Glycogen storage disease type II diagnostic study of choice: Difference between revisions

Jump to navigation Jump to search
VisualWikitext
(Created page with "__NOTOC__ {{Glycogen storage disease type II}} {{CMG}}; {{AE}} == Overview == * The page name should be '''"[Disease name] diagnostic study of choice"''', with only the first...")
 
 
(13 intermediate revisions by the same user not shown)
Line 1: Line 1:
__NOTOC__
__NOTOC__
{{Glycogen storage disease type II}}
{{Glycogen storage disease type II}}
{{CMG}}; {{AE}}
{{CMG}}; {{AE}}{{Anmol}}
== Overview ==
== Overview ==
* The page name should be '''"[Disease name] diagnostic study of choice"''', with only the first letter of the title capitalized. Note that the page is called "Diagnostic study of choice."
Acid α-glucosidase (GAA) activity in [[fibroblast]] of a dried blood sample is the gold standard test for the diagnosis of glycogen storage disease type 2. Decreased activity of GAA in [[fibroblasts]] a dried blood sample is confirmatory of glycogen storage disease type 2.
* '''Goal:'''
**To describe the most efficient/sensitive/specific test that is utilized for diagnosis of [disease name].
**To describe the gold standard test for the diagnosis of [disease name].  
**To describe the diagnostic criteria, which may be based on clinical findings, physical exam signs, pathological findings, lab findings, findings on imaging, or even findings that exclude other diseases.
* As with all microchapter pages linking to the main page, at the top of the edit box put <nowiki>{{CMG}}</nowiki>, your name template, and the microchapter navigation template you created at the beginning.
* Remember to create links within WikiDoc by placing <nowiki>[[square brackets]]</nowiki> around key words which you want to link to other pages. Make sure you makes your links as specific as possible. For example, if a sentence contained the phrase anterior spinal artery syndrome, the link should be to [[anterior spinal artery syndrome]] not [[anterior]] or [[artery]] or [[syndrome]].  For more information on how to create links, click [[here]].
* Remember to follow the same format and capitalization of letters as outlined in the template below.
* You should include the name of the disease in the first sentence of every subsection.


== Diagnostic Study of Choice ==
== Diagnostic Study of Choice ==


===== Template statements =====
=== Gold standard ===
*  Acid α-glucosidase (GAA) activity in [[fibroblast]] of a dried blood sample is the gold standard test for the diagnosis of glycogen storage disease type 2.<ref name="pmid18078773">{{cite journal| author=Pompe Disease Diagnostic Working Group. Winchester B, Bali D, Bodamer OA, Caillaud C, Christensen E et al.| title=Methods for a prompt and reliable laboratory diagnosis of Pompe disease: report from an international consensus meeting. | journal=Mol Genet Metab | year= 2008 | volume= 93 | issue= 3 | pages= 275-81 | pmid=18078773 | doi=10.1016/j.ymgme.2007.09.006 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18078773  }} </ref><ref name="pmid17270480">{{cite journal| author=Kallwass H, Carr C, Gerrein J, Titlow M, Pomponio R, Bali D et al.| title=Rapid diagnosis of late-onset Pompe disease by fluorometric assay of alpha-glucosidase activities in dried blood spots. | journal=Mol Genet Metab | year= 2007 | volume= 90 | issue= 4 | pages= 449-52 | pmid=17270480 | doi=10.1016/j.ymgme.2006.12.006 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=17270480  }} </ref>
* The following result of acid α-glucosidase (GAA) activity in fibroblast of a dried blood sample is confirmatory of glycogen storage disease type 2:
** Decreased activity of GAA in [[fibroblasts]]


