Diagnostic Tests for Ataxia Telangiectasia

Ataxia Telangiectasia: Diagnostic Tests

The list of diagnostic tests mentioned in various sources as used in the diagnosis of Ataxia Telangiectasia includes:

• Fetal proteins blood test

Home Diagnostic Testing

These home medical tests may be relevant to Ataxia Telangiectasia:

• Brain & Neurological Disorders: Related Home Testing:
  • ADHD -- Home Tests
  • Drug Screening Kits

Diagnostic Tests for Ataxia Telangiectasia: Online Medical Books

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ATAXIA: DIAGNOSTIC WORKUP
(Algorithmic Diagnosis of Symptoms and Signs)

The wise clinician should consider a neurologic referral at the outset. If there is vertigo, tinnitus, or deafness, then an audiogram and caloric testing should be done. If these suggest eighth nerve damage, then a CT scan or MRI of the brain should be done. Headaches, sustained nystagmus, or papilledema are other indications for a CT scan or MRI. If multiple sclerosis is suspected, MRI of the brain is very useful, as well as spinal fluid for gamma globulin and myelin basic protein. Perhaps VEP, brain stem evoked potential (BSEP), or SSEP studies should be done. If vascular disease is suspected, magnetic resonance angiography will allow assessment of the vertebral-basilar arteries. If this is not available, four-vessel cerebral angiography may be utilized. Patients with hypoactive reflexes and glove and stocking hypoesthesia and hypalgesia will need a neuropathy workup . When there is ataxia in the presence of a normal neurologic examination, referral to a psychologist for psychometric testing should be done.

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Source: Algorithmic Diagnosis of Symptoms and Signs, 2003

Ataxia: History and physical examination
(Handbook of Signs & Symptoms (Third Edition))

If the patient isn’t in distress, review his history. Ask about multiple sclerosis, diabetes, central nervous system infection, neoplastic disease, previous stroke, and a family history of ataxia. Also, ask about chronic alcohol abuse or prolonged exposure to industrial toxins such as mercury. Find out if the patient’s ataxia developed suddenly or gradually.

If necessary, perform Romberg’s test to help distinguish between cerebellar and sensory ataxia. Instruct the patient to stand with his feet together and his arms at his side. Note his posture and balance, first with his eyes open, and then closed. Test results may indicate normal posture and balance (minimal swaying), cerebellar ataxia (swaying and inability to maintain balance with eyes open or closed), or sensory ataxia (increased swaying and inability to maintain balance with eyes closed). Stand close to the patient during this test to prevent his falling.

If you test for gait and limb ataxia, be aware that motor weakness may mimic ataxic movements, so check motor strength as well. Gait ataxia may be severe, even when limb ataxia is minimal. With gait ataxia, ask the patient if he tends to fall to one side, or if falling occurs more frequently at night. With truncal ataxia, remember that the patient’s inability to walk or stand, combined with the absence of other signs while he’s lying down, may give the impression of hysteria or drug or alcohol intoxication.

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Source: Handbook of Signs & Symptoms (Third Edition), 2006

Ataxia: History and physical examination
(Professional Guide to Signs & Symptoms (Fifth Edition))

If the patient isn’t in distress, review his history. Ask about multiple sclerosis, diabetes, central nervous system infection, neoplastic disease, previous stroke, and a family history of ataxia. Also ask about chronic alcohol abuse or prolonged exposure to industrial toxins such as mercury. Find out if the ataxia developed suddenly or gradually.

If necessary, perform Romberg’s test to help distinguish between cerebellar and sensory ataxia. Instruct the patient to stand with his feet together and his arms at his side. Note his posture and balance, first with his eyes open and then with them closed. Test results may indicate normal posture and balance (minimal swaying), cerebellar ataxia (swaying and inability to maintain balance with eyes open or closed), or sensory ataxia (increased swaying and inability to maintain balance with eyes closed). Stand close to the patient during this test to prevent his falling.

If you test for gait and limb ataxia, be aware that motor weakness may mimic ataxic movements, so check motor strength, too. Gait ataxia may be severe, even when limb ataxia is minimal. Ask the patient with gait ataxia if he tends to fall to one side and if he falls more at night. With truncal ataxia, remember that the patient’s inability to walk or stand, combined with the absence of other signs while he’s lying down, may give the impression of hysteria or drug or alcohol intoxication.

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Source: Professional Guide to Signs & Symptoms (Fifth Edition), 2006

Spider angioma [Arterial spider, spider nevus, spider telangiectasia, stellate angioma, vascular spider]: History and physical examination
(Professional Guide to Signs & Symptoms (Fifth Edition))

Begin your examination by asking the patient how long he has had the spider angiomas and where they’re located. Then carefully examine him yourself, noting the size and location of the angiomas. On palpation, the angiomas may be slightly warmer than the surrounding skin and may have a pulsating central body. Also, check for other skin abnormalities, such as jaundice, dryness, and palmar erythema.

