Question

Mr. Smith is 60 years old. He was diagnosed with a prostate cancer five years ago. Over the past few days, Mr. Smith has been feeling weak and increasingly tired and has also been suffering from a headache that did not respond to over-the-counter medications. He scheduled an appointment with his physician.

His physician performed a physical examination and recommended a battery of laboratory tests and imaging procedures.

The table below shows Reference values in the right-hand column. These values reflect the normal range of values for patients without disease or illness. The center column reflects the resulting values for medical test results obtained for Mr. Smith.

Take note whether Mr. Smith’s values are within normal limits.

	Mr. Smith	Reference Values
K+	2.6 mmol/L	3.8-4.9mmol/L
Hb (Hemoglobin)	7.5 g/dL	13.8 to 18.2 g/dL
Hct (Hematocrit)	20.4%	45-52%
Platelet Count	49x109/L	150-400x109/L

After receiving Mr. Smith’s test results, his physician admits him to the hospital. Hospital staff treated him and discharged him.

The following week, Mr. Smith returns to his physician with the same complaint of weakness and a new complaint of shortness of breath. His blood pressure is 160/100 mmHg. MRI reveals metastasis of prostate cancer to osseous tissue. Abdominal CT shows obstruction of intestine due to nodular enlargement of adrenal glands.

Laboratory results from Mr. Smith’s second hospital admission and medical tests show following findings:

Mr. Smith	Reference Values
K+	2.6 mmol/L	3.8-4.9mmol/L
Hb	7.3 g/dl	13.8 to 18.2 g/dL
Hct	20.4%	45-52%
Platelet Count	20x109/L	150-400x109/L
HCO3	38 mmol/l	22-26 mmol/L
Urinary K+	70 mmol/L/24 hr	25-120 mmol/L/24 hr
Blood Glucose	460 mg/dl	64.8-104.4 mg/dL
Serum Aldosterone	1 ng/dl
24 hour Urinary Aldosterone	8.4 mcg/24 hr	2.3-21.0 mcg/24 hr
Renin	2.1 ng/ml/hr	0.65-5.0 ng/ml/hr
ACTH (Adrenocorticotropic Hormone)	1082 pg/ml	9-46 pg/ml
Cortisol	155.5 microg/dL	0-25 microg/dL

CONCLUSION AND DIAGNOSIS

Laboratory findings, MRI and CT confirmed metastatic prostate adenocarcinoma, hypertension and refractory hypokalemia due to ectopic ACTH production. High levels of circulating cortisol caused continuous activation of mineralocorticoid receptors resulting in hypokalemia, metabolic alkalosis and hypertension.

Question:

Select one of the medical terms from the CONCLUSION and DIAGNOSIS section above and define what it means. Also, discuss, in your own words and based on what you can gather about Mr. Smith’s condition, how the laboratory or imaging tests helped with drawing a conclusion or making the diagnosis. In your own words, discuss how medical providers use the scientific method to come to work through the examination and diagnosis of a patient.

Answer 1

Definition: Metabolic alkalosis is a metabolic condition in which the pH of tissue is elevated beyond the normal range (7.35-7.45). This is the result of decreased hydrogen ion concentration, leading to increased bicarbonate, or alternatively a direct result of increased bicarbonate concentrations.

Metabolic alkalosis shows high pH, normal PaCO2, high bicarbonate.

• Metabolic alkalosis is a primary increase in serum bicarbonate (HCO3-) concentration. This occurs as a consequence of a loss of H+ from the body or a gain in HCO3-. In its pure form, it manifests as alkalemia (pH >7.40).
• As a compensatory mechanism, metabolic alkalosis leads to alveolar hypoventilation with a rise in arterial carbon dioxide tension (PaCO2), which diminishes the change in pH that would otherwise occur.
• Normally, arterial PaCO2 increases by 0.5-0.7 mm Hg for every 1 mEq/L increase in plasma bicarbonate concentration, a compensatory response that is very quick. If the change in PaCO2 is not within this range, then a mixed acid-base disturbance occurs. For example, if the increase in PaCO2 is more than 0.7 times the increase in bicarbonate, then metabolic alkalosis coexists with primary respiratory acidosis. Likewise, if the increase in PaCO2 is less than the expected change, then a primary respiratory alkalosis is also present.
• The first clue to metabolic alkalosis is often an elevated bicarbonate concentration that is observed when serum electrolyte measurements are obtained. Remember that an elevated serum bicarbonate concentration may also be observed as a compensatory response to primary respiratory acidosis. However, a bicarbonate concentration greater than 35 mEq/L is almost always caused by metabolic alkalosis.
• Metabolic alkalosis is diagnosed by measuring serum electrolytes and arterial blood gases. If the etiology of metabolic alkalosis is not clear from the clinical history and physical examination, including drug use and the presence of hypertension, then a urine chloride ion concentration can be obtained. Calculation of the serum anion gap may also help to differentiate between primary metabolic alkalosis and metabolic compensation for respiratory acidosis.
• Mr. Smith laboratory result of bicarbonate concentration is 38mmol/L, so it diagnosed metabolic alkalosis
• serum potassium: 3.6–5.4 mmol/l (plasma, 3.6–5.0 mmol/l); alert levels: less than 3.0 mmol/l and greater than 6.0 mmol/l. Hence Smith value is 2.6 mmol/l or less than 3.0mmol/l.
• Higher values are seen with renal potassium wasting, norma value is 25 mmol/l/24 hr. Smith value is 70mmol/l/24hr

​Hypertension: Home blood pressure measurements or 24-hour ambulatory blood pressure monitoring are useful in the evaluation for white coat hypertension. Obtaining a 24-hour urine collection for sodium and creatinine to assess dietary sodium intake is frequently helpful. An otherwise healthy patient ingesting a diet limited to 2000 mg of sodium should excrete no more than 87 mEq of sodium in a 24-hour urine sample; higher amounts of sodium excretion suggest dietary nonadherence.

The initial task is to detect a medical indication to perform a diagnostic procedure. Indications include:

• Detection of any deviation from what is known to be normal, such as can be described in terms of, for example, anatomy (the structure of the human body), physiology (how the body works), pathology (what can go wrong with the anatomy and physiology), psychology (thought and behavior) and human homeostasis (regarding mechanisms to keep body systems in balance). Knowledge of what is normal and measuring of the patient's current condition against those norms can assist in determining the patient's particular departure from homeostasis and the degree of departure, which in turn can assist in quantifying the indication for further diagnostic processing.
• A complaint expressed by a patient.
• The fact that a patient has sought a diagnostician can itself be an indication to perform a diagnostic procedure. For example, in a doctor's visit, the physician may already start performing a diagnostic procedure by watching the gait of the patient from the waiting room to the doctor's office even before she or he has started to present any complaints.