=== Gold standard/Study of choice: ===
===Diagnostic algorithms===
* [Name of the investigation] is the gold standard test for the diagnosis of [disease name].
<br>
* The following result of [gold standard test] is confirmatory of [disease name]:
<div style="text-align: center;">'''Algorithms for diagnostic approach of glycogen storage disease type 2'''<ref name="pmid16702877">{{cite journal| author=ACMG Work Group on Management of Pompe Disease. Kishnani PS, Steiner RD, Bali D, Berger K, Byrne BJ et al.| title=Pompe disease diagnosis and management guideline. | journal=Genet Med | year= 2006 | volume= 8 | issue= 5 | pages= 267-88 | pmid=16702877 | doi=10.109701.gim.0000218152.87434.f3 | pmc=3110959 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16702877  }} </ref></div>
** Result 1
** Result 2
* The [name of investigation] should be performed when:
** The patient presented with symptoms/signs 1. 2, 3.
** A positive [test] is detected in the patient.
* [Name of the investigation] is the gold standard test for the diagnosis of [disease name].
* The diagnostic study of choice for [disease name] is [name of investigation].
* There is no single diagnostic study of choice for the diagnosis of [disease name].  
* There is no single diagnostic study of choice for the diagnosis of [disease name], but [disease name] can be diagnosed based on [name of the investigation 1] and [name of the investigation 2].
* [Disease name] is mainly diagnosed based on clinical presentation.
* Investigations:
** Among patients who present with clinical signs of [disease name], the [investigation name] is the most specific test for the diagnosis.
** Among patients who present with clinical signs of [disease name], the [investigation name] is the most sensitive test for diagnosis.
** Among patients who present with clinical signs of [disease name], the [investigation name] is the most efficient test for diagnosis.


