In station 5 you may be asked to assess a patient with pins and needles or numbness in their fingers/toes.
HISTORY (3 minutes) – she tells you the numbness is around her mouth, fingers, toes
Ask questions about symptoms of low calcium:
- Muscle spasms/muscle twitching
- Muscle cramps
- Breathlessness (laryngospasm, bronchospasm)
- Bone pain, abdominal pain, headache
- Mood/irritable/anxious/fatigue
- Confusion
- Seizures
- Cataracts, dental problems, kidney stones, gut problems
Ask questions about aetiology of low calcium:
- Head and neck surgery or radiation
- Problem with kidneys
- Sunlight/vitamin D
- Abdominal pain (Pancreatitis)
- Autoimmune conditions- vitiligo, thyroid, addisons
- Blood transfusion
- Infiltrative: Wilsons- liver problems/tremor, Haemochromatosis- diabetes/tired/joint pains, Cancer
PMH
Fx of low calcium/hypoparathyroid disorders
Dx eg. bisphosphonates, chemotherapy
Sx
EXAMINE (3 minutes)
- Observe for a short patient with round face, short neck, shortened 4th+5th metacarpals (pseudohypoparathyroidism “knuckle, knuckle, dimple, dimple” sign on closed fist)
- Mouth- dental abnormalities
- Neck examination
- Abdominal examination
- Offer to test for chvostek’s and trousseau’s signs
- Neuro examination (brisk reflexes, extrapyramidal findings, fundoscopy for papilloedema)
ICE+ Explanation (2 minutes)
“I’d like to test your calcium level and if low replace it. I’ll check the level of other electrolytes too like magnesium. I’d also like to get a tracing of your heart and an opinion from an endocrinology doctor.”
VIVA
Tests:
Confirm low calcium (and correct for abnormality in serum albumin)
Check Mg, K+, Phosphate, pH, PTH, vitamin D, U+E, ALP, amylase.
If autoimmune process is suspected: TFTs, ACTH and adrenal antibodies
24 hour urinary calcium
ECG- QT prolongation, heart block, VF
Renal USS (renal stones)
Brain MRI- basal ganglia calcification
Genetic testing
XR hands- shortened metacarpals
Pseudohypoparathyroidism
Kidney and bone resistance to PTH- low calcium, raised phosphate, raised PTH, low calcitriol, normal U+E. No urinary cAMP response to PTH.
Type 1a: Autosomal dominant. GNAS1 mutation. Albright hereditary osteodystrophy (AHO): round facies, short stature, short fourth and fifth metacarpal bones, obesity, subcutaneous calcifications and developmental delay. NB: paternally transmitted mutations have the phenotype of AHO but with normal calcium, phosphate and PTH (pseudopseudohypoparathyroidism)
Type 1b- no phenotypic features of AHO. Similar biochemistry to AHO.
Type 2- no phenotypic features of AHO. NB: Normal or raised cAMP response in urine
Management: Treatment of hypocalcaemia and refer to endocrinology
Patients with pseudohypoparathyoridism may also require screening for other endocrinopathies, particularly hypothyroidism and hypogonadism
Causes of hypocalcaemia:
- Hypoparathyroidism (Low Ca, low PTH, Low Mg, raised P, normal ALP)
- Post-thyroidectomy/parathyroidectmy/radiation to neck/RI for thyroid/radical neck dissection
- Abnormal magnesium
- Infiltration eg. Haemochromatosis, thalassaemia, wilsons, mets, granulomatous
- Autoimmune
- Genetic eg. abnormal parathyroid development, Digeorge
- Idiopathic
- PTH resistance (Pseudohypoparathyroidism)
- Renal Disease
- Vitamin D deficiency
- Bisphosphonates, calcitonin, phenytoin
- Acute pancreatitis
- Blood transfusion
- Artefact (raised K+, low Mg, Low ALP)
- Rhabdomyolysis
- Tumour lysis
- Hyperphosphatemia
Written by Dr Sarah Kennedy
Resources used to write this document include those listed in the references section of this webpage and also:
https://patient.info/doctor/hypoparathyroidism-pro