Antoine Woodlyn and three other children injured in the Haiti earthquake have been transferred to A.I. Dupont Hospital in Wilmington, Delaware for definitive care of their injuries. Air travel, lodging, clothes, and other expenses were paid for by the Philadelphia Eagles professional football team.
Haiti Children Arrive at A.I. duPont Hospital After Philadelphia Eagles Pay for Transportation
February 14th, 2010Delaware Medical Relief Team Tells of Strife in Haiti with Doctors Without Borders and Plans for Return Trips
February 14th, 2010The Delaware Medical Relief Team has already sent two teams of doctors to Haiti and is planning for more medical mission trips to Jacmel, Haiti. Surgeon Randeep Kahlon and others describe the attempt of the international medical aid organization known in the US as Doctors Without Borders to order the Delaware team to vacate a hospital that they wished to use.
Lung Cancer
February 14th, 2010Pathophysiology
Squamous cell – 1) arises in central part of lung 2) derives from repeatedly injured bronchial lining 3) ulcerates into lung parenchyma 4) most common subtype that forms Pancoast tumor in apex of lung 5) metastases go to hilar and mediastinal lymph nodes, adrenals, and other sites Adenocarcinoma – 6) can arise anywhere but typically distal 7) most common tumor in nonsmokers Large cell – 8) poorly differentiated and can occur anywhere in lung Small cell – 9) fast-growing with early metastases 10) presents usually as perihilar mass 11) most common subtype causing paraneoplastic syndromes
Signs and Symptoms
1) dyspnea 2) cough 3) chest pain 4) hemoptysis 5) obstructive pneumonia 6) lobar collapse 7) pleural effusions 8) weight loss
Characteristic Test Findings
Laboratory – 1) hypercalcemia (squamous cell) 2) ectopic ACTH production (small cell) Radiology – 3) large opaque mass on chest radiograph (usual test of diagnosis)
Histology/Gross Pathology
main histologic subtypes are small cell and non-small cell (squamous, adenocarcinoma and its subtype bronchoalveolar, and large cell)
Associated Conditions
Squamous cell – 1) Pancoast’s tumor 2) Horner’s syndrome 3) superior vena cava syndrome 4) hypercalcemia Small cell – 5) diabetes insipidus 6) Cushing’s syndrome 7) Eaton-Lambert syndrome
Biochemistry
1) k-ras mutations (non-small cell) 2) myc mutations (small cell) 3) p53 and retinoblastoma (RB) mutations (both small cell and non-small cell)
Inheritance/Epidemiology
1) most common cause of cancer death in both men and women in USA 2) peak age of presentation is 60-70 years
Treatment
1) small cell – chemotherapy (very responsive but palliative only) 2) non-small cell resection – resection for cure, if possible, with chemoradiation 3) superior vena caval syndrome – urgent radiation to shrink tumor and decompress venous drainage
Tips for USMLE
1) adenocarcinoma can occur in nonsmokers 2) if a 69 year-old man who has smoked two packs of cigarettes for 50 years has noticed a worsening of his chronic cough, new onset blood-streaked sputum and a 20 pound weight loss over the past two months, think lung cancer
Anorexia Nervosa
February 14th, 2010
Pathophysiology
severe disturbance of caloric intake with refusal to maintain an adequate body weight
Signs and Symptoms
1) self-starvation and over concern with body weight and shape 2) binge eating and purging 3) weight < 85% of normal 4) fear that weight will get out of control with even small caloric intake 5) distorted body image (patients see themselves as fat even when emaciated) 6) lack of menses 7) acrocyanosis of digits 8) cold intolerance 9) hypothermia 10) self-induced vomiting 11) decreased cardiac output 12) cardiac failure 13) bradycardia 14) enlarged salivary glands 15) dental erosion 16) edema 17) lanugo (soft downy hair on body) 18) onset usually in mid to late adolescence
Characteristic Test Findings
Laboratory – 1) hypoglycemia 2) decreased estrogen 3) increased T4 (thyroxine) 4) increased cortisol 5) hypokalemia 6) hypochloremia 7) alkalosis 8) anemia 9) leukopenia 10) increased transaminases Radiology – 11) decreased bone density on nuclear medicine scan
Associated Conditions
1) bulimia 2) physical and/or sexual abuse 3) family history of substance abuse
Inheritance/Epidemiology
1) 10 times more common in females than males 2) occurs in cultures where food is plentiful and thinness is attractive 3) occurs in female professions where thinness is prized (models, ballet dancers) 4) affects 0.5% of female population in USA 5) prognosis is poor” only 25-50% make complete recovery 6) 20% fatality rate
Treatment
1) intensive counseling to correct cognitive distortions around eating 2) psychotherapy for underlying emotional issues
Tips for USMLE
anorexics often have idiosyncratic behavior concerning food (collecting cookbooks, working in the food industry)
Wernicke’s Syndrome
February 14th, 2010
Pathophysiology
1) caused by thiamine deficiency (vitamin B1) 2) usually (but not always) seen in chronic alcoholism
Signs and Symptoms
1) progressive ataxia 2) polyneuropathy 3) impaired ocular motility/nystagmus/lateral rectus palsy 4) mental confusion 5) tachycardia 6) hypotension 7) Charcot’s triad – ophthalmoplegia, ataxia, confusion
