Download A 46-year-old Caucasian man presents with a history of fatigue and

A 46-year-old Caucasian man presents with a history of fatigue and poor
concentration for the last few months. Past medical history is
significant for kidney stones and a treated peptic ulcer years ago. He has
smoked 1 pack of cigarettes each day for the last 15 years. Review
of systems was positive for bilateral hand pain for the past several months, which
was not alleviated by ibuprofen. The patient denies taking
any other medications. Physical examination is unremarkable. Thyroid function
tests and blood glucose are normaI. The serum calcium is 11
mg/dL and serum phosphorus is 2.6 mg/dL. Parathyroid hormone (PTH) is 800
pg/mL. Urine calcium is 425 mg/24 hr.
Question 1 of 5
Which of the following is the most likely diagnosis?
/ A. Primary hyperparathyroidism
/ B. Sarcoidosis
/ C. Secondary hyperparathyroidism due to ectopic secretion of a PTH-Iike
substance
/ D. Secondary hyperparathyroidism due to renal failure
/ E. Vitamin D excess
Explanation - Q: 1.1
Close
The correct answer is A. Primary hyperparathyroidism is most commonly
caused by parathyroid adenomas (85% of the cases), followed by
hyperplasia (12-15%), and rarely, carcinoma (<3%). It is characterized by
excess PTH production, which results in increased serum calcium and
decreased phosphate levels. It is a relatively common disease of the middleaged and elderly. About 85% of the affected patients are asymptomatic and
evidence for the disorder is often found during routine laboratory screening.
One of the initial presentations of sarcoidosis (choice B) is hypercalcemia.
Mononuclear cells in granulomas produce increased 1,25-cholecalciferol
(1,25(OH)2 D3), resulting in increased calcium absorption from the gut.
Phosphate and PTH levels are not affected.
Secondary hyperparathyroidism may manifest in different ways depending
the underlying etiologies. Ectopic secretion of PTH-like substances (choice
C) is associated with a low PTH, because the endogenous PTH is
suppressed by the hypercalcemia from the former. Renal failure (choice D)
exhibits hypocalcemia initially, which leads to the stimulation of PTH
secretion. Phosphate tends to be elevated because of decreased excretion
from the renal insufficiency.
Vitamin D excess from ingestion (choice E) results in hypercalcemia
because more 1,25(OH)2D3 is produced; therefore, PTH becomes
suppressed.
Question 2 of 5
Bilateral hand x-ray films are obtained. They show subperiosteal bone resorption
and some cyst formation. What do these x-ray findings
suggest?
/ A. Hungry bone syndrome
/ B. Osteogenesis imperfecta
/ C. Osteitis fibrosa cystica
/ D. Osteomalacia
/ E. Paget disease of bone
Explanation - Q: 1.2
Close
The correct answer C. Osteitis fibrosa cystica is a characteristic, but rarely
seen, manifestation of primary hyperparathyroidism. The cystic changes in
the bone are due to osteoclastic resorption, and fibrous replacement of
resorbed bone may lead to the formation of nonneoplastic tumor-like masses
(brown tumor) on x-ray films.
Hungry bone syndrome (choice A) is a another rare phenomenon that can
occur after parathyroid surgery. In this disorder, there is calcium uptake into
the bones, so that the serum calcium falls.
Osteogenesis imperfecta (choice B) is a heritable disease associated with
brittle bones, blue sclerae, and dental abnormalities. Patients often have a
history of multiple fractures.
Osteomalacia (choice D) can be secondary to vitamin D deficiency; it is
caused by defective mineralization of the bone matrix. On x-ray films, there is
a "ground glass" appearance of the bony trabeculae and the cortices are
thinned.
Paget disease of the bone (choice E) is a fairly common disease of the
elderly; it is often detected by elevated alkaline phosphatase levels. Lytic
lesions are seen on x-ray films.
Question 3 of 5
Which of the following would be the most appropriate management for this
patient?
/ A. Bisphosphonates
/ B. Calcitonin
/
/
/
C. FIuid hydration with diuretics
D. Observation with yearly measurement of serum calcium and creatinine
E. Parathyroidectomy
Explanation - Q: 1.3
Close
The correct answer is E. This patient would be a candidate for
parathyroidectomy. Criteria for surgery include age less than 50 to minimize
the complications of untreated hypercalcemia, and having a serum calcium >
11 mg/dL. In addition, urolithiasis, impaired renal function, marked
hypercalciuria, and osteoporosis are further indications for surgery. Most
patients with primary hyperparathyroidism tend not to be symptomatic from
their hypercalcemia.
