Mount Sinai Ambulatory Care Pathway Type II Diabetes Mellitus
Ambulatory: Diabetes Mellitus
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Transcript of Ambulatory: Diabetes Mellitus
Ambulatory:Diabetes Mellitus
April 9, 2007
Insulin dependent (Type 1 /IDDM) Abrupt onset, < 30 yrs Autoimmune insulin deficiency due to islet cell
destruction Prone to ketoacidosis
Non-insulin dependent (Type 2/NIDDM) Gradual onset, > 30 yrs Obesity Insulin resistance Impaired insulin secretion (beta cell dysfunction)
Subtypes
Type I DM
Insulin deficiency secondary to β-cell destruction usually by autoimmune process
Insulin and C-peptide levels low May have islet cell autoantibodies,
Autoantibodies to insulin, or antibodies to glutamic acid decarboxylase or tyrosine phosphatases.
20% risk of other autoimmune diseases Typically will present with DKA due to
absolute lack of insulin
Type II
Insulin resistance and relative insulin deficiency - β-cell mass preserved, but decreased secretion and response to insulin.
Strong genetic component with 100% concordance in monozygotic twins.
Ketoacidosis is rare – though it can occur if concurrent infection. Also there are a small group of mainly African American patients in whom insulinopenia leads to a tendency to DKA.
Usually hyperglycemia in Type II develops gradually and pt may be undiagnosed for years.
Subtypes
Gestational Diabetes Dysfunction of glucose metabolism with
presentation in pregnancy Increased fetal morbidity Up to 63% will develop non-gestational DM in 5-
16 years MODY (maturity-onset diabetes of the young)
Subset of Type 2 DM Family history, early age of onset (teens, 20’s) At least 5 subtypes Impairment of β-cell function Resistance to ketoacidosis
Subtypes Secondary Diabetes
Pancreatic disease with resultant insulinopenia
• Chronic pancreatitis, pancreatectomy, CF, hemachromatosis
Drug induced• HCTZ, steroids, estrogen, psychoactive
agents, catacholamines, pentamidine
Subtypes
EndocrinopathiesAcromegaly, pheochromocytoma,
Cushing’s, Conn’s, glucagonomaInsulin receptor abnormalities
Genetic syndromesHyperlipidemia, muscular dystrophies,
Huntington’s chorea
Diagnosis Per the Expert Committee on the Diagnosis and
Classification of Diabetes Mellitus, 2003
Criteria Comment Symptoms of DM Casual plasma glucose concentration ≥ 200 mg/dL OR
Casual defined as any time of day, meal or no meal
** 2 Fasting plasma glucose concentrations ≥ 126 mg/dL OR
No caloric intake for at least 8 hours
2 hour plasma glucose concentration ≥ 200 mg/dL on OGTT
Glucose load equivalent to 75 g of anhydrous glucose in water
Symptoms of Diabetes
ClassicPolyuria, polydipsia, unexplained
weight LOSS Fatigue Blurry vision Nausea, vomiting Infections
Screening for Diabetes
Every 3 years if age 45 or older (if results are normal) More frequent screening if:
Pre-Diabetic• Fasting plasma glucose concentration > 110 mg/dL or < 126 mg dL• a.k.a. “impaired fasting glucose” or “impaired glucose tolerance”
Obese (BMI≥27) 1st degree relatives with DM High risk ethnic group
• African-American, Hispanic-American, Native-American, Asian-American, Pacific Islander-American
Pregnancy • History of Gestational diabetes• Delivery of baby weighing 9 or more pounds
HTN (>140/90) Dyslipidemia
• HDL≤35 mg/dL, TGL≥250 mg/dL
Treatment rationale
DCCTRG39% reduction in progression of
retinopathy for 0.9% reduction in HbA1c
UKPDSGHbA1c of 7% associated with
significant incidence of micro and macrovascular disease
Treatment Rationale
Meticulous glucose control decreases long-term microvascular complication rates
Aggressive insulin therapy in patients with a recent MI was associated with reduced mortality
Treatment of Diabetes Mellitus
Goals set by American Diabetes AssociationPreprandial glucose values of 80 to 120
mg/dLBedtime glucose values of 100 to 140
mg/dLHemoglobin A1C < 7%2 hour post-prandial glucose values <
160 mg/dL
Need insulin Healthy people generally have insulin
production of 24-36 units per day Type 1 DM
0.5 to 1.0 units/kg of insulin daily Varies according to diet, exercise, stress
Various insulin preparations with various regimens Tailor to the patient Attempt to mimic the healthy person’s insulin
peaks and valleys
Treatment of Type 1 Diabetes Mellitus
Rapid Acting Insulins Lispro, Aspart
Short Acting Insulins Regular
Intermediate Acting NPH Lente
Long Acting Ultralente Glargine
Treatment of Type 1 Diabetes Mellitus
Pharmacokinetics of current insulin preparations
Insulin Onset Peak Effective duration
Lispro (Humalog) <15 min 1 hr 4-5 hr
Regular 0.5-1 hr 2-3 hr 5-8 hr
NPH, lente 2-4 hr 6-8 hr 6-16 hr
Ultralente 4 hr Variable 18-22 hr
Glargine (Lantus) 1-2 hr Flat, predictable 22-24 hr
NPH, isophane insulin suspension. Compiled from Barnett and Owens (1), Lepore et al (2), and White et al (3).
