Category Archives: Primary Care

Neuro report! – approach to myopathy

Thank you to Christy for presenting an outpatient case of a patient with progressive proximal>distal lower extremity weakness concerning for myopathy and Kevin Keenan for acting as our neurology consultant.
UpToDate had the best review article I could find on a general approach to myopathies. Here’s a synthesis of that + Kevin’s teaching today.
Weakness framework 2.0
Step 1: distinguish asthenia from true weakness
Step 2: Weakness is best characterized by localization and pattern
localization
  • brain
  • “electrical” (migraine or seizure)
  • spinal cord
  • CSF (like a meningitis)
  • anterior horn cell
  • peripheral nerve
  • neuromuscular junction
  • myopathy
pattern
  • progressive
  • monophasic
  • static
  • relapsing/remiting
  • improving
Myopathy ddx
  • When i hear the word “myopathy” my first instinct is to think about inflammatory causes. Other etiologies are much more common
Common
drug-induced
  • statins, alcohol, stimulants
endocrine
  • cushings
  • hypothyroid
  • vitamin D deficiency
uncommon
inflammatory
  • primary myositis (dermatomyositis, polymyositis, inclusion body myositis)
  • scleroderma
  • SLE
  • overlap syndromes
metabolic
  • glycogen storage disorders etc
  • suspect these when patients report pigmenturia with exertion or other stress
muscular dystrophies
malignant
  • paraneoplastic
First pass workup
  • An awesome neuro exam
    • pay careful attention to respiratory muscle weakness and cranial neuropathies, as these may signal a more emergent condition
  • serum: CBC, chem 10, CK (can also consider LDH and AST if your suspicion is high), ANA, TSH, Vitamin D, hepatitis serologies
    • if very suspicious for an inflammatory myopathy, consider SSA/SSB, anti-SM, anti-RNP, anti Jo-1.
  • Urine: UA to look for myoglobinuria
  • What about an EMG/Nerve conduction study?
    • In patients with true myopathy without an obvious reversible cause (like statins) EMG/NCS is necessary to confirm the diagnosis and should be ordered early in the diagnostic workup.
Bonus pearls
  • Grip strength: Kevin told us to abandon grip strength in our screening motor exam. It is selective preserved in UMN weakness and very hard to grade objectively. When doing a screening motor exam, try pronator drift + one distal muscle group (like wrist extension) + one proximal muscle group (like deltoids)
Evernote:

5.4.16 – VA Ambulatory Report Pearls – Cardiac manifestations of apls

Common Cardiac Manifestations of APLS

  1. Valvular disease
  2. Coronary artery disease
  3. Intracardiac thrombus formation
  4. Pulmonary hypertension
  5. Dilated cardiomyopathy

More details on some of the most common cardiac manifestations listed above:

  • Valvular disease: deposition of immune complexes –> vegetations/irregular thickening of the valve leaflets –> valve dysfunction
    • Leads to increased risk for CVA
    • Note that 40% of APLS patients also have SLE and thus valvular disease can be secondary to SLE versus APLS
    • The most commonly affected valve is the mitral valve (MR) >> aortic and tricuspid valves which is thought to be due to the fact that left-sided valves are more vulnerable to micro injuries from stress/jet/turbulence
    • There is a positive correlation between APLS titers and severity of valvular heart disease
  • Coronary artery disease: patients with APLS are at risk of accelerated atherosclerosis
  • Intracardiac thrombus formation: rare complication
    • Thrombus is most likely to form on the right side
    • A quick word on other thrombogenic complications (e.g., recurrent DVTs) – of patients who present with thrombosis, up to 85% will present with venous > arterial thrombosis and repeat episodes are often of the same type
    • Thrombotic events, unlike intracardiac thrombus formation, are common and occur frequently in microvasculature or smaller vessels and are often recurrent and can impair myocardial function via recurrent microthromboses or microemboli

Reference (article attached here):

Koniari I, Siminelakis SN, Baikoussis NG, Papadopoulos G, Goudevenos J, Apostolakis E. Antiphospholipid syndrome; its implication in cardiovascular diseases: a review. Journal of Cardiothoracic Surgery. 2010;5:101. doi:10.1186/1749-8090-5-101.