Bisphosphonates (choice A) are not used to manage the chronic
hypercalcemia stemming from primary hyperparathyroidism but are more
useful treating hypercalcemia associated with malignancy.
Calcitonin (choice B), as with bisphosphonates, is useful in the treatment of
neoplastic hypercalcemia.
For more urgent and symptomatic hypercalcemia (Ca2+ > 12-13 mg/dL, ECG
changes with short QT intervals, etc.), fluids and diuretics (choice C) are
first-line therapy, especially if the patient seems dehydrated as well as
hypercalcemic.
Observation (choice D) alone is not appropriate. Chronic hypercalcemia can
lead to further calcium deposition in tissues; eventually, untreated
hypercalcemia can lead to coma and cardiac arrest.
Question 4 of 5
If this patient had decreased serum PTH Ievels, which of the following would be
the most likely diagnosis?
/ A. Graves Disease
/ B. Lithium use
/ C. Malignancy
/ D. Sarcoidosis
/ E. Thiazide diuretics
Explanation - Q: 1.4
Close
The correct answer is C. Malignancy (especially bronchogenic squamous
cell carcinoma, multiple myeloma, and renal cell carcinoma) may produce a
PTH-like hormone that functions like PTH and results in hypercalcemia.
However, the hypercalcemia (via negative feedback) suppresses PTH levels
to less than 20 pg/mL. Given the patient's smoking history, one may consider
obtaining a chest x-ray film, CBC, and urinalysis to screen for the above
malignancies.
Moderate hypercalcemia of unknown causes can be seen in patients with
Graves disease (choice A). It is characterized by the presence of a diffusely
enlarged goiter, exophthalmos (eyes protruding out), and pretibial myxedema
as well as decreased TSH.
Lithium (choice B) can increase the PTH threshold such that a higher level
of serum calcium is required to shut off PTH production. The patient does not
have a history of manic depressive disorder and denies taking any
medications other than ibuprofen.
Sarcoidosis (choice D), along with other granulomatous diseases, can
present with hypercalcemia, but the phosphate levels are not affected.
Furthermore, the patient can have alveolar infiltrates and hilar adenopathy on
chest x-ray films as well as respiratory complaints. An elevated ACE level
can confirm the diagnosis.
Thiazides (choice E) can decrease calcium excretion, but this effect tends to
be temporary; furthermore, patients on thiazides can also have low sodium
and potassium levels.
Question 5 of 5
If this patient also stated that his mother had thyroid cancer surgery and his
brother had uncontrolled hypertension, which of the following
diagnoses would be most likely?
/ A. Familial benign hypercalcemic hypocalciuria
/ B. MEN Type l
/ C. MEN Type lI/IIa
/ D. MEN Type llI/IIb
/ E. Pseudohypoparathyroidism
Explanation - Q: 1.5
Close
The correct answer is C. A patient with parathyroid hyperplasia along with a
family history of medullary thyroid cancer and pheochromocytoma
(uncontrolled hypertension) may have MEN II/IIa syndrome/Sipple syndrome.
Like all the MEN syndromes, it is autosomal dominant with variable
expression.
Familial benign hypercalcemic hypocalciuria (choice A) is also autosomal
dominant; patients may have normal PTH levels with elevated serum
calcium. It is benign, and differentiated from hyperparathyroidism by having a
low urinary calcium.
MEN type 1/Wermer syndrome (choice B) has a variety of symptoms
caused by hyperplasia/adenomas/cancers of parathyroid, pituitary, and islet
cells of the pancreas.
MEN type III/IIb (choice D) is similar to MEN type II/IIa because it is also
associated with medullary thyroid carcinoma and pheochromocytoma;
however, parathyroid hyperplasia is rare. It is distinguished by the presence
of mucosal neuromas.
Pseudohypoparathyroidism (choice E) is a hereditary disorder associated
with hypoparathyroidism because of tissue resistance to PTH. Therefore, the
PTH levels are high with low serum calcium and phosphate levels. Patients
can have short stature and moon facies as well as having characteristic short
4th fingers.
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A 52-year-old woman presents to her physician's office complaining of an
enlarging nose, thickening of her tongue, and coarsening of her
facial features. She had started noticing the gradual change 2-3 years earlier,
accompanied by soreness of the hands. No change in shoe size
or enlargement of the limbs was reported. The patient denies having headaches.
