This document discusses nervous system manifestations of chronic kidney disease (CKD). It covers several topics: 1. Neurological complications are common in CKD, affecting the central and peripheral nervous systems. Patients on dialysis tend to have reduced strength, activity levels and exercise capacity compared to healthy individuals. 2. Specific conditions discussed include peripheral neuropathy, carpal tunnel syndrome, autonomic neuropathy, cognitive dysfunction, uremic encephalopathy, dialysis disequilibrium syndrome, stroke, and myopathy. 3. Pathophysiology involves the retention of toxins in CKD that can damage nerves. Treatment focuses on renal replacement therapy through dialysis or transplantation to remove toxins from the body.

1. Nervous
system
manifestations
of CKD
Dr Manish Singla
28-02-2012

2. Introduction
 Neurological complications occur in
almost all patients with severe
CKD, potentially affecting all levels of the
nervous system, from the CNS through
to the PNS.
 Patients on dialysis tend to be weaker
and less active, and to have reduced
exercise capacity, when compared with
healthy individuals
 Cognitive impairment, peripheral and
autonomic neuropathy

3. Objectives
 Neuropathy
 Cognitive dysfunction
 Uremic encephalopathy
 Dialysis disequilibrium syndrome
 Stroke
 Myopathy

4. Neuropathy
 Peripheral neuropathy
 Carpal tunnel syndrome
 Autonomic neuropathy
 Pruritis

6. Peripheral neuropathy
 About 50 per cent of patients starting
treatment had clinical evidence of a
peripheral neuropathy in early days of
dialysis
 Because of earlier initiation of dialysis
these days, neuropathy is usually
asymptomatic
 Nerve conduction abnormalities have
been reported in up to 60% of patients
receiving dialysis
 Abnormalities in motor nerve conduction
velocity parallel the decline in GFR

7. Peripheral neuropathy
 Uremic neuropathy is a
distal, symmetric, mixed sensorimotor
polyneuropathy.
 Loss of ankle vibration sensation and
the ankle jerk are often the first
manifestations, progressing to a
burning sensation in the feet, followed
by motor deficit, such as weakness of
ankle dorsiflexion

8. Peripheral neuropathy
 It typically involves the lower
extremities more often than the upper
extremities, and sensory symptoms
precede motor symptoms.
 Motor involvement usually indicates
advanced disease
 Progress to a stocking neuropathy
with weakness and wasting of the
distal leg muscles

9. Wasting of intrinsic hand muscles, with prominent
bilateral atrophy of thenar muscles, in a patient with
severe neuropathy resulting from chronic kidney
disease

10. Pathophysiology of uraemic
neuropathy
 Typically the large diameter axons in
the distal nerve trunks supplying the
legs are affected, with relative sparing
of the unmyelinated and the small
myelinated afferent neurons.
 Predominant defect is one of axonal
loss with secondary demyelination
 Repeated episodes of demyelination
followed by remyelination - onion like
structures on nerve biopsies

11. Pathophysiology of uraemic
neuropathy
 Biochemical pathogenesis of uraemic neuropathy is
multifactorial
 Ouabain sensitive calcium ATPase pump activity has
been shown to be decreased in uraemia, thereby
affecting the sodium-calcium exchanger, and
hence, reducing the normal calcium gradient
 Various uraemic toxins (middle molecules) have been
proposed, including guanidine compounds, particularly
methylguanidine which can inhibit the sodium ATPase
pump, PTH
 Polyamines, phenol metabolites, myoinositol, and 3-
carboxy-4-methyl-5-propyl-2-fluranpropanoic
acid, (which inhibits organic acid transport)
 toxin induced inhibition of transketolase, and pyridoxal
phosphate kinase

12. Transketolase
 Transketolase is a thiamine-
dependent enzyme of pentose
phosphate pathway.
 Found mainly in myelinated
neurons.
 it maintains axon-cylinder
myelin sheaths.
 Guanidinosuccinic acid can
inhibit transketolase resulting
demylination.
 It also inhibit excitatory
synaptic transmission in CA1
region of
hippocampus, contributing to
cognitive syndrome in UE.

13. Pathophysiology of uraemic
neuropathy
 Clinical symptoms and nerve
conduction parameters improve
rapidly following renal
transplantation, often within days of
surgery
 Rapidity of these changes suggests
that toxin-mediated blockade of neural
transmission has an important role in
the neurological dysfunction
associated with CKD.

