A 16-year-old girl is brought to the physician by her parents. Her mother is concerned because the girl has lost 10 pounds in the last 3 months. She constantly feels weak and tired. She is doing well in high school. The patient says that she eats well, although her appetite has decreased. Her last menstrual period was 3 months ago. She is not sexually active. She does not use tobacco, alcohol, or illicit drugs. Physical examination shows a young, thin girl with multiple brown freckles. The patient has a decreased amount of axillary and pubic hair for her age. Patchy brown spots are seen on her lips and buccal mucosa. Mild generalized muscular tenderness is present. She appears well-groomed, alert, and communicative and does not appear to be especially anxious. Her parents, on the other hand, are worried about her condition and want to know her diagnosis. The patient returns with her parents for a follow-up visit. She complains of intermittent abdominal pain during the past week. Examination findings remain unchanged from the previous visit. Laboratory results are as follows:
Urinalysis is normal. Pregnancy test is negative. Which of the following is the most likely diagnosis?

Question

A 16-year-old girl is brought to the physician by her parents.  Her mother is concerned because the girl has lost 10 pounds in the last 3 months.  She constantly feels weak and tired.  She is doing well in high school.  The patient says that she eats well, although her appetite has decreased.  Her last menstrual period was 3 months ago.  She is not sexually active.  She does not use tobacco, alcohol, or illicit drugs.  Physical examination shows a young, thin girl with multiple brown freckles.  The patient has a decreased amount of axillary and pubic hair for her age.  Patchy brown spots are seen on her lips and buccal mucosa.  Mild generalized muscular tenderness is present.  She appears well-groomed, alert, and communicative and does not appear to be especially anxious.  Her parents, on the other hand, are worried about her condition and want to know her diagnosis. The patient returns with her parents for a follow-up visit.  She complains of intermittent abdominal pain during the past week.  Examination findings remain unchanged from the previous visit.  Laboratory results are as follows:
 Urinalysis is normal.  Pregnancy test is negative.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

Explanation: 11ec2b69_c12e_739e_8f63_4b85eb61d542_MD0005_00 The patient has features consistent with chronic adrenal insufficiency (Addison's disease), including weight loss, abdominal pain, asthenia, amenorrhea, fatigue, weakness, and poor appetite. Physical examination shows muscle tenderness, decreased axillary and pubic hair (due to decreased adrenal androgen production), and increased pigmentation (due to co-secretion of adrenocorticotropic hormone [ACTH] and melanocyte-stimulating hormone). More specific findings are the patient's electrolyte abnormalities: hyponatremia (present in 85%-90% of patients with Addison's disease), hyperkalemia (60%-65% of patients), and an associated mild hyperchloremic metabolic acidosis. A tendency for hypoglycemia can also be seen in chronic adrenal insufficiency. The next step in evaluation of this patient is measurement of a morning plasma cortisol with concurrent ACTH; low cortisol with elevated ACTH is diagnostic for primary adrenal insufficiency. If results are equivocal, this can be followed with an ACTH stimulation test (or the ACTH stimulation test may be ordered at the same time as the morning cortisol to expedite the evaluation). (Choice B) An eating disorder might be suspected in a young woman presenting with weight loss and menstrual irregularities. Anorexia nervosa is also commonly associated with electrolyte abnormalities, which can be severe and intractable. Hyperpigmentation and signs of androgen deficiency, however, would not be expected. (Choice C) Hyperthyroidism shares some similar clinical manifestations with Addison's disease (eg, weight loss, asthenia). However, other findings such as fatigue, androgen deficit signs, hyponatremia, and hyperkalemia are not typical for hyperthyroidism. Hypothyroidism, not hyperthyroidism, is more commonly associated with fatigue and hyponatremia, though not with hyperkalemia. (Choice D) Hypoaldosteronism usually presents as asymptomatic hyperkalemia with mild metabolic acidosis. Hyponatremia is generally not seen unless there is concurrent cortisol insufficiency. In addition, hyperpigmentation is not seen as there is no increased production of ACTH/melanocyte-stimulating hormone. (Choice E) The most common etiology for chronic adrenal insufficiency is autoimmune destruction. Metastatic disease, infection (eg, tuberculosis), and hemorrhagic infarction are other potential causes but would be much less common, especially in a young patient without other features of these conditions. Educational objective: Chronic adrenal insufficiency should be suspected in patients with fatigue, weight loss, myalgias, increased pigmentation, and decreased axillary and pubic hair. Hyponatremia, hyperkalemia, and hyperchloremic metabolic acidosis are characteristic laboratory findings. The most common etiology of this condition is primary adrenal insufficiency (Addison's disease). Diagnosis is confirmed with low morning plasma cortisol and elevated adrenocorticotropic hormone [ACTH] (often performed with an ACTH stimulation test). References: Autoimmune Addison's disease. (http://www.ncbi.nlm.nih.gov/pubmed/21164269)

A 16-Year-Old Girl Is Brought to the Physician by Her