When she was 42 years old, she was diagnosed with chronic
bronchitis. At the age of 51, she underwent thyroid surgery for multinodular
goiter. On examination, her blood pressure is 140/90 mm Hg and
her pulse is 68/min. A chest x-ray film shows a welI-demarcated opacity, 5 cm in
diameter, Iocated in the posterobasal part of the right
pulmonary lobe.
Question 1 of 5
Which of the following is the most likely diagnosis?
/ A. Gigantism
/ B. McCune-AIbright syndrome
/ C. NAME syndrome
/ D. Paraneoplastic syndrome
/ E. Pituitary adenoma
Explanation - Q: 2.1
Close
The correct answer is D. This patient has acromegaly secondary to a
paraneoplastic syndrome. Paraneoplastic syndromes refer to a large group
of medical problems in patients suffering from cancer. They are defined as
clinical syndromes that result from systemic effects of substances produced
by the tumor. The symptoms are mostly endocrine, but may be
neuromuscular, cutaneous, hematologic, renal, gastrointestinal or
miscellaneous, depending on the chemical nature of the substance
produced. Tumors can produce antibodies, hormones, hormone-like
substances or hormone precursors, fetal proteins, or cytokines. Endocrine
symptoms usually resemble the more common endocrine disorders (e.g.,
Cushing syndrome, acromegaly). Lung tumors can cause several types of
endocrine paraneoplastic syndrome. Cushing syndrome and SIADH are
related to the ectopic production of hormone-like substances by small cell
cancer of the lung. Hypercalcemia, caused by the secretion of parathyroid
hormone related peptide (PTHrP), and acromegaly, caused by an ectopic
secretion of growth hormone, are endocrine paraneoplastic syndromes
associated with squamous cell carcinoma of the lung. Acromegaly caused by
an ectopic secretion of growth hormone (GH) is difficult to differentiate from
that of pituitary origin. Provocation tests (oral glucose, TRH test, GHRH test)
may be normal or may yield paradoxical results. The usual episodic pattern
of secretion is missing in cases of ectopic GH secretion. Long-acting
somatostatin analogues and dopamine agonists are used in the treatment of
this condition. Surgical or other treatment of the lung tumor represents
definitive therapy for the patient.
Hypersecretion of GH in childhood will result in gigantism (excessive linear
growth; choice A); onset in late adolescence will produce tall stature and
acromegaly.
McCune-Albright syndrome (choice B) is manifested clinically with fibrous
dysplasia of bones, hyperpigmented skin changes, goiter, acromegaly,
hyperparathyroidism, and hypophosphatemic hyperphosphaturic rickets.
NAME syndrome (nevi, atrial myxoma, myxoid neurofibromas, and
ephelides) (choice C) is associated with acromegaly due to pituitary GHsecreting tumors.
GH hypersecretion that occurs after epiphyseal fusion is termed acromegaly.
More than 90% of acromegaly cases are caused by pituitary adenomas
(choice E) secreting excess GH.
Question 2 of 5
The pituitary cells that normally produce the hormone involved in this patient's
disease process belong to which of the following types?
/ A. Corticotrophs
/ B. Gonadotrophs
/ C. Mammotrophs
/ D. Somatotrophs
/
E. Thyrotrophs
Explanation - Q: 2.2
Close
The correct answer is D. Cells of the anterior lobe of the pituitary have
been broadly classified, based on their staining features as chromophils,
which stain with acidic and basic dyes, and chromophobes, that have little
affinity for these stains. Chromophils are further subdivided as basophils,
which stain blue (10% of population) and acidophils, which stain red (40%).
Chromophobes (50%) are the predominant type and are thought to be either
inactive chromophil progenitors or resting, exhausted cells. Modern
immunocytochemical techniques using specific antisera against a particular
hormone are necessary to allow identification of these cell types.
Somatotrophs (acidophils) are small round cells with dense 350 nm granules,
and are believed to synthesize growth hormone.
Round or oval cells with granules and lipid droplets are called corticotrophs
(choice A) and they synthesize ACTH.
FSH and LH are produced within large and small round cells that are called
gonadotrophs (choice B).
Mammotrophs (choice C) are cells with a variable size and the presence of
dense pleomorphic 600 nm granules. These cells synthesize prolactin.
Thyrotrophs (choice E) are TSH-producing cells, which are large and
polygonal with 150 nm granules.
Question 3 of 5
Which of the following is the major inhibitor of the release of the hormone in
question?