VA Report Pearls: Microcytic Anemia!

Pearl 1: A good way to think (and teach) about microcytic anemia is to consider the ways in which microcytosis occurs. RBCs become microcytic due to a lack of hemoglobin, which can result from:

  • Lack of iron (iron deficiency, anemia of chronic inflammation)
  • Defects in heme synthesis (sideroblastic anemias)
  • Defects in the production of hemoglobin protein (thalassemias and hemoglobinopathies)

Pearl 2: Remember that in thalassemia (unlike iron deficiency and anemia of chronic inflammation), the RBC count may be normal or elevated, since the bone marrow is making large numbers of small cells. 

See the attached review article from the NEJM for more on microcytic anemia!

Microcytic Anemia_NEJM

Evernote Link

4.13.16 – VA Ambulatory report pearls – premature heart disease

  • Epidemiology: autopsy study of 760 young patients that investigated the presence of coronary atheromas in patients stratified by age
    • Advanced coronary atheroma in 2% of men and 0% of women aged 15-19yo
    • Advanced coronary atheroma in 20% of men and 8% of women aged 30-34yo; of those with advanced coronary atheroma 19% of men and 8% of women had a > 40% stenosis of the LAD
  • How does coronary disease differ in younger patients versus older patients?
    • One of the largest reports of angiographic findings in young patients is from a substudy of the Coronary Artery Surgery Study (CASS) which compared the results of angiography in 504 young men < 35yo and young women < 45yo as compared to 8300 older patients.
    • Younger patients were more likely to have the following:
      • Grossly normal coronary arteries on angiography (18% of younger patients versus 3% of older patients)
      • Single vessel disease (38% of younger patients vs 24% of older patients)
      • Predilection for LAD
  • Differential for ACS in younger patients:
    • Embolization (from PFO)
    • Substance use especially cocaine or other stimulants
    • Clotting disorders and hypercoagulable states (e.g., Factor V Leiden, APLS, nephrotic syndrome)
    • H/o Kawasaki disease as child (coronary aneurysms –> stenosis)
    • Spontaneous coronary dissection (more common in young women; increased risk during peripartum period)
    • H/o chest radiation (ostial disease most common)
    • OCP use + heavy smoking in young women
    • Psychosocial factors/exposure to chronic stressful situations
    • Hypoestrogenemia (ACS may be more common during follicular phase of the menstrual cycle when estrogen levels are lowest)
    • Myocardial bridging which is a congenital anomaly where the coronaries can be embedded into the myocardium
  • Risk factors for premature CAD
    • Smoking – most common and most modifiable
    • Family history
    • Lipid abnormalities
    • DM
    • HTN
    • Obesity
    • Paradoxical embolism
    • OCP use + heavy smoking

VA Report: Carbamazepine, HLA-B*1502, and SJS/TEN!

Pearl:
1) There is a strong association between the presence of HLA-B1502 and carbamazepine-induced SJS/TEN in Han-Chinese, Thai, and Malaysian populations.  

2) The FDA has recommended screening patients of Asian ancestry for the HLA-B1502 allele before starting carbamazepine.

3) Overall, carbamazepine is the most common cause of SJS-TEN!

Tangamornsuksan et al. Relationship between the HLA-B*1502 allele and carbamazepine-induced Stevens-Johnson Syndrome and toxic epidermal necrolysis. JAMA Dermatology. 2013;149(9):1025-1032.

 

Also, take a look at this figure for a great DDx of short-lasting headaches!

Short lasting HAMatharu MS, Goadsby PJ. Trigeminal autonomic cephalgias. J Neurol Neurosurg Psychiatry. 2002;72(Suppl II):ii19-ii26.

Evernote Link!

 

3.21.16 – VA Ambulatory Report Pearls – Reticular Rashes and Cold AIHA

Reticular Rashes

We discussed the differential for various reticular rashes and in particular mentioned livedo reticularis and erythema ab igne. There are two great clinical images (attached) – one from NEJM and one from JGIM – to check out.

(1) Livedo Reticularis (clinical image is in the setting of cold agglutinins)

  • Reticulated network with red-blue or violaceous hue
  • Localized or widespread
  • Patchy
  • Results from compromise of blood flow in medium sized vessels
  • Can be secondary to vasospasm, vasculitis, hypercoagulable states, thrombosis, increased blood viscosity, or embolic phenomena.

