Approach to a child with
weakness
Dr. Pushpa Raj Sharma
Professor of Child Health
Institute of Medicine
Weakness/paresis/paralysis
 Upper Motor Neuron.
 Lower Motor Neuron
 Myopathic
Pattern of weakness
Sign
UMN
LMN
 Atrophy
-
+++
+
 Fasciculations
-
+++
-
 Tone
+++
Myopathic
-
+/-
 Distribution
Regional
Segmental
Proximal
 Tendon reflexes
+++
-/--
+/-
 Babinski’s sign
+
-
-
Important fact:
When there is a discrepancy between the
history and physical findings, it is usually
because the patient complains of
weakness, whereas symptoms are
actually due to other causes.
Child Abuse may be the cause.
Motor Neuron Disease
Asymmetric
Upper and lower motor neurones







Amyotrophic Lateral Sclerosis (ALS)
Sporadic ALS
Hereditary ALS
Superoxide Dismutase; Chromosome 21; Dominant
Other ALS: Recessive & Dominant
Multi-system disorders
ALS with Ophthalmoplegia & Extrapyramidal
Disorders
 Polyglucosan body disease
 Motor neuronopathy with cataracts and skeletal
abnormalities
 Multiple system atrophy
Motor Neuron Disease
Symmetrical and proximal
SMN: Chromosome 5q; Recessive
Androgen Receptor (Bulbo-spinal Muscular Atrophy):
X-linked; Recessive
Hexosaminidase A (Tay-Sachs): Chromosome 15;
Recessive
Hand weakness
Bulbar involvement
Motor Neuron Disease
Lower motor neurones only
• Distal Lower Motor Neuron (LMN) Syndrome
 IgM vs GM1 ganglioside
 IgM vs GalNAc-GD1a ganglioside
 Also see: Multifocal motor neuropathy
• Proximal Lower Motor Neuron Syndromes
 Brachial amyotrophic diplegia
 ? Associated with IgM vs asialo-GM1
 Rare: Upper > Lower limbs with anti-Hu antibodies
Motor Neuron Disease
Lower Motor Neuron Syndrome without antibodies
(PMA)
ALS variants
• Hereditary
• Sporadic
Focal motor neuron disease
• Monomelic Amyotrophy
• Paraspinous muscle amyotrophy
• Cervical amyotrophy
Motor Neuron Disease
Paraneoplastic motor neuro(no)pathy
• Mild weakness: With lymphoma
• Severe weakness: With breast cancer
Hopkins' syndrome: Acute post-asthmatic
amyotrophy
Polio & Post-polio syndrome
SMN2 (SMNC) deletions
Neurofibromatosis, Type 25
Motor Neuron Disease
Symmetric & Proximal: Hereditary Spinal
Muscular Atrophy
SMN: Chromosome 5q; Recessive
Androgen Receptor (Bulbo-spinal Muscular
Atrophy): X-linked; Recessive
Hexosaminidase A (Tay-Sachs): Chromosome
15; Recessive
Motor Neuron Disease
 Rapid onset
Acute Axonal Motor Neuropathy
 (with Campylobacter jejuni or serum IgG vs
GM1)
Poliomyelitis
Porphyria
 4 types cause neurologic attacks
•
•
•
•
Acute intermittent
Variegate Porphyria
Coproporphyria
δ-amino-levulinic acid dehydratase deficiency
 Urine: All types produce increased δ-amino-levulinic acid
during attacks
Motor Neuron Disease
Painful
Acquired
Others
Motor Neuron Disease
Acquired
Toxic: Lead; Dapsone; Botulism; Tick Paralysis
Infections
Polio
West Nile
Central European encephalitis
Creutzfeld-Jacob
• Amyotrophy
• Polyneuropathy (± Demyelinating)
Weakness/ paresis/ paralysis indicates the lesions in the upper motor
nurone or lower motor neurone or myoneural junction or muscles.
Preservation of sensation/ Increased or absent or diminished jerks/
atrophy or hypertrophy indicates the site of lesions.
The major clinical diagnosis associated
with AFP (n= 517) *
Guillain-Barre syndrome (30.2%),
Central nervous system infection (16.2%),
Transverse myelitis (10.6%)
Non-polio enterovirus infection (6.2%),
Hypokalaemic paralysis (5.2%).
* Hussain IH, Ali S, Sinniah M, Kurup D, Khoo TB, Thomas TG,
Apandi M, Taha AM J Paediatr Child Health. 2004 Mar;40(3):12730
Age distribution of Guillain-Barré syndrome.
AIDP=acute inflammatory demyelinating polyradiculoneuropathy; FS=Fisher syndrome
Lyu, R.-K. et al. J Neurol Neurosurg Psychiatry 1997;63:494-500
Seasonal distribution of Guillain-Barré syndrome
Lyu, R.-K. et al. J Neurol Neurosurg Psychiatry 1997;63:494-500
Recurrent Guillain Barre' Syndrome
Of the 220 patients of acute idiopathic
demyelinating polyneuritis (AIDP/GBS)
seen over a seven year period, 15 patients
(M:F:11:4) had a relapsing course (6.8%).
They had 36 episodes at a variable
interval of 3 months to 25 yrs.
 Taly AB, Gupta SK, Anisya V, Shankar SK, Rao S, Das KB, Nagaraja D,
Swamy HS. J Assoc Physicians India. 1995 Apr;43(4):249-52.
Follow-up of AGBS
At a follow-up of 1 year or more, 20
patients recovered and 3 had residua.

