further diabetic complications

[Guest guest]

Diagnosis and Management of Type 2 Diabetes, 10th Edition, Ch 15, Pt 5

Long-Term Complications and Treatments

Diagnosis_and_Management_of_Type_2_DiabetesSteve V. Edelman, MD

R. Henry, MD

Microvascular Complications (cont'd)

Gastroparesis

This neuropathy should be suspected in patients with nausea, vomiting, early

satiety, abdominal distention, and bloating following a meal, and is

secondary to delayed emptying and retention of gastric contents. The delay

in gastric emptying usually is asymptomatic, although glycemic control can

be affected. Postprandial hypoglycemia and delayed hyperglycemia develop

when the balance between exogenous insulin administration and nutrient

absorption is disrupted because of gastric stasis. Therefore, gastroparesis

should be considered even in the absence of GI symptoms in a patient who

suddenly develops unexplainable poor glycemic control after having had

satisfactory control....

Advertisement

Primary treatment is focused on optimizing glucose control with insulin:

secondary treatment involves dietary modifications in the form of a low-fat,

low-residue diet. When patients remain symptomatic despite these measures,

treatment with the following prokinetic agents is recommended:

* Erythromycin lactobionate 1.5 to 3.0 mg/kg body weight intravenously

every 6 to 8 hours (acute treatment, effective in eliminating residue from

stomach); common side effects are nausea and vomiting.

* Oral treatment with cisapride (only obtained by special request

because of cardiac side effects), 10 to 20 mg before meals and at bedtime

(enhances gastric emptying through serotoninergic mechanisms, effective in

acute conditions); minimal side effects (abdominal cramping, frequent bowel

movements); long-term use may cause hyper prolactinemia, galactorrhea,

menstrual irregularities.

* Oral metoclopramide HCl is generally used with caution because of

adverse reactions (nervousness, anxiety, dystonic effects, and the potential

for irreversible tardive dyskinesia).

* Oral treatment with domperidone, a peripheral dopamine antagonist

(FDA approval pending),10 to 20 mg 3 to 4 times daily (accelerates gastric

emptying); minimal side effects (abdominal cramping, frequent bowel

movements) and rare adverse reactions (hyperprolactinemia, galactorrhea).

Diabetic Diarrhea

Intermittent diarrhea may alternate with constipation and can be difficult

to treat. Diabetic diarrhea is a diagnosis of exclusion. High-fiber intake

can be helpful, along with diphenoxylate (Lomotil), loperamide (Imodium), or

clonidine. Small-intestine stasis contributes to bacterial overgrowth,

causing diarrhea. Treatment with one of the following antibiotics for 10 to

14 days is recommended:

* Doxycycline hyclate, 100 mg every 12 hours

* Amoxicillin trihydrate, 250 mg every 6 hours

* Metronidazole, 250 mg every 6 hours

* Ciprofloxacin HCl, 250 mg every 12 hours.

A trial of pancreatic enzymes is also recommended to rule out exocrine

pancreatic insufficiency. In many instances, tincture of opium is the only

medication that can help the patient live a nearly normal daily life.

Neurogenic Bladder

Frequent small voidings and incontinence that may progress to urinary

retention characterize this neuropathy. Confirmation of this diagnosis

requires demonstration of cystometric abnormalities and large residual urine

volume. Most medical treatment is inadequate, although scheduling frequent

voidings every 3 to 4 hours combined with bethanechol 10 to 50 mg 3 to 4

times daily supplemented by small doses of phenoxybenzamine may be helpful.

Surgical intervention may be necessary if patients do not respond to

pharmacologic therapy because chronic urinary retention can lead to UTI.

Impaired Cardiovascular Reflexes

Orthostatic hypotension and fixed tachycardia are the most disturbing and

disabling autonomic symptoms. Typical treatment of orthostatic hypotension

includes elevating the head of the bed, compression stockings for lower

limbs and torso, supplementary salt intake, and the use of fludrocortisone

(0.05 mg initially with gradual increases of 0.1 mg up to 0.5 to 1 mg). This

pharmacologic therapy should be used cautiously in patients with cardiac

disease because it causes sodium and water retention and may precipitate

CHF.