(2) Erythema Ab Igne (clinical image is in the setting of cannabinoid hyperemesis)

  • Reticulated network with erythematous pigmentation
  • Can occur at any site on body
  • Typically asymmetrical
  • Usually asymptomatic
  • Skin changes usually clear spontaneously in several weeks to months after removal of heat source from skin, however, longstanding lesions/exposures can lead to permanent hyperpigmentation
  • Results from repeated exposures to moderate heat (e.g., laptop users who hold computer on thighs, repeated use of warm compresses/heating pads/heated car seats) or infrared radiation

Cold Agglutinin AIHA

  • Results from antibodies that interact with red cells at temperature below the core body temperature
  • Symptoms
    • Anemia (35%)
    • Acrocyanosis (24%)
    • Fatigue (21%)
    • Weakness or dyspnea on exertion (7%)
    • Hemoglobinuria (3%)
    • Skin changes include livedo reticularis and urticaria
  • Almost always IgM antibodies (versus IgG)
  • Coombs testing results = positive for C3, negative for IgG
  • Produced in response to infection (e.g., Mycoplasma pneumonia, infectious mononucleosis, influenza) or by paraneoplastic or neoplastic growth
  • Treatment
    • Avoidance of exposure to cold
    • If severe symptoms, treatment may include rituximab +/- fludarabine

3.16.16 – VA Ambulatory Report Pearls – The Power of Vitamin C

The History of Scurvy

LT enlightened us this morning on the history of scurvy. To recap, James Lind (1716-1794) was born in Edinburgh,Scotland and became a surgeon in the British Royal Navy. He served in the Mediterranean on the HMS Salisbury and it was there that he conducted the first ever clinical trial and developed the theory that citrus fruits were a treatment for scurvy. He documented this in a book titled, “A Treatise of the Scurvy,” which “contains an inquiry in the nature, causes and cure, of that disease.”

You can read Lind’s ground-breaking clinical trial here: http://www.jameslindlibrary.org/lind-j-1753/

A Brief Word on Scurvy

Sources:

Main sources of vitamin C include citrus fruits, tomatoes, potatoes, brussel sprouts, cauliflower, broccoli, strawberries, cabbage, and spinach.

Function of vitamin C:

Ascorbic acid is crucial for collagen synthesis and deficiency results in impaired wound healing, defective tooth formation, and deficient osteoblast and fibroblast function.

Diagnosis:

Onset of symptoms is usually 3 months after deficient intake. Diagnosis of vitamin C deficiency (or scurvy) is made clinically based on the following symptoms:

  1. Perifollicular hemorrhage with petechiae and coiled hairs
    1. Note: the skin lesions are typically in dependent areas (e.g, lower extremities) and can coalesce and become palpable; they can mimic systemic vasculitis findings
  2. Ecchymoses
  3. Gingivitis with bleeding and receding gums and dental caries
  4. Impaired wound healing
  5. Arthralgias secondary to hemorrhage into the muscles or periosteium
  6. Edema
  7. Anemia
  8. Generalized systemic symptoms include weakness, malaise, anorexia, depression, neuropathy, and vasomotor instability

Scurvy occurs mostly in severely malnourished individuals, patients with h/o illicit drug use or heavy alcohol use, or those with food insecurity and in the elderly can be due to simply poor dietary intake.

Should I check a vitamin C level?

Yes and no. Be wary that recent vitamin C bolus can normalize plasma ascorbic acid concentrations even when the tissue levels are still deficient. You can measure ascorbic acid levels in leukocytes, which is a better measurement of body stores, but the test is not widely available.

Treatment:

A wide range of replacement doses have been used successfully. Adults are usually treated with 300-1000mg daily for one month.

Many of the constitutional symptoms improve within 24 hours of treatment! Bruising and gingival bleeding resolve within a few weeks!

Vitamin C Deficiency in Patients on Warfarin

We discussed the importance of recognizing vitamin deficiencies in patients taking warfarin. The rationale behind this is that many of the vitamin K rich foods that patients are advised to avoid can also be critical sources of vitamin C. There is a great clinical vignette on this in JGIM and is attached here.