Amongst the principal metabolic situations that can require emergency attention in the oncology patient we find: hypercalcaemia, hyponatraemia, tumoural lysis syndrome,
lactic acidosis, hyperuricaemia,
renal failure, hyperammonaemia, hypermpotasaemia, etc. Hypercalcaemia is the most frequent metabolic complication in oncology, appearing in 10-30% of these patients. It has two main mechanisms, tumoural lysis and humoural hypercalcaemia mediated by
PTHrP (a
protein related to
parathormone). The principal factor for its diagnosis is suspicion, since some symptoms are non-specific and can be attributed to other causes such as
somnolence,
constipation, etc. Treatment will be based on intensity and is started with calciuretic measures with an intense hydration with physiological serum and on some occasions with
furosemide. Anti-reabsorptive measures include
calcitonin,
bisphosphonates,
mithramycin,
gallium nitrate and on occasions
corticoids.
Bisphosphonates such as
pamidronate and
zoledronate seem to be highly useful in these cases. Hyponatraemia is classified depending on plasmatic osmorality; when this is low we find ourselves facing an authentic hyponatraemia that can develop with an extra-cellular volume that is high (cardiac insufficiency,
cirrhosis,
nephrotic syndrome and
renal insufficiency), low (renal and extra-renal
sodium losses) and normal (principally
SIADH, related to a high elimination of
sodium in the urine with high urinary osmolarity in spite of this being low in blood). Several types of tumour and different
chemotherapy drugs can produce this
SIADH. Treatment will vary according to the type and intensity, but in general this is based on hydric restriction and the replacement of the
sodium deficit, either through physiological serum or through hypertonic saline serums depending on the case, and on occasions
furosemide for the elimination of excess water.