An unusual cause of acute hypercapneic respiratory failure.

Abstract

We present a rare cause of hypercapneic respiratory failure through this case report of a 72-year-old man presenting with progressive dyspnea and dysphagia over two years. Hypercapneic respiratory failure was acute on chronic in nature without an obvious etiology. Extensive workup for intrinsic pulmonary disease and neurologic causes were negative. Laryngoscopy and diagnostic imaging confirmed the diagnosis of diffuse idiopathic skeletal hyperostosis, also known as DISH, as the cause of upper airway obstruction leading to hypercapneic respiratory failure.

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Clinical Medicine Insights: Circulatory, Respiratory and Pulmonary Medicine 2011:5 81–85
doi: 10.4137/CCRPM.S7687
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Clinical Medicine Insights: Circulatory,
Respiratory and Pulmonary Medicine
C A S e R e P o R T
Clinical Medicine Insights: Circulatory, Respiratory and Pulmonary Medicine 2011:5
81
An Unusual cause of Acute Hypercapneic Respiratory Failure
Janice Wang1, Astha Chichra2 and Seth Koenig3
1Pulmonary, Critical Care and Sleep Medicine Fellow, North Shore/Long Island Jewish Medical Center, 410 Lakeville
Road, Suite 107, New Hyde Park, NY 11040. 2Internal Medicine Resident, North Shore/Long Island Jewish Medical
Center, 410 Lakeville Road, Suite 107, New Hyde Park, NY 11040. 3Pulmonary and Critical Care Medicine Faculty,
North Shore/Long Island Jewish Medical Center, 410 Lakeville Road, Suite 107, New Hyde Park, NY 11040.
Corresponding author email: drasthachichra@gmail.com
Abstract: We present a rare cause of hypercapneic respiratory failure through this case report of a 72-year-old man presenting with
progressive dyspnea and dysphagia over two years. Hypercapneic respiratory failure was acute on chronic in nature without an obvious
etiology. Extensive workup for intrinsic pulmonary disease and neurologic causes were negative. Laryngoscopy and diagnostic imaging
confirmed the diagnosis of diffuse idiopathic skeletal hyperostosis, also known as DISH, as the cause of upper airway obstruction lead-
ing to hypercapneic respiratory failure.
Keywords: hypercapneic respiratory failure, diffuse idiopathic skeletal hyperostosis (DISH), hypercarbia, dysphagia and dyspnea

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A 72-year-old man lifelong nonsmoker presented to
the emergency department with one week of progres-
sive dyspnea on exertion, a non-productive cough and
generalized weakness. Review of systems revealed
progressive dysphagia, primarily to solids, over two
years. He had an incomplete esophagogastroduo-
denoscopy (EGD) due to difficulty passing the scope.
Further workup was deferred by the patient and he
modified his diet to include mostly liquids. Multiple
episodes of “bronchitis” were treated with antibiotics
and he was given a diagnosis of chronic bronchitis
by his primary care physician. Past medical history
included hypertension, coronary artery disease and
diabetes. He denied use of alcohol, narcotics or seda-
tives. While all personal identifiers pertaining to our
patient have been removed, we received consent by
the patient to publish the diagnostic images and clini-
cal information relating to this case in our report.
physical examination
Vital signs were normal with a room air oxygen
saturation of 97%. His respiration rate initially in
the emergency department was between 16–18
per minute. He was alert and oriented. Neck exam
showed limited range of motion for flexion, extension,
rotation and tilt. Accessory respiratory muscle use
was absent and his lung exam revealed upper airway
inspiratory and expiratory wheezing. Positional
changes from sitting upright to supine did not result
in any immediate physical changes on exam, although
the patient reported less dypsnea in the upright
position. Peripheral lung fields were clear without
adventitial sounds. Cardiovascular and abdominal
exams were unremarkable. He had no peripheral
edema. Neurological exam revealed normal strength
and sensation with intact reflexes.
Laboratory and Radiographic
Findings
Blood work revealed mild leukocytosis with absent
left shift and a bicarbonate level of 32 mEq/L. Arterial
blood gas (ABG) done 10 hours after arrival to the
emergency room showed severe acute on chronic
respiratory acidosis: pH 7.14, pCO2 111 mmHg, pO2
56 mmHg and O2 saturation 82.4%. Two hours after
initiation of non-invasive ventilation (NIV), the ABG
was pH 7.18, pCO2 90 mmHg, pO2 121 mmHg, and
O2 saturation 98.5% and the patient’s mental status
improved. Twenty four hours after initiation of
NIV, ABG improved to pH 7.39, pCO2 62, pO2 65
and O2 saturation 92%. CXR revealed right basilar
atelectasis (Fig. 1). CT, MRI and MRA of the brain
were performed to evaluate for neurologic disease
that could contribute to his mental status change and
hypercapnia, however they were unremarkable. The
toxicology screen was negative. Thyroid stimulating
hormone was normal and acetylcholine receptor anti-
bodies were not detected. He was maintained on NIV
continuously while sleeping and intermittently dur-
ing the day. The patient’s history of a difficult EGD
led to a suspicion for hypercapnia secondary to air-
way obstruction. Laryngoscopy demonstrated extrin-
sic compression of the posterior pharyngeal wall
with significant anterior displacement (Fig. 2).
Diagnosis
Hypercapneic respiratory failure secondary to diffuse
idiopathic skeletal hyperostosis (DISH).
clinical course
Our patient presented with acute on chronic hyper-
capneic respiratory failure manifested by increasing
dyspnea and lethargy. He was initially treated for an
exacerbation of chronic obstructive pulmonary dis-
ease (COPD) with methylprednisolone, ceftriaxone
and azithromycin. In the emergency department he
became lethargic and hypoxemic and NIV was begun
UPRIGHT
Figure 1. Chest radiograph revealed mild right basilar atelectasis. No
signs of hyperinflation or focal consolidation present.