Characteristic Test Findings
Laboratory – 1) decreased serum thiamine 2) abnormal erythrocyte transketolase activity
Histology/Gross Pathology
1) petechiae in mamillary bodies, hypothalamus, and periaqueductal gray matter 2) necrosis of nerve cells 3) “ring” hemorrhages in brain
Associated Conditions
1) occurs in patients with – chronic alcoholism, hyperemesis, starvation, renaly dialysis, cancer, HIV 2) increased incidence of – cardiomyopathy, high-output cardiac failure
Treatment
1) considered a medical emergency, and thiamine must be given in first few days of symptoms before condition becomes irreversible 2) parenteral thiamine (50mg) for the first several days and then by mouth until symptoms resolve
Biochemistry
glutamate accumulates in the brauin owing to malfunctioning alpha ketoglutarate dehydrogenase activity
Inheritance/Epidemiology
may be a genetic predisposition owing to a variant type of transketolase (thiamine is a cofactor for this enzyme)
Tips for USMLE
1) Wernicke’s syndrome and Wernicke-Korsakoff syndrome are different clinical syndromes 2) Wernicke-Korsakoff (or Korsakoff psychosis) is impaired memory (often with confabulation) seen in chronic alcoholism, neuronal loss in the medial-dorsal nucleus 3) glucose given before thiamine can unmask subclinical Wernicke’s so thiamine is always given to chronic alcoholics before IV containing glucose 4) there are two different Charcot’s triads – ophthalmoplegia, ataxia, and mental confusion in Wernicke’s and pain, fever, and jaundice in cholangitis
Viral Encephalitis
February 14th, 2010
Pathophysiology
1) infection and inflammation of brain parenchyma 2) sometimes occurs with meningeal and spinal cord involvement
Signs and Symptoms
1) high fever 2) headache (often severe) 3) stiff neck 4) mental status changes (from lethargy to confusion/delirium/hallucinations to coma) 5) seizures 6) focal neurological deficits – ataxia, aphasia, hemiparesis, ocular palsies
Characteristic Test Findings
Lumbar puncture – 1) CSF findings – identical to viral meningitis: increased lymphoctyes, normal glucose (except in mumps, which is decreased), and normal or slightly elevated protein 2) diagnosis is by CSF PCR
Histology/Gross Pathology
1) inflammatory exudate with lymphoctyic infiltration of small arteries and veins 2) hemorrhage 3) in herpes simplex 1, temporal lobes are more often affected 4) in Epstein-Barr cases, atypical lymphocytes are found in brain parenchyma
Associated Conditions
1) herpes simplex type 1 2) varicella 3) enteroviruses 4) mumps 5) arboviruses – easter equine, western equine, Venezuelan, California viruses 6) west Nile virus
Inheritance/Epidemiology
20,000 cases/year in USA
Treatment
1) acyclovir empirically until herpes simplex virus type 1 is ruled out 2) ganciclovir and foscarnet in CMV 3) ribavirin in California (LaCrosse) virus 4) prophylactic antiseizure medications 5) fluid restriction
Tips for USMLE
1) eastern equine virus is usally the most severe 2) mumps is unusual among viral encephalitis because glucose is decreased instead of normal 3) neurologic findings are usually more dramatic and acute than in bacterial causes
Retinoblastoma
February 13th, 2010
Pathophysiology
1) neoplasm originating in retinal neurons 2) malignant spread is either via the optic nerve into the cranial vault or via the blood system (hematogenously) 3) able to grow toward vitreous body (endophytic) or between retinal layers (exophytic)
Signs and Symptoms
1) white pupil reflex (leukocoria) 2) red and painful eye 3) squinting 4) vision loss 5) detached retina 6) cat’s eye reflex (yellowish glint in eye)
Characteristic Test Findings
Funduscopic exam – 1) mass 2) detached retina
Histology/Gross Pathology
1) whitish tumor mass with chalk-like flecks (calcification) 2) morphologically can have Flexner-Wintersteiner rosettes (radial cells around central cavity) or a fleur-de-lis pattern
Associated Conditions
1) secondary glaucoma in affected eye 2) metastasizes to bone marrow 3) inherited form – increase incidence in Ewing’s sarcoma, pinealoblastoma, and osteogenic sarcoma
Inheritance/Epidemiology
1) occurs in 1: 20,000 to 1:34,000 2) presents at birth or in first 2 years of life 3) most cases sporadic, but 6-8% familial 4) bilateral 30% of time in familial disease 5) cause is defect in retinoblastoma tumor suppressor gene on 13q14
Treatment
if treated early with enucleation, survival rate is 90%
Tips for USMLE
if a 2 year old girl has been squinting for the past 2 weeks and then starts rubbing a reddish left eye that has a milky tint to the pupil, think retinoblastoma
Neuroblastoma
February 13th, 2010
Pathophysiology
1) malignant tumor of neural crest origin, from adrenal medulla or sympathetic ganglia 2) 33% of tumors occur in adrenals, 33% in abdomen, 20% in posterior mediastinum 3) metastasizes to regional lymph nodes, lungs, bone, liver, eye
Signs and Symptoms
1) common presenting sign is an enlarging abdominal mass with calcification 2) ascites from liver metastases 3) pain and irritability from bone metastases 4) respiratory distress from lung compression 5) gait and sphincter problems
