  It is well known that low mass young stellar objects (LMYSOs) gain a
significant portion of their final mass through episodes of very rapid
accretion, with mass accretion rates up to $\dot M_* \sim 10^{-4}
M_{\odot}$~yr$^{-1}$. Recent observations of high mass young stellar objects
(HMYSO) with masses $M_* \gtrsim 10 M_{\odot}$ uncovered outbursts with
accretion rates exceeding $\dot M_*\sim 10^{-3}M_{\odot}$~yr$^{-1}$. Here we
examine which scenarios proposed in the literature so far to explain accretion
bursts of LMYSOs can apply to the episodic accretion in HMYSOs. We utilise a 1D
time dependent models of protoplanetary discs around HMYSOs to study burst
properties. We find that discs around HMYSOs are much hotter than those around
their low mass cousins. As a result, much more extended regions of the disc are
prone to the thermal hydrogen ionisation and MRI activation instabilities. The
former in particular is found to be ubiquitous in a very wide range of
accretion rates and disc viscosity parameters. The outbursts triggered by these
instabilities, however, always have too low $\dot M_*$, and are one to several
orders of magnitude too long compared to those observed from HMYSOs so far. On
the other hand, bursts generated by tidal disruptions of gaseous giant planets
formed by the gravitational instability of the protoplanetary discs yield
properties commensurate with observations, provided that the clumps are in the
post-collapse configuration with planet radius $R_{\rm p} \gtrsim 10 $ Jupiter
radii. Furthermore, if observed bursts are caused by disc ionisation
instabilities then they should be periodic phenomena with the duration of the
quiescent phase comparable to that of the bursts. This may yield potentially
observable burst periodicity signatures in the jets, the outer disc, or the
surrounding diffuse material of massive HMYSOs. (abridged)