Basal/Bolus regimen
Basal/Bolus regimen Daily insulin dose consists of a basal insulin to inhibit
hepatic glucose production and pre-meal insulin to cover intake
• mimics natural insulin production Typically this is achieved with Lantus QHS and Novolog
(aspart) QAC. Patients on this regimen should either be given a Sliding
scale instructing them how to cover their premeal accuchecks and how to “Carb count” OR they need a standard dose of premeal insulin which you review when you see them in clinic based on their readings.
15g carbs = 1 unit of insulin Requires multiple insulin injections and accuchecks, but
provides greater flexibility in matching insulin to meal.
Treatment of Type 1 Diabetes Mellitus Pancreas Transplant with or without Kidney
transplant To help protect the transplanted kidney from
hyperglycemia Meet certain criteria, in general, frequent,
acute metabolic complications and failure with insulin therapy
Survival, immunosuppression Pancreatic islet cell transplant
Similar criteria Immunosuppression
Treatment of Type 2 Diabetes
Weight Loss, Diet, Exercise Decrease in body weight as little as 4-7% can help
increase insulin sensitivity United Kingdom Prospective Diabetes Study
(UKPDS)• < 25% treated with diet and exercise alone maintain
Hgb A1C < 7% after 3 years and < 10% after 9 years• Attributed in part to progressive loss of β-cell
secretion of insulin Supporting evidence of dual therapy with oral
agents, i.e. one agent augmenting insulin secretion, another improving insulin action
Treatment of Type 2 Diabetes
Insulin Secretagogues (“Beta-beaters”) Sulfonylurea Meglitinides
Biguanides – decrease hepatic gluconeogenesis Metformin
Thiazolidinediones – insulin sensitizer The “glitizones”
Alpha-glucosidase Inhibitors – decreased GI absorption Acarbose
Sulfonylurea First line after diet and exercise 20-25% primary failure rate Caution in hepatic/renal dysfunction Mechanism of action
Promote increased pancreatic secretion Side effects
Hypoglycemia, usually within 1st 4 months• Increased in elderly, worsening renal function, irregular meal schedules
Weight gain Medications
Glyburide (Micronase, Diabeta)• Duration of action 18-24 hours• Hypoglycemia still common
Glipizide (Glucotrol) Glimepiride (Amaryl)
• Indicated for use with insulin• “safe” in renal failure
Meglitinides (rapid acting secretogogues)
Theoretically offers improved post prandial control May benefit patients with unpredictable meal schedules or
large post prandial glucose levels Q meal dosing
Mechanism of action Similar to sulfonylureas, quicker “on-off” action
Side effects Hypoglycemia Weight gain
Medications Repaglinide (Prandin) Nataglinide (Starlix)
• Ultra short acting• Most effective agent for post-prandial control• Hypoglycemic contraindication with insulin
Biguanides Weight loss due to appetite reduction Less hypoglycemia than sulfonylurea therapy Major effects:
Increased hepatic insulin sensitivity Decreased gluconeogenesis and glycogenolysis
Side effects LACTIC ACIDOSIS GI intolerance
Mechanism of action is unclear Medication
Metformin (Glucophage)• Optimal dose 2000mg/d• BID dosing
Biguanides
Contraindications to metformin Serum creatinine >= 1.5 mg/dL in men, >=
1.4 mg/dL in women Age > 75years Discontinue before any radiologic contrast