/ A. Gastrin
/ B. GHRH (growth hormone releasing hormone)
/ C. GIP (gastric inhibitory peptide)
/ D. Secretin
/ E. Somatostatin
Explanation - Q: 2.3
Close
The correct answer is E. The cyclic tetradecapeptide hormone,
somatostatin, was first described as the major physiological inhibitor of GH
secretion, but it has been since shown that it can also inhibit the secretion of
insulin, glucagon, gastrin, and secretin. Somatostatin is found in various
parts of the brain, where it functions as a neurotransmitter/neuromodulator
affecting sensory input, locomotor activity, and cognitive function. It is also
found in the retina, where it probably acts as an inhibitory neurotransmitter.
In the hypothalamus, it is secreted into the portal hypophyseal vessels,
travels to the pituitary somatotrophs, and inhibits GH secretion.
Gastrin (choice A) is secreted by G-cells in the antrum of the stomach, and
then travels to the parietal cells to stimulate acid secretion.
GHRH (growth hormone releasing hormone) (choice B) is a 44 amino acid
peptide and is the major stimulator of GH release. Its secretion from the
hypothalamus is episodic, and these fluctuations coincide with most of the
surges in growth hormone secretion.
Fatty acids in the duodenum cause the release of GIP (choice C), which acts
directly on parietal cells to reduce acid secretion.
Duodenal cells in the presence of acid, fat, and protein, release secretin
(choice D). The major target tissue is the pancreas, but it also inhibits gastric
acid secretion.
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Question 4 of 5
Some of the involved hormone's actions are mediated by somatomedins (IGFs).
Which of the following effects would most likely be a result of
the action of IGFs (insulin-Iike growth factors)?
/ A. Decreased insulin sensitivity
/ B. Epiphyseal growth
/ C. Increased GI absorption of Ca2+
/ D. Lipolysis
/ E. Na+retention
Explanation - Q: 2.4
Close
The correct answer is B. Insulin-like growth factors (IGFs), or
somatomedins, are a family of peptide hormones with mitogenic properties
and insulin-like features that mediate the effects of GH on skeletal tissue,
e.g. by stimulating epiphyseal growth. They are synthesized primarily in the
liver, but are also made in cartilage, pituitary, and brain. The principal
circulating somatomedins in humans are insulin-like growth factor I (IGF-I,
somatomedin C) and IGF-II (somatomedin A). Secretion of IGF-I is
independent of GH in utero, but it is stimulated by GH after birth. Its
concentration in plasma peaks at the time of puberty and then declines to
low levels at old age. IGF-II does not play a physiological role after birth, and
its concentration is constant during postnatal development. Some of GH's
actions are direct, and some are indirect, i.e., mediated by IGF-I. IGF-I
stimulates proliferation of chondrocytes, sulfate incorporation, and collagen
synthesis. It stimulates both the differentiation and proliferation of myoblasts,
and stimulates amino acid uptake and protein synthesis, thereby playing an
important role in muscle growth. GH plays a permissive role by converting
the cartilage stem cells into cells that respond to IGF-I. IGF-I possesses
insulin-like activity, increases protein synthesis, stimulates DNA thymidine
incorporation, and expresses antilipolytic actions. Synthetic IGF-I
(somatomedin-1) can be used in children with growth disorders caused by
GH insensitivity. The other actions listed are not thought to be mediated by
somatomedins.
Human GH increases hepatic glucose output and exerts anti-insulin effects
(choice A) in muscle. Long-exposure to this hormone is usually associated
with hyperinsulinemia, and produces the state of insulin resistance. The
mechanism is not clear, but involves receptor and postreceptor interactions.
GH increases intestinal absorption of calcium (choice C).
GH increases circulating FFA (free fatty acids) levels (choice D), which is an
important energy source for cells during hypoglycemia, fasting or stressful
situations.
GH causes Na+ retention (choice E) by inhibiting excretion of sodium by
kidneys.
Question 5 of 5
The lung carcinoma seen on the chest x-ray film is most likely which of the
following pathologic types?
/ A. Adenocarcinoma
/ B. Large cell carcinoma
/ C. Pancoast tumor
/ D. Small cell carcinoma
/ E. Squamous cell carcinoma
Explanation - Q: 2.5
Close
The correct answer is E. Paraneoplastic syndromes are clinical syndromes
resulting from tumor-produced hormones and occur in 10-15% of cancer
patients. Lung cancers can cause several paraneoplastic syndromes based
on the humoral factor being produced. Squamous cell carcinomas are one of
the most common primary malignancies of the lung and are often seen in
smokers. They usually arise from central bronchi, producing a hilar mass.