Characteristic Test Findings
Laboratory – 1) increased urinary catecholamines – norepinephrine, VMA, HVA, dopamine 2) increased secretion of VIP
Histology/Gross Pathology
1) differentiating neuroblasts (small, round, blue cells) 2) mature ganglion cells (more mature tumors have higher proportion of ganglion cells) 3) rosettes and pseudorosettes (Homer-Wright rosettes)
Associated Conditions
1) deletions on chromosome 1 (1p35-36) 2) duplications on chromosome 2 3) affected gene is N-myc (which can be amplified, depending on differentiation
Inheritance/Epidemiology
1) mostly sporadic inheritance 2) 10% of childhood cancers 3) usually occurs before age 3 years 4) best prognosis – presents < age 2 years, extra-adrenal location, highly differentiated, VMA/HVA > 1, TRK gene expression
Treatment
1) if isolated mass, surgical resection 2) if metastatic, chemotherapy/radiation
Tips for USMLE
1) if question mentions a 2 month-old child with a large abdominal mass (with calcification on radiograph) that suddenly shrinks, think neuroblastoma 2) neuroblastomas “cross the midline,” whereas Wilms’s tumors do not
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Meningioma
February 13th, 2010
Pathophysiology
1) tumor of arachnoid cells of meninges 2) usually attached to dura 3) may invade skull but rarely invades brain tissue 4) found most commonly along dorsal surface of spinal cord, along sagittal sinus, over cerebral convexities, and at the cerebellar-pontine angle
Signs and Symptoms
1) occasionally, is asymptomatic and found incidentally 2) symptoms are generally caused by mass effect 3) focal seizures 4) focal neurologic findings 5) increased intracranial pressure 6) loss of smell (if located in frontal lobes) 7) visual defects of optic neuropathy in one eye and hemianopia in the other if located anterior to chiasm
Characteristic Test Findings
Radiology – 1) well-circumscribed, intensely contrast-enhancing lesion on CT and MRI 2) “dural tail” of contrast streak may be seen on CT scan 3) commonly associated with hyperostosis of skull
Histology/Gross Pathology
1) arises from meningothelial cells of arachnoid 2) most tumors are in intimate contact with dura 3) well-circumscribed tumors with whorls of spindle cells and psammoma bodies
Associated Conditions
neurofibromatosis types 1 and 2
Inheritance/Epidemiology
1) second most common primary brain neoplasm after astrocytoma 2) uncommon in children 3) rarely can be overtly malignant
Treatment
1) resection for cure, if possible 2) if not easily approached surgically, local external beam radiation, or gamma-knife radiation is used 3) if small and asymptomatic in an elderly patient, it can be observed with serial CT scans, as tumors are very slow growing
Tips for USMLE
if brain tumor appears to be attached to the dura, think meningioma
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Bipolar Disease
February 13th, 2010
Pathophysiology
1) psychiatric disorder marked by unpredictable swings in mood from mania to depression 2) variants exist where there are repeated manic episodes without the intervening depressive episodes and vice versa 3) rapid cycling variant – four or more episodes of mania or depression per year
Signs and Symptoms
Manic phase – 1) increased psychomotor activity 2) decreased need for sleep 3) excessive social extroversion 4) impulsive actions 5) irritability 6) grandiose delusions 7) paranoia Depressive phase – 8) loss of interest in life or surroundings 9) decreased libido 10) significant weight gain or loss 11) feelings of fatigue and tiredness 12) sleep disturbances 13) feelings of hopelessness and intense sadness
Characteristic Test Findings
Radiology – abnormally high incidence of subcortical white matter abnormalities
Associated Conditions
1) strong genetic predisposition (30% concordance rate in monozygotic twins) 2) altered circadian rhythms
Biochemistry
exact underlying biology is unknown but may involve alterations in glutamate regulation
Inheritance/Epidemiology
1) affects 3 million people in USA 2) occurs roughly equally in men and women, but men have more manic episodes and women have more depressive episodes 3) age of onset is most common in late teens to age 30 4) prognosis is mixed, with 50% of patients unable to function normally in work and psychosocial roles even with treatment
Treatment
1) lithium and valproate are mainstays of treatment 2) common adjunctive drugs – carbamazepine and lamotrigine 3) antidepressants – used if depressive phase is severe but should not be started in maintenance phase, as they may precipitate a manic breakthrough
Tips for USMLE
if a 23 year old man returns home from graduate school and excitedly tells his family that he is quitting school because he has founded a company that he is sure will revolutionize the computer industry and he is so confident of his success that he has purchased (on credit) a Mercedes Benz and 500 bottles of expensive wine, think bipolar disease
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