==== The comparison table for diagnostic studies of choice for [disease name] ====
{|
{|
|- style="background: #4479BA; color: #FFFFFF; text-align: center;"
! colspan="2" style="background:#DCDCDC;" align="center" + |Diagnostic algorithm for Infantile onset glyogen storage disease type II
! style="background: #FFFFFF; color: #FFFFFF; text-align: center;" |
! style="background: #4479BA; color: #FFFFFF; text-align: center;" |Sensitivity
! style="background: #4479BA; color: #FFFFFF; text-align: center;" |Specificity
|-
|-
! style="background: #696969; color: #FFFFFF; text-align: center;" |Test 1
| colspan="2" |
| style="background: #DCDCDC; padding: 5px; text-align: center;" |✔
| style="background: #DCDCDC; padding: 5px; text-align: center;" |...%
|-
|-
! style="background: #696969; color: #FFFFFF; text-align: center;" |Test 2
! style="background:#DCDCDC;" align="center" + |COMMON PRESENTING SYMPTOMS
| style="background: #DCDCDC; padding: 5px; text-align: center;" |...%
| align="center" + |
| style="background: #DCDCDC; padding: 5px; text-align: center;" |✔
{{Family tree/start}}
{{Family tree|boxstyle=background: #DCDCDC; color: #000000;| A01 | | A02 | | A03 | | A04 |A01='''CARDIOVASCULAR'''<br>[[Cardiomegaly]];<br>[[Congestive heart failure]];<br>[[Arrhythmias]] such as<br> supraventricular<br>tachycardia;<br>[[Cardiac arrest]] during<br>[[surgery]].|A02='''PULMONARY'''<br>Frequent [[infections]];<br>[[Respiratory distress]]/<br>insufficiency.|A03='''NEUROLOGICAL'''<br>[[Hypotonia]];<br>[[Developmental delay]];<br>Gross motor delay;<br>Loss of early motor milestones.|A04='''GASTROINTESTINAL'''<br>[[Failure to thrive]];<br>[[Feeding difficulties]]. }}
{{Family tree/end}}
<br>
|-
! style="background:#DCDCDC;" align="center" + |PERTINENT PATIENT FINDNGS
| align="center" + |
{{Family tree/start}}
{{Family tree|boxstyle=background: #DCDCDC; color: #000000;| B01 | | B02 | | B03 | | B04 |B01='''CARDIOVASCULAR'''<br>[[Murmur]], [[gallop]], pulsatile<br>[[precordium]], excessive<br>[[sweating]] ([[cardiac]] related);<br>[[Cardiomegaly]];<br>[[Cardiomyopathy]];<br>(hypertrophic +/- LVOTO)<br>progressing to dilated<br>[[cardiomyopathy]].|B02='''PULMONARY'''<br>Progressive [[respiratory]]<br>involvement, nasal flaring;<br>Use of accessory<br>muscles, IC and SC<br>retractions, decreased<br>breath sounds in LLL;<br>Coarse breath sounds.|B03='''NEUROLOGICAL'''<br>Delayed motor<br>milestones<br>[[Hypotonia]], head lag,<br>floppy baby with ability to<br>"slip through", frog leg<br>position, hypertrophy of<br>[[gastrocnemius muscle]].|B04='''GASTROINTESTINAL'''<br>[[Macroglossia]], open<br>mouth, low facial tone,<br>decreased [[gag reflex]],<br>[[failure to thrive]], poor suck<br>and swallow, difficulty<br>feeding with pooling of<br>oral secretions;<br>[[hepatomegaly]]. }}
{{Family tree/end}}
<br>
|-
! style="background:#DCDCDC;" align="center" + |INITIAL CLINICAL FINDINGS AND INVESTIGATIONS
|
{{Family tree/start}}
{{Family tree|boxstyle=background: #FFFFFF; color: #000000;| | | | | | | | |,|-| C03 | C03=If GAA present, follow-<br>up with confirmatory<br>testing, if strong clinical<br>suspicion.}}
{{Family tree|boxstyle=background: #DCDCDC; color: #000000;| C01 | | C02 |-|(| |  C01='''CLINICAL STUDIES'''<br>Chest X-ray- Cardiomegaly;<br>EKG - huge R wave, short PR interval and broad<br>QRS complex;<br>Echocardiography - [[cardiomyopathy]]<br>Electrophysiology (EMG/NCS) - [[myopathy]].|C02='''LABORATORY (BLOOD OR URINE)'''<br>Elevated [[CK]], [[AST]], [[ALT]], [[LDH]] (in [[blood]])<br>Glc4 (in urine);<br>GAA activity in dried blood spots.<br>lymphocytes, or leukocytes with blocking<br>antibodies to neutral maltase;<br>Mutation testing in familial mutation<br>known }}
{{Family tree|boxstyle=background: #FFFFF; color: #000000;| | | | | | | | |`|-| C04 | C04=If GAA absent, obtain<br>confirmatory studies for<br>definitive diagnosis.}}
{{Family tree/end}}
<br>
|-
! style="background:#DCDCDC;" align="center" + |CONFIRMATOY STUDIES
| align="center" + |
{{Family tree/start}}
{{Family tree|boxstyle=background: #DCDCDC; color: #000000;| D01 | | D02 | | D03 |D01='''DNA'''<br>GAA [[mutation]] testing|D02='''ENZYMOLOGY'''<br>GAA activity testing in [[fibroblasts]] or [[muscle]]<br>(the gold standard). Caution with [[muscle]]<br>biopsy is needed sue to [[anesthesia]] risk.|D03='''HISTOLOGY/<br>HISTOCHEMISTRY'''<br>Increased [[lysosomal]] [[glycogen]]<br>Vacuolated cells }}
{{Family tree/end}}
|-
| colspan="2" style="background:#7d7d7d; color: #FFFFFF;" + |<small>'''Adapted from GENETICS IN MEDICINE'''<ref name="pmid16702877">{{cite journal| author=ACMG Work Group on Management of Pompe Disease. Kishnani PS, Steiner RD, Bali D, Berger K, Byrne BJ et al.| title=Pompe disease diagnosis and management guideline. | journal=Genet Med | year= 2006 | volume= 8 | issue= 5 | pages= 267-88 | pmid=16702877 | doi=10.109701.gim.0000218152.87434.f3 | pmc=3110959 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16702877  }} </ref></small>
|}
|}
<small> ✔= The best test based on the feature </small>
<br>


===== Diagnostic results =====
<small>ABBREVIATIONS: LVOTO - left ventricular outlet tract obstruction; IC - intercostal; SC - subcostal; LLL - left lower lung; EMG - [[Electromyography]]; NCS - [[Nerve conduction study]]; GAA - acid-alpha glucosidase; [[CK]] - [[creatine kinase]]; [[AST]] - [[aspartate aminotransferase]]; [[ALT]] - [[alanine aminotransferase]]</small>
The following result of [investigation name] is confirmatory of [disease name]:
* Result 1
* Result 2