studies (stop during or before) or upon hospitalization
Hepatic dysfunction Dehydration Metabolic acidosis CHF requiring treatment
Thiazolidinediones (TZD) Mechanism of action
Not fully understood Decrease insulin resistance, increase insulin sensitivity, probably at the
peripheral skeletal muscle ? Smaller effect on liver gluconeogenesis
Additive effect with metformin Favorable lipid profile effects, ? atherosclerosis Side effects
Weight gain Edema – caution with CHF Hypoglycemia, especially if coupled with other diabetic medication Liver dysfunction? – monitor LFTs
Medications Rosiglitizone (Avandia) - increase HDL levels Pioglitizone (Actos) - increase HDL, decrease TG levels
Contraindicated: Hepatic dysfunction Age greater than 80 Advanced CHF
Thiazolidinediones (TZD)
Monotherapy or combo with metformin, sulfonylureas, and insulin
Other effects:• Slightly reduce BP• Enhance fibrinolysis• Improve endothelial function
Alpha-glucosidase Inhibitors
Decreases digestion of complex carbohydrates in small bowel
Slows monosaccharide absorption Effective only with diets >40% carbohydrates Lowers post-prandial>pre-prandial glucose Not as efficacious as other agents (decreases A1C by
0.5% - 1%) Side effects major limitation
Gas, abdominal pain, diarrhea Minimized with slow titration
Medications Acarbose (Precose) Miglitol (Glyset)
Oral Agent Monotherapy and Glycemic Control
Drug Baseline HbA1c
Decrease in HbA1c (%)
Sulfonylurea
Glipizide XL 8.7 1.8
Glimepiride 8.1 1.9
Rapid acting secretogogue
Repaglinide 8.7 1.8
Nateglinide 8.1 0.9
Biguanide
Metformin 8.4 1.8
Alpha-glucosidase Inhibitor
Miglitol 8.9 0.74
Thiazolidinediones
Rosiglitazone 8.8 1.5
Pioglitazone 10.3 1.6
Miscellaeous
Glucovance 8.2 1.5
Combination Oral Therapy
Lowers A1C levels by about 2% No evidence that a specific
combination is any more effective in lowering glucose levels or more effective in preventing complications than another
Thus, patients with an HbA1C >9% who are receiving monotherapy are unlikely to reach a target of <7%
A 56-year-old woman who has had type 2 diabetes mellitus for 12 years is evaluated because of poorly controlled diabetes. She is obese (body mass index, 32 kg/m2). She takes glyburide, and over the past 6 months, her hemoglobin A1C level has increased from 6.8% to 8.5%, while measurements of her fasting plasma glucose have been greater than 200 mg/dL and postprandial measurements range from 250 to 350 mg/dL. She refuses to take insulin.
Which of following is the best therapy for this patient? ( A ) Discontinue glyburide and initiate metformin
( B ) Discontinue glyburide and initiate a thiazolidinedione( C ) Continue glyburide and add metformin( D ) Continue glyburide and repeat measurement of hemoglobin A1C( E ) Continue glyburide and add acarbose
Critique (Correct Answer = C)
Type 2 diabetes mellitus is a progressive disorder, and studies have documented that response to monotherapy is limited. Four options are available to obese patients who have become unresponsive to sulfonylureas: 1) add metformin, 2) add a thiazolidinedione, 3) add an α-glucosidase inhibitor, and 4) add insulin. Arguably the best treatment could be to initiate insulin at bedtime and continue the sulfonylurea.
