AJTCCM VOL. 29 NO. 1 2023 27
CORRESPONDENCE: SCIENTIFIC LETTERS
V Gupta, MBBS, MD (Radiodiagnosis)
Department of Radiodiagnosis, Dr D Y Patil Medical College, Hospital
and Research Centre, Dr DY Patil Vidyapeeth, Pune, Maharashtra, India
S Goyal, MBBS, MD (O&G)
Government Medical College, Amritsar, Punjab, India
goyalshreeya@gmail.com
1. Diddee R, Shaw IH. Acquired tracheo-oesophageal stula in adults. Cont Educ
Anaesth Crit Care Pain 2006;6(3):105-108. https://doi.org/10.1093/bjaceaccp/mkl019
2. Swami GA, Punpale A, Samudre SS, Asawa GR. A rare case of acquired
tracheo-esophageal fistula in adult. Int Surg J 2021;8(9):2796-2798. https://doi.
org/10.18203/2349-2902.isj20213619
3. Rao SV, Boralkar AK, Jirvankar PS, Sonavani MV, Kaginalkar VR, Chinte C.
Tracheoesophageal stula following endotracheal intubation for organophosphorus
poisoning. J Assoc Physicians India 2016;64(12):84-85.
4. Epstein SK. Late complications of tracheostomy. Respir Care 2005;50(4):542-549.
5. Hameed AA, Mohamed H, Al-Mansoori M. Acquired tracheoesophageal stula due to
high intracu pressure. Ann orac Med 2008;3(1):23-25. https://doi.org/10.4103/1817-
1737.37950
6. Kaloud H, Smolle-Juettner FM, Prause G, List WF. Iatrogenic ruptures of the
tracheobronchial tree. Chest 1997;112(3):774-778. https://doi.org/10.1378/
chest.112.3.774
7. Babu MS, Suvarna D, Shetty C, Nadella A. Tracheo-esophageal stula. Br J Med Pract
2014;7(2):a717.
Afr J Thoracic Crit Care Med 2023;29(1):e267. https://doi.
org/10.7196/AJTCCM.2023.v29i1.267
Motor neuron disease presenting with acute hypercapnic
respiratory failure
TO THE EDITOR: Motor neuron disease (MND) is rare, and
respiratory failure at initial presentation is even rarer. Most patients
present with asymmetrical limb weakness.[1] We present a case of
MND presenting with acute hypercapnic respiratory failure.
A previously well 61-year-old black African man who worked as
a trauma nurse complained of breathlessness while at work. He
reported a 3-month history of intermittent shortness of breath and a
2-week history of a non-productive cough. He was initially assessed
as stable with normal vital signs. However, 45 minutes later while
in the emergency department, he became tachypnoeic, hypoxic
and confused. Arterial blood gas (ABG) measurement (Table1)
demonstrated acute hypercapnic respiratory failure. He was initially
started on facemask oxygen and subsequently escalated to continuous
positive-pressure ventilation, resulting in an improvement clinically
and on repeat ABG measurement (Table1).
e initial dierential diagnosis included a pulmonary embolus and an
infective process (including COVID-19). However, further investigations
for these conditions were negative.
A more detailed history revealed motor decits and fasciculations. e
patient reported a 3-month history of diculty opening glass vials of
medication when at work, suggestive of intrinsic hand muscle weakness,
and a 2-month history of ‘jumping’ pectoral muscles. He was also
intermittently confused on awakening, which was suggestive of carbon
dioxide narcosis, with relative hypoventilation during sleep. He had
unintentional weight loss of 25 kg of muscle bulk over the last few months.
On examination, the patient was in respiratory distress and globally
wasted with orid shoulder girdle fasciculations. e cranial nerves
were normal. There was no nystagmus and no ophthalmoplegia.
Bulbar signs were not elicited, and there was a normal jaw jerk. ere
was no extension or neck exion weakness. On motor examination, he
had proximal and distal muscle wasting of the upper limbs with split
hand wasting and fasciculations. He had normal tone with reduced
power of 4/5 in all muscle groups and brisk reexes of 3/4. His lower
limbs had no obvious wasting, normal tone, and reduced power
proximally and preserved power distally. He had brisk knee reexes of
3/4 with no ankle jerks and an upgoing plantar reex on the right. e
ndings on sensory examination were normal, and he was not ataxic.
He was assessed as having a predominant or pure motor syndrome
with combined upper and lower motor neuron signs.
Electrodiagnostic studies were performed. Nerve conduction
studies showed normal latency and conduction velocity, with
decreased amplitude in motor bres. Sensory bres were normal.
Repetitive nerve stimulation of the accessory nerve demonstrated
no decrease in the amplitude of the motor response. e patient was
diagnosed with MND, amyotrophic lateral sclerosis variant. He hadan
atypical presentation with acute hypercapnic respiratory failure.
Table1. Serial blood gas levels and laboratory results
Variabl e
Initial
(reference)
Aer non-invasive
ventilation
pH 7.23 (7.35 - 7.45) 7.34
PO2 (mmHg) 50.9 (80 - 100) 185
PCO2 (mmHg) 93.4 (35 - 45) 57
H2CO3 (mEq/L) 29.9 (22 - 26) 32
D-dimers (mg/L) 0.13 (<0.50) n/a
C-reactive protein
(mg/L)
2 (0 - 10) n/a
Procalcitonin (ng/mL) 0.04 (<0.05) n/a
PO2 = partial pressure of oxygen; PCO2 = partial pressure of carbon dioxide;
H2CO3 = bicarbonate; n/a = not applicable.
