ABSTRACT
Stiff-person syndrome is a rare neurological disorder with a one-in-a-million occurrence rate. Its characteristics include rigidity of the trunk and limbs with increased sensitivity to loud noises, sensory stimuli, or emotional distress. It has an autoimmune basis. In about 60% of patients, Glutamic Acid Decarboxylase (GAD) antibodies have been observed.
Our patient presented with relapsing signs of Stiff Person Syndrome of a progressive nature. She exhibited typical features of muscle rigidity, worsening with external stimuli. However, her GAD antibodies were negative.
She had two previous similar episodes of skeletal muscle stiffness, which improved spontaneously. The ideal treatment protocol will be to relieve symptoms by administering diazepam, baclofen, immunomodulation by intravenous immunoglobulin and plasmapheresis (or in refractory cases, by rituximab).
INTRODUCTION
This is an autoimmune disease of the brain & spinal cord, frequently associated with other autoimmune diseases such as Diabetes Mellitus Type I & Type II, Thyroiditis & Pernicious Anemia. Initially, it was known as “Stiff Man Syndrome”, and was first found in a man aged 32years. It was first Described in 1956 by Moersch & Woltman. It is a rare neurological disorder that affects one person in one million.
- Its Paraneoplastic form may be associated with breast, lung or colon cancer.
- There is increased activity of the nerves that cause muscle contraction, pain, spasm, stiffness, rigidity & postural abnormalities.
RISK GROUP :
- ♂️ :♀️ = 1 : 5 (Women > Men)
- Age of Onset : 30 to 60 years
- 50% of the patient may have sphincter disturbances
CLINICAL FEATURES:
Spontaneous spasms & rigidity occur in both agonist & antagonist muscles, causing abnormal posturing like hunch over posturing. In Lumbar Hyperlordosisit causes a wooden or fixed posture.
Other features include:
- Bad posture; stiffness leads to change in posture
- Dromophobia
- Progressive stiffness in truncal muscles.
- Stiffness in thoracolumbar paraspinal & abdominal muscles initially
- Patients develop a rigid gait – Tin Solider Gait
- Persistent Lumbar Hyperlordosis
- Chronic Somatalgia & episodes of pain during spasms
- Attacks of spasm when stimuli given
- Brisk Stretch reflex
- Tachycardia
- Hypertension
- Dizziness
- Agoraphobia
- Spasmodic Dysphonia
PSYCHIATRY FEATURES :
- Anxiety & Depression (Crying or laughing)
TRIGGERING FACTORS :
- Sudden movements
- Sensory stimuli
- Auditory stimuli
- Emotional stimuli
THE AREA OF MUSCLE MOST INVOLVED:
- Muscles of the Trunk
- Proximal Limb muscles.
CASE REPORT
A 62 years old female from Karnataka, with a known case of systemic hypertension, and a past medical history that included 2 episodes of weakness associated with stiffness of limbs. The 1st episode that occurred in September 2009 involved right upper limb weakness & aphasia, which improved in 15 – 20 days. In November 2009 she had visual & auditory hallucinations. The 2nd episode occurred in 2019 with generalised weakness & slurring of speech. At both these times, she was hospitalised in Karnataka & treated symptomatically. There was no evidence of an acute stroke. Investigations done previously, including ANA/ ANCA, were negative. The vitamin B12 level was low and thyroid antibodies were unremarkable. The patient presented with hoarseness of voice and emotional instability and laughing episodes. She had sphincter constrictions leading to urinary retention. An ultrasound of the abdomen with PVR was done. She had a residual urine volume of 200ml, hence urinary catheterisation was done. The EEG was normal. A CSF analysis revealed no cells; glucose and protein were normal. The autoimmune encephalitis panel was negative. The ANA Cytoplasmic component was positive (++); the ANA profile was negative as was the ANCA. GAD antibodies to rule out Stiff Person Syndrome was negative. Vitamin B12 was more than 500, Vitamin D was 51. HbA1C done in January 2022 was 6.3%. Regular blood tests including CBC/TSH/LFT and RFT were normal. An echocardiogram was normal. Her blood culture done on the day of admission was aseptic.
Clinical features with muscle spasms triggered by movement or sensory stimulation favoured the clinical diagnosis of Stiff Person Syndrome although GAD antibodies were negative. As Stiff Person Syndrome has an immune basis, the patient was given initially IV steroids. Due to financial constraints, Intravenous Immunoglobulins were not given. She received IV Methylprednisolone 250 mg BD for 4 days.
The patient showed a slight improvement on the second day of Steroids. However, she had intermittent muscle spasms that progressed to an extent of creating difficulty in walking. EMG showed spontaneous motor unit discharges in agonist and antagonist muscles, in keeping with Stiff Person Syndrome. T. Tizanidine and Lorazepam IV were added to the medication. She had swallowing difficulty with oropharyngeal involvement. A Ryles tube was inserted for feeding. IV steroids were stopped after 4 days. The patient developed a fever after 4days of steroids, so no oral steroids/immunomodulators were added. Later the patient had tachypnea (RR-43/min), SPO2 – 96% on room air. She had reduced responsiveness to verbal commands &was not orientating. She was shifted to the ICU immediately with Non invasive ventilator support. Benzodiazepines were withheld because of reduced responsiveness. As her CBG was above 400, Insulin infusion was initiated.
She maintained a good respiratory rate and oxygen saturation on room air. Gradually her conscious level and alertness improved. As her conscious level improved, Tizanidine and Baclofen dosage was increased. An infectious disease specialist’s opinion was sought for further advice on antibiotics. Fever spikes were reduced with antibiotics. The patient gradually improved.
DISCUSSION:
The long-term outlook for people affected by Stiff Person Syndrome (SPS) can vary widely depending on the symptoms of each person. For some people with this syndrome, symptoms resolve with treatment, or symptoms only affect a particular area of the body. For other people, symptoms may progress to include the muscles of the face, and some of the muscles in the body may be constantly rigid. The progression of the symptoms related to SPS can lead to frequent falls, which can be dangerous.
The treatment approach should be based on the patient’s clinical condition. In our case, she was treated with a short duration of IV steroids. Due to financial constraints, intravenous immunoglobulins could not be administered. Rituximab was deferred because of her sepsis. But the patient showed gradual remarkable relief from painful spasms and rigidity with benzodiazepines, baclofen & Neurobion Forte. She is being followed up as an outpatient post-discharge.
