UMEM Educational Pearls

GOUT part 1

Gout is an inflammatory arthritis that classically affects the first metatarsal phalangeal joint

Gout prefers cool ambient temperature hence gouty tophi prefer the great toe (one of the coldest parts of the body) and avoids "warmer" joints such as the hip and shoulder.

Remember that gout can affect other joints as well (elbow, wrist, knee and ankle) and  can cause painful bursitis and tendonitis

Multiple joints can be involved simultaneously (leading to confusing with RA and OA)

The involved joint will often be red, hot, swollen and very painful leading to easy confusion with cellulitis and or a septic arthritis

Diagnose gout by demonstrating monosodium urate crystals in the synovial fluid.

**Remember previous pearl by Dr. Bond regarding the coexistence of gout with septic joint**

Serum uric acid levels are commonly elevated but can be normal or even low

Use caution with this test because asymptomatic hyperuricemia is much more common than gout

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• seborrheic dermatitis is most common in infants within the first two months of birth
• appears as  erythematous, greasy yellow scales most commonly on the scalp (cradle cap), and may also occur on the face
• most cases resolve spontaneously within weeks to months, but severe cases may be treated with 1% hydrocortisone cream, sahmpooing with selenium sulfide, and using an emollient to remove scales
• in extreme cases, consider hte possibility of Langerhans cell histicytosis, especially if atrophy, ulceration, or purpura are also present
• rarely occurs in children between 1 and 12 as they do not have active sebaceous glands, but will appear as dandruff in adolesecents
   

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Note that yesterday's Neurology pearl should have read as follows -

Amongst others, diagnostic criteria for NMS includes:

Exposure to a dopamine ANTAGONIST (NOT AGONIST) or dopamine agonist withdrawal within past 72 hours.

Apologies for the type-o.

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Could this be another risk factor for DVT/PE. Maybe not yet but it is worth mention. A recent observatioal study in BMJ showed that there was  an associated increase with DVT or PE. From a database of 25,532 patients over a 3 year period of time and finding match controls, the results were:

1. 32% overall increase risk of DVT/PE in patient who were taking antipsychotics
2. Recent initiation of therapy within 3 months increased risk 2-fold
3. Risk was greater with atypical antipsychotics (Odds Ratio 1.73 Atypical vs 1.23 Old)
4. Risk was greater with lower dose than higher dose

Limitations were this is was an observational study with missing data. BMI was missing in these records and it is always difficult to tease out the multiple medications these patients are on.  Also don't have a great biological mechanism (yet). Still makes you go hmm....

Antipsychotic drugs and risk of venous thromboembolism, Parker, BMJ, 2010.

• Neuroleptic Malignant Syndrome (NMS) is a life-threatening complication of anti-psychotic medication therapy.
   
• While NMS is rare (0.02 to 2.44% amongst those taking neuroleptic drugs), its associated mortality (up to 12%) and morbidity (i.e. rhabdomyolysis, pneumonia, seizures, renal failure, disseminated intravascular coagulation (DIC), respiratory failure) are severe.
   
• Historically, there has been little consensus about universally accepted diagnostic criteria for NMS, until an expert panel of various physician specialists recently convened and determined the following criteria:

           - Exposure to dopamine agonist or dopamine agonist withdrawal within past 72 hours
           - Hyperthermia
           - Rigidity
           - Mental status alteration
           - Elevated creatinine phosphokinase
           - Sympathetic nervous system lability (2 or more of the following: elevated blood pressure, fluctant blood pressure, urinary incontinence, diaphoresis)
           - Tachycardia and tachypnea
           - Negative work-up for infectious, metabolic, neurologic, or toxic etiologies.

• Treatment includes immediate withdrawal of any antipsychotic medication and is, otherwise, largely supportive.

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Aspiration Pneumonitis and Pneumonia

• Aspiration of low pH gastric fluid or food matter is common in critically ill patients and often underdiagnosed.
• Patients with aspiration initially develop a pneumonitis that, in some, can be complicated by bacterial pneumonia.  Up to 33% develop severe ALI/ARDS, with an associated 30% mortality rate.
• Aspiration pneumonitis presents with hypoxia and a CXR demonstrating infiltrates in the dependent portion of the lungs.  Often, the degree of respiratory distress is worse than the CXR appearance.
• Since it is challenging to differentiate aspiration pneumonia from aspiration pneumonitis, current recommendations suggest initiating empiric antibiotics with agents that have adequate Gram-negative coverage.  Routine coverage against anaerobic bacteria is not currently recommended, except in patients with severe periodontal disease and those with a lung abscess on CXR or CT.
• Despite the initial inflammatory response, steroids are not indicated for patients with aspiration.

