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A 64 y/o Woman with Dyspnea
Pamela Ryan MD
February 14, 2007
January 30, 2006
• CC: “I’m short of breath.”
• 64 y/o woman with increased dyspnea on exertion over the past 2 weeks.
• Notes a “heaviness in my chest”, also described it as a band of pressure across her chest and upper abdomen.
• Denies PND, orthopnea. No personal hx of CAD or pulmonary disease.
64 y/o woman with dyspnea
• Past Medical History– Htn– Obesity– Rosacea– h/o lower extremity cellulitis– s/p hysterectomy
64 y/o woman with dyspnea
• ROS: significant for an increase in lower extremity edema, recent episodes of urinary incontinence, occasional visual changes, reports her “eyelids feel heavy”, and generalized fatigue.
• The patient also notes she has not been taking her bp medication.
64 y/o woman with dyspnea
• Meds:– HCTZ 25 mg po qd (had not taken for the past
few weeks)– Minocycline
• Social Hx– Widow– Lifetime non smoker; rare ETOH– Lives on a dairy farm.
Exam
• BP: 214/116 Pulse:98 Temp 98.1 RR 14• O2 Sat on room air is 97%• HEENT: No papilledema. ?Slight right
eyelid droop. EOMI PERRLA• CV: RRR nl S1 S2. S4 also present.• Lungs: Clear• Abd: Soft, nontender• Ext: 1+ pitting edema bilaterally.
64 y/o woman with dyspnea
• EKG: NSR, rate 86. Poor R wave progression—unchanged compared to 2003 EKG.
• Troponin ordered.
• CXR: within normal limits.
64 y/o woman with dyspnea
• Hypertensive urgency
• Concern for CAD.
• Pt was given O2, nitro SL and ASA, and transferred to UW Cardiology.
Inpatient Evaluation/Treatment
• Ruled out for MI. Begun on metoprolol, captopril, and lasix.
• Echo: Mildly dilated left atrium, normal RV size and systolic function, LV: Distal posterolateral wall is thin and hypokinetic relative to other segments. Normal chamber size. Global systolic function is at the lower limits of normal.
Inpatient Eval/Treatment
• Dobutamine stress: 71% of predicted heart rate, test stopped secondary to anxiety. No evidence of wall motion abnormalities. No ischemia.
• Discharged to home 02/01/06
Inpatient evaluation/Treatment
• Assessment: DOE was secondary to hypertensive urgency.
• Discharged on ASA, toprol XL, lisinopril, HCTZ and a statin. Rec: wt loss, low sodium, low cholesterol diet.
F/U visits
• 02/09/06 Pt reports “some improvement” in dyspnea. F/U on bp. Discussed PFT’s—pt would like to wait. Increased metoprolol.
• 2/20/06 Pt reporting increased fatigue and dyspnea. Decreased metoprolol dose (from 100 mg to 50 mg) and ordered PFTs.
• 2/27/06 Drug rash. Dyspnea and fatigue continue. Ordered dopplers of LE and D-dimer. (both negative) PFT’s to be performed later that day.
2/27 Pulmonary Function Tests
• Moderate reduction in FEV1 and FVC; significant improvement in FEV1 following albuterol administration.
• Testing consistent with a combined restrictive and obstructive ventilatory defect.
Restrictive Lung Disease
• Intrinsic lung diseases, which cause inflammation or scarring of the lung tissue (interstitial lung disease) or fill the airspaces with exudate or debris (acute pneumonitis). (DLCO generally reduced)
• Extrinsic disorders, such as disorders of the chest wall or the pleura, which mechanically compress the lungs or limit their expansion.
• Neuromuscular disorders, which decrease the ability of the respiratory muscles to inflate and deflate the lungs.
03/06/06
• Patient reports she feels tired. Eyes are “droopy”. New onset of intermittent double vision over the past week.
• Dyspnea is worse. No cough. No wheezing. Feels anxious. Occasional chest tightness.
