Polycythemia

Polycythemia

Primary polycythemia/ Polycythemia vera

  • a.k.a polycythemia rubra vera; erythremia
  • common in age 60 – 75
  • overproduction of all three hematopoietic cell lines with predominant elevation in red cell counts
  • mutation in the JAK2 protein which regulates marrow production
  • red cells grow wildly despite a Low erythropoietin level
  • high serum leukocyte alkaline phosphate
features:
  • Headache, blurred vision, and tinnitus
  • pruritus, especially after hot bath (due to histamine release from increased numbers of basophils)
  • HTN, facial plethora, fatigue, Splenomegaly
  • Bleeding from engorged blood vessels
  • Thrombosis from hyperviscosity
Investigation,
  • elevated Hct >60%*
  • low MCV and Low iron (because of excessive usage and production)
  • however, Vit. B12 levels are elevated for unclear reason
  • exclude hypoxia first; normal Oxygen level and *low erythropoietin level in PV
* RCC also has elevated Hct, but the erythropoietin is elevated.
* A small number of patients can convert to AML.
Tx
  • initial 1st line – Phlebotomy and aspirin prevent thrombosis – target Hct 45%
  • Hydroxyurea helps lower the cell count
    • indicated in old age >70 years; has thrombosis; has a platelet count >1500; and has cardiovascular risk factors
  • Allopurinol or rasburicase protects against uric acid rise
  • Antihistamines
  • Interferon alpha may be used in refractory cases
Platelet counts elevate temporarily after spleen removal

Secondary polycythemia
Increased erythropoietin level
2° to chronic tissue hypoxia
 

Kidney cancer is an important differential diagnosis of secondary polycythemia.

Renal Cell Carcinoma is a neoplastic condition that can initially appear with many different paraneoplastic manifestations.

The initial presentation may include hypertension, flank mass, gross or microscopic hematuria, hypercalcemia, fever, weight loss, and/or polycythemia.

Polycythemia may be the presenting sign in 3% of cases of kidney cancer.

Careful evaluation is important in patients presenting with polycythemia and hematuria.

Polycythemia is secondary to a hypersecretion of tumor cytokines, including renin.

The patient’s erythropoietin level is usually high.

Surgical removal of the cancer resolves the polycythemia.

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Poisoning with Alcohol and Related Substances

Poisoning with Alcohol and Related Substances

Methanol and Ethylene glycol poisoning

1) Methanol can cause retina injury leading to blindness ( eye manifestations can happen as early as 15-20 hours post ingestion) ?  secondary to the accumulation of formic acid/ formaldehyde;

That’s why the first thing you do in suspected methanol poisoning is …

to check retinal inflammation

Methanol can be found in wood solvent, sterno, paint thinner, photocopier fluid, and cleaning solutions such as windshield washer solution

2) Ethylene glycol (coolant, anti-freeze) poisoning
toxic metabolite is Oxalic acid/ oxalate >> damage kidneys
usually has 3 distinct clinical phases-

  1. first stage- CNS effects ( first 12 hours),
  2. second stage- cardiopulmonary effects ( HTN, CCF, ARDS etc) metabolic acidosis with high anion gap and high osmolar gap and
  3. third stage- renal effects- ARF.

Tip to memorize: You see? going from top to bottom in order –  CNS -> CVS -> Renal

Initial Dx – check hypocalcemia, envelope-shaped oxalate crystals in urine

Mx

Acute management include gastric lavage and correct the metabolic acidosis.
fomepizole, an inhibitor of alcohol dehydrogenase, is now used first-line in preference to ethanol, however it cannot remove toxic substance formed already.


Haemodialysis can be done for effective and faster removal of the toxic metabolites.

Folinic acid can be used to protect against ocular toxicity of methanol whereas thiamine are administered to drive metabolism of ethlylene glycol to non-toxic metabolism.

Isopropyl alcohol ingestion and toxicity may be known only by the history, presentation with normal anion gap acidosis and specific drug level.

Alcohol

Mild withdrawal:
  • tremors, tachycardia, and anxiety;
  • Seizures may occur 6-12 hrs after the last drink
Delirium tremens (DT):
  • manifests 48-72 hrs after the last drink but can last up to 10 days
  • Mental confusion
  • autonomic hyperactivity
  • visual hallucinations
  • severe agitation
  • diaphoresis
Alcoholic hallucinosis:
  • may be confused with DT
  • starts 12-24 hours after last drink but can last days to weeks
  • Paranoid psychosis without tremors and confusion
  • Normal vital signs (no HTN and tachycardia)
  • No agitation
  • Normal appearance except for auditory (most common), visual, or tactile hallucinations
Wernicke encephalopathy:
  • Confusion, ataxia, and ophthalmoplegia (nystagmus)
Korsakoff psychosis:
  • Amnesia and confabulations
*alcohol withdrawal has a very high mortality rate (5%)
Tx
Benzodiazepines
avoid antipsychotics/neuroleptics such as haloperidol (due to risk of lower seizure threshould and prolonged QT interval)

Food Poisoning from Fish/Seafood

Food Poisoning from Fish/Seafood
Scombroid food poisoning
results from eating spoiled (decayed) fish — most commonly reported with mackerel, tuna , bluefish, mahi-mahi , bonito, sardines , anchovies , and related species of fish that were inadequately refrigerated or preserved after being caught.
most rapid onset; allergic symptoms — wheezing, flushing, rash; in severe cases – resp distress, blurred vision, tongue swelling
Tx: antihistamines (eg, DPH)
 
Ciguatera
is the most common nonbacterial foodborne illness caused by eating certain reef fish whose flesh is contaminated with toxins originally produced by dinoflagellates such as Gambierdiscus toxicus which live in tropical and subtropical waters.
Most commonly implicated fish are barracuda, red snapper, and grouper
Onset within 2-6 hours;
S/S – Neurological symptoms – paresthesias, numbness, weakness, reversal of heat and cold as well as nausea, vomiting, and abdominal cramps
Saxitoxin is the toxin found in shellfish that ingest particular dinoflagellates
The toxin affects neuronal transmission leading to symptoms of cranial nerve dysfunction and muscle weakness — high risk for respiratory failure
Tetrodotoxin is the toxin expressed by the puffer fish, a fish considered to be a delicacy in some eastern Asian countries
S/S-  perioral numbness, increasing neurologic dysfunction, and eventual respiratory arrest secondary to profound muscle weakness