These two videos are from a middle-aged man presenting with progressive bilateral lower limb and right upper limb weakness for few months. In the first video, there are prominent fasciculations over the entire right upper limb. Whilst in the second video, fasciculations can also be noted over both lower limbs, but more prominent on the left leg. Limb power was reduced over the distal muscles of both lower limbs and right arm. There were in addition brisk reflexes throughout and bilateral upgoing plantar reflexes. The patient had absence of any sensory symptoms nor any bulbar symptoms. Family history for a significant neurodegenerative disorder was negative. Investigations including imaging of the cervical spine excluded presence of a significant cervical / lumbosacral radiculopathy causing the symptoms and subsequent nerve conduction and studies and electromyography confirmed the diagnosis of a sporadic, limb-onset amyotrophic lateral sclerosis.
Posts Tagged ‘Fasciculations’
Amyotropic Lateral Sclerosis
Sunday, June 14th, 2015Upper Limbs
Monday, August 25th, 2014Subtitles in English for this video can be displayed by clicking on 
(first button on the bottom right hand corner of the video).
Inspection of the Upper Limbs
After adequate exposure, one should then lay the patient’s arms out comfortably.
The examiner should stand at the end of the bed / facing the patient if the patient is sitting, and inspect for any obvious asymmetry, wasting or abnormal posturing. If the patient is lying down, one should then stand on the right hand side of the patient and inspect the upper limbs in greater detail, focusing on whether there is any muscle wasting (proximal and / or distal muscles), fasciculations, scars and tremor. If the patient’s arms initially laid in the prone position, the examiner could then place them at the “palm-up position” and examine the ventral aspect of the upper limbs. The opposite could be done if the patient’s arms are initially laid in the “palm-up position”.
Eliciting Fasciculations of the Upper Limbs
If there are no fasciculations visible on inspection, one can tap onto the muscle bulk gently, which may bring out the fasciculations in a patient with an underlying lower motor neuron disorder. However, one common pitfall is that students often rush through tapping of the muscle bulk, but do not observe long enough for the fasciculations to appear. Often a time, the fasciculations may be visible without tapping if the muscle bulk was examined in detail (see videos of a patient with fasciculations under ‘lower motor neuron signs’).
Determining the Tone of the Upper Limbs
The tone of the upper limbs could be determined via examining the elbow and wrist joints as shown in the video. The patient’s tone should then be classified as normal, hypertonic or hypotonic. One may also be able to delineate whether the patient has lead-pipe rigidity, cogwheel rigidity (e.g. in parkinsonism), or spasticity (e.g. in patients with an upper motor neuron lesion).
Determining the Power of the Upper Limbs
The power of the upper limbs could be determined as shown in the video. One should examine the power of muscles involved in abduction and adduction of the shoulders as well as flexion and extension of the elbows, wrists and fingers. The power of the small hand muscles: finger abduction, thumb abduction and thumb opposition should then be elicited. Further detailed examination of other muscles could also be performed if the clinical history or physical examination raises clinical suspicion.
The power of the muscles should then be graded according to the Medical Research Council (MRC) scale for muscle strength as follow:
- Grade 5: Muscle contracts normally against full resistance
- Grade 4: Muscle strength is reduced but muscle contraction can still move joint against resistance
- Grade 3: Muscle strength is further reduced such that the joint can be moved only against gravity
- Grade 2: Muscle can move only if the resistance of gravity is removed
- Grade 1: Only a trace or flicker of movement is seen or felt in the muscle, or fasciculations are observed in the muscle
- Grade 0: No movement is observed
Eliciting the Upper Limb Reflexes
The reflexes of the upper limbs including the biceps, triceps and supinator reflex should be examined as shown in the video. The patient’s upper limbs should be fully relaxed. To elicit the biceps tendon reflex, roll the thumb along the biceps tendon and gently tap onto the thumb with the tendon hammer. The tendon hammer should be held towards the end and the wrist should be used to ensure a good swinging motion.
If the reflex is absent, one should proceed by performing the reinforcement maneuver (Jendrassik maneuver) by asking the patient to clench his or her teeth tightly upon tapping the tendon with the tendon hammer. The patient’s reflex should then be classified as normal, brisk (hyper-reflexic), hypo-reflexic or absent.
Testing Coordination of the Upper Limbs
A video of how rebound is elicited is also shown here.
The patient’s coordination should be assessed by the finger-nose test (to elicit intention tremor and dysmetria) and asking the patient to perform rapid alternating movements of the hand (to elicit dysdiadochokinesia).