There is no consensus about which option is most effective. Adding metformin to the regimen provides an effective agent that complements the action of sulfonylurea. Several studies document that fasting plasma glucose and hemoglobin A1C values decline with this combination of sulfonylurea and metformin in patients with body mass indexes in the range of 27 to 30 kg/m2. Maximum dosages (2000 mg) of metformin should be administered in divided doses. A trial of this combination for 6 to 8 weeks should determine its effectiveness. If hemoglobin A1C values do not fall to the 7.0% to 7.5% range, the patient should be encouraged to start insulin therapy.
A thiazolidinedione and acarbose (an α-glucosidase inhibitor) are less powerful as hypoglycemic agents than sulfonylureas and metformin, and probably would be less effective in this patient than combination therapy. The patient’s obesity indicates that insulin resistance is a likely factor in the progressive hyperglycemia, and a thiazolidinedione warrants consideration; however, if it is used, greater laboratory monitoring is required.
Oral Agent Metabolic Effects Sulfonylurea Rapid acting
secretogogues Metformin Thiazoidiniones
Insulin Resistance
0 0 Marked decrease
Marked decrease
Hyperinsulinemia 0 0 Marked decrease
Marked decrease
LDL 0 0 Small decrease
Small decrease
HDL 0 0 0 Marked increase
Triglycerides 0 0 Small decrease
Moderate decrease
LP(a) 0 0 Moderate decrease
Moderate decrease
Body weight Moderate increase
Moderate increase
Moderate decrease
Moderate increase
A 52-year-old woman is found to have a fasting plasma glucose concentration of 168 mg/dL during her annual physical examination. Her lifestyle is sedentary. Obesity has been a problem since early adulthood, and her weight in recent years has ranged from 90 to 103 kg (196 to 226 lb). Her blood pressure has been elevated for the past 18 years, and while taking captopril, it is in the 160/90 to 180/100 range. The hemoglobin A1C level is 8.4%.
After meeting with a dietitian and nurse educator, she starts a calorie-restricted diet and an exercise program; 6 weeks later, she weighs 91.8 kg (202 lb) and her hemoglobin A1C is 8.6%. Other laboratory tests include a total cholesterol of 238 mgldL and a fasting triglyceride level of 278 mgldL.
What is the best hypoglycemic agent for this patient? ( A ) Insulin
( B ) A sulfonylurea( C ) Metformin( D ) Acarbose( E ) Rosiglitazone
Critique (Correct Answer = C)
Persistent hyperglycemia and hypertriglyceridemia in an obese patient make metformin an ideal agent. The drug will facilitate weight loss and have beneficial effects on the hypertriglyceridemia. The United Kingdom Prospective Diabetes Study indicated that insulin and sulfonylureas equally lower plasma glucose but do not help weight loss or prevent weight gain. The thiazinolinediones as monotherapy also increase weight as well as possibly adversely affecting serum cholesterol levels. Although metformin as well as insulin and sulfonylureas reduce hyperglycemia and consequently lower the risk for the several microvascular complications, these agents do not significantly alter the risk for myocardial infarction.
Insulin is most effective as the first choice in symptomatic patients, especially those who are normal weight or only slightly overweight. In the setting of infection, a vascular accident, or other medical problem, the patient with recent-onset type 2 disease benefits from insulin as first treatment.
Sulfonylureas would also probably lower plasma glucose in this patient, but weight gain or inability to lower weight are possible complications. In 10% to 15% of recently diagnosed patients, sulfonylureas are ineffective as hypoglycemic agents. The exact cause of this primary failure is unclear, although beta cells exposed to hyperglycemia for prolonged periods will not respond to sulfonylureas.
Acarbose is reserved for patients with type 2 diabetes mellitus in whom postprandial hyperglycemia is the major problem. In patients with elevated fasting glucose levels, acarbose will have limited effect.
The thiazolidinediones effectively reduce fasting plasma glucose concentration. These agents increase serum LDL-and HDL cholesterol slightly and lower triglycerides by about 10-15%.
Which one of the following describes the effect of the thiazolidinediones?