Sexual Dysfunction

Erectile dysfunction, or impotence, is defined as the consistent inability

of a man to attain or keep an erection for satisfactory sexual intercourse.

It is a couples' disorder, as both patient and partner suffer. Diabetic

impotence is usually caused by circulatory and nervous system abnormalities

and is a very common complaint in the male diabetic population. The classic

clinical picture includes a patient with normal sexual desire but the

inability to physically act on that desire. If a patient says that he has

morning erections, he can masturbate without problems, or his libido is

abnormally low, look for other causes of impotence such as psychological

problems or a low androgen state. Orgasm and ejaculation are usually normal.

Even if the patient does not have any psychological problems that could

cause the impotence, he may develop a secondary psychological fear of

failure that could complicate the clinical picture. A woman may experience

lack of lubrication and painful intercourse.

The diagnosis can be made in most cases by a good sexual, psychosocial, and

medical history, a physical examination, and laboratory tests. A

testosterone level should be drawn to rule out a low androgen state, which

is rarely a cause for impotence.

Hyperprolactinemia is also an uncommon cause of impotence. Hemochromatosis

is a condition that is underdiagnosed and is associated with impotence and

glucose intolerance. Serum iron stores, including ferritin levels, are

abnormally high in this disorder. If the patient has femoral bruits and/or

peripheral occlusive disease, a vascular workup may help identify the cause

of impotence.

It is important to be sure the patient is not taking any medications that

can cause impotence such as â-blockers and thiazide diuretics. ACE

inhibitors, ARBs, CCBs, and á-blockers do not generally cause impotence.

Despite the prevalence of this disorder, nearly all patients can be

successfully treated with either nonsurgical or surgical means. Yohimbine

HCl, a 2-adrenergic blocking agent, has been widely used as a nonhormonal

medication for the treatment of impotence. However, there has been a

consistent lack of data to show that it is more effective than placebo.

Testosterone given by injection or via a scrotal or skin patch is only

indicated when the serum testosterone levels are low on several occasions.

If there might be binding protein abnormalities, a free testosterone level

is indicated. As mentioned above, a low testosterone state is rarely a cause

of impotence.

Until the late 1990s, there were no truly effective oral medications for

erectile dysfunction (ED). Since then, the convenience and outcomes of the

treatment of ED have improved considerably as a result of the availability

of the class of drugs called phosphodiesterase-type 5 (PDE-5) inhibitors,

which include sildenafil (Viagra), vardenafil (Levitra), and tadalafil

(Cialis). All improve erectile function in the same basic way, by

inactivating cyclic GMP thereby resulting in an increase in nitric oxide

levels leading to relaxation of the vessels that supply blood to the

erectile tissue in the penis. The PDE-5 inhibitors do not automatically

trigger erections; sexual stimulation also is needed to start the process.

Many clinical trials have shown sildenafil, vardenafil, and tadalafil

improve erectile function regardless of the underlying cause or causes

including diabetes. Although all of these PDE-5 inhibitors increase the

number and quality of erections and sexual experiences in men with diabetes,

they have slightly different chemical structures that affect how quickly

they work and how quickly they wear off (Table 15.10). Which drug may be

best for an individual patient is not known since there have been no studies

that compared these medications.

TABLE 15.10 - Dosing of Phosphodiesterase-5 Inhibitors

Edelman15Tab10

The side effects of the PDE-5 inhibitors include headaches, lightheadedness,

dizziness, flushing, distorted vision, dyspepsia, syncope, and MI. Men at

highest risk for syncope are those taking nitrates. They may also have

adverse effects in individuals with hypertrophic cardiomyopathy because of a

decrease in preload and afterload, which can increase the outflow

obstruction, culminating in an unstable hemodynamic state. In 1999, the

American College of Cardiology and the AHA published recommendations for the

use of sildenafil, which would also apply to vardenafil and tadalafil. The

document reiterates caution with respect to the use of sildenafil in the

following situations:

* Patients with active coronary ischemia who are not taking nitrates

* CHF and borderline blood pressure or low volume status

* Complicated, multidrug, antihypertensive regimen

* Patients taking drugs that prolong the half-life by blocking enzyme

CYP3A4 (e.g., erythromycin, cimetidine).

