Thursday, December 21, 2006

Nocturnal leg cramps

Cortlandt Forum has a nice short article on Nocturnal leg cramps:
By Russel Kirkby, MD, and Brian Alper, MD, MSPH

Description• Involuntary nighttime painful leg muscle contraction that does not relax

ICD-9 codes• 728.85 spasm of muscle • 729.82 cramp of limb

Prevalence• 95% of people sometime in their lives • Especially common in women and elderly
Most commonly affected muscle groups• Calf • Foot

Etiology• Most commonly no cause found• Possible causes (or associated conditions) include —Fluid and electrolyte imbalance: hypocalcemia, hyponatremia, hypomagnesemia, hypokalemia, hyperkalemia, chronic diarrhea, hemodialysis —Endocrine disease: thyroid disease, diabetes mellitus, Addison’s disease — Neuromuscular disease: nerve-root compression, motor-neuron disease, mononeuropathies, polyneuropathies, dystonias —Drugs: calcium channel blockers (nifedipine), diuretics, phenothiazines, fibrates, selective estro- gen receptor modulators (raloxifene), ethanol, morphine withdrawal —Toxins: lead, strychnine, spider bites —Congenital disease: McArdle’s disease, glycogen storage disease, autosomal dominant cramping disease —Peripheral vascular disease —Iron deficiency anemia —Liver cirrhosis, chronic alcoholism, sarcoidosis —HIV myelopathy• Pathophysiology speculative, may include reduced blood flow and oxygen supply
Likely precipitating factors• Activity excessive for condition of muscle• Sleeping prone or supine with toes fully extended • Pregnancy (insufficient calcium intake)• Older age
Complications• Insomnia • Irritability • Anxiety • Depression

Clinical evaluation• History of onset and clues to underlying condition• Drug history crucial• Local exam: arterial pulses, skin, nerves—Pulses and capillary fill (rule out vascular compromise) —Assess skin changes—Sensation/vibration
Differential diagnoses• Intermittent claudication• Peripheral neuritis• Restless legs syndrome• HIV myelopathy• Physiologic cramps due to heat, exercise, excessive activity• Electrolyte abnormalities: hyponatremia, hypokalemia, hypomagnesemia• Polycythemia• Endocrine disease: diabetes, thyroid disease, parathyroid disease, adrenal disease • Muscle diseases: glycogen storage or mitochondrial

Testing (for recurrences or underlying disease)• Electrolytes • Glucose • Blood urea nitrogen, creatinine • Calcium, magnesium, phosphate • Hemoglobin, ferritin • Zinc • Liver function tests • Thyroid function tests• HIV if appropriate• Doppler studies of arteries• Electromyelography

Nonpharmacologic management• Reassurance to exclude causes that might cause patients concern, e.g., vascular disease• Major thrust is to avoid sleep disturbance• Trial of omitting possible causative medication• Other treatments to consider—Local heat —Massage —Osteopathic manipulative therapy (OMT): myofascial release, facilitated positional release

Medications to consider• Quinine sulfate 200-400 mg nightly —Beware long-term use.—Rare but serious side effects described (disseminated intravascular coagulopathy, thrombocytopenia, pancytopenia, hemolytic uremic syndrome) —Consider monitoring complete blood count or platelets.• Other drugs similar to quinine —Hydroquinine 300 mg —Quinidine sulfate 400 mg• Other drugs not similar to quinine—Verapamil 120 mg nightly—Gabapentin (Neurontin) may reduce frequency and severity of muscle cramps.—Magnesium not clearly effective• Benzodiazepines (clonazepam, diazepam) or baclofen—Not traditionally associated with nocturnal cramp therapy but helpful in other spastic muscle conditions, e.g., tetanus, status epilepticus, and back muscle spasm —Address treatment goals of avoiding sleep disturbance.• Gastrocnemius trigger point injection of 1% lidocaine• Randomized n-of-1 trials alternating drug and placebo may determine efficacy of specific drugs for individual patients.

Prevention• Stretching exercises — e.g., nightly or twice daily • 20-minute walk may enhance stretching exercises.
See for references.
Quinine is the most commonly used treatment for this poorly understood condition; however with this medication cinchonism needs to be monitored for.