( A ) Inducing weight loss effect( B ) Decreasing low-density lipoprotein cholesterol( C ) Increasing production of insulin from pancreatic beta cells( D ) Increasing glucose transporter expression
Critique (Correct Answer = D)
Resistance to the action of insulin is a prime cause of the hyperglycemia in most patients with type 2 diabetes. The thiazolidinediones are a group of drugs that improve sensitivity to insulin in several tissues by binding to PPAR-γ receptors, leading to increased expression of glucose transporters. The agent causes weight gain when used as monotherapy and in combination with insulin. Serum triglyceride values fall, whereas both LDL and HDL cholesterol values increase; the rise in LDL cholesterol in several studies is about 10% to 15%. The currently available thiazolidinediones, rosiglitazone and proglitazone, are equally effective in lowering glucose in patients with type 2 diabetes mellitus. Hemoglobin A1C levels fall about 1.5% in studies of these agents. Several cases of severe liver toxicity have been reported after troglitazone therapy, so it was removed from the market in March of 2000. The U.S. Food and Drug Administration recommends baseline and every 2 month monitoring of liver function tests during the first year of therapy if this class of drugs is used. The incidence of elevated liver enzyme levels in patients treated with proglitazone and rosiglitazone are 0.25% and 0.2% respectively, values similar to those in patients receiving placebos.
Insulin Therapy in Type II DM
Newly diagnosed patients with DM2 have < 50% of normal insulin secretion at diagnosis
< 25% of normal insulin secretion 6 years after diagnosis
Indications for Insulin Therapy in Type II DM
Why More than 30% of type 2 diabetics require insulin Progressive β-cell deterioration Addition of a qHS basal insulin can reduce the Hgb A1C level from 8.6% to 6.9
% (Yale, Annal Int Med, 2001) When
Persistent Fasting plasma glucose ≥ 250 mg/dL Hgb A1C > 8% on maximum oral therapy Hepatic or renal dysfunction that prohibits oral agents All pregnant type II diabetics
• All oral agents are contraindicated How
UKPDS showed combination therapy with insulin and oral agent had better control
No recommended combinations at this time• Metformin + sulfonylurea + insulin• Sulfonylurea + bedtime insulin• Lispro + glyburide
Not recommended: thiazolidinediones + insulin = HYPOGLYCEMIA
A 56-year-old overweight woman has had urinary frequency, nocturia, and dysuria for 5 days. She also reports increasing thirst.
On physical examination, her temperature is normal, she appears dehydrated, and has no costovertebral angle tenderness. Her plasma glucose concentration is 620 mg/dL. Urinalysis reveals 4+ glucose, no ketones, strongly positive protein, and 8 to 10 leukocytes per high-power field. Antibiotic therapy is begun for the urinary tract infection.
Which one of the following therapies is the most appropriate at this time?
( A ) Sulfonylurea( B ) Diet and exercise program( C ) Insulin( D ) Metformin( E ) α-Glucosidase inhibitor
Critique (Correct Answer = C)
The therapeutic goals in this patient are to alleviate symptoms and control hyperglycemia. When a newly diagnosed patient has symptoms, evidence of a urinary tract infection and markedly elevated plasma glucose concentration, treatment with insulin is the best assurance that symptoms will resolve and that the infection will respond readily to appropriate therapy. Hospitalization is usually not warranted unless ketoacidosis or severe dehydration and hypotension are present. Some patients will respond to oral agents, such as metformin, but that response may be slow and insufficient to alleviate symptoms. After prolonged periods of markedly elevated glucose, the response to sulfonylureas is blunted as the beta cells of the pancreas produce little or no insulin because of the glucose toxicity. After 6 to 8 weeks of good glycemic control effected by insulin, therapy may be switched to an oral agent if the patient prefers. A benefit of tight glycemic control with intensive insulin therapy in such patients is the reversal of glucose toxicity, with the improvement of both insulin sensitivity and insulin secretion. α-Glucosidase inhibitors like acarbose, reduce postprandial hyperglycemia by delaying glucose absorption, but do no affect glucose utilization or insulin secretion. They are less potent agents and therefore would not be the correct agents to use to control her hyperglycemia.
Every patient with newly diagnosed diabetes mellitus should be offered an educational program that emphasizes the importance of diet and exercise. In symptomatic patients with this severe a degree of hyperglycemia, diet and exercise are inadequate to achieve the desired goals.
