F C S Teixeira, A Lebre, S A Cunha-Ramos, M Costa e Silva, E Kawano, M Domingues-Ferreira.
Emergency Service Medical Clinic of the São Luiz Gonzaga Hospital, Irmandade da Santa Casa de São Paulo, São Paulo – Brazil
Corresponding author: Mauricio Domingues Ferreira - email: madofe@uol.com.br
SMJ 2009 54(2):
Abstract
Hyperkalemia
paralysis is a very rare disorder that can be easily managed by the adjustment
of serum potassium levels. It is characterised by an ascending flaccid motor
weakness and differential diagnosis, mainly Guillan-Barré syndrome, should be
considered. We describe a case of ascending flaccid paralysis in a patient
admitted to an emergency unit in Sao Paulo, Brazil. The patient had previously
received Spironolactone and examination revealed hyperkalemia and chronic renal
failure due to a polycystic kidney disease. With the improvement in his
potassium levels, the paralysis disappeared until complete remission occurred.
This report indicates another important and poorly recognised manifestation of
hyperkalemia.
Key words: Ascending
paralysis, hyperkalemia, cecondary hyperkalemic paralysis, chronic renal
failure.
Introduction
The
harmful effects of hyperkalemia on cardiac excitability are very well known in
the emergency room. However, another rare and important manifestation of
hyperkalemia, ascendant paralysis, is not expected and less often recognised as
a prime clinical manifestation of hyperkalemia. The mechanism of this paralysis
is not completely understood. The classical cause of paralysis related to serum
potassium levels is hereditary episodic hyperkalemic paralysis, however rare
reports of secondary causes have been described in medical literature. Most of
cases are the result of trauma, diuretic drugs, and iatrogenic agents.
However,renal failure is the main aetiological agent.1 This disorder
is characterised by flaccid tetraplegia that spare the cranial nerves and lack
sensory impairment, sometimes resembling other forms of paralysis, such as
Guillan-Barré syndrome.1 Differential diagnosis must be established
quickly, because of the control of potassium level reversal promptly resolves
this disturbance. In this paper, we report a case of secondary ascending
hyperkalemic paralysis diagnosed in an emergency unit in the city of Sao Paulo,
Brazil.
Case
history
A
72 year-old Caucasian male was admitted to our emergency unit with a two-day
history of progressivve and ascending muscle weakness, starting from his legs
and progressively moving to his arms. On admission, the leg weakness was so
severe that he was no longer able to walk or stand unaided. The patient did not
present with any symptoms such as seizures or tingling. The patient did report,
that 15-days prior to admission, he had experienced four days of intestinal
obstipation and a couple of days of influenza-like symptoms. Past medical
history revealed a 30-year history of arterial hypertension and an acute
myocardial infarction two years previously, for which he received myocardial
revascularisation surgery. The patient did not smoke or drink alcohol
habitually.
He was taking the following medication: Amiodarone, Isosorbide
5-Mononitrate, Furosemide, Spironolactone and Losartan.
On
examination, the patient was aware, alert and fully oriented, normothermic and
presented stable haemodynamics. His Glasgow coma scale score was 15/15. His
blood pressure was 100/70mmHg and his pulse was regular at 74 beats per minute.
There were no signs of heart failure or any other disorder in the remaining
systems, aside from the flaccid tetraparesis detected during the neurological
examination. Muscular strength was abnormal (degree II) in the upper limbs and
absent (degree zero) in the lower limbs. His patellar, Achilles, left bicipital
and left tricipital reflexes were absent. The right bicipital reflex was deeply
depressed, though no sensitivity disturbance had occurred and cerebellar
function was normal. Examination of the cranial nerves revealed no abnormality.
Anal sphincter tone was normal and there was no urinary retention. The patient
presented no respiratory disorder and was able to speak without problems. An
ascending flaccid paralysis syndrome was diagnosed, with suspected Guillan-Barré
syndrome. The results of subsidiary exams revealed glycemia of 4.95 mmol/L
(90mg/dL), calcium of 2.48 mmol/L (9.9mg/dL), magnesium of 1.15mmol/L (2.3mg/dL),
sodium of 135 mmol/L and normal aminotransferases and creatine phosphokinase.
The urea presented nitrogen levels of 59.6 mmol/L (167mg/dL) (uraemia),
creatinine was 415.48 µmol/L (4.7mg/dL) and his serum potassium level was 9.5
mmol/L (hyperkalemia). The blood count showed 8.2% haemoglobin, 26% hematocrit
(anaemia), 11.600 leukocytes, 70% segmented neutrophils, 1% band neutrophils,
and 212.000 platelets. The arterial blood gases in room air were: pH 7.23; PCO2
of 28.9 mmHg, PO2 of 72.7 mmHg, base excess of -13.9 mmol/L and serum
bicarbonate of 11.8 mmol/L, compatible with metabolic acidosis. The chest x-ray
revealed moderate widening of the left heart ventricles. Several
electrocardiograms (ECG) were performed, demonstrating minimal abnormality and
sinus rhythm with PR and QT intervals within the normal range. The ECGs did not
present T wave abnormalities or hyper acute T waves at any time during the
hospitalisation period. The only abnormality presented was the slightly
prolonged duration of QRS intervals. When a new sample was taken, the serum
potassium level was again 9.5 mmol/L. A lumbar puncture was performed. About 10
ml of fluid was collected, showing 1 cell/mm3, 1 erythrocyte, no leukocytes, 34
mg/dL of protein, 3.63 mmol/L (66mg/dL) of glucose; 123 mmol/L of chlorides. A
cranial and spinal cord computerized tomography (CT) scan showed no significant
abnormalities.