===== Sequence of Diagnostic Studies =====
<br>
The [name of investigation] should be performed when:
{|
* The patient presented with symptoms/signs 1, 2, and 3 as the first step of diagnosis.
! colspan="2" style="background:#DCDCDC;" align="center" + |Diagnostic algorithm for Late onset (>1 year) glyogen storage disease type II
* A positive [test] is detected in the patient, to confirm the diagnosis.
|-
 
| colspan="2" |
=== Diagnostic Criteria ===
|-
* Here you should describe the details of the diagnostic criteria.
! style="background:#DCDCDC;" align="center" + |COMMON PRESENTING SYMPTOMS
*Always mention the name of the criteria/definition you are about to list (e.g. modified Duke criteria for diagnosis of endocarditis / 3rd universal definition of MI) and cite the primary source of where this criteria/definition is found.
| align="center" + |
*Although not necessary, it is recommended that you include the criteria in a table. Make sure you always cite the source of the content and whether the table has been adapted from another source.
{{Family tree/start}}
*Be very clear as to the number of criteria (or threshold) that needs to be met out of the total number of criteria.
{{Family tree|boxstyle=background: #DCDCDC; color: #000000;| A01 | | A02 | | A03 | |A01='''PULMONARY'''<br>Frequent [[infections]];<br>Respiratory insufficiency/distress;<br>[[Sleep apnea]];<br> [[Somnolence]]<br>Morning [[headaches]].|A02='''MUSCULOSKELETAL'''<br>Limb girdle weakness<br>[[Back pain]];<br>Exercise tolerance;<br>Rigid spine syndrome.|A03='''GASTROINTESTINAL'''<br>Feeding and [[Dysphagia|swallowing difficulties]];<br>Poor weight gain. }}
*Distinguish criteria based on their nature (e.g. clinical criteria / pathological criteria/ imaging criteria) before discussing them in details.
{{Family tree/end}}
*To view an example (endocarditis diagnostic criteria), click [[Endocarditis diagnosis|here]]
<br>
*If relevant, add additional information that might help the reader distinguish various criteria or the evolution of criteria (e.g. original criteria vs. modified criteria).
|-
*You may also add information about the sensitivity and specificity of the criteria, the pre-test probability, and other figures that may help the reader understand how valuable the criteria are clinically.
! style="background:#DCDCDC;" align="center" + |PERTINENT PATIENT FINDNGS
* [Disease name] is mainly diagnosed based on clinical presentation. There are no established criteria for the diagnosis of [disease name].
| align="center" + |
* There is no single diagnostic study of choice for [disease name], though [disease name] may be diagnosed based on [name of criteria] established by [...].
{{Family tree/start}}
 
{{Family tree|boxstyle=background: #DCDCDC; color: #000000;| B01 | | B02 | | B03 | | B04 |B01='''RESPIRATORY'''<br>Respiratory insufficiency;<br>[[orthopnea]], [[sleep apnea]];<br>exertional [[dyspnea]];<br>Weak [[cough]].|B02='''MUSCULOSKELETAL'''<br>Progressive proximal limb-girdle<br>[[muscle weakness]]
* The diagnosis of [disease name] is made when at least [number] of the following [number] diagnostic criteria are met: [criterion 1], [criterion 2], [criterion 3], and [criterion 4].
(lower<br>extremities. upper extremities;<br>gain abnormalities; exercise<br>intolerance; lordosis/scoliosis;<br>hypotonia; lower back pain;<br>Gower's sign.|B03='''GASTROINTESTINAL'''<br>Difficulty maintaining<br>normal weight;<br>Difficulty chewing or jaw<br>muscle fatigue;<br>Decreased [[gag reflex]];<br>[[hepatomegaly]].|B04='''CARDIOVASCULAR'''<br>Infrequent<br>[[cardiomegaly]]<br>(juveniles). }}
* The diagnosis of [disease name] is based on the [criteria name] criteria, which includes [criterion 1], [criterion 2], and [criterion 3].
{{Family tree/end}}
 
<br>
* [Disease name] may be diagnosed at any time if one or more of the following criteria are met:
|-
** Criteria 1
! style="background:#DCDCDC;" align="center" + |INITIAL CLINICAL FINDINGS AND INVESTIGATIONS
** Criteria 2
|
** Criteria 3
{{Family tree/start}}
 