DKA HONC
Glucose 300-600 600-1200
Sodium 125-135 135-145
Potassium Nml to increased Nml
Magnesium Nml Nml
Phosphate Decreased Nml
CRE Nml to slight increased Mod increased
Ketones ++++++ -----
HCO3 <15 meq/l Nml to slightly decreased
Ph 6.8-7.3 >7.3
Anion Gap Increased Nml to increased
Initial Visit
History Physical – don’t forget eye exam and
foot exam (monofilament) Labs
Fasting Chem 7, Hgb A1C (not diagnostic!!!), fasting lipids, LFTs, UA with urine microalbumin, TSH
ECG
Prevent, Monitor, Manage and Educate Diet, exercise, weight control Smoking cessation Blood pressure (strict BP goals) Lipids (remember DM = CAD equivalent) Renal function Annual eye exam Podiatric/orthopedic exam Pneumovax, influenza vaccine
Prevent, Monitor, Manage and Educate Weekly, monthly follow up Diabetic education!!!
Medication administration Blood glucose monitoring Lifestyle changes
HgbA1C q 3-6 months along with any other labs
Support groups Websites (www.diabetes.org) Your encouragement, support
Diabetic Complications Coronary Artery Disease Acute Complications
DKA, HONK Hyperglycemia, Hypoglycemia
Long Term Complications CAD Peripheral Vascular Disease Diabetic Retinopathy
• Nonproliferative, proliferative Diabetic Nephropathy Diabetic Neuropathy
• Peripheral Sensory• Cardiovascular Autonomic• Gastrointestinal Autonomic• Erectile dysfunction
Diabetic Foot• Dr. Attinger
Cardiovascular Disease
BP goal < 130/80 Lipids: LDL < 100, TG < 150, HDL > 40/50 Statins for DM patients > 40 to achieve LDL reduction of
30% regardless of baseline (Heart Protection Study) Aspirin for primary or secondary prevention Smoking cessation Cardiac stress testing
any symptoms – typical or atypical abnormal EKG h/o peripheral vascular disease Sedentary lifestyle, age > 35 and plans to exercise > 2 risk factors (dyslipidemia, HTN, smoking, FH,
micro/macroalbuminuria)
Peripheral vascular disease/Foot care
Examine feet at every visit
Check pedal pulses Check skin and
nails Vibrations sense,
monofilament exam Recommend
podiatry
Retinopathy
Optimal glycemic and BP control can substantially reduce the risk and progression of DM retinopathy
Annual screening for most Laser therapy can reduce the risk of vision
loss in patients with high risk characteristics (disc neovascularization or vitreous hemorrhage with any retinal neovascularization)
Retinopathy
Background retinopathy
Vision normal Microaneurysms Hemorrhages Exudates May see a
macular star
Pre-proliferativeRetinopathy
Cotton-wool spots Venous dilatation Large deep
hemorrhages
Diabetic maculopathy
Retinopathy in macula
Causes reduced visual accuity and blindness and requires urgent laser therapy
Proliferative retinopathy
Retinal neovascularization
Vitreous hemorrhage
Fibrosis and retinal detachment
A 41-year-old man with type 1 diabetes mellitus has a funduscopic examination during a routine office visit. The findings are seen on the funduscopic photograph. What does the funduscopic photograph on the left show?( A ) Diabetic background retinopathy( B ) Diabetic proliferative retinopathy( C ) Diabetic macular degeneration( D ) Papilledema
Nephropathy
25-30% of patients with diabetes develop nephropathy Can be prevented or delayed with tight glycemic and BP
control All pts need screening UA
If UA shows proteinuria then needs 24 hour urine protein
If UA negative check for microalbuminuria (30-299 mg/24hr) annually
• Spot albumin:Cr ratio vs. 24hr albumin measurement Albuminuria is associated with a 4-8 fold increased
cardiovascular risk If albuminuria present pt should be started on ACE
inhibitor/ARB and glycemic control should be tightened.
