|| Department of medical
|King George III's urine and indigo
Wilfred Niels Arnold
Department of Biochemistry and Molecular Biology, University of Kansas
Medical Center, Kansas City, Kansas, 66160-7421, USA (Prof W N Arnold PhD)
illness of King George Conclusion
Attending physicians to King George III (1738-1820) recorded unusual
colours in his urine on at least four occasions.1
Sir George Baker,
on Oct 18, 1788, wrote in his diary that the urine was "bilious" (golden brown)
and on Aug 26, 1819, Dr Matthew Baille and Dr John Willis reported on "bloody
water". Those departures from the normal yellow of urochrome can be explained
with a 20th century hypothesis1--namely, that the king had a form of porphyria,
in which excessive amounts of 5-aminolevulinic acid and porphobilinogen are
excreted during medical crises. These compounds are colourless but can cause
pigmentation of the urine upon ageing.2
The formation of brown,
reddish-brown, or purple hue is due to non-enzymic reactions yielding mixtures
of porphyrins and other pigments such as porphobilin.3
colour of acute porphyric urine depends on initial concentrations of the
compounds undergoing polymerisation, light intensity, and storage time.
On the other hand, two reports by Sir Henry Halford about blue
pigments were listed but not explained by Macalpine and Hunter.1
Jan 14, 1812, specimens containing 8 and 9 fluid ounces of "bluish" urine were
registered on behalf of the King. In the bulletin of Jan 6, 1811, Sir Henry
wrote, "The water is of a deeper colour--and leaves a pale blue ring upon the
glass near the upper surface". Concurrent documentation showed that the patient
was suffering from one of many intractable bouts of constipation and vomiting.
Clearly, the blue compound was sparingly soluble and, because the precipitate
developed near the surface, I reasoned that oxygen was involved. The hue pointed
to indole chemistry.
The following working hypothesis may explain the early 19th century
observations. Because the patient was constipated, putrefaction during stasis of
the bowel led to indole formation from dietary tryptophan by the normal
intestinal flora. Some indole was absorbed into the blood stream and converted
in the liver first to indoxyl and then to the sulphate ester. The colourless,
water-soluble indoxyl sulphate (metabolic indican in the older published
research) was excreted in the urine. In the presence of a sulphatase of
bacterial origin, either from a urinary tract infection or as an environmental
contaminant of the chamber pot, indoxyl was slowly released by hydrolysis and
oxidatively dimerised into indigo blue, which precipitated on the porcelain.
I have demonstrated a model for the latter steps in laboratory
experiments. 1 mL samples of normal urine, with or without fortification by
(1 mg/mL), were placed in porcelain crucibles (25 mm
diameter at the top). Some pots were inoculated with
0·1 mL of a suspension
colony forming units/mL) of Providencia stuartii
cells, which had been flushed from the surface of an agar slant with fresh
urine. Controls were samples of normal urine, and of urine plus indoxyl
sulphate, that were not inoculated. The crucibles were placed on moist paper
towels, in a covered jar, and the mixtures were incubated overnight at room
temperature (23°C). The samples that contained both indoxyl sulphate and P
stuartii developed a dark blue pigmentation (figure 1). The blue ring on the
crucible itself was more obvious after the urine had been removed with a
syringe. This pigment was insoluble in water but dissolved in chloroform and
displayed an absorption maximum at 604 nm, consistent with indigo blue
The formation of blue pigment depended on incubation time, and on the
initial concentrations of indoxyl sulphate and of bacterial suspension. A bluish
tinge was apparent after 1 to 2 days, even when only 25% of the indoxyl sulphate
and 10% of the bacterial inoculum were used. The blue colour was more intense
and developed faster if the urine was initially adjusted to pH 7·0 than if it
were adjusted to pH 6·0 or lower; this accords with the chemistry of indigo blue
formation, rather than that of indigo white or indigo red.5,6
Figure 1: Simulation of Sir Henry Halford's observations of
"The water is of a deeper colour" (left) . . . "and leaves a
pale blue ring upon the glass" (right). Controls (left vessel of each panel) are
included. The liquid from the vessel on the far right has been removed
reveal the blue ring.
was chosen as the test microorganism because it has
been associated with urinary tract infections and aryl sulphatase activity (the
species was named after C A Stuart, bacteriologist of Providence, Rhode Island,
USA, and has no connection to the Royal House of Stuart). Of the eight isolates
of this organism (supplied by William Bartholomew and Rebecca Horvat, University
of Kansas, and Harry Mobley, University of Maryland), two contained enough aryl
sulphatase to be useful in my experiments. Importantly, they also contained
urease, which promoted alkalisation of the incubation mixtures and the yield of
indigo blue. I also obtained a positive result by setting up the porcelain
crucibles with 0·1 mL suspensions of P stuartii
, drying them overnight at
room temperature, and then adding the urine with indoxyl sulphate. P
is not essential to the working hypothesis; any species with
adequate aryl sulphatase and urease activities, and a tolerance of human urine,
would perform similarly and generate a blue ring. The shape and material of the
vessel, together with the kinetics of the chemical reactions, determine the
disposition of the indigo and the extent of a "Halford blue ring".
Sir Henry Halford (1766-1844) was created a baronet by King George III.