15. Diagnosis of uremic
neuropathy
 First step in the diagnosis of uremic
neuropathy is to exclude other causes of
neuropathy
 Serological testing should be undertaken to
exclude vas-culitic neuropathy in those
rapidly evolving weakness
 Nerve conduction studies (NCS) remain the
gold standard in the diagnosis of uremic
neuropathy.
 NCS demonstrate generalized neuropathy of
the axonal type, with reductions in sensory
amplitudes > motor amplitudes
 Sural sensory amplitude is the most sensitive
indicator of uremic neuropathy

16.  Systemic diseases that contribute to
ESRD and also affect nerve function-
◦ Diabetes mellitus
◦ Amyloidosis
◦ SLE

17. Treatment
 Renal transplantation remains the only
cure for uremic neuropathy and must be
considered in any patient with
progressive neuropathy.
 Rapidly progressive neuropathy is an
accepted indication for patients to be
triaged to urgent, nonmatched
transplantation lists.
 Following transplantation, clinical
recovery typically occurs over a period of
3-6 months

19. Carpal tunnel syndrome
 Carpal tunnel syndrome (CTS) is due
to compression of the median nerve
as it passes deep to the flexor
retinaculum at the wrist, causing
numbness, tingling, and burning
sensations in the hand and fingers
 Attributable to dialysis-associated
amyloidosis or ischemic
mononeuropathy associated with an
arteriovenous fistula.
 Prevalence of 26% in patients who
have been on dialysis for more than 4

22. Carpal tunnel syndrome
 Pain is typically worse at night and
during haemodialysis.
 Eventually weakness of thumb
abduction occurs with wasting of the
thenar eminence.
 CTS is more common in
◦ middle aged and older women
◦ diabetics
◦ patients with hypothyroidism
◦ patients on dialysis > 7 years

23. Carpal tunnel syndrome
 Diagnosis of CTS can be confirmed by
measuring a delay in median nerve
conduction across the wrist, and also
by ultrasound of the wrist
demonstrating bone cysts and
distortion of the flexor tendons
 Haemodialysis with a high flux
polyacrylonitrile, or
haemodiafiltration, have been reported
to reduce the deposition of β2-
microglobulin

24. Carpal tunnel syndrome
 Splinting or local corticosteroid
injections for mild disease
 Surgical decompression in cases
where symptoms are either refractory
to conservative treatments or where
NCS have demonstrated changes
indicative of axonal loss
 Extended carpal tunnel release
procedure

26. Autonomic neuropathy
 Autonomic dysfunction is a common
and potentially life-threatening
complication of CKD, and can occur in
the absence of length-dependent
uremic neuropathy.
 More common in diabetics and elderly
patients
 Cardiovascular autonomic dysfunction
in CKD is associated with an
increased risk of cardiac arrhythmia
and sudden cardiac death

27.  Impotence remains the most common
symptom of autonomic dysfunction in
CKD
 Other common clinical features include
bladder and bowel dysfunction, impaired
sweating, and orthostatic intolerance
 Intradialytic hypotension
 Renal transplantation leads to
considerable improvement in autonomic
function
 Sildenafil , midodrine

29. Objectives
 Neuropathy
 Cognitive dysfunction
 Uremic encephalopathy
 Dialysis disequilibrium syndrome
 Stroke
 Myopathy

31. Cognitive dysfunction
 Cognitive dysfunction increases in
prevalence with CKD severity,
potentially affecting up to 80% of
patients
 Cognitive impairment in CKD not only
increases the risk of mortality, but also
has major implications for informed
consent in relation to dialysis initiation
and maintenance, and, ultimately,
renal transplantation

32. Acute Cognitive Impairment
 In addition to chronic cognitive
dysfunction and dementia, acute
disturbances of cognition are
prevalent in CKD.
 In the early days of dialysis, these
acute disturbances frequently took the
form of the 'dialysis disequilibrium
syndrome'

33. Acute Cognitive Impairment
 Acute disturbances in cognitive function
typically relate to metabolic abnormalities
that complicate the uremic state, including
electrolyte disturbances (for
example, hypercalcemia, hypophosphatemi
a and hyponatremia), acute fluid shifts
during dialysis, which lead to cerebral
hypoperfusion, and malignant hypertension

34. EFFECT OF HD
 Rapid variations in cognitive function
was emphasized by a study of patients
with CKD who underwent cognitive
testing at multiple time points before and
after a single dialysis session
 In these patients, global cognitive
function varied markedly, with the
greatest impairments being noted during
the dialysis session, particularly with
regard to memory, executive functioning
and verbal fluency.

35. Chronic Cognitive Impairment
and Dementia
◦ mild cognitive impairment,
◦ subclinical dementia,
◦ residual syndrome, and
◦ chronic dialysis-dependent
encephalopathy

36. Chronic Cognitive Impairment
and Dementia
 Moderate renal impairment that does
not require dialysis is also associated
with a significantly increased risk of
dementia
 Cognitive tests demonstrate objective
evidence of moderate to severe
cognitive impairment in 70% of
patients with CKD, with dysfunction
most commonly noted in the domains
of memory and executive function.

