Global Health Asia-Pacific September 2020 September 2020 | Page 36

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Kidney Stone
What causes kidney and urinary stones?
(such as calcium, oxalate, phosphate, uric acid and
others) and a low concentration of substances that
stop stone formation (urinary inhibitors such as citrate
and magnesium). Most urinary stones are made up of
calcium oxalate or calcium phosphate, whilst struvite,
uric acid and cysteine stones are less commonly
encountered. �isk factors for urinary stone formation
include (1) urinary tract infections� (2) cystic kidney
disease� and (�) various metabolic disorders such as
gout.
How are kidney stones diagnosed?
Kidney stones are often asymptomatic. They are
usually detected when they cause severe cramping
pain in the �anks, which may spread down to the
lower abdomen. Nausea, vomiting, and blood in the
urine may be accompanying symptoms. Fever, chills
and painful urination suggest that the stone may be
associated with a urinary infection. Urine analysis,
X-rays of the abdomen and pelvis and ultrasonography
of the kidneys are usually the first tests to confirm the
diagnosis (figure 1). Computer tomography of the urinary
tract, popularly known as a CT urogram, gives the most
accurate information of the position of the stones and
the associated anatomy of the kidneys, which may be
swollen from the stone causing obstruction to passage
of urine down the ureters.
What treatments are available for urinary stones?
Most urinary stones are small (��mm), and will pass out
of the body spontaneously without need for surgery. For
larger or impacted stones, treatment objectives are to
eradicate the stone and relieve obstruction to promote
recovery of kidney function. In recent years, new
approaches and technologies have been developed to
eradicate such stones.
1. Medical expulsive treatment of ureteric stones
In the past decade, medical expulsive therapy (M�T)
for ureteric stones has become increasingly popular.
Various medications, such as calcium channel blockers,
�-blockers, and corticosteroids have been investigated.
Failure of stones to pass out after 4 to 6 weeks of
medical treatment will necessitate intervention to remove
these stones.
Urine is produced by the two kidneys situated high
in the abdominal cavity, and comprises water
associated with waste products of the body. It
passes down narrow tubes called the ureters into the
bladder, which stores urine until a convenient time for it
to be excreted.
Stones in the kidneys and urinary tract occur
commonly in Singapore and Southeast Asia, and usually
occur in patients aged above 40 years. They affect men
more often than women, and form as a as a result of
urine with a high concentration of certain chemicals
Figure 1: Abdominal X-rays showing
(a) stone in the left upper ureter;
(b) staghorn stones in both kidneys.
34 SEPTEMBER-OCTOBER 2020 GlobalHealthAsiaPacific.com