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Source: Professional Guide to Signs & Symptoms (Fifth Edition), 2006

Ataxia: Physical examination
(The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter)

A. Neurologic examination. Evaluate for dysmetria (finger-nose difficulty), saccadic eye movements (differentiated from nystagmus by multidirectionality), titubation (head bobbing), truncal swaying, and dysdiadochokinesia (difficulty with rapid alternating movements). Observe speech patterns (wandering pitch, volume). The typical ataxic gait is wide based. Cerebellar ataxia can be differentiated from sensory ataxia or poor proprioception by Romberg’s sign, where the removal of visual input dramatically reduces compensatory ability in sensory ataxia. Unilateral symptoms suggest a focal cerebellar insult (stroke, arteriovenous malformation, tumor), and deviation occurs ipsilateral to the lesion.

B. Associated symptoms can reveal specific processes. An older child with intermittent ataxia from basilar migraine, for example, will have a normal neurologic examination, whereas a child with hereditary periodic ataxia can present with nystagmus and more mild symptoms (1). Ataxia can precede the characteristic lesions of ataxia-telangiectasia, which tend to appear around 5 years of age. Opsomyoclonus warrants a search for neuroblastoma. The photosensitive rash of Hartnup’s disease and the specific findings of maple syrup urine disease can assist in diagnosis. Look for signs and symptoms of hypothyroidism (Chapter 14.4). Pes cavus and scoliosis are associated with Friedreich’s ataxia.

Testing

A. Diagnostic imaging. Most evaluations should begin with imaging of the brain, because clinical pictures suggest specific diagnoses only on occasion. Magnetic resonance imaging is superior to demonstrate tumors, multiple sclerosis, and malformations. Imaging differentiates between posttraumatic posterior fossa hemorrhage and postconcussion syndrome. Lumbar puncture may be necessary to rule out an infectious cause. An electroencephalogram helps uncover intermittent, seizure-related ataxia (“pseudoataxia”).

 B. Clinical laboratory tests. As indicated, check amino acid screening, toxin screening, and thyroid function. Younger individuals may benefit from testing for IgA, ceruloplasmin, and phytanic acid deficiency to rule out ataxia-telangiectasia, Wilson’s disease, and Refsum’s disease, respectively. Pyruvate is a marker of mitochondrial disease. Vanillymandelic acid and homovanillic acid levels occasionally help to detect occult neuroblastomas. Paraneoplastic cerebellar degeneration is an immunologic phenomenon, most often associated with small cell lung cancer, for which Hu and Yo antibodies may be diagnostic. Approximately 40% of patients with Friedreich’s ataxia have frank or occult glucose intolerance, and there are associated electrocardiogram abnormalities.

Diagnostic assessment.

 The list of conditions that cause ataxia is long, but most fall under the categories of neoplastic, infectious or immunologic, hereditary (metabolic or primary cerebellar), structural, degenerative (idiopathic or secondary), toxic, traumatic, or vascular disease. The time course can suggest more or less likely diagnoses. Although degenerative and hereditary diseases occur across the lifespan, certain diseases occur more frequently at certain ages.

References

1. Fenichel GM. Clinical pediatric neurology: a signs and symptoms approach, 3rd ed. Philadelphia: WB Saunders, 1997.

2. Lieber CS. Medical disorders of alcoholism. N Engl J Med 1995;333:1058–1065.

3. Marsden CD, Fowler TJ. Clinical neurology, 2nd ed. London: Arnold Med Publishers, Ltd., 1998.

4. Sudarsky L. Gait disturbances of the elderly. N Engl J Med 1990;322:1441–1446.

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Source: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, 2000

Ataxia: Diagnostic Approach
(Field Guide to Bedside Diagnosis)

Hemiparetic gait, a stroke residua, results from abduction/circumduction of the leg with a contralateral tilt of the body. Paraparetic gait, found with spinal cord disease or cerebral palsy, is marked by “scissoring,” or crossing with each step. A steppage gait, seen with peroneal neuropathy, has a foot drop with a high step to avoid toe dragging, and the foot slaps down. With a waddling gait, in proximal leg weakness such as myopathy, the leg is lifted high, and the trunk leans opposite. A Parkinsonian gait has a forward stoop with flexion of the hips, knees, and elbows and short shuffling steps, which accelerate. An apraxic gait, with bilateral frontal lobe disease, is shuffling, but the gait is hesitant and not maintained. A cerebellar/ataxic gait is broad-based and irregular. A sensory/ataxic gait is broadly based with a positive Romberg. With a vestibular gait, the patient falls to one side whether walking or standing. With hysterical gait, there is normal leg coordination while sitting but dramatic falls when standing.