He had been summoned to attend Princess Amelia, who died in 1810, and was then
retained by the King, who was 72 years old. Halford spent almost half the year
of 1811 at Windsor Castle where he joined in sympathetic consultations with Dr
Matthew Baille and Dr William Heberden and had an uneasy relationship with Dr
John Willis and Dr Robert Willis, who were in favour of more restraining
treatments for the King.7
Halford was not involved with any of the
previous eight episodes of serious illness, the first of which occurred in the
King's third decade.
Figure 2: The formation of indigo blue from dietary
Enzymically catalysed steps occur in intestinal bacteria,
liver, and urinary bacteria, in this sequence. The final chemical reaction is a
non-enzymic oxidative dimerisation.
Halford speculated that King George's illness was primarily due to
ageing, and that the medical crises were associated with "climacterics"
occurring at intervals with mystical multiples of seven.8
studies, most notably by Ray in 1855 and Guttmacher in 1941, did not advance any
real understanding of the King's illness because they embraced only selected
aspects of the records and presented the case for manic depressive psychosis by
excluding all but mental symptoms.1
Macalpine and Hunter were the first to address the well-documented
physical signs and symptoms as well as the psychotic episodes. Thus, the crises
involving colicky abdominal pain accompanied by constipation and vomiting,
paralysis, peripheral neuritis, tachycardia, sweating, brown or red urine,
insomnia, delirium, the exacerbation of symptoms due to infections (caused by
cupping), and the absence of any permanent neurological deficit after each
crisis were noted and reasonably seen as acute intermittent
I believe that the age of onset of first symptoms, the
dynamics of all severe episodes, and the deleterious effects of some of the
medications, all exemplified by modern examples of acute intermittent
should also be added to that list.
Macalpine and Hunter subsequently modified their original working
hypothesis to variegate porphyria, primarily to accommodate skin sensitivity,
for which the evidence was meagre.9,10
Objection to their
retrospective categorical diagnosis and to specifics of variegate porphyria, and
a preoccupation with prevalence rates of the disorder in the general population,
became the thrusts of subsequent criticisms, which were often vehement and
remarkably uninterested in the total medical picture of King George III (see for
example Dean11 and references therein). Some sort of toxic psychosis is
indicated within which a metabolic disorder such as acute intermittent
porphyria, which will accommodate all of the neurological symptoms as well as
the exacerbation factors,2
remains a strong possibility. Indeed,
Rimington (quoted in Dean,11
p 168) opined that there was "so much
in the records being suggestive of porphyria and difficult to explain on any
other basis". But what about the blue urine?
The normal bacterial flora of the colon includes species with
tryptophanase, which catalyses the formation of indole, pyruvic acid, and
ammonia from dietary tryptophan.12
Indole is rapidly absorbed from
The sequential biochemical steps in intestinal bacteria,
liver, and urinary bacteria, leading to indoxyl in the urine and thence by
non-enzymic oxidative dimerisation to indigo blue are summarised in figure 2.
Excretion of indoxyl sulphate (indican) up to 140 mg per day is not uncommon in
The bag attached to a urinary catheter sometimes
develops a purple colouration, which is due to excretion of indican, increased
presentation time to adventitious bacteria with sulphatase, and an affinity of
the plastics for indigoid pigments.15
Some nutritional abnormalities and disease states are attended with
substantial increases in indican. For example, Rodnight and
reported that a young boy with pellegra and psychotic
symptoms had a six-fold increase of indican in his urine before the condition
was resolved with dietary supplements of nicotinamide. Patients with Hartnup
disease, caused by a congenital abnormality in the absorption of some aminoacids
including tryptophan, may produce 400 mg/day of indican.17
A case of
sprue was marked by increased concentrations of indole derivatives in the
urine.18 A familial disease in which hypercalcaemia and nephrocalcinosis are
associated with decreased transport of intestinal tryptophan is accompanied by
excessive indole production and abnormal indican concentrations in the
At least two reports on acute intermittent porphyria may be of immediate
relevance. Ludwig and Epstein20 studied a family with an especially high degree
of penetrance, and observed that some of the family members showed increased
urinary indican even in remission. Price and colleagues21
abnormal response to tryptophan loading in some of their porphyria patients. It
is noteworthy that the sporadic reports of increased concentrations of various
indole derivatives in the urines of mentally ill patients do not show a direct
relation with mental disturbance. Rather, indicanuria is most often associated
with bowel stasis and influenced by dietary protein composition and intestinal
Sir Henry Halford's bulletin of Jan 6, 1811, euphemised King George's
constipation: "2·5 hours sleep after midnight . . . up to the w. closet twice
with little or no effect". The doctor prescribed powdered Aloes socotrina (a
cathartic) and extract of Taraxacum officinale (a laxative and diuretic). Thus,
the King probably had a condition that would lead to overproduction of urinary
indican. I have suggested a role for a bacterial sulphatase and shown a positive
result with conditions simulating either urinary tract infection or poor
hygiene. The amount of indoxyl sulphate in the test was within physiological
limits, although evaporation would actually increase concentrations. I also
suggest that Halford's observations of blue urine can be accommodated by a
background of acute intermittent porphyria, because severe and recurrent
constipation is a hallmark of that disease.
The incentive for this study came from the play by Alan Bennett (The
madness of George III. London: Faber & Faber, 1992). About a quarter way,
one of the King's pages remarks upon His Majesty's urine being blue and a second
attendant argues purple. A similar exchange occurs in the penultimate scene. The
subsequent film script fixed upon blue alone in the final scene, and raised the
eyebrows of students of porphyria.
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