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Rib fractures are associated with significant morbidity and mortality in the elderly, and the risk increases dramatically with each successive rib fractured. An elderly patient with 3 rib fractures has a mortality of 20% and risk of pneumonia is 31%. As a general rule, you should really think twice about discharging home any elderly patients with rib fractures.

[credit to Dr. Joe Martinez for bringing forth this information]

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Talar Neck Fractures

Have a high rate of avascular necrosis (AVN), nonunion, and arthritis.  Almost all require ORIF

• Hawkins 1:
  • 0- 13% AVN rate
  • non-displaced fracture
• Hawkins 2:
  • 20- 50% AVN rate
  • Displaced fracture with subluxation or dislocation of the posterior facet of the subtler joint. Subtalar joint usually dislocated posteriory
• Hawkins 3:
  • 20-100% AVN rate
  • Displaced fracture of the talar neck with dislocation of the body of the talus from both the subtalar joint and the ankle joint

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Most have converted from succinylcholine to rocuronium for their choice of paralytic in RSI. Succinylcholine-induced hyperkalemia secondary to muscle fasciculations is considered usually clinically insignificant though there may be a hyperkalemic renal patient that this may tip them over. The fasciculations also may worsen traumatic long bone fractures.  Here is the argument in a head to head comparison:

Duration = injection of drug to 25% recovery of single twitch height (clinically relevant recovery in ED - essentially breathing may return)

Recovery Index = time from 25% to 75% recovery of single twitch height

The main reason succinylcholine was utilized was because of its fast onset and short duration. Rocuronium is comparable enough to succinylcholine in these characteristics tilting the overall benefits to rocuronium. If the FDA ever approves it, suggamadex is a possible reversal agent for rocuronium - currently used in Europe. Imagine having that in your RSI kit.
 

• Given the common need to treat conditions such as Clostridium difficile colitis, refractory bacterial vaginosis/trichomoniasis, and bacteremia/sepsis with prolonged courses of metronidazole, the astute clinician should be mindful of metronidazole-induced neuropathy as the possible etiology of numbness, tingling, and parasthesias in patients taking this medication.
• This is a rare, but serious side effect which is dose and duration dependent; doses of 1000 mg to 2400 mg for at least 30 days duration is typically required to cause neuropathy.
• The lower extremities are most commonly affected.
• In suspected cases, use of metronidazole should immediately be stopped; sometimes symptoms never completely resolve even after cessation of use, particularly in cases of prolonged oral therapy.

Many changes in pulmonary physiology occur during pregnancy. These changes are generally well tolerated but can become problematic when pathologic states arise.

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Question

65 yo female with breast cancer presents with dyspnea and CXR shown below. Diagnosis? Can anything help clarify the diagnosis? 

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Elderly patients are prone to hypovolemia for the following two major reasons:
1. They have a decreased thirst response.
2. They have decreased renal vasopressin response to hypovolemia.

The result is that elderly patients have an impaired ability to compensate for a decreased cardiac output, which causes them to develop shock earlier and more easily with stressor.

Takeaway point: Always assume that most elderly patients are hypovolemic, and when they are stressed, give them fluids early!
 

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Cubital Tunnel Syndrome aka Radial Tunnel Syndrome

• The most common neuropathy of the elbow
• Entrapment of the ulnar nerve as it passes posterior to the medial epicondyle of the elbow
• HX: medial elbow and forearm pain occasionally associated with ulnar digit paresthesias.
• May be due to trauma, degenerative changes or throwing sports.
• PE:  Pain with elbow flexion. Tenderness to palpation over the cubital tunnel. Positive Tinnel's sign.
• **Up to a quarter of normal asymptomatic patients will have a positive Tinnel's**
• DDx: Ulnar collateral ligament strain/tear and medial epicondylitis
• Tx: Ice, NSAIDs, activity modification, night splints with elbow in 45 degrees flexion and finally surgical decompression or nerve transposition    

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Several medications/chemicals can cause unique toxicologic reactions in pediatric patients.

• Ethanol: hypoglycemia.  Reported with ethanol levels as low as 20 mg/dL.
• Clonidine and imidazolines: central nervous system effects.  Agents such as tetrahydrozoline, oxymetazoline, naphazoline, and clonidine can cause CNS depression, respiratory depression, bradycardia, miosis, and hypotension.
• Benzyl alcohol: gasping syndrome.  Preservative which has been removed from most medications and IV flush solutions used in neonates.  Syndrome includes severe metabolic acidosis, encephalopathy, respiratory depression, and gasping.
• Chloramphenicol: gray baby syndrome.  Broad-spectrum antibiotic not used frequently in U.S.  Syndrome includes abdominal distension, vomiting, metabolic acidosis, progressive pallid cyanosis, irregular respirations, hypothermia, hypotension, and vasomotor collapse.

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The onset of idiopathic seizures typically affects patients between ages 5 and 20. 

