Tuesday, February 26, 2013

ADHD - Making the Diagnosis

We need to proceed to accurately describe the two major barriers obstructing our path from chief complaint of school and behavioral problems to valid diagnosis and effective treatment.
     The first barrier to diagnosis is the pitiful lack of hard scientific evidence.  There are currently no specific physical findings or laboratory tests that we can use to help us diagnosis any behavioral problem such as ADHD, depression, anxiety or obsessive compulsive disorder.  Our vaunted medical problem-solving system that should flow from history, physical and lab test to correct diagnosis fails us miserably.  This not to say that a complete physical examination including a neurological assessment should not be performed on every child with school problems.  Certainly there may be specific labs that we may want to obtain if the physical examination suggests disorders such as anemia, lead poisoning, hyperthyroidism or fetal alcohol syndrome, Such causes of “acquired” ADHD are for the most part very rare.  Medical research is daily adding to our knowledge concerning the genetics, neuroanatomy and physiology (structure and function of the brain) associated with ADHD.  Although it is encouraging and enlightening to discover evidence supporting the existence of a brain-based disorder, none of them separately or together can be used as a gold standard for the official stamp of approval for diagnosing ADHD.  The bad news for us all is that there is no test for ADHD.
     What to do?  Actually this is a dilemma that occurs more often in medicine than physicians would like to admit.  Life and death treatment decisions must sometimes be based on our best guesses at underlying causes when there is limited supportive physical or laboratory evidence.  Asthma, for example, is not diagnosed by any specific test or sign but rather on the history that the parent and child describe.  Our confidence in our diagnosis is increased if we are able to add findings of audible wheezes heard while listening to the lungs and flattened diaphragms or hyperinflated lungs seen on chest X ray films.  We fare better in the case of the strep throat because current technology provides a rapid, reliable test for the presence of the bacteria.   Not too long ago, however, we had to wait 24 to 48 hours for our bacterial colonies on the throat swab to grow on blood agar plates incubated at 100 degrees and show a zone of growth inhibition around the bacitracin discs to prove the presence of beta-hemolytic Group A strep.  Despite these limitations we were able to immediately correctly diagnose and treat patients for strep in the “old days”. We simply had to work harder.  Without the weight of the positive strep test to confirm the diagnosis we had to gather more information to tip the balance one way or the other.  We were forced to expand our history, increase our physical findings and augment our laboratory tests to be as certain as we could be before risking definitive treatment.
     The conscientious physician would ask a lot more questions after “Does your throat hurt?”.  For instance “Do you have a headache or stomach ache? (common with strep).  How about cold symptoms or cough? (rarely associated with strep). Have you ever had an illness like this before?  Do you know what strep feels like? Have there been strep infections in your class recently?  Has anyone else been ill at home? In the same way we would look for more positive evidence from our physical examination.  We would not simply note the red throat, but we would look more closely for white or yellow exudates on the tonsils, tiny red spots or petechial rash on the roof of the mouth or a strawberry appearance on the surface of the tongue, We would palpate the neck at the angle of the jaw for the presence of enlarged and tender lymph nodes.  We would check the abdomen to see if the liver and spleen were enlarged – signs more compatible with mononucleosis.  A severely ill child with strep-associated complication of rheumatic fever might have warm swollen joints, subcutaneous nodules on the arms, unusual choreioform movements of the extremities and a heart murmur.  And although we did not have the new rapid strep test , we could order stat some more general tests that are often positive in patients with bacterial infections such as a complete blood cell count (CBC) with differential white cell percentages, erythrocyte sedimentation rates or C-reactive protein levels. 
      None of these findings prove that strep is present and causing the illness but the weight of the evidence improves the odds in our favor.  Lawyers use this strategy of building a case when they defend their client or prosecute a defendant.  This painstaking process done in partnership with families is the only sure way to develop enough data to tip the diagnostic balance in our favor and lead us to effective therapy and successful future follow-up care.  We will use this approach to navigate around the two major barriers or roadblocks on our journey to solve our children’s school and behavioral problems. Those barriers of uncertainty and complexity will next on our agenda.

Tuesday, February 5, 2013


Obviously starting with the correct diagnosis is critical for our medical-problem solving system to work. If I think you have a strep throat but you really have diabetes, we are both in a lot of trouble. Doctors understand here is always some degree of uncertainty in every patient. The only physician who knows the diagnosis without a doubt is the pathologist at the autopsy—absolutely sure about everything but way too late to help. In real life we need to come up with a way to reduce the uncertainty of the diagnosis of ADHD and school problems right now.
Physicians use evidence from the history, physical and lab test to build a case for the most likely diagnosis. If you say that your throat hurts, your tonsils are big and red, and your throat culture is positive, the probability that you have a strep throat is high. You will be given a prescription for penicillin with instructions to call back tomorrow to check for improvement or side effects. Our working diagnosis is like a three-legged stool that securely rests on history, physical and lab results. The problem with behavioral diagnoses such as ADHD is that there are no positive physical findings or test. There should be because we know that ADHD is more strongly inherited even than height. Research evidence is accumulating towards specific ADHD genetic patterns, MRI findings and neurotransmitter brain levels that someday will help us nail the diagnosis—but not yet.
Before we give up and throw away our shaky one-legged diagnosis stool, we need to consider how we might strength it. If we could expand the history to form a rock-solid post, it might be able to hold a circus elephant. The diagnosis of ADHD requires a complete history from the child or adolescent, the parent as well as the teacher. Specific behavior patterns need to be looked for and then compared to same-age children using standardized questionnaires.

It is possible to make the diagnosis of ADHD and start safe, effective educational, behavioral, and medical treatment. Parents can do this. Next up, dealing with complexity.