{{Family tree|boxstyle=background: #FFFFFF; color: #000000;| | | | | | | | |,|-| C03 | C03=If GAA present, follow-<br>up with confirmatory<br>testing, if strong clinical<br>suspicion.}}
IF there are clear, established diagnostic criteria:
{{Family tree|boxstyle=background: #DCDCDC; color: #000000;| C01 | | C02 |-|(| |  C01='''CLINICAL STUDIES'''<br>[[Pulmonary function test|Lung function testing]] lying and sitting;<br>Muscle strength testing;<br>Electrophysiology (EMG/NCS) - [[myopathy]];<br>Muscle biopsy - histology and<br>histochemistry.|C02='''LABORATORY (BLOOD OR URINE)'''<br>Elevated [[CK]], [[AST]], [[ALT]], [[LDH]] (in [[blood]])<br>Glc4 (in [[urine]]);<br>GAA activity in dried blood spots,<br>[[lymphocytes]], or [[leukocytes]] with<br>blocking antibodies to neutral maltase;<br>Mutation testing in familial mutation<br>known }}
*The diagnosis of [disease name] is made when at least [number] of the following [number] diagnostic criteria are met: [criterion 1], [criterion 2], [criterion 3], and [criterion 4].
{{Family tree|boxstyle=background: #FFFFF; color: #000000;| | | | | | | | |`|-| C04 | C04=If GAA absent, obtain<br>confirmatory studies for<br>definitive diagnosis.}}
*The diagnosis of [disease name] is based on the [criteria name] criteria, which include [criterion 1], [criterion 2], and [criterion 3].
{{Family tree/end}}
*The diagnosis of [disease name] is based on the [definition name] definition, which includes [criterion 1], [criterion 2], and [criterion 3].
<br>
IF there are no established diagnostic criteria: 
|-
*There are no established criteria for the diagnosis of [disease name].
! style="background:#DCDCDC;" align="center" + |CONFIRMATOY STUDIES
| align="center" + |
{{Family tree/start}}
{{Family tree|boxstyle=background: #DCDCDC; color: #000000;| D01 | | D02 | | D03 |D01='''DNA'''<br>GAA mutation testing|D02='''ENZYMOLOGY'''<br>GAA activity testing in [[fibroblasts]] or [[muscle]]<br>(the gold standard);<br> ClinicaL coorelation with test result is required.|D03='''HISTOLOGY/<br>HISTOCHEMISTRY'''<br>(dependent on the site of biopsy)<br>Increased [[lysosomal]] [[glycogen]];<br>Vacuolated cells }}
{{Family tree/end}}
|-
| colspan="2" style="background:#7d7d7d; color: #FFFFFF;" + |<small>'''Adapted from GENETICS IN MEDICINE'''<ref name="pmid16702877">{{cite journal| author=ACMG Work Group on Management of Pompe Disease. Kishnani PS, Steiner RD, Bali D, Berger K, Byrne BJ et al.| title=Pompe disease diagnosis and management guideline. | journal=Genet Med | year= 2006 | volume= 8 | issue= 5 | pages= 267-88 | pmid=16702877 | doi=10.109701.gim.0000218152.87434.f3 | pmc=3110959 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16702877  }} </ref></small>
|}


<small>ABBREVIATIONS: EMG - [[Electromyogtaphy]]; NCS - [[Nerve conduction study]]; GAA - acid-alpha glucosidase; [[CK]] - [[creatine kinase]]; [[AST]] - [[aspartate aminotransferase]]; [[ALT]] - [[alanine aminotransferase]]</small>


==References==
==References==
{{Reflist|2}}
{{WH}}
{{WH}}
{{WS}}
{{WS}}
[[Category:Endocrinology]]
[[Category:Hepatology]]
[[Category:Gastroenterology]]
[[Category:Pediatrics]]
[[Category:Up-To-Date]]
[[Category:Genetic disorders]]
[[Category:Metabolic disorders]]

Latest revision as of 17:55, 2 October 2018

Glycogen storage disease type II Microchapters

Home

Patient Information

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Glycogen storage disease type II from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications and Prognosis

Diagnosis

Diagnostic Study of Choice

History and Symptoms

Physical Examination

Laboratory Findings

Electrocardiogram

X Ray

CT

MRI

Echocardiography or Ultrasound

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

Secondary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Glycogen storage disease type II diagnostic study of choice On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Glycogen storage disease type II diagnostic study of choice

