+ 120 meq/L, K+ 7.5 meq/L, HCO3 − 12 meq/L, BUN 20 mg/dL. In addition to intravenous fluid replacement with normal saline, administration of which of the following would be most important?
(A) diuretics
(B) potassium exchange resin
(C) glucose and insulin
(D) antibiotics
(E) hydrocortisone

Ans:  (E) The child described probably has congenital adrenal hyperplasia (CAH), an inborn metabolic error of the adrenal cortex. The acidosis (HCO3 −12 meq/L) helps to rule out pyloric stenosis as the cause of the emesis, as most infants with pyloric stenosis have a metabolic alkalosis. The enzyme deficiency in CAH results in decreased production of cortisol and other adrenal cortical hormones and secondary hypertrophy of the adrenal gland. Accumulation of androgen-like precursors of cortisol during fetal development leads to masculinization of the female fetus and ambiguous genitalia, which is an important clue in this case. The low serumsodium and high serum potassium levels are classic findings in this condition, reflecting the lack of mineralocorticoids. In addition to the use of saline, administration of a mineralocorticoid such as cortisone or hydrocortisone is critical. The elevated serum potassium level usually responds rapidly to administration of saline and steroids, and specific therapy with exchange resins or glucose and insulin usually is unnecessary.

As did the preceding question, this question tests the examinee’s ability of recall rather

than recognition, a more difficult but clinically more relevant skill. Instead of providing a list of

diseases or syndromes as possible answers, it provides a list of additional features or findings, one of which is associated with the disorder in question. In this case, as in the preceding question, the feature to be selected is the appropriate therapy. The question tests more than the examinee’s ability to recite the treatment of hyperkalemia. It tests his or her ability to analyze the

clinical situation, make a correct diagnosis, set priorities, and tailor therapy to the specific

pathophysiology involved.

CAT SCRATCH DISEASE

Q.6) A6-year-old girl presents with unilateral nonpainful, nonsuppurative conjunctivitis and preauricular lymphadenitis. What is the most likely causative organism?
(A) Mycobacterium avium
(B) Bartonella henselae
(C) Adenovirus
(D) Staphylococcus aureus
(E) Chlamydia trachomati

Ans: (B) Bartonella henselae
This patient presents with Parinaud oculoglandular syndrome. This syndrome is the

most common atypical presentation of cat scratch disease (CSD) but can also occur with

tularemia, tuberculosis, and syphilis. CSD is one of the most common causes of subacute

lymphadenitis in children. Bartonella henselae is the organism that has been associated with the

clinical syndrome of CSD. Bartonella henselae is transmitted among cats by fleas and bacteremic cats transmit the disease to humans through saliva. Human-to-human transmission does not occur. The conjunctiva is the site of inoculation in oculoglandular syndrome and the conjunctivitis is typically painless and nonsuppurative. A conjunctival granuloma may be present at the inoculation site. 

Lymphadenopathy most often occurs in the preauricular nodes and less commonly submandibular.

REFEEDING SYNDROME

Q.5) A 23-month-old female is hospitalized for severe malnutrition. Which of the following problems is most likely to be the result of inappropriately rapid treatment of the severely malnourished child?
(A) hyperkalemia
(B) hyponatremia
(C) hyperglycemia
(D) congestive heart failure
(E) renal failure

Ans:  (D)

 Congestive heart failure is very easy to precipitate in a severly malnourished child particulary if colloid (blood) or crystalloid (sodium) is infused aggressively. Because the heart is malnourished, contractility and therefore cardiac output is already impaired. By increasing plasma volume which would occur by infusing either of the above substances, the preload to the heart would increase in the face of animpaired pump, resulting in congestive heart failure.

MECONIUM ASPIRATION

Q.3) A term infant requires intubation in the delivery room after aspiration of thick meconium and is brought to the neonatal intensive care unit. Which of the following is the most likely risk factor for meconium aspiration syndrome in this infant?

(A) chromosomal anamoly

(B) congenital heart disease

(C) cystic fibrosis

(D) fetal distress

(E) tracheoesophageal fistula

Ans: D.

 Fetal distress is the major risk factor for meconium aspiration. The mechanism involves the loss of anal sphincter tone, passage of meconium into the amniotic fluid, and aspiration by the distressed, gasping infant during the process of birth. The thick meconium obstructs the airways, causing tachypnea, retractions, and grunting.

This is the type of question in which a little common sense is required. If you knew that meconium aspiration was a relatively common problem in the delivery room, you could eliminate (C) cystic fibrosis (a relatively uncommon disease) as its cause. 
(Meconium ileus, which is associated with cystic fibrosis, has nothing to do with meconium aspiration.) If you realized that aspiration of meconium can only occur before or during delivery, you also could eliminate (B) congenital heart disease and (A) neonatal meningitis, as neither of these generally cause distress during delivery. 
Finally, you should be able to figure out that a tracheoesophageal fistula with or without associated esophageal atresia, would lead to aspiration of saliva, milk, or gastric contents after birth but would not predispose to aspiration of meconium.

A severe pneumonia following meconium aspiration occurs as an in utero response to significant hypoxic or ischemic stress. Infants who have fetal distress, thick meconium, and APGAR scores of less than 7 at 1 and 5 minutes are at increased risk for meconium aspiration syndrome.

When meconium staining of amniotic fluid is noted, the appropriate approach to care of the infant according to The Neonatal Resuscitation Program (NRP) of the American Academy of Pediatrics and American Heart Association include intubation when the infant is not vigorous (defined as having poor respiratory efforts, poor muscle tone, and a heart rate less than 100 beats/minute).