Running Head: CASE STUDY ANALYSIS
Case Study Analysis
Ashley Johnson
NUR 3129
University of Florida College of Nursing
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Case Study Analysis
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Case Study Analysis
The client is a 24 year old Caucasian male with type 1A pseudohypoparathyroidism. He
was admitted for severe tetanus in setting of hypocalcemia, secondary to his type 1a
pseudohypoparathyroidism. He has a presumed medical history of presumed seizure disorder
(last episode in 2003), hypertension, a chronic history of hypocalcemia, hypothyroidism, and
pseudohypoparathyroidism. In addition, the patient has had orthopedic surgery. The patient has
severe tetanus, cataracts, positive Chvostek’s sign, nonspecific shortening of metacarpals
(second through fifth), calcification in basal ganglia, round face, short stature, and delayed
mental status. Furthermore, he has hypoxemia with partially compensated metabolic alkalosis.
Vital Signs
T 98.4°F
HR 93
RR 20
BP 133/79
SaO2 98%
Pain 0
Ht 5‘2”
Wt 114 lbs
L abs Values
Electrolyte Values
Na 137 mEq/L
Cl 96 mEq/L
K 2.8 mEq/L
BUN 14 mg/dl
Creat. 0.8 mg/dl
CO2 29 mmol/L
Ca 6.1 mg/dl
Mg 2.3 mEq/L
Phos 8.3 mg/dl
Gl (meter) 168 mg/dl
Alb 5.1g/dl
CBC Values
RBC 5.76 mill/mm3
Hgb 17.4 g/dl
Hct 49.3%
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MCV 85.6
MCH 30.2
MCHC 35.3%
Retic N/A
Total Bili 0.6 mg/dl
Platelets 185 /mm3
WBC 7.2 /mm3
Polys 62.8%
Bands 0%
ANC 4.55
Lymphs 27.2%
ALC 1.97
Eos 1.2%
Monos 6.5%
Basos 0.6%
pH 7.44
HCO3 31 mEq/l
pCO2 46 mm Hg
pO2 54 mm Hg
O2 Sat 88%
Other Lab Values
ABG
Other Values (lab value ranges from Web MD)
PTH 230 pg/ml (10 – 65 pg/mL)
FSH 3.2 IU/L (1.42 – 15.4 IU/L)
LH 6.6 IU/L (1.24 – 7.8 IU/L)
TSH 15.14 mU/L (0.4 - 4.2 mU/L)
Pathophysiology
Pseudohypoparathyroidism (PHP) is a rare group of genetic disorders that mimics
hypoparathyroidism—with hypocalcemia and hyperphosphatemia—but causes resistance to the
parathyroid hormone (PTH) (Topiwala, 2012). This disorder produces abnormally high serum
concentration of PTH rather than lower levels of PTH like hypoparathyroidism. The patient has
type 1a pseudohypoparathyroidism, also known as Albright’s Hereditary Osteodystrophy, which
is an autosomal dominant inherited disorder. According to Topiwala (2012), individuals with
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type 1a PHP often have a short stature, round face, and short hand bones, along with the
manifestations that evolve with hypocalcemia and hyperphosphatemia.
PHP involves dysfunction in the parathyroid glands. The parathyroid glands, located
behind the thyroid glands, produce PTH which controls serum calcium levels. Calcium levels, as
well as phosphate and magnesium levels, affect the production and secretion of PTH. When an
individual has hyperphosphatemia, calcium levels decrease because of calcium-phosphate
precipitation in soft tissue and bones (McCance, Huether, Brashers, & Rote, 2010, p. 113). The
hyperphosphatemia influences the PTH levels indirectly.