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Glycogen storage disease type II diagnostic study of choice

CDC on Glycogen storage disease type II diagnostic study of choice

Glycogen storage disease type II diagnostic study of choice in the news

Blogs on Glycogen storage disease type II diagnostic study of choice

Directions to Hospitals Treating Glycogen storage disease type II

Risk calculators and risk factors for Glycogen storage disease type II diagnostic study of choice

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Anmol Pitliya, M.B.B.S. M.D.[2]

Overview

Acid α-glucosidase (GAA) activity in fibroblast of a dried blood sample is the gold standard test for the diagnosis of glycogen storage disease type 2. Decreased activity of GAA in fibroblasts a dried blood sample is confirmatory of glycogen storage disease type 2.

Diagnostic Study of Choice

Gold standard

  • Acid α-glucosidase (GAA) activity in fibroblast of a dried blood sample is the gold standard test for the diagnosis of glycogen storage disease type 2.[1][2]
  • The following result of acid α-glucosidase (GAA) activity in fibroblast of a dried blood sample is confirmatory of glycogen storage disease type 2:

Diagnostic algorithms


Algorithms for diagnostic approach of glycogen storage disease type 2[3]
Diagnostic algorithm for Infantile onset glyogen storage disease type II
COMMON PRESENTING SYMPTOMS
CARDIOVASCULAR
Cardiomegaly;
Congestive heart failure;
Arrhythmias such as
supraventricular
tachycardia;
Cardiac arrest during
surgery.
 
PULMONARY
Frequent infections;
Respiratory distress/
insufficiency.
 
NEUROLOGICAL
Hypotonia;
Developmental delay;
Gross motor delay;
Loss of early motor milestones.
 
GASTROINTESTINAL
Failure to thrive;
Feeding difficulties.


PERTINENT PATIENT FINDNGS
CARDIOVASCULAR
Murmur, gallop, pulsatile
precordium, excessive
sweating (cardiac related);
Cardiomegaly;
Cardiomyopathy;
(hypertrophic +/- LVOTO)
progressing to dilated
cardiomyopathy.
 
PULMONARY
Progressive respiratory
involvement, nasal flaring;
Use of accessory
muscles, IC and SC
retractions, decreased
breath sounds in LLL;
Coarse breath sounds.
 
NEUROLOGICAL
Delayed motor
milestones
Hypotonia, head lag,
floppy baby with ability to
"slip through", frog leg
position, hypertrophy of
gastrocnemius muscle.
 
GASTROINTESTINAL
Macroglossia, open
mouth, low facial tone,
decreased gag reflex,
failure to thrive, poor suck
and swallow, difficulty
feeding with pooling of
oral secretions;
hepatomegaly.


INITIAL CLINICAL FINDINGS AND INVESTIGATIONS
 
 
 
 
 
 
 
 
 
 
 
If GAA present, follow-
up with confirmatory
testing, if strong clinical
suspicion.
 
 
 
CLINICAL STUDIES
Chest X-ray- Cardiomegaly;
EKG - huge R wave, short PR interval and broad
QRS complex;
Echocardiography - cardiomyopathy
Electrophysiology (EMG/NCS) - myopathy.
 
LABORATORY (BLOOD OR URINE)
Elevated CK, AST, ALT, LDH (in blood)
Glc4 (in urine);
GAA activity in dried blood spots.
lymphocytes, or leukocytes with blocking
antibodies to neutral maltase;
Mutation testing in familial mutation
known
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
If GAA absent, obtain
confirmatory studies for
definitive diagnosis.
 
 


CONFIRMATOY STUDIES
DNA
GAA mutation testing
 
ENZYMOLOGY
GAA activity testing in fibroblasts or muscle
(the gold standard). Caution with muscle
biopsy is needed sue to anesthesia risk.
 