Hung PL, Chang WN, Huang LT, Huang SC, Chang YC, Chang CJ, Chang CS, Wang KW, Cheng BC, Chang HW, Lu
CH. Pediatr Neurol. 2004 Feb;30(2):86-91.
permanent neurological defects in children
under 15 years of age was 1.4/10 million
annually

Rantala H, Uhari M, Niemela M. Arch Dis Child. 1991 Jun;66(6):706-8; discussion 708-9.
Subacute Inflammatory Demyelinating
Polyneuropathy.
progressive motor and/or sensory
dysfunction consistent with neuropathy in
more than one limb with time to nadir
between 4 and 8 weeks,
electrophysiologic evidence of
demyelination in at least two nerves,
no other etiology of neuropathy, and
no relapse on adequate follow-up.
Complete recovery was achieved in 69%
of cases and partial recovery in others.
 Oh SJ, Kurokawa K, de Almeida DF, Ryan HF Jr, Claussen GC.
Neurology. 2003 Dec 9;61(11):1507-12.
Chronic Inflammatory Demyelinating
Polyradiculoneuropathy
A low frequency of antecedent events.
Weakness accompanied by sensory loss
and diminished tendon reflexes
Pain and cranial neuropathies are
uncommon
Progressive weakness for two months.
 Sladky JT; Ashwal S: Peripheral neuropathies in childre. Pediatric Neurology Principles and
Practice. Ed. Swaiman KS; Ashwal S. 3rd ed.1999. Publisher: Mosby
Causes Inflammatory
Polyradiculoneuropathy
GB Syndrome
58%
Chronic inflammatory demyelinating
polyneuropathy
31%
Associated with collagen
vascular disease
7%
Other immune/infectous
disorders
4%
HOPKINS' SYNDROME: Acute postasthmatic amyotrophy
Onset
After acute asthmatic attack: Latency 1 to 18
days
Mild pain: Limb, neck or meningismus
Rapid onset weakness
HOPKINS' SYNDROME: Acute postasthmatic amyotrophy
Weakness
Single limb; Asymmetric; May be Proximal >
Distal
Severity: Mild to severe
Arm or leg
Sensory: Normal
HOPKINS' SYNDROME: Acute postasthmatic amyotrophy
CSF
Pleocytosis
Protein: ± Increased
MRI: May show signal (T2) in spinal cord
Prognosis: Permanent paralysis
Flaccid or hyper tonicity