Hypercalcemia, caused by the secretion of parathyroid hormone-related
peptide (PTHrP), and acromegaly, caused by an ectopic secretion of growth
hormone, are endocrine paraneoplastic syndromes associated with
squamous cell carcinoma of the lung.
Adenocarcinoma (choice A) often forms on scars, or in lungs with interstitial
disease. It is the most prevalent form in the U.S. (35% of cases). It often
induces fibrotic changes, usually accompanied by hilar and mediastinal node
involvement. Adenocarcinoma is less strongly associated with smoking than
squamous cell carcinoma.
Large cell lung carcinoma (choice B) may be of a giant cell or a clear cell
variant. Giant cell carcinoma is a large cell type with a component of highly
pleomorphic, multinucleated cells. It is particularly aggressive and carries a
very poor prognosis.
Apical localization, with tumor invading the brachial plexus and sympathetic
chain, pain in the shoulder, and Horner syndrome (ipsilateral miosis, ptosis
and anhidrosis) are pathognomonic for Pancoast tumor (choice C). These
tumors most commonly represent a local extension of a squamous cell
carcinoma to the upper part of the lung.
Small-cell (oat-cell) carcinoma (choice D) occurs almost exclusively in
smokers. It is a very aggressive type and often metastasizes before the
tumor reaches a large size. Microscopically, small cells with minimal
cytoplasm are seen. SIADH (syndrome of inappropriate secretion of
antidiuretic hormone) is most common in cases with small cell lung cancer.
A frantic mother brings her 2-week-old daughter to the emergency department
because of protracted vomiting. She states her baby has been
vomiting for the last few days and was not tolerating any Pedialyte, milk, or
water. The baby had been "very fussy" but had not been feverish.
The course of her pregnancy was uneventful and she was vaginally delivered
without any complications.On examination, the baby appears ilI,
but well developed. Her blood pressure is 50/30 mm Hg, pulse is 176/min, and
respiratory rate is 35/min. Her oral mucosa look dry and she is
not tearing much. Her anterior fontanelle appears sunken, and mild tenting can
be elicited in her skin. An enlarged clitoris and partial fusion of
the labial folds is noted. Serum electrolytes are significant for sodium of 123
mEq/L, chloride of 92 mEq/L, and bicarbonate of 27 mEq/L.
Question 1 of 5
Which of the following is most likely diagnosis?
/ A. Congenital adrenal hyperplasia
/ B. Hermaphroditism
/ C. Mixed gonadal dysgenesis
/ D. Pyloric stenosis
/ E. Viral gastroenteritis
Explanation - Q: 3.1
Close
The correct answer is A. Congenital adrenal hyperplasia (CAH) is an
autosomal recessive disease typified by adrenal insufficiency (hyponatremic
hypovolemia and/or shock) from decreased aldosterone production and
abnormal sexual development. In the classic form, female newborns present
with ambiguous genitalia ranging from an enlarged clitoris, partial to
complete fusion of the labioscrotal folds, and presence of a urogenital sinus.
Adrenal crisis with severe salt wasting may occur. For patients with salt
wasting congenital adrenal hyperplasia, both glucocorticoids (to replace
cortisol) and mineralocorticoids (to replace aldosterone) should be used in
addition to IV fluids for resuscitation.
True hermaphroditism (choice B) is a condition in which both an ovary and a
testis are present. The external genitalia can display all gradations of the
male-to-female spectrum so an enlarged clitoris and labioscrotal fusion can
be seen. However, there is no associated adrenal crisis.
Mixed gonadal dysgenesis (choice C) is the 2nd most common cause of
ambiguous genitalia; however, there is no associated adrenal insufficiency. It
may become more apparent during sexual maturation during puberty.
Babies with pyloric stenosis (choice D) can have projectile bilious vomiting in
the first few days of their birth and can become severely dehydrated.
However, they do not have ambiguous genitalia.
Similarly, patients with viral gastroenteritis (choice E) can be dehydrated
from vomiting, but do not have ambiguous genitalia.
Question 2 of 5
Which of the following is the most common cause of ambiguous genitalia?
/ A. 5-alpha-reductase deficiency
/ B. 11-hydroxylase deficiency
/ C. Maternal ingestion of virilization drugs during pregnancy
/ D. Mosaic 45,X/46,XY
/ E. 21-hydroxylase deficiency
Explanation - Q: 3.2
Close
The correct answer is E. 21-hydroxylase deficiency is the most common
cause of ambiguous genitalia and accounts for 80-95% of CAH. There are 2
types of deficiencies; the classic and salt wasting form tends to present in the
newborn but the non-classic form can occur in late childhood and
adolescence and is less associated with salt wasting. The ambiguous
genitalia results from the virilization effects of excess DHEA produced.