In Pathophysiology, McCance et. al (2010, p. 711) describes the physiology of the
parathyroid glands. Parathyroid glands stimulate the production of PTH. Thereafter, PTH enters
into the serum in an unbound form. PTH then attaches to receptors on the plasma membrane in
specific tissues. For example, with the bones, PTH arouses osteoblasts to release receptor
activators for M-CSF and NF-κβ, which mobilize calcium from the bones, thus increasing serum
calcium. In the kidneys, PTH stimulates the receptor on the nephrons of the distal and proximal
tubules to increase reabsorption of calcium and reduce phosphate. PTH also decreases
reabsorption of bicarbonate in the proximal tubules. However, this process becomes interrupted
when there are molecular defects to the gene GNAS (guanine nucleotide-binding α-subunit),
which impairs actions of PTH in the kidneys, as well as thyrotropin (TSH) in the thyroid and
gonadotropins (usually in females). This causes the PTH receptor and its signal transduction
pathway causing resistance to PTH and increasing serum PTH (Mantovani, 2011).
Furthermore, the resistance to TSH in the thyroid causes hypothyroidism (Balavonine et.
al, 2008). Hypothyroidism occurs because the TSH releasing hormone receptor on the pituitary
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gland is a receptor for the G-protein and acts in sync with GNAS, and there is a defect in the
expression of the GNAS protein in the thyroid. Normally, TSH stimulates growth and
maintenance of the thyroid gland (McCance et. al, 2010). However, with hypothyroidism
secondary to type 1a PHP, the thyroid gland becomes resistant to TSH, increasing its serum
concentration significantly and does not produce thyroid hormone (TH) (Balavonine et. al,
2008). Characteristic of hypothyroidism related to PHP, there is normal or low thyroid hormone
levels and no goiter.
Many forms of PHP have been discovered; most of the information regarding PHP is
about type 1a PHP (Abraham, 2013). The gene GNAS1 (mentioned above) contains “the alpha
subunit of the stimulatory GTP-binding protein (Gsa)” (Abraham, 2013). The molecular defects
from GNAS1 influence at least three types of PHP—type 1a, type 1b, and pseudo-PHP. Type 1a
PHP, which is the disorder the patient has, is inherited via an autosomal dominant manner; only
one parent has to have the faulty gene to develop the condition (Saddala, 2012). Type 1b PHP is
resistance only to the kidneys, which inhibits reabsorption of calcium by the nephrons in the
proximal and distal tubules. Type 2 is very similar to type 1; yet, type 2 does not have any
characteristics.
Explanation of Abnormal Lab Values
The patient presents with hypocalcemia. His decreased calcium level results from the
resistance of the G-protein receptor cells towards the parathyroid hormone. Under physiologic
conditions, PTH increases renal reabsorption of calcium, intestinal absorption of calcium, and
bone resorption of calcium (McCance & Huether, 2010, slides 102-105). Consequently, the
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patient’s resistance to PTH decreases the amount of calcium from the bone released into the
blood. Therefore, the body absorbs less calcium, lowering serum levels.
Likewise, the patient’s hyperphosphatemia occurs in response to the patient’s
hypocalcemia. Calcium and phosphate have an indirect relationship (McCance and Huether,
2010, slides 102-105 ). Because the patient has resistance to PTH lowering plasma calcium
levels, the phosphate levels increase consequently. PTH affects the kidney’s reabsorption of
calcium. When the kidney’s ability to absorb calcium is inhibited, like in the patient,
hyperphosphatemia ultimately occurs, as kidney dysfunction contributes to increased phosphate.
The patient’s kidney dysfunction occurs from the defect of GNAS in the nephrons of the
proximal and distal tubules, causing resistances to PTH stimulation.
The patient’s hypokalemia occurs as a result of his arterial blood gas levels indicating
partially compensated metabolic alkalosis with hypoxemia. The metabolic alkalosis occurs
because the patient’s pH level is 7.44, bicarbonate is 31, and carbonic acid is 46.
Physiologically, PTH decreases the reabsorption of bicarbonate in the proximal tubule (McCance
et. al, 2010). However, pseudohypoparathyroidism causes PTH resistance in the kidneys, thus
increasing the amount of bicarbonate absorbed by the kidneys. The high levels of bicarbonate in
the kidneys causes an increase in the serum pH, which partially compensates for the kidney
dysfunction. Similarly, the increase in carbonic acid occurs because of respiratory
compensation; however, the compensation is partial, resulting is partial compensated metabolic
alkalosis. The patient’s hypoxemia, indicated by the patient’s pO2 of 54 and O2 Sat of 88%
ensues as a result of hypoventilation due to the respiratory compensation (Brandis). The
hypoxemia could also result from the severe tetanus, which can interfere with breathing
(McCance et. al, 2010, p. 112).