AJTCCM VOL. 29 NO. 1 2023 28
CORRESPONDENCE: SCIENTIFIC LETTERS
Once normocarbic, the patient was slowly weaned o non-invasive
ventilation with arrangements to continue bilevel positive airway
pressure ventilation at home. However, he experienced two signicant
decompensations. At his request he was not reintubated, and he
subsequently died. His survival time from presentation to death was
5weeks.
MND, also known as Lou Gehrig disease and amyotrophic lateral
sclerosis, is a degenerative disease that involves both upper and lower
motor neurons. Clinical presentation depends on the initial aected
body segment and may manifest as upper motor neuron- or lower
motor neuron-type pathology.[1] While the El Escorial criteria are
more well known, the current standard of diagnosis is based on the
updated Gold Coast criteria, which allow for earlier diagnosis, earlier
intervention, and enrolment into clinical trials.[1]
Predominant and pure respiratory muscle weakness is an uncommon
initial presentation of MND, with an estimated frequency between
2.7% and 5.0%.[2,3] ese patients experience dyspnoea or orthopnoea,
voice changes, a weak cough, and features of carbon dioxide retention
including morning headaches, hallucinations, confusion and daytime
somnolence.[3] Even within this subset, acute type 2 respiratory failure,
as seen in this case, is rare.
Despite our patient’s preceding asymmetrical limb weakness, he
worked as a nurse until his acute deterioration. is aspect of the case
highlights patients’ ability to functionally compensate for illness and the
importance of a detailed clinical assessment.
Most patients with MND die within 3 - 5 years of diagnosis.[1] Older
age at onset, rapid change in function, executive dysfunction, respiratory
subtype MND or an increased level of the biomarker neurolament
light chain are associated with decreased survival.[4] Our patient had
rapid functional decline and respiratory weakness.
Most treatment is symptom directed. e two main disease-modifying
drugs are riluzole and edaravone. Riluzole, which improves survival,
decreases glutamate-induced excitotoxicity.[5] Edaravone decreases
the rate of functional decline by acting as a free radical scavenger
and decreasing oxidative stress.[6] In our setting, a public hospital in a
middle-income country, availability of these drugs is limited. Research
on emerging therapies such as gene therapy oers promise.
In conclusion, type 2 respiratory failure is easily diagnosable on
ABG measurement. Owing to its various possible causes, a structured
approach to diagnosis is essential. e presentation pattern of MND
is broad and, as in this rare case, includes acute respiratory failure.
H Moola, MB ChB, Dip Int Med (SA), Dip HIV (SA)
Department of Internal Medicine, Chris Hani Baragwanath Hospital,
Johannesburg, South Africa, Department of Medicine, Faculty of Health
Sciences, University of the Witwatersrand, Johannesburg, South Africa
A Govind, MB ChB, FCP (SA), FC Neurol (SA)
Department of Internal Medicine, Chris Hani Baragwanath Hospital,
Johannesburg, South Africa, Department of Medicine, Faculty of Health
Sciences, University of the Witwatersrand, Johannesburg, South Africa
J R Elo, MB ChB
Department of Internal Medicine, Chris Hani Baragwanath Hospital,
Johannesburg, South Africa
A van Blydenstein, MB ChB, FCP (SA), Cert Pulmonology (SA)
Department of Internal Medicine, Chris Hani Baragwanath Hospital,
Johannesburg, South Africa, Department of Medicine, Faculty of Health
Sciences, University of the Witwatersrand, Johannesburg, South Africa
1. Tsai M, Hsu C, Sheu C, Brown RH, Al-Chalabi A. Amyotrophic lateral sclerosis. NEngl
J Med 2017;377:1602. https://doi.org/10.1056/NEJMc1710379
2. Park HS. A case of motor neuron disease presenting as dyspnea in the emergency
department. Korean J Fam Med 2012;33(2):110-113. https://doi.org/10.4082/
kjfm.2012.33.2.110
3. Shoesmith CL, Findlater K, Rowe A, Strong MJ. Prognosis of amyotrophic lateral
sclerosis with respiratory onset. J Neurol Neurosurg Psychiatry Res 2007;78(6):629-631.
https://doi.org/10.1136/jnnp.2006.103564
4. Su W, Cheng Y, Jiang Z, etal. Predictors of survival in patients with amyotrophic
lateral sclerosis: A large meta-analysis. EBioMedicine 2021;74:103732. https://doi.
org/10.1016/j.ebiom.2021.103732
5. Riviere M, Meininger V, Zeisser P, Munsat T. An analysis of extended survival in patients
with amyotrophic lateral sclerosis treated with riluzole. Arch Neurol 1998;55(4):526-
528. https://doi.org/10.1001/archneur.55.4.526
6. Abe K, Itoyama Y, Sobue G, etal. Conrmatory double-blind, parallel-group, placebo-
controlled study of ecacy and safety of edaravone (MCI-186) in amyotrophic lateral
sclerosis patients. Amyotroph Lateral Scler Frontotemporal Degener 2014;15(7-8):610-
617. https://doi.org/10.3109/21678421.2014.959024
Afr J Thoracic Crit Care Med 2023;29(1):e573. https://doi.
org/10.7196/AJTCCM.2023.v29i1.573