In the testes, 5-alpha-reductase (choice A) converts testosterone to
dihydrotestosterone and a single mutation in the enzyme could result in
ambiguous genitalia.
11-hydroxylase deficiency (choice B) can present similarly to late-onset 21hydroxylase deficiency, with hirsutism and abnormal menses, but it is less
common.
Maternal ingestion of progesterone (choice C) has been associated with
virilization in utero.
Mosaic 45X/46,XY (choice D) is the karyotype for mixed gonadal
dysgenesis.
Question 3 of 5
Which of the following results would be diagnostic of this patient's condition?
/ A. Decreased serum ACTH
/ B. Decreased serum aldosterone
/ C. Increased serum DHEA
/ D. Increased serum 17-OH-progesterone
/ E. Increased urinary 17-ketosteroids
Explanation - Q: 3.3
Close
The correct answer is D. Patients with 21-hydroxylase deficiencies have
elevated 17-OH-progesterone because the enzyme deficiency prevents the
formation of aldosterone, so the pathway is shunted toward the formation of
DHEA and cortisol. Since 21-hydroxylase is also needed for cortisol
synthesis, 17-OH-progesterone is accumulated. Therefore, patients have
both aldosterone and cortisol deficiency and go into adrenal crisis.
Since the cortisol is low, ACTH (choice A) is elevated in patients with 21hydroxylase deficiency, resulting in the hyperplasia of adrenals.
Decreased aldosterone (choice B), elevated DHEA (choice C), and
elevated urinary 17-ketosteroids (choice E) can be seen in both 11- and 21hydroxylase deficiencies. 17-OH-progesterone is more specific for a 21hydroxylase deficiency.
Question 4 of 5
If a young woman had 11-hydroxylase deficiency, which of the following
presentations would be most likely?
/ A. Adrenal insufficiency
/ B. EIevated 11-deoxycortisol
/
/
/
C. Hyperkalemia and hypotension
D. Increased aldosterone
E. Normal menses and hair growth
Explanation - Q: 3.4
Close
The correct answer is B. Patients with 11-hydroxylase deficiency present
with features of androgen excess, rather than adrenal insufficiency (choice
A). 11-hydroxylase deficiency results in the accumulation of 11deoxycorticosterone and 11-deoxycortisol. Since 11-deoxycorticosterone is
an active mineralocorticoid, it has the properties of aldosterone and patients
can have hypertension and hypokalemia (compare with choice C).
Therefore, the measurable aldosterone level is low (compare with choice D)
in these patients.
Hirsutism and abnormal menses (compare with choice E), pre- or
postpubertally, tend to be the cause of investigation and diagnosis in these
patients.
Question 5 of 5
Which of the following would help differentiate between polycystic ovary disease
and late-onset 21-hydroxylase deficiency?
/ A. Abnormal menses or primary amenorrhea
/ B. FSH/LH ratio
/ C. Hirsutism
/ D. PIasma androgens (testosterone and DHEA)
/ E. Urinary 17-ketosteroids
Explanation - Q: 3.5
Close
The correct answer is B. Polycystic ovarian disease (PCOD) is classically
associated with a ratio of LH/FSH > 3. These are normal in CAH.
Both PCOD and CAH are part of the workup for any abnormal menses or
primary amenorrhea (choice A) and hirsutism (choice C), which occurs from
the elevated plasma androgens (choice D). Increased plasma androgens
tend to lead to elevated urinary excretion of 17-ketosteroids (choice E).
A 19-year-old Hispanic man is brought in to the emergency department by his
family because of 3-4 days of nausea, vomiting, and fatigue.
The patient also complained of diffuse abdominal cramping as well as a few
watery stools over the last few days. He admitted to "partying a
Iittle" with his friends prior to the onset of symptoms and drank a "few beers" as
well as eating at local taco stands in Tijuana. Since then, he
has been urinating frequently and drinking juice, but he has not been eating
much. When he is able to eat, it does not exacerbate his
abdominal pain. He denies any fever, chills, dysuria, or constipation. The
patient's mother, who is diabetic, is very concerned about her son's
habits and lifestyle. On examination, the patient appears slightly lethargic, but
answers questions appropriately. His lips and oral mucosa are
parched and dry and there is a slightly stale "sweet" odor on his breath. His pulse
is 101/min and respirations are 18/min. The patient has mild
diffuse tenderness in his abdomen, but no peritoneal signs, including rebound
tenderness, can be elicited. No hepatosplenomegaly is
detected and the rectal examination is normaI.