The
immediate focus of the treatment was the control of the metabolic disorder and
hyperkalemia. Spironolactone was suspended and the patient received furosemide,
sodium bicarbonate, insulin (intravenous pushes of 10 units regular plus
glucose) and sodium polystyrene sulphate. The level of potassium decreased
progressively until reaching 5.9 mmol/L on the fourth day of hospitalisation. As
a result, the patient showed significant improvement in the flaccid paralysis
concomitantly with the diminishing potassium level, until he became completely
asymptomatic when his potassium level reached 5.9 mmol/L. The concomitant
neurological remission and decrease in potassium levels was absolutely
astonishing. The patient’s flaccid tetraparesis disappeared completely. During
this period the creatinine and urea levels remained unaltered. An abdominal
ultrasonographic study revealed multiple cystic images of various sizes in both
the kidneys and the liver. An adult polycystic kidney disease and chronic renal
failure were strongly suggested. The investigation and treatment proceeded after
the neurological picture had completely remitted and potassium had reached
normal levels, since the creatinine and urea levels had not improved. On the
twentieth day of hospitalisation, the patient’s potassium level was 3.5 mmol/L.
The patient remained completed asymptomatic when he suddenly suffered
ventricular fibrillation and passed away.
Discussion
When
the patient arrived in our emergency unit, we initially assumed that the
patient’s clinical status was compatible with Guillan-Barré syndrome (GBS).
In addition to the neurological disorder, the patient presented renal failure,
metabolic acidosis, anaemia and significant hyperkalemia, which was promptly
treated and returned to normal levels. The patient had presented influenza
symptoms two weeks before developing the ascending paralysis, which could have
triggered GBS, but he did not present symptoms like tingling and
“pins-and-needles sensations” in the feet or dull low-back pain, which are
frequent initials GBS symptoms prior to the onset of paralysis.2 The
cerebrospinal fluid analysis was not compatible with Guillan-Barré syndrome,
characterised by a protein level range of 100-400mg/dl in the absence of
significant pleocytosis; although these abnormalities can appear after the first
week.2 Total remission of GBS progressively takes a number of weeks
or months; in contrast, the patient presented remarkable remission in four days,
concomitantly with the decrease in serum potassium levels. When potassium
reached normal levels, the neurological symptoms were completely normalised. He
was able to walk without problem, presenting quite asymptomatic. This strongly
suggested the participation of hyperkalemia as the genesis of the ascending
paralysis. Even after remission, the patient still presented high levels of urea
and creatinine. This discards the participation of uraemia in relation to the
patient’s ascending paralysis. The cranial and spinal cord CT scan did not
reveal any significant abnormalities and discarded other conditions, such as
central nervous ischemia and neoplasic infiltration or traumatic spinal cord
injury, malign neoplasms, such as multiple myeloma, or metastasis from prostate
cancer or other tumours that compromise vertebras.
The
mechanism underlying secondary hyperkalemia paralysis is not completely
understood. Some authors believe in the direct action of potassium on the muscle
cell membrane or on the muscle fibre,1, 4 others suggest that a
functional peripheral neuropathy occurs due to the abnormal depolarisation of
the nerve membrane caused by the high level of potassium.1, 5 Few
cases of secondary hyperkalemic paralysis have been reported in the literature,
most of which probably derived from an additive effect of Spironolactone
associated with mild renal failure.1 Certainly, our patient could be
included in this group, as he presented chronic renal failure due to adult
polycystic renal disease and was using Spironolactone until the day of his
admission. Another interesting fact is that the patient did not present
exuberant cardiological symptoms and his electrocardiography exams showed only
minimal abnormalities, despite the high potassium level (9,5mmol/L) seen on
admission day. This situation contrasted with the intense neurological symptoms
that he presented during his hyperkalemic state and an intriguing question
remains; what mechanisms might induce certain rare hyperkalemic patients to
develop ascending paralysis rather than arrhythmias? Further studies must be
conducted to elucidate this phenomenon.
Conclusion
When
facing a picture of ascending paralysis, hyperkalemia should be included as a
differential diagnosis. Though it is a rare manifestation, it can occur and is
easily remitted by reducing the serum potassium level. It is a necessary
precaution when potassium-sparing drugs are used on patients presenting renal
failure. This situation could provoke hyperkalemia and its cardiac and
neuromuscular complications.
References:
Evers
S, Engelien A, Karsch V, Hund M. Secondary hyperkalaemic paralysis.
Griffin,
J.W.; Immune-Mediated Neuropathis. In Goldman,L;
Bennett,J.C. Cecil textbook of medicine; 21nd edition; W.B.Saunders
Company. 2000; Page 2193-2194.
Livingstone
IR, Cumming WJ. Hyperkalaemic paralysis resembling Guillain-Barre syndrome.
Lancet. 1979 Nov 3;2(8149):963-4
Villabona
C, Rodriguez P, Joven J, Costa P, Avila J, Valdes M. Potassium disturbances
as a cause of metabolic neuromyopathy. Intensive
Care Med. 1987;13(3):208-10.
Shinotoh H,
Hattori T,
Kitano K,
Suzuki J.
. Hyperkalaemic paralysis following traumatic rupture of the urinary
bladder. J Neurol Neurosurg Psychiatry. 1985 May;48(5):484-5