HISTOLOGY/
HISTOCHEMISTRY
Increased lysosomal glycogen
Vacuolated cells
Adapted from GENETICS IN MEDICINE[3]


ABBREVIATIONS: LVOTO - left ventricular outlet tract obstruction; IC - intercostal; SC - subcostal; LLL - left lower lung; EMG - Electromyography; NCS - Nerve conduction study; GAA - acid-alpha glucosidase; CK - creatine kinase; AST - aspartate aminotransferase; ALT - alanine aminotransferase


Diagnostic algorithm for Late onset (>1 year) glyogen storage disease type II
COMMON PRESENTING SYMPTOMS
PULMONARY
Frequent infections;
Respiratory insufficiency/distress;
Sleep apnea;
Somnolence
Morning headaches.
 
MUSCULOSKELETAL
Limb girdle weakness
Back pain;
Exercise tolerance;
Rigid spine syndrome.
 
GASTROINTESTINAL
Feeding and swallowing difficulties;
Poor weight gain.
 


PERTINENT PATIENT FINDNGS
RESPIRATORY
Respiratory insufficiency;
orthopnea, sleep apnea;
exertional dyspnea;
Weak cough.
 
MUSCULOSKELETAL
Progressive proximal limb-girdle
muscle weakness (lower
extremities. upper extremities;
gain abnormalities; exercise
intolerance; lordosis/scoliosis;
hypotonia; lower back pain;
Gower's sign.
 
GASTROINTESTINAL
Difficulty maintaining
normal weight;
Difficulty chewing or jaw
muscle fatigue;
Decreased gag reflex;
hepatomegaly.
 
CARDIOVASCULAR
Infrequent
cardiomegaly
(juveniles).


INITIAL CLINICAL FINDINGS AND INVESTIGATIONS
 
 
 
 
 
 
 
 
 
 
 
If GAA present, follow-
up with confirmatory
testing, if strong clinical
suspicion.
 
 
 
CLINICAL STUDIES
Lung function testing lying and sitting;
Muscle strength testing;
Electrophysiology (EMG/NCS) - myopathy;
Muscle biopsy - histology and
histochemistry.
 
LABORATORY (BLOOD OR URINE)
Elevated CK, AST, ALT, LDH (in blood)
Glc4 (in urine);
GAA activity in dried blood spots,
lymphocytes, or leukocytes with
blocking antibodies to neutral maltase;
Mutation testing in familial mutation
known
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
If GAA absent, obtain
confirmatory studies for
definitive diagnosis.
 
 


CONFIRMATOY STUDIES
DNA
GAA mutation testing
 
ENZYMOLOGY
GAA activity testing in fibroblasts or muscle
(the gold standard);
ClinicaL coorelation with test result is required.
 
HISTOLOGY/
HISTOCHEMISTRY
(dependent on the site of biopsy)
Increased lysosomal glycogen;
Vacuolated cells
Adapted from GENETICS IN MEDICINE[3]

ABBREVIATIONS: EMG - Electromyogtaphy; NCS - Nerve conduction study; GAA - acid-alpha glucosidase; CK - creatine kinase; AST - aspartate aminotransferase; ALT - alanine aminotransferase

References

  1. ↑ Pompe Disease Diagnostic Working Group. Winchester B, Bali D, Bodamer OA, Caillaud C, Christensen E; et al. (2008). "Methods for a prompt and reliable laboratory diagnosis of Pompe disease: report from an international consensus meeting". Mol Genet Metab. 93 (3): 275–81. doi:10.1016/j.ymgme.2007.09.006. PMID 18078773.
  2. ↑ Kallwass H, Carr C, Gerrein J, Titlow M, Pomponio R, Bali D; et al. (2007). "Rapid diagnosis of late-onset Pompe disease by fluorometric assay of alpha-glucosidase activities in dried blood spots". Mol Genet Metab. 90 (4): 449–52. doi:10.1016/j.ymgme.2006.12.006. PMID 17270480.
  3. ↑ 3.0 3.1 3.2 ACMG Work Group on Management of Pompe Disease. Kishnani PS, Steiner RD, Bali D, Berger K, Byrne BJ; et al. (2006). "Pompe disease diagnosis and management guideline". Genet Med. 8 (5): 267–88. doi:10.109701.gim.0000218152.87434.f3 Check |doi= value (help). PMC 3110959. PMID 16702877.

Template:WH Template:WS

Retrieved from "https://www.wikidoc.org/index.php?title=Glycogen_storage_disease_type_II_diagnostic_study_of_choice&oldid=1496229"