Question 1 of 5
Which of the following is the most likely diagnosis?
/ A. Acute appendicitis
/ B. AIcoholic hepatitis
/ C. AIcoholic pancreatitis
/ D. Diabetic ketoacidosis
/ E. Traveler's diarrhea
Explanation - Q: 4.1
Close
The correct answer is D. The patient is presenting with new onset diabetes
(Type 1) in the form of diabetic ketoacidosis (DKA).There is often a history of
diabetes in the family. The patient is exhibiting classic symptoms such as
polydipsia and polyuria, as well as "fruity" breath from the acidosis. The
stupor the patient is manifesting can progress into coma if left untreated.
Patients with DKA also have nonspecific abdominal pain and cramps. Often,
DKA can be precipitated when diabetic patients become acidotic and
dehydrated from an alcoholic binge.
If the patient had acute appendicitis (choice A), he would likely initially
present with periumbilical pain, which can then migrate down to the right
lower quadrant. Low grade fever, nausea, vomiting, a sense of constipation,
and anorexia are common. Patients can have positive psoas signs (pain with
hyperextending right thigh while lying on the left hip) and obturator signs
(flexing and rotating the hip) along with uncomfortable rectal exams.
However, acute appendicitis can have many atypical presentations and can
mimic gynecological disorders and gastroenteritis.
Patients with alcoholic hepatitis (choice B) can vary from being
asymptomatic with an enlarged liver to being critically ill. Often symptoms
include anorexia, nausea, jaundice, as well as hepatomegaly. They can also
have abdominal tenderness and ascites, and encephalopathy can also be
present.
Patients with pancreatitis (choice C) often have nausea, vomiting, abdominal
pain, and can become severely dehydrated. Abdominal pain is often
exacerbated by eating and alleviated by remaining NPO (nothing by mouth).
Traveler's diarrhea (choice E) is associated with nausea/vomiting/watery
stools, but is not particularly associated with polydipsia/polyuria/fruity breath.
Furthermore, most patients do not become severely dehydrated and are able
to tolerate some food
Question 2 of 5
Laboratory results show:
Sodium
136 mEq/L
GIucose
437 mg/dL
Potassium
4.8 mEq/L
Bicarbonate
15 mEq/L
Chloride
98 mEq/L
Urea nitrogen (BUN)
9 mg/dL
Creatinine
0.5 mg/dL
Leukocyte count
18,000/mm 3
Which is the most appropriate next step in management?
/ A. Cefazolin and gentamicin
/ B. Cimetidine
/ C. IV fluids and insulin
/ D. Observation only
/ E. Prochlorperazine
Explanation - Q: 4.2
Close
The correct answer is C. Patients with diabetic ketoacidosis should be
treated with IV fluids and insulin in order to reverse the ketoacidosis and
correct the volume depletion.
Even though the patient has an elevated white blood cell count, this
leukocytosis is most likely due to ketoacidosis. Therefore, antibiotics (choice
A) are not needed unless the patient demonstrates other signs of infection,
i.e., fever, or positive blood or urine cultures.
Cimetidine (choice B) is used to decrease acid production; this is only useful
if the patient had gastroesophageal reflux disease (GERD) reflux and
alcoholic gastritis.
Observation (choice D) alone would result in a worsening of the patient's
ketoacidosis and would worsen the stupor, leading to coma and death.
Prochlorperazine (choice E) would decrease the patient's nausea and
vomiting, but would not treat the underlying problem.
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Question 3 of 5
Which of the following test results would best confirm the likely diagnosis?
/ A. Acidic pH on arterial blood gas analysis
/ B. High anion gap
/ C. Low serum bicarbonate
/ D. Positive serum ketones
/ E. Positive urine ketones
Explanation - Q: 4.3
Close
The correct answer is D. Serum ketone positivity is an important criterion
used to separate diabetic ketoacidosis from hyperglycemic hyperosmolar
nonketotic coma (HHNC) seen in type 2 diabetics. In addition to the
bicarbonate level, it is also used as a measure to gauge the resolution of the
ketoacidosis; it disappears after treatment. Ketogenesis results from insulin
deficiency and glucagon excess; insulin deficiency favors lipolysis, leading to
elevated plasma fatty acids and ketone bodies (beta-hydroxybutyrate and
acetoacetate).