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The patient has hyperglycemia; however, the patient presents no maternal or paternal
history of diabetes. The occurrence of his hyperglycemia could be related to his eating habits.
Perhaps more logically, the increase in blood glucose transpires because of the stress on the body
from PHP. Pseudohypoparathyroidism stresses the endocrine system, the bones, the kidneys,
and the body’s metabolism.
High levels of the parathyroid hormone in the patient would indicate
hyperparathyroidism. The patient has type 1a PHP, which mimics hypoparathyroidism.
However, the genetic disorder produces a significant increase in PTH because of the resistance
created by the molecular defect in the GNAS gene of multiple receptors in the bones and
kidneys. Physiologically, PTH stimulates the bones to release calcium and the kidneys to
reabsorb calcium. Consequently, the patient’s body consistently produces PTH because the
body’s resistance to PTH causes a decrease in serum calcium.
Due to the patient’s type 1a PHP, he has abnormally high thyroid stimulating hormone
(TSH) levels. TSH, produced by the pituitary gland, stimulates the thyroid gland to produce T3
and T4 hormones, which help control the body’s metabolism (WebMD, 2010). The patient has
high levels of TSH, which contributes to hypothyroidism. Similar to PTH, the resistance of TSH
on the thyroid gland occurs because of the same molecular defect of gene GNAS (Balavonine et.
al, 2010). The mutated GNAS gene impairs the expression in the thyroid gland, increasing
resistance to TSH, thus decreasing the amount of TH produced by the thyroid gland. The
continual resistance creates an increase in serum TSH.
Case Study Analysis
Concept Map
Fig. 1 Pathophysiology of and relationship of the effects of the molecular defects to the GNAS
gene in type 1a pseudohypoparathyroidism and hypothyroidismand clinical manifestations that
are characteristic of the disease in the patient.
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Clinical Manifestations
Upon admission, the patient exhibits severe tetanus. He had many episodic muscle
spasms prior to admission. These acute muscle spasms were the result of the patient’s
hypocalcemia and hyperphosphatemia. Calcium and phosphate inversely function to maintain
plasma membrane stability and permeability and help control the transmission of nerve impulses
and contraction of muscles (McCance et. al, 2010, p. 111-112). When calcium levels lower,
neuromuscular excitability ensues causing partial depolarization of nerves and muscles. The
partial depolarization requires less calcium need to stimulate an action potential.
Associated with the tetany is the patient’s positive Chvostek’s sign. Chvostek’s sign
results from tapping on the facial nerve—cranial nerve VII (McCance et. al, 2010, p. 112). The
consequence of this test is a twitch of the nose or lip. Again, the twitch occurs because of the
patient’s hypocalcemia and hyperphosphatemia. The neuromuscular excitability occurs in the
ipsilateral facial muscles, giving rise to the positive Chvostek’s sign (Chvostek’s sign).
The patient has cataracts in both eyes. Cataracts can form under several circumstances.
The likely reason for his cataracts is the genetic mutation to the gene GNAS which causes
hypothyroidism and pseudohypoparathyroidism. Cataracts cause clouding of the lens in the eye,
leading to a decrease in vision (Wikipedia, 2013). Genetics affect the protection and
maintenance of the lens. In the patient’s case, the gene defect could affect this mechanism.
The patient’s CT scan of his brain shows calcification of the basal ganglia.
Calcification—when calcium deposits in body tissues—typically occurs in the bones and teeth
(Dugdale, 2012). However, when disturbances occur in calcium levels and chemicals that
interact with calcium, calcification can occur in other parts of the body, like the brain. The
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patient’s type 1a PHP causes hypocalcemia because the kidneys and bones become resistant to
PTH stimulation. The deficiency in serum calcium contributes to the calcium deposits in the
basal ganglia.