Vacuum constrictor devices are a viable therapeutic option for diabetic

patients with impotence. No surgery or injections are required, patient

acceptance is excellent, and there are few side effects. The majority of

these external penile devices have a vacuum chamber that goes over the

penis, a vacuum pump that creates negative pressure within the chamber

allowing for engorgement of the penis with blood, and a constrictor band

that is placed over the base of the penis when tumescence is achieved. Side

effects are minor and include ecchymoses, hematomas, and pain. These devices

are effective in men with both total and partial impotence. Many patients

discover that they do not need the device after a brief period of time,

which indicates that a fear of failure or other psychological problems were

the initial cause of impotence.

Intracavernosal injection of vasoactive agents such as papaverine or

prostaglandins can be self administered and work by relaxing corporal smooth

muscle. Intracavernosal injections will work best in patients with diabetic

impotence whose arterial inflow and corporal veno-occlusion mechanism are

normal. Side effects include the formation of painless fibrotic nodules

within the corpora cavernosa and priapism. Titration guidelines should be

followed when initiating therapy. Despite the route of administration,

patient acceptance is also good. The Medical Urethral System for Erection

(MUSE) is also available.

Penile prostheses represent an excellent surgical option for the treatment

of impotence. The options range from simple malleable or semirigid

prostheses to inflatable devices that use hydraulic principles to inflate

and deflate the penis when desired. Surgical complications are very low,

especially when the patient's glycemic control has been acceptable prior to

surgery. With the availability of oral medications, intracavernosal

injections, and vacuum devices, surgery is chosen less often.

Diabetic Foot Disorders

More than half of all nontraumatic amputations in the United States occur in

individuals with diabetes, and the majority of these could have been

prevented with proper foot care. Efforts aimed at prevention, early

detection, and treatment of diabetic foot disorders can have a significant

impact on the incidence of these problems.

Detection and Treatment

The physician and patient must diligently examine the patient's feet on a

regular basis for signs of redness or trauma, especially if neuropathy is

present. Lack of pain, position, and vibratory sensations caused by

neuropathy, associated deformities, and vascular ischemia can facilitate the

development of foot lesions. Foot pressure that is abnormally distributed

predisposes a neuropathic patient to pressure ischemia and skin breakdown.

Autonomic neuropathy causes decreased sweating and dry skin that can result

in cracked, thickened skin that is susceptible to infection and ulceration.

Pressure perception can be assessed using the Semmes Weinstein (SW)

monofilaments, which are available in three thicknesses: 1-g fiber (SW 4.17

rating), 10-g fiber (SW 5.07 rating), and 75-g fiber (SW 6.10 rating). The

following evaluation procedure has been recommended:

Place the monofilament against the skin and apply pressure to different

areas of the bottom of the foot until the filament buckles. The patient

should be able to feel the monofilament when it buckles and identify the

location being tested. The 5.07-thickness monofilament, which is equivalent

to 10-g of linear pressure, detects the presence or absence of protective

sensation and is useful for identifying a foot at risk for ulceration and in

need of special care.

Daily inspection of feet can help detect early skin lesions, and proper

footwear can minimize the development of foot problems. Patients should be

taught to cut toenails straight across, not trim calluses themselves,

regularly wash their feet with warm water and mild soap, and avoid going

barefoot or wearing constricting shoes. Minor wounds that are not infected

can be treated with mild antiseptic solution, daily dressing changes, and

foot rest.

Podiatrists should be consulted for assistance with more serious foot

problems and for regular nail and callus care in high-risk individuals. If

an ulcer develops, the skin must be debrided and the pressure alleviated;

infections should be treated promptly with medications appropriate for the

offending organism. Healing is facilitated by bed rest with foot elevation

and the use of an orthopedic walking cast to relieve pressure but allow

mobility. IV antibiotics, surgical debridement, distal arterial

revascularization, and local foot-sparing surgery may help prevent

amputation in cases of seriously infected foot ulcers.

You can purchase this text