An acidic pH on ABG (choice A) is present in any acidotic state, and is not
specific for ketoacidosis.
A high anion gap (choice B) can be seen in other states, e.g., uremia,
methanol poisoning, salicylate ingestion. It is not specific to diabetic
ketoacidosis.
Low bicarbonate (choice C) is associated with any form of primary or
compensatory metabolic acidosis, and is not specific for ketoacidosis.
Positive urine ketones (choice E) can be seen in both diabetic ketoacidosis
and HHNC; it can also accompany starvation ketoacidosis as well as alcoholinduced acidosis. Therefore, the presence of ketonuria is not diagnostic for
diabetic ketoacidosis.
Question 4 of 5
Prior to instituting therapy, blood samples are sent for repeat electrolyte
determination and arterial blood gas analysis, yielding the following
results:
Sodium
Potassium
Bicarbonate
Chloride
136 mEq/L
4.8 mEq/L
15 mEq/L
98 mEq/L
Arterial blood gases (ABG):
pH
pCO2
Bicarbonate
O2 saturation
7.3
31
15 mEq/L
98% on room air
Which of the following acid-base disorders is present in this patient?
/
/
/
/
/
A. High anion gap metabolic acidosis
B. High anion gap metabolic acidosis with compensatory respiratory alkalosis
C. Metabolic alkalosis
D. Metabolic alkalosis with compensatory respiratory acidosis
E. Normal anion gap metabolic acidosis with respiratory alkalosis
Explanation - Q: 4.4
Close
The correct answer is B. Diabetic ketoacidosis is a form of high anion gap
metabolic acidosis. In general, metabolic alkalosis is characterized by
elevated bicarbonate (>24) so choices C and D can be eliminated. There
are instances in which patients with chronic metabolic alkalosis would have
compensatory respiratory acidosis so that the HCO3- is within normal limits
(around 23-24).
Conversely, low HCO3- (<24) is suggestive of metabolic acidosis. To
differentiate amongst the remaining 3 choices, one must calculate the anion
gap. The anion gap formula is [Na+ - (Cl- + HCO3-)]. Normal anion gap is 12.
For this patient, his anion gap is [136-(98+15)] = 23. Therefore, he has high
anion gap metabolic acidosis. This rules out choice E.
Next, one needs to determine whether the patient has compensatory
respiratory alkalosis. An easy way of determining the equilibrium between
PaCO2 (from ABG) and HCO3- is as follows:
For example, if a drop of HCO3- of 10 (in metabolic acidosis) occurs, a
compensatory respiratory alkalosis (breathing rapidly to remove the excess
acid in the body) should occur and a drop of 10 would be present on the
PaCO2 on the ABG.
For this patient, his primary acid-base disorder is a metabolic acidosis from
overproduction of the ketoacids. His HCO3- level has dropped by 9 and so his
PaCO2 should compensate by dropping 9 (40-9 = 31). Therefore, the patient
has high anion gap metabolic acidosis with compensatory respiratory
alkalosis (compare with choice A).
Question 5 of 5
Repeat labs after therapy begins shows a glucose 285 mg/dL, and potassium of
3.1 mEq/L. Which of the following is the cause for the drop in
potassium after treatment?
/ A. Diarrhea
/ B. Dilutional effect
/ C. Protracted vomiting
/ D. Renal tubular acidosis
/ E. Reversal of acidosis
Explanation - Q: 4.5
Close
The correct answer is E. Patients with DKA may commonly have normal, or
even elevated potassium levels on initial labs. This hyperkalemia is due to
decreased insulin, which shifts K+ extracellularly, and as well as
hyperosmolality (intracellular K+ concentration of the dehydrated cell
increases and K+ diffuses extracellularly). As acidosis is reversed via insulin
and fluids, K+ is shifted intracellularly. Therefore, it is common to give
patients K+ supplements even if their K+ levels are normal when they first
present.
Profound diarrhea (choice A) can result in mild hypokalemia but it should
have presented in the initial labs.
Hypokalemia from protracted vomiting (choice C) should have been present
on initial labs and does not manifest after hydration. Hydration alone should
not drop the potassium by 1.7 from a dilutional effect (choice B) since a drop
of 1 mEq/L suggests at least a total body deficit of about 350 mEq.
Renal tubular acidosis (choice D) can result in metabolic acidosis and have
resulting hypokalemia; diabetics can have type 4 RTA, but this is associated
with hyperkalemia. There is no indication that the patient has long-standing
diabetes resulting in RTA, or has any form of bicarbonate wasting through
the kidneys.