Nonspecific shortening of the second through fifth metacarpals, round face, short stature,
and delayed mental status result from the patient’s genetic disorder, type 1a
pseudohypoparathyroidism and history and current presence of hypothyroidism, which he has
had since birth. All of these abnormal manifestations result from the congenital genetic defect
the disorder has on the body. Over time, the chronicity of the hypocalcemia has likely
contributed to decreased calcium in the bones which in return has caused his short stature (height
of 5’2”) and the shortening of his metacarpals. The thyroid gland helps control metabolism,
regulate growth, and assists brain development (Scheinberg, 2008). The longer hypothyroidism
exists undetected, the more damage that can occur in the body. Thus, hypothyroidism has
prospectively also influenced the patient’s short stature and the delayed mental development.
His round face is merely one of the physical symptoms of type 1a PHP.
Evaluation
The evaluation for this patient should include and electrolyte profile since his calcium,
phosphate, glucose, and potassium levels have abnormal levels. He should have an electrolyte
profile taken routinely because of the chronicity and severity of his hypocalcemia and
hyperphosphatemia. His needs a profile of his arterial blood gases to monitor his metabolic
alkalosis and hypoxemia. Routine endocrine profile should occur to monitor his PTH and TSH
levels which are the causative factors of his hypocalcemia, hyperphosphatemia, and metabolic
alkalosis and hypoxemia. Furthermore, the patient needs to have routine blood glucose levels
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monitored for his hyperglycemia. The moderately high glucose levels can be reduced when the
stress on his body diminishes or subsides.
The patient needs to be monitored for severe muscle spasm episodes. The patient should
have seizure precautions since he has a history of seizures, even though the patient declares he
has not had a seizure since 2003. Considering the severity of his tetanus and history of seizures,
the patient should be evaluated hourly on his risk for falls hourly. In addition to fall risks, that
patient needs to be on telemetry to monitor heart rhythms since hypocalcemia and hypokalemia
affect the rate and rhythm of the heart. Lastly, the patient’s blood pressure needs to be routinely
checked to ensure he does not develop hypertension since he has a history of high blood
pressure.
Treatment
The treatment for the patient will involve intravenous intervention of 10% calcium
glutonate to increase his serum calcium levels (McCance et. al, 2010, p. 112-113). Oral calcium
supplements should be administered, especially during meals to help with absorption of calcium
from food. He also could receive a phosphate binder to bind the abundance of phosphate to
eliminate it, but still allow deposits in the nervous system and bones. The patient should receive
potassium oral replacements for his hypokalemia, which will also improve his metabolic
alkalosis (McCance et. al, 2010, p. 109). However, the dosage should be no more than 40 - 80
mEq/day since his renal function is normal and pH level is between 7.4 and 7.45. His breathing
needs support to help recover the hypoxemia, which also helps with the metabolic alkalosis.
In addition, the patient needs to receive insulin therapy to prevent increased elevations of
blood glucose. He also needs to receive hormone replacement therapy for his increased TSH
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levels (McCance et. al, 2010, p. 741). He can take levothyroxine (synthroid), a synthetic
hormone, for his hypothyroidism. His PTH levels can be alleviated by treating his hypocalcemia
(McCance et. al, 2010, p. 745).
Priority Concerns
Priority concerns for nurses caring for the patient are presented as follows:
Nursing Diagnoses and Interventions
1. Risk for cardiac dysrhythmias r/t hypocalcemia and hypokalemia
a. Monitor vital signs, especially heart rate.
b. Place patient of telemetry to monitor any possible dysrhythmias.
c. Auscultate for any adventitious heart sounds.
d. Administer medications and/or supplements to restore calcium and potassium
levels, as ordered by doctor.
2. Risk for falling r/t tetany and seizure disorder.
a. Place call light within reach and bed in lowest position.
b. Remove all obstacles in the client’s way, provide a urinal.
c. Make sure belongings are within reach.
d. Evaluate the patient’s fall risk with Morse Fall Scale hourly.
e. Educate the patient about the risks of falls outside of the hospital, such as getting
bracelet or card declaring his seizure disorder for others’ awareness and finding
the nearest chair or sitting down if he feels the onset of severe muscle spasms that
could affect his mobility.