Therefore, be highly suspicious of a diagnosable etiology in patients who present with new onset seizure prior to age 5 or after age 20.

Common causes of such seizures include:

• Tumors or other structural brain lesions (i.e. intracranial hemorrhage)
• Traumatic brain injury
• Abrupt cessation of alcohol abuse
• Dementia ( i.e. Alzheimer's disease)
• Congenital brain defects
• Intra-partum brain injury
• Hypoglycemia or hyponatremia
• Renal or hepatic insufficiency
• Cocaine or amphetamine illicit drug use
• Abrupt cessation of benzodiazepines, barbiturates, analgesics (i.e. morphine, gabapentin), or sleeping pills
• Infection (i.e. brain abscess, meningitis, encephalitis, neurosyphilis, AIDS)
• Phenylketonuria (PKU) in infants

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The Severely Hypoxemic ED Patient

• Most define hypoxemia as a P_aO₂ < 60 mm Hg.
• Perhaps a better definition of hypoxemia is a P_aO₂ that is associated with continued tissue hypoxia (rising lactate, low S_cvO₂), the need for vasopressor medications, or severe metabolic acidosis.
• For ED patients that remain hypoxemic despite increased F_iO₂ and high levels of PEEP, consider the following rescue therapies:
  • Recruitment maneuvers - brief periods of high PEEP (35-50 cm H₂O) or pressure-controlled breaths to reopen collapsed alveoli
  • High-frequency oscillatory ventilation - employs a high airway pressure to recruit closed alveolar segments
  • Prone positioning - believed to improve oxygenation through a redistribution of ventilation and perfusion
  • Extracorporeal membrane oxygenation

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Adverse drug effects are a major issue in geriatrics.
Elderly patients take, on average, 5 prescription medications + 2 over-the-counter medications.
Adverse drug effects account for approximately 5% of all hospital admissions.
Nearly 20% of patients brought to the ED for psychiatric complaints have symptoms that are primarily caused by medication effects.

Be very wary whenever prescribing ANY new medications for even a short time to elderly patients.

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Sulfamethoxazole (SMX)/trimethoprim (TMP) is the treatment of choice for PCP pneumonia. The IV formulation has been unavailable for almost a year due to shortage. It is contraindicated in patients with sulfa allergy. Here are the alternatives with adverse effects. You'll quickly see why pentamidine should generally be reserved for those with sulfa allergy and G6PD deficiency.

Mild-to-moderate disease:

1. Primaquine 15-30 mg PO PLUS Clindamycin 600 mg IV or 300-450 mg PO
2. Dapsone 100 mg PO PLUS TMP 5 mg/kg PO
3. Atovaquone suspension 750 mg PO

Moderate-to-severe disease:

1. Primaquine 15-30 mg PO PLUS Clindamycin 600 mg IV or 300-450 mg PO
2. Pentamidine 4 mg/kg IV

Adverse Effects:

• Primaquine: Rash, fever, methemoglobinemia, hemolytic anemia (check for G6PD deficiency)
• Clindamycin: Rash, diarrhea, Clostridium difficile colitis, abdominal pain
• Dapsone: Rash, fever, gastrointestinal upset, methemoglobinemia, hemolytic anemia (check for G6PD deficiency)
• TMP: Rash, gastrointestinal distress, transaminase elevation, neutropenia
• Atovaquone: Rash, fever, transaminase elevation
• Pentamidine: Nephrotoxicity, hyperkalemia, hypoglycemia, hypotension, pancreatitis, dysrhythmias, transaminase elevation

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Now that influenza season is in full swing, remember that early antiviral treatment can reduce the risk of complications in high-risk individuals. One of those high-risk groups is children <2 years, with the highest hospitalizations and mortality in infants <6 months.

According to the CDC website:
Recommended antiviral medications (neuraminidase inhibitors) are not FDA-approved for treatment of children aged <1 year (oseltamivir) or those aged <7 years (zanamivir). Oseltamivir was used for treatment of 2009 pandemic influenza A (H1N1) virus infection in children aged <1 year under an Emergency Use Authorization, which expired on June 23, 2010. Nevertheless,

•  3-11 months => Treatment: 3 mg/kg/dose BID, Chemoprophylaxis: 3 mg/kg/dose once daily
•  infants <3 months => Treatment: 3 mg/kg/dose BID, Chemoprophylaxis: not recommended
• newborns <14 days => 3 mg/kg/dose once daily
• treatment doses for children >1 year of age varies by weight:

•  <15 kg: 30 mg BID
• 15-23 kg: 45 mg BID
• 23-40 kg: 60 mg BID
• >40 kg: 75 mg BID

Current CDC guidance on treatment of influenza should be consulted; updated recommendations from CDC are available at http://www.cdc.gov/flu

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