Once again, clear, simple instructions are vital. Common pitfalls of medical students, is that during the finger-nose test, the examiner’s finger is either held too close to the patient (thus intention tremor could not be accurately assessed) or too far away. The examiner’s finger should be ideally at arm’s length from the patient. It is useful to hold onto the patient’s hand and perform the test with the patient first before asking the patient to perform it himself.
Lower Limbs
Monday, August 25th, 2014Subtitles in English for this video can be displayed by clicking on (first button on the bottom right hand corner of the video).
Inspection of the Lower Limbs
After positioning the patient on the bed and ensuring adequate exposure, the lower limbs should be inspected as follow:
The examiner should stand at the end of the bed and inspect for any obvious leg length discrepancy, asymmetry, wasting or abnormal posturing. One should then stand on the right hand side of the patient and inspect the lower limbs in greater detail, focusing on whether there is any muscle wasting (proximal and / or distal muscles), fasciculations, scars, tremor, pes cavus and clawing of toes.
Eliciting Fasciculations of the Lower Limbs
If there are no fasciculations visible on inspection, one can tap onto the muscle bulk gently, which may help bring out the fasciculations if an underlying lower motor neuron lesion is present. However, one common pitfall of medical students is that they often rush through the tapping of the muscle bulk, but do not observe long enough for the fasciculations to appear.
Determining the Tone of the Lower Limbs
The tone of the lower limbs could be determined first of all by gently rolling the lower limb on the bed as if it was a log. In patients with hypertonia, there would be increased resistance with this manoeuvre. The normal swinging motion of the foot will also be reduced. This should be followed by gently lifting up the thigh of the lower limb and releasing it back onto the bed. In patients with hypertonia, the heel of the foot would often elevate from the surface of the bed. The tone of the lower limb is classified as normal, hypertonic or hypotonic.
Determining the Power of the Lower Limbs
The power of the lower limbs could be determined as shown in the video. One should examine the flexion, extension, adduction and abduction of the hip muscles, followed by extension and flexion of the knee muscles. Finally, foot dorsiflexion, dorsiflexion of the big toe, foot plantar flexion, foot inversion and eversion should be examined.
Again, the power of the muscles should then be graded according to the Medical Research Council (MRC) scale for muscle strength as follow:
- Grade 5: Muscle contracts normally against full resistance
- Grade 4: Muscle strength is reduced but muscle contraction can still move joint against resistance
- Grade 3: Muscle strength is further reduced such that the joint can be moved only against gravity
- Grade 2: Muscle can move only if the resistance of gravity is removed
- Grade 1: Only a trace or flicker of movement is seen or felt in the muscle, or fasciculations observed in the muscle
- Grade 0: No movement is observed
One should then compare the muscle power between the right leg and left leg, as well as between proximal and distal leg muscles.
Eliciting the Lower Limb Reflexes
The reflexes of the lower limbs including the knee jerk, Achilles tendon reflexes and plantar reflexes can be examined as shown in the video.
Testing Coordination of the Lower Limbs
The heel-shin test is performed as demonstrated in the video shown here.
Examining the Gait
Fasciculations
Wednesday, August 20th, 2014These two videos are from a middle-aged man presenting with progressive bilateral lower limb and right upper limb weakness for few months. In the first video, there are prominent fasciculations over the entire right upper limb. Whilst in the second video, fasciculations can also be noted over both lower limbs, but more prominent on the left leg. This man was subsequently diagnosed to have motor neuron disease.
Discussion of the sign
Fasciculations are involuntary, non-rhythmic contraction of muscle groups caused by spontaneous firing of motor units. They appear as fine, rapid, flickering muscle contractions which are irregular in timing and location. In the presence of other lower motor neuron signs (e.g. weakness, hypotonia, hyporeflexia), the presence of fasciculations signify the presence of lower motor neuron dysfunction. In these circumstances, denervation and reinnervation of muscle fibres secondary to lower motor neuron disease causes spontaneous excitation of individual motor units. Common lower motor neuron lesions that may result in fasciculations include anterior horn cell disease (e.g. motor neuron disease, poliomyelitis), radiculopathy, and less commonly, in entrapment neuropathy and peripheral neuropathy.
Fasciculations can also be found in patients with cholinergic toxicity (e.g. organophosphate poisoning) and can also be a normal phenomenon (benign fasciculations) if no other neurological sign could be elicited.
A common pitfall of students is that they do not observe long enough for the fasciculations to appear. Sometimes, stimulating the muscle bulk gently may elicit the fasciculations. However, students often rush through this process and are simply “flicking” the muscle but not observing long enough for the fasciculations to appear.