38. Dialysis dementia
 Dialysis dementia is a term reserved
to describe a syndrome of progressive
dementia related to aluminum
intoxication and first described several
decades ago when aluminum
contamination of dialysate fluid and
the use of aluminum-containing
binders were more prevalent;
however, this disorder is now rare.

39.  Treatment :- DFO therapy

40. Pathophysiology of Cognitive
Impairment
 vascular dementia
 high incidence of clinically silent
cerebrovascular disease
 MRI studies have shown that clinically
silent white matter disease is present
in 50% of patients with
CKD, compared with 10% in the
general population
 Traditional and non traditional
vascular risk factors (inflammatory
mediators)

41. Pathophysiology of Cognitive
Impairment
 Modern techniques of water
purification and the use of non-
aluminum phosphorus binders
have, however, made aluminum
intoxication a rare complication of
CKD
 Potential roles of secondary
hyperparathyroidism and anemia as
risk factors for cognitive impairment
 PTH – neurotoxic

43. Clinical evaluation of
dementia
 The Mini-Mental State Exam is the best
known cognitive test for dementia screening
and requires 7 to 10 minutes to administer.
 A score below 24 (out of a maximum score of
30) has a sensitivity and specificity of greater
than 80% for dementia detection in the
general population.
 Other cognitive tests that can be
administered in 5 minutes or less, such as
the clock drawing task, the Minicog
(consisting of the clock drawing task plus
uncued recall of three words), and the Short
Portable Mental Status Questionnaire, have
similar performance characteristics in the
general population

44. Effects of Renal
Transplantation
 Improvements in cognition in relation
to baseline values were demonstrated
6 months after transplantation
 Improvements in both
neuropsychological tests, such as the
Mini-Mental State Examination, and
neurophysiological markers of
cognitive function, as measured using
evoked potential latencies and EEG
rhythms

45. Treatment
 Although kidney transplantation is
optimal therapy for most patients with
ESRD, many patients with chronic
cognitive impairment may not be
eligible for transplantation
 Intensification of the dialysis regimen
remains a potential management
strategy

46. EEG from a patient with uraemic encephalopathy.
The recording is predominantly δ (4-8 Hz) and θ (4 Hz)
wave activity, with no normal α (>8-13 Hz) or β (>13 Hz)
waves

47. Uremic encephalopathy
 Uremic encephalopathy is an acute or
subacute organic brain syndrome that
regularly occurs in patients with acute or
chronic renal failure when glomerular
filtration rate declines to less than 10% of
normal
 Seen in untreated or inadequately
treated ESRD
 Characterized by lethargy and confusion
in early stages and can progress to
seizures or coma
 May be accompanied by other
neurologic signs, such as
tremor, myoclonus, or asterixis

50. Pathophysiology
 A large number of solutes are retained in uremia
and several may have direct neurotoxicity or
contribute indirectly to the pathogenesis of
uremic encephalopathy by altering the blood–
brain barrier.
 guanidine compounds, including
guanidinosuccinic acid, methylguanidine, and
homoarginine induce seizures, possibly through
their effects on N-methyl-D-aspartic acid (NMDA)
receptors or by modulating calcium channels
 ADMA, is a potent endogenous inhibitor of nitric
oxide synthesis and causes cerebral
vasoconstriction by impairing endothelial
relaxation
 Anemia and hyperparathyroidism

51.  A 50 year old male , known case of DM /
ESRD on intermittent acute PD, getting HD
sessions in between as well, past h/o
smoking, receiving diuretics for edema, poor
dietry intake, received one HD session from
regional centre and brought in altered state (
history : duration?? )
 On probing attendants gave h/o low grade
fever for last 3-4 days
 Medication review – aluminium based
phosphate binders, OHA tablets
 Residents notices some weakness on left
side of body – but not sure
 Diagnosis : ………………..

53. Treatment
 After other causes of delirium have been
ruled out, prompt treatment of uremic
encephalopathy with initiation or
intensification of renal replacement
therapy is indicated.
 Resolution of symptoms typically occurs
within days.
 Correction of anemia (i.e., hemoglobin
<10 g/dL) may also be of benefit.
 Dietary protein restriction is another
adjunctive measure used to delay the
development of uremic symptoms,

54.  A 12 year old male child, recently
diagnosed to have b/I contracted
kidneys, received 2 HD sessions at
regional hospital and brought in
altered state
 On probing attendants gave h/o low
grade fever for last one day, headache
and vomiting
 Diagnosis : ………………..