A positive Romberg (unsteady with eyes closed, steady with eyes open) indicates posterior column disease. Gross lesions of the spinal cord rarely present with ataxia because of prominent weakness and spasticity. Cerebellar lesions produce dysmetria and decomposition of movement. Speech may be scanning, with each syllable pronounced separately.

With sensory ataxia, loss of touch causes little ataxia, but loss of proprioception causes severe ataxia, which increases with the eyes closed. The gait is wide-based with the feet landing with force. Both Romberg and pursuit (finger to nose or heel to shin) will be abnormal. It is caused by a lesion of the peripheral nerves, posterior columns (vitamin B₁₂ deficiency subacute combined degeneration), posterior roots (tabes), medial lemniscus, thalamus, or sensory cortex. Polyneuritis may be caused by diabetes, polyarteritis nodosa, alcohol, arsenic, Guillain-Barré, or porphyria.

Points of differentiation are as follows:

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Source: Field Guide to Bedside Diagnosis, 2007

Telangiectasias/Angiomas: Diagnostic Approach
(Field Guide to Bedside Diagnosis)

Linear telangiectasias are simple red or blue lines that blanch with pressure and disappear with diascopy. They are common with actinic damage, rosacea, carcinoid, ataxia-telangiectasia, or cutaneous inflammation (such as discoid lupus).

Spider angiomata have a central pulsating punctum (seen with diascopy), radial legs, and a halo of pallor caused by a vascular steal phenomenon.

Periungual nailfold telangiectasias, resembling glomeruli on 10-fold magnification, are found in lupus, scleroderma, and dermatomyositis.

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Source: Field Guide to Bedside Diagnosis, 2007

Ataxia: Physical assessment
(Signs & Symptoms: A 2-in-1 Reference for Nurses)

If necessary, perform Romberg’s test to help distinguish between cerebellar and sensory ataxia. Instruct the patient to stand with his feet together and his arms at his sides. Note his posture and balance, first with his eyes open, then closed. Test results may indicate normal posture and balance (minimal swaying), cerebellar ataxia (swaying and inability to maintain balance with eyes open or closed), or sensory ataxia (increased swaying and inability to maintain balance with eyes closed). Stand close to the patient during this test to prevent his falling.

If you test for gait and limb ataxia, be aware that motor weakness may mimic ataxic movements and check motor strength, too. Gait ataxia may be severe, even when limb ataxia is minimal. With gait ataxia, ask the patient if he tends to fall to one side and if falling usually occurs at night. With truncal ataxia, remember that inability to walk or stand, combined with the absence of other signs when lying down, may give the impression of hysteria or drug or alcohol intoxication.

» READ BOOK EXCERPT ONLINE »

Source: Signs & Symptoms: A 2-in-1 Reference for Nurses, 2007

Ataxia: Diagnostic Approach
(The Diagnostic Approach to Symptoms and Signs in Pediatrics)

Types of Ataxia

Cerebellar Ataxia

Labyrinthine Ataxia

Sensory Ataxia

Frontal Lobe Ataxia

Evaluation

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Source: The Diagnostic Approach to Symptoms and Signs in Pediatrics, 2006

Ataxia: History and physical examination
(Nursing: Interpreting Signs and Symptoms)

If the patient isn't in distress, review his history. Ask about multiple sclerosis, diabetes, central nervous system infection, neoplastic disease, previous stroke, and a family history of ataxia. Ask about chronic alcohol abuse or prolonged exposure to industrial toxins such as mercury. Find out if the patient's ataxia developed suddenly or gradually.

If necessary, perform Romberg's test to help distinguish between cerebellar and sensory ataxia. Instruct the patient to stand with his feet together and his arms at his side. Note his posture and balance, first with his eyes open, and then closed. Test results may indicate normal posture and balance (minimal swaying), cerebellar ataxia (swaying and inability to maintain balance with eyes open or closed), or sensory ataxia (increased swaying and inability to maintain balance with eyes closed). Stand close to the patient during this test to prevent his falling.

If you test for gait and limb ataxia, be aware that motor weakness may mimic ataxic movements, so check motor strength as well. Gait ataxia may be severe, even when limb ataxia is minimal. With gait ataxia, ask the patient if he tends to fall to one side, or if falling occurs more frequently at night. With truncal ataxia, remember that the patient's inability to walk or stand, combined with the absence of other signs while he's lying down, may give the impression of hysteria or drug or alcohol intoxication.

» READ BOOK EXCERPT ONLINE »

Source: Nursing: Interpreting Signs and Symptoms, 2007