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Hypercapneic respiratory failure
Clinical Medicine Insights: Circulatory, Respiratory and Pulmonary Medicine 2011:5
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for suspected hypercapnia secondary to COPD. He did
not receive narcotics or benzodiazepines prior to eval-
uation by the medical intensive care unit (MICU). He
was placed on NIV and transferred to the MICU for
further workup and management. The patient’s respi-
ratory and mental status improved on NIV. He stayed
in the ICU for close monitoring of his respiratory status
and possible need for immediate endotracheal intuba-
tion however he remained alert on NIV with eventual
complete resolution of hypercarbia. With improve-
ment in the PCO2 levels, the patient was allowed to
rest off of NIV for a few hours at a time as tolerated
however, elevations in PCO2 were found on repeat
ABGs, making it difficult to wean him off NIV. The
history of dysphagia with a difficult EGD remained
highly suspicious and prompted the performance of a
laryngoscopy and CT scan of cervical spine.
The findings on laryngoscopy were confirmed on
a CT scan of the cervical spine which revealed diffuse
ossification anteriorly with a large anterior osteo-
phyte at the C3–C4 level and severe mass effect on
the hypopharynx and laryngeal inlet with multilevel
anterior osteophytic ridging (Fig. 3). The hypercap-
neic respiratory failure was secondary to upper air-
way obstruction, a rare complication of DISH.
Orthopedics and otolaryngology were consulted
for possible surgical treatment. After a difficult
endotracheal intubation was performed in the operat-
ing room, both orthopedic and otolaryngology sur-
geons partnered to perform a partial corpectomy of
C4 and C5. A transverse lateral approach was done
with lateral mobilization of the carotid artery and
revealed extensive ossification of the entire anterior
aspect of the cervical spine. After excision of the
osteophyte, a high-speed burr was used to smooth
the bony surface, and the trachea and esophagus were
subsequently decompressed. The patient was extu-
bated on post-operative day 3 without complications.
His blood gas normalized and he was discharged on
room air without the need for NIV. At one month
follow-up in clinic, he reported improved swallowing
without symptoms of dysphagia, dyspnea or lethargy
off NIV. Both his ABG and pulmonary function tests
were normal.
Discussion
DISH, also known as ankylosing hyperostosis and
Forestier’s disease, is a noninflammatory process with
calcification of spinal ligaments and entheses and
hypertrophic anterior cervical osteophytes (HACO).
Enthesopathy is part of the normal aging process
and is usually asymptomatic; however in extreme
cases such as DISH it can lead to life- threatening
symptoms. The prevalence of DISH varies in the lit-
erature from 10% to 35% of patients above 70 years
of age, worse in elderly men.1 Involvement of the
cervical spine from the fourth to seventh vertebra
with anterior osteophytes most commonly causes
Figure 2. (A) Laryngoscopy showed extrinsic compression of the poste-
rior pharyngeal wall (open arrow) with significant anterior displacement
toward the epiglottis (arrow) and absent visualization of the vocal cords.
(B) Shows visualization of the pharynx and vocal cords (arrowhead) on
a normal exam.
Figure 3. Noncontrast CT scan of the cervical spine revealed a large
anterior osteophytic ridging at C3–C4 (arrow) with severe mass effect
upon the hypopharynx and laryngeal inlet.