• Exam: BP 146/86 Pulse 60 O2 Sat 94%– Bilateral ptosis noted. EOMI PERRLA– Rest of neuro exam normal
Summary at this point
• Increased DOE, hypertension, restrictive/obstructive component on PFT’s, bilateral ptosis, unrevealing cardiac workup.
• Discussed obtaining spiral CT, optho evaluation and EMG.
• Ordered anti-acetylcholine receptor antibody.
64 y/o woman with dyspnea
• EMG results: “Electrodiagnostic Findings indicate a postsynaptic neuromuscular transmission defect consistent with myasthenia gravis.”
• Anti-acetylcholine receptor antibody level still pending.
• Patient was begun on pyridostigmine 30 mg qid.
Objectives
Discussion of Myasthenia Gravis– Epidemiology– Clinical Presentation– Diagnosis– Associated Conditions– Treatment
Myasthenia Gravis
• Most common disorder of neuromuscular transmission.
• Hallmark of the disorder is a fluctuating degree of weakness involving the respiratory, ocular, limb and bulbar muscles.
• Weakness is the result of antibodies to the acetylcholine receptor in the postsynaptic membrane of the NM junction.
Epidemiology
• Annual incidence is 10-20 new cases per million people.
• Occurs at any age, but tends to have a bimodal distribution—early peak in second and third decades (> women) and late peak in sixth to eighth decade (>men)
Clinical
• Fluctuating weakness and fatigue in specific muscle groups.
• More than 50% present with ptosis and/or diplopia.
• 15% present with bulbar sxs (dysarthria, dysphagia, and fatigable chewing)
• Extraocular muscles often involved.
Myasthenia Gravis
• Two clinical forms:– Ocular: limited to the eyelids and extraocular
muscles.– Generalized: may affect ocular muscles, but
also bulbar, limb and respiratory muscles.
Clinical Course
• Early on, symptoms are often transient. Maximal extent of disease is typically seen by 3 years of onset of sxs.
Drugs which can exacerbate MG
• All beta blockers
• Fluoroquinolones
• Aminoglycosides
• OCPs
• Narcotics
• Phenytoin and Gabapentin
Diagnosis
• Clinical diagnosis, supported by electrophysiological studies as well as autoantibodies.
• Tensilon Test• Serologic Testing—autoantibodies against the
acetylcholine receptor. Present in 85% of patients with generalized disease. These are highly specific.
• If the AChR antibodies are negative, an assay for MuSK(muscle specific receptor tyrosine kinase) antibodies should be performed.
Diagnosis
• Electrophysiologic studies:– Repetitive nerve stimulation (sens. 75%)– Single fiber electromyography (sens-95%)
– Positive 90-95% of the time on ocular MG– Positive >95% of the time in generalized MG
Associated conditions
• Autoimmune disorders– Autoimmune thyroid disease, RA, SLE
• Thymic tumors (thymic hyperplasia, primary thymoma)– Imaging of the mediastinum should be
considered part of the evaluation in any patient with MG.
Treatment
• Symptomatic
• Immunomodulating treatments (steroids and other immunosuppressive drugs)
• Rapid immunomodulating treatments (plasma exchange and IVIG)
• Surgical (thymectomy)
Treatment
• Acetylcholinesterase inhibitors—pyridostigmine
• Commonly used immunomodulating drugs in MG are prednisone, azathioprine, cyclosporine, and mycophenolate.
• Plasmapheresis and IVIG are rapid acting, but have a short duration of action—typically reserved for myasthenic crisis, as a bridge to initiation of other therapies
My patient
• Treated with pyridostigmine 30 mg qid and had a remarkable improvement in her symptoms.
• Discussed treatment with steroids, but patient was hesitant due to long term consequences of steroid therapy.
• CT scan of chest was normal (no thymoma) • One year later she continues to do well on the
pyridostigmine alone.