Causes of Daytime Sleepiness

1. Medications (sedatives, tranquilizers, anticonvulsants,antihistaminics, anti depressants, Beta blockers,dopamine agonists, L-dopa, alcohol abuse)

2. Acute medical illness of mononucleosis type, including mundane respiratory and gastrointestinal infections

3. Post-surgical, post-concussive and post-anesthetic states

4. Chronic neurologic diseases- MS, Dementias

5. Depression

6. Metabolic derangements - hypothyroidism, Addison`s disease, severe diabetes

7. Encephalitic disease - Post Viral encephalitis, Trypanosomiasis, Encephalitis lethargica (historical)

8. Lesions of hypothalamus - Kleine - Levin syndrome, Hypothalamic tumor or granuloma

9. Sleep apnea syndrome : Central and Obstructive

10. Narcolepsy - cataplexy

11. Idiopathic hypersomnia

(From : Adams and Victor)

Phenytoin metabolism

As serum concentration of phenytoin rises, particularly above 15mg/l, the metabolism slows substantially. This is called 'zero order kinetics'. At levels below 15 mg/l, doubling the dose will lead to doubling of serum concentration and the half life is 24 hrs. As metabolism slows at higher concentrations, even a 50 mg change in dose can double the serum concentration, and the half life increases to 48-70 hrs.Since the half life is so prolonged, a steady state after dose adjustments may not occur for weeks, with serum levels slowly rising over this time. This can easily lead to serious phenytoin toxicity.

Ref : Therapeutic Strategies in Epilepsy ( French and Delanty)

Understanding neuromuscular disorders.

coming soon.......

Primary Progressive Aphasia

Primary progressive aphasia (PPA) involves changes in the ability to communicate—to use language to speak, read, write, and understand what others are saying. Problems with memory, reasoning, and judgment are not apparent at first but can develop over time. In addition, some people with PPA may experience significant behavioral changes, similar to those seen in bvFTD, as the disease progresses. As symptoms get worse, people with PPA cannot live alone safely.

Currently, there are three types of PPA, categorized by the kind of language problems seen at first.

In semantic PPA, also called semantic dementia, a person slowly loses the ability to understand single words and sometimes to recognize the faces of familiar people and common objects.

In agrammatic PPA, also called progressive nonfluent aphasia, a person has trouble saying words that link nouns and verbs together—for example, "of," "from," and "for." Eventually, the person may no longer be able to speak at all. He or she may also have difficulty swallowing and develop movement symptoms similar to those seen in corticobasal syndrome.

In logopenic PPA, a person has trouble finding the right words during conversation but can understand words and sentences. The person does not have problems with grammar.

Behavioral Problems in Dementia.

This is a good paper which discusses behavioral problems related with dementia and their management.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC181170/

Clinical Manifestations of the Serotonin Syndrome

Cognitive and behavioral features:
confusion/disorientation, agitation/irritability, coma/unresponsiveness, anxiety,
hallucinations (visual and auditory)
Autonomic features:
hyperthermia, diaphoresis, sinus tachycardia, hypertension, dilated pupils, nausea,
flushing
Neuromuscular:
myoclonus (legs especially), hyperreflexia, muscle rigidity, restlessness/hyperactivity,
tremor, ataxia, extensor plantar responses

Clinical Features of Neuroleptic Malignant Syndrome

Administration of neuroleptics (especially high-potency conventional agents)
Hyperthermia >38.0C
Muscle rigidity (may have cogwheel rigidity)
Tremor, myoclonus
Stupor, mutism, delirium
Autonomic instability – tachycardia, labile BP
Tachypnea, dyspnea
Sweating, sialorrhea, incontinent
Dysarthria, dysphagia
Raised CPK & WCC, metabolic acidosis, hypoxia, low serum iron, raised
catecholamines, theta or delta waves on EEG
Complications: rhabdomyolysis, ARF, aspiration pneumonia, pulmonary embolus,
cardiac arrest, DIC, limb contractures, ischemic brain injury
Exclude other central or systemic or toxic causes of hyperthermia