The presence of nonthrombocytopenic palpable purpura, colicky abdominal pain, and arthritis in a pediatric patient is most consistent with which one of the following?
Correct Answer E:
The most common pediatric vasculitis is Henoch-Schönlein purpura. It is an IgA-mediated small-vessel vasculitis that classically presents with the triad of nonthrombocytopenic palpable purpura, colicky abdominal pain, and arthritis.
Kawasaki disease is manifested by conjunctival injection, mucosal erythema, rash, and lymphadenopathy. Takayasu arteritis has numerous manifestations, including night sweats, fatigue, weight loss, myalgia, and arthritis. Later findings may include hypertension, skin lesions, and cardiac disorders. Wegener granulomatosis causes constitutional symptoms also, including weight loss and fatigue, with later findings including respiratory problems, ophthalmologic lesions, neuropathies, glomerulonephritis, and skin lesions.
Polyarteritis nodosa is another disease that causes constitutional symptoms such as fatigue, fever, and myalgias. It also causes skin lesions, gastrointestinal symptoms such as postprandial abdominal pain, and cardiac lesions.
A 7-year-old boy is brought to your department by his parents because he had a reddish rash of both legs and buttocks for the last 5 days. The boy also has been complaining of abdominal pain and pain in both knees. He was recently evaluated for sore throat. Physical examination reveals erythematous papules on both legs and buttocks, knee joints are swollen and tender on palpation, and the abdomen is diffusely tender.
Which of the following is a key feature of this condition?
Correct Answer C:
This patient presents with Henoch-Schonlein purpura (HSP) triad of erythematous rash, abdominal pain/renal failure, and arthralgias. While some patients with HSP may not have all the 3 symptoms at presentation and others could have other symptoms, majority of patients with this condition have been observed to have these 3 major symptoms. 75% of affected patients are between 2 and 11 years of age. HSP is a clinical diagnosis and generally laboratory evaluation is not necessary to establish this diagnosis. The key feature of this disease is nonthrombocytopenic purpura (choice C).
→ Rickettsia infection (choice A) is a key feature of Rocky Mountain spotted fever, a disease that should be in the differential of HSP. Patients affected with Rocky Mountain spotted fever usually have an erythematous rash that can sometimes be confused with HSP, but they do also have some clear exposure to ticks, vectors of Rickettsia rickettsii.
→ Consumptive coagulopathy (choice B) characterizes disseminated intravascular coagulation, which results in abnormalities of most clotting indicators such as bleeding time, prothrombin time, and partial thromboplastin time.
→ Thrombocytopenic purpura (choice D) can be idiopathic or thrombotic. HSP is a nonthrombocytopenic vasculitis.
→ Nonimmune hemolytic anemia (choice E) characterizes hemolytic uremic syndrome, another condition in the differential of HSP. It is often associated with E. coli O157:H7 infection and results in acute renal failure. Erythematous rash is not commonly seen.
Key point:
Erythematous macules, abdominal pain, and arthralgias in a child < 12 years old, is suggestive of Henoch-Schonlein purpura. The key feature of this disease is nonthrombocytopenic purpura.
A 6-month-old girl presents with vomiting and diarrhea of acute onset. Her systolic blood pressure is 40 mm Hg, pulse is 160/minute, she has poor peripheral circulation and is very lethargic. Her serum sodium concentration is 158 mmol/L.
Which one of the following is the best initial management?
Correct Answer A:
Hypernatremia is plasma Na concentration > 145 mEq/L caused by a deficit of water relative to solute. A major symptom is thirst; other clinical manifestations are primarily neurologic (due to an osmotic shift of water out of cells), including confusion, neuromuscular excitability, seizures, and coma. Diagnosis is by measuring serum Na.
Severely dehydrated infants must have their circulating blood volume restored first, usually with 0.9% saline in aliquots of 20 mL/kg IV. Treatment is then with 5% D/W/0.3% to 0.45% saline solution IV in volumes equal to the calculated fluid deficit, given over 2 to 3 days to avoid a rapid fall in serum osmolality, which would cause rapid movement of water into cells and potentially lead to cerebral edema. Maintenance fluids should be provided concurrently. The goal of treatment is to decrease serum Na by about 10 mEq/L/day.
A 14-year-old boy is referred with a blood pressure of 145/80 mmHg. There is family history of essential hypertension. His general physical examination and urinalysis are normal. Home blood pressure readings are consistently between 100-110 mmHg systolic and 70-80 mmHg diastolic.
Which one of the following is the most likely cause of his hypertension?
White coat hypertension is a phenomenon in which patients exhibit elevated blood pressure in a clinical setting but not when recorded by themselves at home. It is believed that this is due to the anxiety some people experience during a clinic visit and see a physician in a ‘white coat’.
As the notion of "normal" is subjective and changes from individual to individual, a reference measurement is necessary. As night-time and self measured values are often not subject to daily stress while clinical values are subject to unusual anxiety, daytime ambulatory blood pressure is used as a reference because it takes into account daily stress but not in excess. Due to specificity involved in diagnosis of white coat hypertension, many problems have been incurred in its diagnosis and treatment.
Which one of the following is the most common cause of hypertension in children under 6 years of age?
Although essential hypertension is most common in adolescents and adults, it is rarely found in children less than 10 years old and should be a diagnosis of exclusion. The most common cause of hypertension is renal parenchymal disease, and a urinalysis, urine culture, and renal ultrasonography should be ordered for all children presenting with hypertension. Other secondary causes, such as pheochromocytoma, hyperthyroidism, and excessive caffeine use, are less common, and further testing and/or investigation should be ordered as clinically indicated.
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