An unusual cause of Stridor

Vigneshvarprashanth Umapathy1, G. Dominic Rodriguez2,*, Stephy George3

1Resident Internal Medicine, Kauvery Hospital, Tennur, Trichy, India

2HOD Internal Medicine, Kauvery Hospital, Tennur, Trichy, India

3Consultant Physician, Kauvery Hospital, Tennur, Trichy, India



A patient who had chronic stridor for 2 years, undergone tracheostomy first, followed by a diagnosis of bilateral abductor vocal cord paralysis for which Kashima’s lateral cordotomy had been done, came for assessment 2 months later after being referred from the ENT surgeon. He was also noted to have autonomic dysfunction(bladder dysfunction), Parkinsonism (bilateral cogwheel rigidity, gait & speech disturbance, dystonia), and cerebellar nystagmus. Based on the above findings a diagnosis of Multiple System Atrophy(MSA-P) was made.

Keywords: Multiple System Atrophy; Stridor; Vocal cord paralysis.

Case Presentation

A 57-year-old gentleman had been well 2 years ago. He noticed erectile dysfunction first, subsequently found to be snoring excessively in sleep, and then underwent further assessment. He was diagnosed with Obstructive Sleep Apnoea (OSA) initially. His noisy breathing persisted even during the daytime & a diagnosis of bilateral abductor vocal cord paralysis was made. Tracheostomy was done initially, followed by Kashima’s lateral cordotomy (of the vocal cords). His speech improved and he came for further assessment.

He had generalized tiredness, occasional tremors, swaying to the right side, erectile dysfunction, and urinary incontinence. He was a diabetic and hypertensive.

On Examination

He was afebrile, conscious, alert and oriented

Tracheostomy: insitu

PR: 98/min, BP: 130/70 mmHg, SpO2: 96% in room air, RR: 20/min

CVS: S1 S2(+); RS: NVBS

P/A: Bladder distended above umbilicus


EOM: full, Cranial nerves: Normal

Speech: mild dysphasia (+), loss of facial expression, monotonous speech with loss of prosody.

Palate movements: Normal

Motor: Tone – Hypertonia of upper limb – Right > Left

Cog wheel rigidity (+)

Horizontal nystagmus on left gaze (+)

Decreased blinking

Power: Upper limb – Right (5/5)-Left(5/5)

Power: Lower limb – Right (5/5)-Left(5/5)

Reflexes: Brisk DTR

Bilateral Plantar reflex – flexor

Gait: short steps, swaying to right side, decreased arm swing

Gait ataxia (+), leaning to right side

Sensory: Normal


MRI brain (done already) showed age-related cerebral atrophy.

MRI spine did not show any significant findings.

Other baseline investigations were normal.


Stridor is an unusual symptom in adults. Stridor is an abnormal, high-pitched sound produced by turbulent airflow through a partially obstructed airway at the level of the supraglottis, glottis, subglottis, or trachea [1].

Stridor is a symptom, not a diagnosis or a disease, and the underlying cause must be determined. It may be inspiratory (most common), expiratory, or biphasic, depending on its timing in the respiratory cycle, and the three forms each suggest different causes, as follows [2]:

  1. Inspiratory stridor suggests a laryngeal obstruction
  2. Expiratory stridor implies tracheobronchial obstruction
  3. Biphasic stridor suggests a subglottic or glottic anomaly

Stridor can be acute or chronic. Here are some differentials of acute and chronic stridor:


Acute stridor

Chronic stridor





Aspiration of foreign body

Subglottic stenosis


Bacterial tracheitis

Vocal cord dysfunction (Recurrent laryngeal nerve palsy- unilateral and bilateral vocal cord paralysis)


Retropharyngeal abscess

Laryngeal dyskinesia


Peritonsillar abscess

Laryngeal webs


Spasmodic croup

Laryngeal cysts



Laryngeal haemangiomas



Laryngeal papillomas






Tracheal stenosis

The clinical finding of stridor calls for urgent assessment of the cause. Acute causes of stridor require immediate diagnosis and intervention. Chronic stridor needs to be assessed meticulously, along with a thorough systemic examination. Almost one-third of patients with MSA develop stridor due to Vocal Fold Abductor Paralysis (VFAP) [4].

Diagnosis of Multiple System Atrophy:

Our patient was diagnosed as probable MSA-P as he fulfilled the Consensus criteria with parkinsonism features being more predominant.

Table 1. Consensus criteria for the diagnosis of probable MSA (2008) [3]:

A sporadic
Autonomic failure involving urinary incontinence (inability to control the release of urine from the bladder
Poorly levodopa-responsive parkinsonism (bradykinesia with rigidity
A sporadic, progressive, adult (>30 y)-onset disease characterized by
Autonomic failure involving urinary incontinence (inability to control the release of urine from the bladder, with erectile dysfunction in males) or an orthostatic decrease of blood pressure within 3 min of standing by at least 30 mmHg systolic or 15 mmHg diastolic AND
Poorly levodopa-responsive parkinsonism (bradykinesia with rigidity, tremor, or postural instability) OR
A cerebellar syndrome (gait ataxia with cerebellar dysarthria, limb ataxia, or cerebellar oculomotor dysfunction.

Table 2. Clinical features in our patient with probable MSA

1Age 57 years
2Autonomic features:

1. Urinary incontinence
2. Erectile dysfunction

1. Tremors
2. Cogwheel rigidity
3. Bradykinesia
4. Postural instability

Cerebellar symptoms:

1. Gait ataxia
5Additional features:

1. Stridor (early onset)
2. Increased snoring


MSA should be kept in the differential diagnoses in patients presenting with chronic stridor due to vocal cord abductor paralysis. Although there is no cure for this disease, early diagnosis is crucial to prolong the life of patients with appropriate treatment preventing falls and aspiration.


  1. Stridor in infants and children. Schoem SR, Darrow DH, eds. Pediatric Otolaryngology for Primary Care. 2nd ed. Itasca, IL: American Academy of Pediatrics; 2020. 321-54.
  2. Benson BE. Stridor. Medscape. 2022.
  3. Gilman S, Wenning GK, Low PA, et al. Second consensus statement on the diagnosis of multiple system atrophy. Neurology. 2008;71(9):670-6.
  4. Hughes RG, Gibbin KP, Lowe J. Vocal fold abductor paralysis as a solitary and fatal manifestation of multiple system atrophy. J Laryngol Otol. 1998;112(2):177-8.

Dr. G. Dominic Rodriguez

General Physician