Page 215 Guide to Pain Management in Low-Resource Settings

Management of Pain in HIV/AIDS 203

consider surgical placement of a ventriculoperitoneal or Name all the contributory factors of the
lumbar-peritoneal shunt if increased pressure persists. peripheral neuropathy!
HIV itself, possible vitamin B defi ciencies, and isoniazid
Which analgesics are contraindicated for use
with raised intracranial pressure? prophylaxis or treatment.
Morphine sulfate, pethidine (meperidine). Which NRTI agents should be avoided,
if possible, in such a case?
Case report 6 (“peripheral Stavudine and didanosine, as both can cause peripher-
neuropathy”) al neuropathy with long-term use owing to mitochon-
drial toxicity.
A young woman, 23 years old, is referred to the antiret-
roviral (ARV) clinic with a recent positive HIV-ELISA Which nutritional defi ciencies can cause
peripheral neuropathy?
6
test and absolute CD4 of 19 × 10 /L. She is ARV-naive.
She complains of a burning sensation on the soles of both Vitamin B (Th iamine), vitamin B , vitamin B , vitamin B .
1
12
6
3
feet. Positive fi ndings on examination include marked
Why did the neuropathy progress to grade 2?
muscle wasting, malnourishment, a weight of 50 kg, pal-
lor, a right-sided 5-cm supraclavicular lymphadenopa- Th e initial presenting neuropathy was most likely sec-
thy, and a grade 1 sensorimotor peripheral neuropa- ondary to HIV. Th e pain was exacerbated by the addi-
thy. Of note in the blood results is HIV-1 viral load by tion of isoniazid, a component of TB treatment and a
branched DNA, 238,810 copies/mL, and normocytic cause of peripheral neuropathy via vitamin B (pyridox-
6
normochromic anemia. Chest X-ray reveals hilar ad- ine) depletion. Peripheral neuropathy has also been re-
enopathy. A fi ne needle aspirate is undertaken of the ported as a side eff ect of cotrimoxazole (used in higher
lymph node and is consistent with TB. She is commenced doses for treatment and lower doses in prophylaxis of
on cotrimoxazole prophylaxis, TB treatment, pyridoxine Pneumocystis jirovecii pneumonia treatment).
25 mg daily, and vitamin B complex.
What drug used to treat peripheral neuropathy
Ten days after starting TB treatment, she calls
may be unsuitable for this patient?
the doctor at 3 am to complain of worsening foot pain,
and is advised to present herself to the clinic at 8 am Carbamazepine may be unsuitable because it induces
that day. She does so, in a wheelchair and wearing slip- the metabolism of efavirenz and nevirapine via the cyto-
pers, and complains that she cannot bear to walk on her chrome P450 3A4 system.
own because of the pain in her feet, so she sleeps all day.
At the consultation, the causes and course of her periph- Remember the WHO analgesic
eral neuropathy, now grade 2 sensory and grade 3 mo- ladder for pain management
tor, are explained to her. Amitryptiline 25 mg at night,
ibuprofen and paracetamol, are started, and pyridoxine Step 1: MILD PAIN
dosage is increased to 50 mg daily. Vitamin B and fo- Paracetamol (acetaminophen), nonsteroidal anti-in-
12
late levels are normal, and iron studies suggest anemia fl ammatory drugs) (NSAIDS) (and adjuvants if needed)
of chronic disorders. Adjuvants include (if there is neuropathic pain): tri-
Th ree days later she calls the doctor at 1 am cyclic antidepressants (TCAs), anticonvulsants, steroids
and complains of the nonresolution of her foot pain. She Step 2: MILD TO MODERATE PAIN
is asked once more to come in, and is assessed again as Mild-acting opioids + step 1 nonopioids (and adju-
having grade 2 peripheral neuropathy. Pyridoxine is in- vants if needed)
creased to 75 mg daily, amitryptiline to 50 mg at night, Mild-acting opioids: codeine, dihydrocodeine, dex-
and a highly active antiretroviral therapy (HAART) regi- tropropoxyphene
men of nucleoside analog reverse transcriptase inhibitors Step 3: MODERATE TO SEVERE PAIN
(NRTIs) and non-nucleoside reverse transcriptase inhibi- Stronger opioids + Step 1 nonopioids (and adjuvants
tors (NNRTIs) is started. After 3 months, the neuropathy if needed)
regresses to grade 1, and after 6 months the neuropathy Stronger opioids: morphine, diamorphine, fentanyl,
has resolved completely. hydromorphone