Neuropathies Peripheral sensory neuropathy
Symmetrical distal dysasthesias and pain Initially loose vibration sense Tx with tricyclics and gabapentin
Autonomic neuropathy Presents with orthostatic hypotension, absent
normal variation of heart rate with breathing Tachycardia and sudden death Treat orthostatic hypotension with
Fludrocortisone and Midodrine
Neuropathies II
GI autonomic neuropathies Gastroparesis
• Nausea, vomiting, bloating and GERD Diarrhea
• Especially nocturnal diarrhea Treatment: Metoclopramide (Reglan)
Erectile dysfunction > 50% of men with DM have erectile
dysfunction Typically unable to achieve both nocturnal and
morning erections (distinguishes arousal problem from vascular problem)
Treatment: Sildenafil, but avoid in pts with cardiovascular disease or on nitrates.
Neuropathies III
MononeuropathiesCan develop wrist drop (radial nerve),
foot drop (sciatic nerve) or CN III palsyProbably related to damage to
microvascular supply to nerve Diabetic Amyotrophy
Pain, atrophy and fasciculations of the limb girdle muscles.
A 70-year-old woman has developed weakness and numbness of her legs and arms during the past 8 months. The symptoms began with tingling in her feet. Later, severe weakness gradually developed. For 2 years, she has been taking oral hypoglycemic agents to treat diabetes.
On physical examination, the patient has a pulse rate of 70/min and a blood pressure of 120/85 mm Hg. She cannot rise from her chair without pushing off with her arms. She has moderately severe weakness (3/5) of the thigh and lower leg muscles. There is little movement remaining in her feet and toes (1/5). Her hands are also very weak (2/5). She has no deep tendon reflexes in her lower extremities. Vibration sensation and position sense are slightly reduced at the toes and malleoli. Pinprick and touch sensations are normal. Her toes do not move in response to plantar stimulation. Fasting plasma glucose level is 95 mg/dL; the 2-hour postprandial plasma glucose level is 125 mg/dL. HgbA1C is 5.6%.
Which of the following is the most likely diagnosis? ( A ) Spinal cord tumor
( B ) Polymyositis( C ) Hemispheric stroke( D ) Chronic inflammatory demyelinating polyneuropathy
Critique (Correct Answer = D)
This woman has chronic inflammatory demyelinating polyneuropathy predominantly affecting motor fibers, causing significant limb paralysis. The combination of greater distal than proximal muscle weakness, areflexia, and distal loss of vibration sense is characteristic of a peripheral polyneuropathy that affects mostly myelinated fibers. A muscle disease such as polymyositis would cause greater proximal than distal weakness. A spinal cord lesion would not be symmetric, and sensory loss would not be limited to vibration. A hemispheric stroke would produce unilateral signs and symptoms. The differential diagnosis is between a demyelinating polyneuropathy and a diabetic peripheral polyneuropathy.
Diabetic peripheral polyneuropathy is most often a rather mild disorder that causes some decreased sensation in the toes and feet and a loss of ankle reflexes. More severe polyneuropathies do occur, especially in long-standing diabetes, especially if diabetic control is poor. This woman had very mild diabetes that is well controlled. A rapidly progressive, severe, paralyzing polyneuropathy explained by diabetes would be extremely rare in her circumstances. Chronic inflammatory demyelinating polyneuropathy is a relatively common polyneuropathy presumed to be of an autoimmune basis in which proximal and distal weakness and areflexia are common. Usually sensory loss is limited to vibration and position sense, sensory functions mediated by large myelinated fibers within peripheral nerves. Some have thought of this disorder as a kind of chronic Guillain-Barré syndrome. The history and physical examination presented are typical of chronic inflammatory demyelinating polyneuropathy. Electrophysiologic studies will document widespread decrease in motor and sensory nerve conduction velocities indicative of a demyelinating polyneuropathy.
Summary• GLYCEMIC CONTOL (GOALS)
• Pre-prandial glucose: 80-120• 2 hour post prandial glucose: <160• Pre-bed glucose: 100-140• HbA1c <6.5 - 7%
• REVIEW REGIMEN• Insulin vs. oral hypoglycemics
• MONITORING• HbA1c • Urine microalbumin• Lipid profile LDL < 100, TG<150, HDL>50
• CLINICAL EXAM• Fundoscopy• Foot exam• Cardiac and peripheral pulses• BP <130/80
• EDUCATION• Smoking• Diet• Exercise• Consider Aspirin unless contraindication