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Wang et al
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Clinical Medicine Insights: Circulatory, Respiratory and Pulmonary Medicine 2011:5
dysphagia due to compression of the esophagus from
the osteophyte. Dysphagia to solid food occurs in 17
to 28 percent of patients with DISH.2 Upper airway
obstruction secondary to DISH is very rare and can
manifest as dyspnea, stridor, cough, or dysphonia,
which results from displacement of the laryngophar-
ynx by a large osteophyte typically at the C3 to C4
level.1 Injury to the recurrent laryngeal nerve on the
left side can cause vocal cord paralysis. Several case
reports have been published2–5 describing patients
with severe stridor causing respiratory distress and
requiring emergent tracheostomy however acute
hypercapneic respiratory failure secondary to DISH
is rarely described.
There are multiple causes of hypercapneic respi-
ratory failure; our patient’s hypercapnia was not
consistent with the most common causes. He was
not a smoker and did not have COPD by history.
CXR revealed no hyperinflation or a significant lung
parenchymal process. Obstructive sleep apnea or
obesity hypoventilation was unlikely as the patient
denied any sleep-related complaints and did not have
the typical body habitus. Drug-induced hypercapnia
was unlikely as the patient denied taking any medi-
cations known to induce hypercapnia, such as seda-
tives or narcotics. There were no apparent neurologic
symptoms to suggest a cerebrovascular accident or
myositis and radiographic imaging of his brain was
normal. Antibodies for myasthenia gravis were
negative. Musculoskeletal or chest wall abnormali-
ties were also unlikely. The patient’s history of dys-
phagia and recurrent bronchitis likely secondary to
aspiration led to imaging studies that confirmed the
diagnosis of DISH causing osteophytic pharyngeal
compression.
Mainstay treatment is surgical excision of the
osteophyte, allowing for extrinsic decompression
of the laryngopharynx and esophagus with potential
reversal of airway obstruction and dysphagia.
However, large osteophytes can irritate the pharynx
and esophagus, causing inflammatory hyperplasia
leading to intrinsic compression of these structures.3
Therefore an osteophectomy without addressing
possible intrinsic compression may not fully resolve
the airway and esophageal obstruction. Carlson et al
conducted a retrospective chart review on patients
who underwent osteophectomy and found that six
of nine patients were diagnosed with DISH. Of the
six, two had airway compromise; one required
emergent tracheostomy and the other a concurrent
tracheostomy. Both patients were reported to have
complete resolution of their airway symptoms
post-osteophectomy and underwent successful
decannulation.6
DISH is a rare cause of upper airway obstruction
that may manifest as hypercapneic respiratory failure.
Consider DISH in the differential diagnosis of hyper-
capneic respiratory failure when common etiologies
have been ruled out and the history and physical exam
suggest an upper airway obstruction. Radiologic
imaging, such as CT, MRI, and plain radiographs,
of the cervical spine is the major diagnostic tool
for confirmation of DISH. Laryngoscopy is vital in
evaluating for extrinsic compression of the posterior
pharyngeal wall causing an upper airway obstruction.
Severe airway compression caused extrinsically by
a cervical osteophyte can be potentially reversed by
osteophectomy however it is important to consider a
reactive inflammatory process as a cause for intrinsic
obstruction as well.
Disclosures
Consent was obtained from the patient by the authors
to reproduce information and photographs appearing
in this article. Author(s) have provided signed confir-
mations to the publisher of their compliance with all
applicable legal and ethical obligations in respect to
declaration of conflicts of interest, funding, author-
ship and contributorship, and compliance with ethi-
cal requirements in respect to treatment of human
and animal test subjects. If this article contains iden-
tifiable human subject(s) author(s) were required to
supply signed patient consent prior to publication.
Author(s) have confirmed that the published article is
unique and not under consideration nor published by
any other publication and that they have consent to
reproduce any copyrighted material. The peer review-
ers declared no conflicts of interest.
References
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130–5.
2. Demuynck K, Van Calenbergh F, Goffin J, et al. Upper airway obstruction
caused by a cervical osteophyte. Chest. 1995;108:283–4.

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