Calcium Disorders Flashcards
What the hell is going on with primary hyperparathyroidism?
In primary hyperparathyroidis, excess secretion of PTH causes hypercalcemia.
80% of these cases are benign parathyroid adenomas, with the last 20% being parathyroid hyperplasia
Primary hyperparathyroidism is usually asymptomatic, and is discovered based on elevated calcium on incidental findings.
When symptomatic, we see symptoms in:
- Renal
- Skeletal
- GI
- Neurologic
What are they?
Renal - Polyuria, hyperca;ciuria, and renal calculi (calcium oxalate). Can progress to renal failure if chronic
Skeletal - Bone Pain due to extra osteoclast activity
GI - Nausea, vomiting, weight loss, constipation, anorexia, peptic ulcer disease and acute pancreatitis. So basically you have ulcers and weight loss cause you’re throwing up all your food and your pancreas gets upset.
Neurologic - Mental Status changes, depression, fatigue
What 3 main symptoms comprise a hypercalcemic process?
Polyuria, dehydration, mental status changes. Your brain goes nuts cause you’re peeing out all your water.
In Primary hyperparathyroidism, what will we see on serum chemistry? What other tests can we run?
Increased Ca2+, decreased phosphate. Chloride is also often elevated.
Also:
- PTH related peptide
- Vitamin D levels
- Alkaline phosphatase
- Urine calcium
How do we treat Primary hyperparathyroidism?
- Curative treatment is surgical exploration and parathyroidectomy of the adenomatous gland
- Diuretics like furosemide to enhance calcium excretion
- AVOID thiazide diuretics as they can exacerbate hypercalcemia
- Can also give bisphosphonates or calcitonin to inhibit bone loss
What is renal osteodystrophy and how does it cause hypercalcemia? How does the body respond?
Renal osteodystrophy is a consequence of secondary hyperparathyroidism resulting from the death of proximal tubule cells in renal failure patients. Loss of these cells results in decreased Vitamin D activation by 1a-hydroxylase.
In response, the chief cells of the parathyroid glands produce excess PTH, resulting in excess bone resorption. Serum calcium levels are typically low or low-normal in secondary hyperparathyroidism.
Can cancer cause hypercalcemia? If so, how?
Malignancy-induced hypercalcemia can result from lytic bone metastases like breast cancer, or tumor producing PTHrP, including squamos cell carcinoma of the lung and renal adenocarcinoma.
PTH levels are low.
What can give us a Vitamin D toxicity that would lead to hypercalcemia?
Certain lymphomas, histoplasmosis, and granulomatous diseases like sarcoidosis and tuberculosis) are all causes of Vitamin D toxicity
What happens in granulomatous disease to cause Vitamin D deficiency?
In granulomatous disease, lymphocytes in the granulomas make 1a-hydroxylase, which leads to increased Vitamin D, which causes increased calcium resorption.
PTH levels are low.
What the hell is familial hypocalciuric hypercalcemia and what causes it?
Autosomal dominant disorder caused by a mutation in calcium-sensing receptors on the parathyroid glands, leading to inappropriate secretion of PTH which leads to mild hypercalcemia.
Unlike other causes of hypercalcemia, urinary calculi and renal failure are not seen in cases of FHH.
What is Milk-Alkali syndrome?
Ingestion of excessive amounts of calcium antacids.
Most common cause of primary hypothyroidism?
- Hypoparathyroidism following thyroid surgery in which the surgeon accidentally removes or damages the parathyroids
Others, from most to least common
- Autoimmune gland failure
- Gland infiltration
- Pseudohypoparathyroidism due to PTH end-organ resistance
- DiGeorge syndrome
In parathyroid hyperplasia, how does a surgeon avoid hypoparathyroidism?
In the case of parathyroid hyperplasia, the surgeon removes 3 of the 4 parathyroid glands and autotransplants (reimplants) the remaining gland into the patient’s forearm to avoid hypoparathyroidism.
How does primary hypoparathyroidism present?
Neuromuscular excitability due to hypocalcemia
- Muscle fatigue and weakness
- Numbness and tingling, particularly the mouth, hands, and feet
- Tetany. Can be one of two signs: Chvostek sign (tapping of the facial nerve in front of the ear leading to an upper lip and facial muscle contraction) and Trousseau sign (inflation of a BP cuff to higher than systolic pressure causing carpal spasms)
- Laryngeal spasm
Others:
- Basal ganglia calcifications that can cause parkinsonian symptoms
- Ocular lens calcifications leading to cataracts
- Depression, psychosis
How do we treat primary hypoparathyroidism?
Calcium supplements, vitamin D supplements (calcitriol), and IV calcium gluconate for acute symptoms.