Tuesday, December 19, 2006

The Challenges of Treating Restless Legs Syndrome

The following case report appears in this month's Journal of General Internal Medicine (abstract below):
Medication Tolerance and Augmentation in Restless Legs Syndrome: The Need for Drug Class Rotation
Roger Kurlan, MD, Irene Hegeman Richard, MD, Cheryl Deeley, RNP
Restless legs syndrome (RLS) is a common condition characterized by an unpleasant urge to move the legs that usually occurs at night and may interfere with sleep. The medications used most commonly to treat RLS include dopaminergic drugs (levodopa, dopamine agonists), benzodiazepines, and narcotic analgesics. We report the cases of 2 patients with RLS who illustrate the problems of tolerance (declining response over time) and augmentation (a worsening of symptoms due to ongoing treatment) that can complicate the pharmacotherapy of RLS. We discuss the optimal management of RLS and propose strategies to overcome tolerance and augmentation such as a rotational approach among agents from different classes.

Tolerance and augmentation (see abstract above for definitions) were significant problems with Sinemet, which was previously commonly used to treat RLS. Tolerance and augmentation are less of a problem with the Requip and Mirapex, two dopamine agonists FDA approved for the treatment of RLS. However augmentation and tolerance still occur with these meds, and there is little research about the best way to deal with this vexing problem. I usually treat RLS initially with Requip or Mirapex monotherapy. If tolerance or augmentation occur, I first add another RLS agent (Neurontin, benzodiazepines, or opioids) and then later switch from 1 opioid agonist to another.

Wednesday, December 06, 2006

Mississippi Sleep Criminal

The case of John L. White, a Mississippi commercial truck driver, sounds like an accident—and now a pending law suit—that didn’t have to happen.
White of Gulfport, recently collided his vehicle into a tractor-trailer, causing the death of one man and a multiple-vehicle pile up. Sadly, White is charged with involuntary manslaughter and accused of violating sleep requirements.
The National Highway Traffic Safety Administration estimates that 100,000 police-reported crashes are the direct result of driver fatigue each year. This results in an estimated 1,550 deaths, 71,000 injuries and $12.5 billion in monetary losses. What’s more, approximately 5,600 people are killed annually in crashes involving commercial trucks. While not all of these can be attributed to sleep disorders or drowsiness, research shows that commercial drivers are at risk for everything from highway hypnosis to obstructive sleep apnea (OSA).In the case of 42-year-old trucker John White, court records say he violated commercial truck driving laws requiring at least eight hours of sleep within a certain period of time on the road. According to the Kansas City Star, White was hauling a load of bananas to a Wal-Mart distribution center when he attempted to cross over US 71 and collided with a tractor-trailer. Tragically, the driver of that vehicle, Steven B. Cousineau of Wisconsin, was pronounced dead at the scene. In addition, the crash caused two other motor vehicle wrecks, but none of the other drivers reported any injuries. The news report makes no mention of White suffering from a sleep disorder and does not clearly state that he fell asleep at the wheel. The case is focused strictly on his state of sleep deprivation while on duty. A recent study by University of Pennsylvania researchers looked at why so many commercial drivers get drowsy or fall asleep at the wheel. They concluded that the two biggest culprits are chronically insufficient sleep and obstructive sleep apnea. Of the 247 commercial drivers tested by the researchers, the percentage of drivers with two or three performance impairments after less than 5 hours of sleep was 49.5%. Clearly, there is good reason for commercial drivers to abide by sleep laws intended for their own safety and the safety of others.

Friday, December 01, 2006

Childhood sleep question

A reader e-mailed the following exam question regarding sleep disorders in children:

The Q with its alternatives is>as follows;All the following do not constitute>pathologic criteria for sleep except 1.hypnic jerk>2.increased somnolence 3.sleep myoclonus.are there any>different pathologic criteria for children other than>ICSD2.if so what are these criteria.Your reply would>be of immense help for my exams.

My answer was:
hypnic jerk is benign. Somnolence and myoclonus are pathologic.

If anyone has a better answer for this question, please post it in the comments.