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3. Risk of hypertension r/t self-health management
a. Educate the patient on the importance of maintaining a healthy, balanced diet with
exercise.
b. Discuss patient’s development of hyperglycemia and how it can develop into
diabetes and the risks between diabetes and HTN.
c. Support positive health perception and health promotion that the patient
possesses.
4. Risk of insufficient health maintenance r/t lack of knowledge of disease
a. Educate patient about genetic disorder and how it affects the body.
b. Encourage patient increase intake of calcium and potassium.
c. Teach patient the importance of a healthy, balanced diet and daily exercise.
d. Teach patient the effects of hypocalcemia and hypothyroidism and when he
should notify his primary provider.
The nurse needs to immediately focus on assessing the patient’s heart rates and rhythm to ensure
he does not experience a shift in rhythm. The nurse should constantly assess the patient’s fall
risk every hour. Upon discharge, the nurse needs to educate the patient about the importance of
a healthy diet and increased exercise to maintain a stable metabolism.
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References
Abraham, Mini R. (2013 April 23). Pseudohypoparathyroidism. Medscape. Retrieved from
http://emedicine.medscape.com/article/124836-overview
Albright’s hereditary osteodystrophy. (2012 October 17). Genetic and Rare Diseases
Information Center (GARD). Retrieved from
http://rarediseases.info.nih.gov/gard/5770/albrights-hereditaryosteodystrophy/resources/1
Balavonine, A., Ladsous, M., Velayoudom, F., Vlaeminck, V., Cardot-Bauters, C., d’Herbomez,
M., & Wemeau, J. (2008 June 25). Hypothyroidism in patients with
pseudohypoparathyroidism type Ia: clinical evidence of resistance to TSH and TRH.
European Journal of Endocrinology. Retrieved from http://www.ejeonline.org/content/159/4/431.full
Brandis, K. Metabolic Alkalosis – Metabolic Effects. Acid-Base Physiology. Retrieved from
http://www.anaesthesiamcq.com/AcidBaseBook/ab7_4.php
Cataract. (2013 November 24). Wikipedia: The Free Encyclopedia. Retrieved from
http://en.wikipedia.org/wiki/Cataract
Dugdale, D. C. (2012 August 30). Calcification. Medline Plus: Trust Health Information for
You. Retrieved from http://www.nlm.nih.gov/medlineplus/ency/article/002321.htm
Chvostek’s Sign. East Tennessee State University College of Medicine: Medical Mystery.
Retrieved from http://www.etsu.edu/com/medicalmystery/Chvostek.aspx
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Mantovani, G. (2011 October). Pseudohypoparathyroidism: Diagnosis and Treatment. Journal
of Clinical Endocrinology & Metabolism. Retrieved from
http://jcem.endojournals.org/content/early/2011/07/28/jc.2011-1048.full.pdf
McCance, K. L., Huether, S. E., Brashers, V. L., & Rote, N.S. (2010). Chapter 3: The Cellular
Environment: Fluids and Electrolytes, Acids and Bases. In S. Clark (Ed.),
Pathophysiology: The Biologic Basis for Disease in Adults and Children (pp. 96-125).
Maryland Heights, MO: Mosby Elsevier.
McCance, K. L., Huether, S. E., Brashers, V. L., & Rote, N.S. (2010). Unit VI: The Endocrine
System. In S. Clark (Ed.), Pathophysiology: The Biologic Basis for Disease in Adults
and Children (pp. 708-712, 739-745). Maryland Heights, MO: Mosby Elsevier.
Saddala, P. (2012 September 19). Pseudohypoparathyroidism pathophysiology. WikiDoc.
Retrieved from
http://www.wikidoc.org/index.php/Pseudohypoparathyroidism_pathophysiology
Scheinberg, D. (2008). Congenital Hypothyroidism. Department of Pediatrics: Division of
Pediatric Endocrinology. Retrieved from
http://pediatrics.med.nyu.edu/endocrinology/patient-care/congenital-hypothyroidism
Topiwala, S. (2012 July 19). Pseudohypoparathyroidism. Medline Plus: Trusted Health
Information for You. Retrieved from
http://www.nlm.nih.gov/medlineplus/ency/article/000364.htm