55. Dialysis disequilibrium
syndrome
 Attributable to the dialysis procedure itself
and is seen during or shortly after the first
several dialysis treatments.
 It is most likely to occur in pediatric or elderly
patients, patients with severe azotemia, and
patients undergoing high-efficiency
hemodialysis
 However, it has also been reported in
patients undergoing peritoneal dialysis and
maintenance hemodialysis
 Dialysis dysequilibrium is characterized by
symptoms of headache, visual disturbance,
nausea, or agitation and in severe cases,
delirium, lethargy, seizures, and even coma.

56.  Two hypotheses have been suggested to
explain the development of brain edema.
 In the first, rapid removal of urea by
dialysis leads to a urea gradient between
the blood and brain, in turn leading to
influx of water into the brain
 In the second theory, the formation of
idiogenic osmoles within the brain
contributes to the development of
cytotoxic edema when an osmolar
gradient is developed during dialysis.
(MRI similarities with ODS)

57. Differential diagnosis of dialysis
disequilibrium syndrome

60. Objectives
 Neuropathy
 Cognitive dysfunction
 Uremic encephalopathy
 Dialysis disequilibrium syndrome
 Stroke
 Myopathy

61. Stroke
 Compared with the general
population, stroke event rates and stroke
mortality rates are increased six- to 10-
fold among patients on dialysis
 Like the general population, ischemic
stroke is more common than
hemorrhagic stroke
 Posterior circulation strokes involving the
vertebrobasilar system occur more
commonly in patients on dialysis than in
the general population

62.  Kidney transplantation is associated
with 30% lower risk for stroke or TIA
compared with patients remaining on
the transplant wait list,
 allograft failure increases the risk for
stroke or TIA by 150%

64. Risk factors
 Traditional risk factors
 Proteinuria was associated with a 50% to
70% increased risk for stroke (meta-
analysis of stroke cohort studies
involving more than 140,000)
 Dialysis related factor
◦ Intradialytic hypotension
◦ Overcorrection of anemia, especially in the
setting of ultrafiltration, may lead to vascular
stasis and thrombosis
◦ anticoagulation

65. Risk factors

66. Management
 Non contrast CT
 gadolinium-enhanced MR angiography
must be carefully weighed against the
potential benefits of the imaging
procedure
 Safety, efficacy, and practicality of
thrombolytic therapy in the setting of
CKD and ESRD remain unclear
 In trials of thrombolytic therapy
conducted in the setting of acute
MI, patients with CKD were2-4 times as
likely to experience major
bleeding, including ICH
 Prevention – role of aspirin

67. Uremic myopathy
 Leads to proximal muscle weakness and
wasting, predominantly in the muscles of the
lower limbs
 Uremic myopathy typically develops with
glomerular filtration rates of <25 ml/min, and
has been associated with fatigability and
reduced exercise capacity
 Electromyography and creatine kinase levels
are generally normal, and the diagnosis
is, therefore, made largely on clinical
grounds.
 Muscle biopsy tends to demonstrate
nonspecific features, including type II fiber
atrophy with internalized nuclei and fiber

68.  Possible etiologies include :-
◦ Hyperparathyroidism,
◦ Metabolic bone disease with vitamin D
deficiency
◦ Impaired potassium regulation
◦ Accumulation of uremic toxins
◦ Carnitine deficiency, which can lead to
mitochondrial dysfunction
◦ Malnutrition

69. summery

70. Key points
 Urenic toxin mediated disturbances in resting axonal
membrane potential leads to length-dependent neuropathy in
CKD
◦ Polyneuropathy
◦ Mononeuropathy
◦ Autonomic neuropathy
 Presentation in acute delirius/ confusional state is common in
CKD patients and can have wide array of differential
diagnosis
 Cognitive impairment is common in patients on
dialysis, typically manifesting as a vascular-type dementia
with prominent deficits in executive function
 Renal transplantation improves cognitive function, peripheral
neuropathy and autonomic neuropathy
 Stroke is a common factor adding to morbidity and mortality
in these patients. Management strategies - unclear
 Exercise programs, adequate nutritional intake and treatment

71. Medicolegal Pitfalls
71

72. Medicolegal Pitfalls
1. Failure to recognize RF as the cause of
encephalopathy in a patient who presents
with altered mental status.
2. Failure to promptly initiate dialysis in a
patient with UE.
3. Failure to adequately monitor drug levels
may lead to toxicity & further complications.
4. The slow onset of symptoms may lead to
complications that might be grounds for
litigation.

73. Thank
you
73